|Replacement Information||AB1541 is a recommended replacement for AB1556|
Key Specifications Table
|Species Reactivity||Key Applications||Host||Format||Antibody Type|
|H, R||IHC, WB||Sh||Affinity Purified||Polyclonal Antibody|
|Presentation||Purified sheep polyclonal liquid in 150 mM NaCl, 10 mM HEPES (pH 7.5), 100 μg/mL BSA and 50% glycerol.|
|Safety Information according to GHS|
|Material Size||100 µL|
References | 25 Available | See All References
|Reference overview||Application||Species||Pub Med ID|
|Effects of chronic fluoxetine treatment on neurogenesis and tryptophan hydroxylase expression in adolescent and adult rats. |
Klomp, A; Václavů, L; Meerhoff, GF; Reneman, L; Lucassen, PJ
PloS one 9 e97603 2014
The antidepressant drug fluoxetine (Prozac) has been increasingly prescribed to children and adolescents with depressive disorders despite a lack of thorough understanding of its therapeutic effects in the paediatric population and of its putative neurodevelopmental effects. Within the framework of PRIOMEDCHILD ERA-NET, we investigated; a) effects of chronic fluoxetine treatment on adult hippocampal neurogenesis, a structural readout relevant for antidepressant action and hippocampal development; b) effects on tryptophan hydroxylase (TPH) expression, a measure of serotonin synthesis; c) whether treatment effects during adolescence differed from treatment at an adult age, and d) whether they were subregion-specific. Stereological quantification of the number of proliferating (Ki-67+) cells and of the number of young migratory neurons (doublecortin+), revealed a significant age-by-treatment interaction effect, indicating that fluoxetine affects both proliferation and neurogenesis in adolescent-treated rats differently than it does in adult-treated rats. In terms of subregional differences, fluoxetine enhanced proliferation mainly in the dorsal parts of the hippocampus, and neurogenesis in both the suprapyramidal and infrapyramidal blades of the dentate gyrus in adolescent-treated rats, while no such differences were seen in adult-treated rats. Fluoxetine exerted similar age-by-treatment interaction effects on TPH cells mainly in the ventral portion of the dorsal raphe nucleus. We conclude that fluoxetine exerts divergent effects on structural plasticity and serotonin synthesis in adolescent versus adult-treated rats. These preliminary data indicate a differential sensitivity of the adolescent brain to this drug and thus warrant further research into their behavioural and translational aspects. Together with recent related findings, they further call for caution in prescribing these drugs to the adolescent population.
|Dorsal raphe neuroinflammation promotes dramatic behavioral stress dysregulation. |
Howerton, AR; Roland, AV; Bale, TL
The Journal of neuroscience : the official journal of the Society for Neuroscience 34 7113-23 2014
Impulsivity, risk-taking behavior, and elevated stress responsivity are prominent symptoms of mania, a behavioral state common to schizophrenia and bipolar disorder. Though inflammatory processes activated within the brain are involved in the pathophysiology of both disorders, the specific mechanisms by which neuroinflammation drives manic behavior are not well understood. Serotonin cell bodies originating within the dorsal raphe (DR) play a major role in the regulation of behavioral features characteristic of mania. Therefore, we hypothesized that the link between neuroinflammation and manic behavior may be mediated by actions on serotonergic neurocircuitry. To examine this, we induced local neuroinflammation in the DR by viral delivery of Cre recombinase into interleukin (IL)-1β(XAT) transgenic male and female mice, resulting in overexpressing of the proinflammatory cytokine, IL-1β. For assertion of brain-region specificity of these outcomes, the prefrontal cortex (PFC), as a downstream target of DR serotonergic projections, was also infused. Inflammation within the DR, but not the PFC, resulted in a profound display of manic-like behavior, characterized by increased stress-induced locomotion and responsivity, and reduced risk-aversion/fearfulness. Microarray analysis of the DR revealed a dramatic increase in immune-related genes, and dysregulation of genes important in GABAergic, glutamatergic, and serotonergic neurotransmission. Behavioral and physiological changes were driven by a loss of serotonergic neurons and reduced output as measured by high-performance liquid chromatography, demonstrating inflammation-induced serotonergic hypofunction. Behavioral changes were rescued by acute selective serotonin reuptake inhibitor treatment, supporting the hypothesis that serotonin dysregulation stemming from neuroinflammation in the DR underlies manic-like behaviors.
|Extrasynaptic glycine receptors of rodent dorsal raphe serotonergic neurons: a sensitive target for ethanol. |
Maguire, EP; Mitchell, EA; Greig, SJ; Corteen, N; Balfour, DJ; Swinny, JD; Lambert, JJ; Belelli, D
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology 39 1232-44 2014
Alcohol abuse is a significant medical and social problem. Several neurotransmitter systems are implicated in ethanol's actions, with certain receptors and ion channels emerging as putative targets. The dorsal raphe (DR) nucleus is associated with the behavioral actions of alcohol, but ethanol actions on these neurons are not well understood. Here, using immunohistochemistry and electrophysiology we characterize DR inhibitory transmission and its sensitivity to ethanol. DR neurons exhibit inhibitory 'phasic' post-synaptic currents mediated primarily by synaptic GABAA receptors (GABAAR) and, to a lesser extent, by synaptic glycine receptors (GlyR). In addition to such phasic transmission mediated by the vesicular release of neurotransmitter, the activity of certain neurons may be governed by a 'tonic' conductance resulting from ambient GABA activating extrasynaptic GABAARs. However, for DR neurons extrasynaptic GABAARs exert only a limited influence. By contrast, we report that unusually the GlyR antagonist strychnine reveals a large tonic conductance mediated by extrasynaptic GlyRs, which dominates DR inhibition. In agreement, for DR neurons strychnine increases their input resistance, induces membrane depolarization, and consequently augments their excitability. Importantly, this glycinergic conductance is greatly enhanced in a strychnine-sensitive fashion, by behaviorally relevant ethanol concentrations, by drugs used for the treatment of alcohol withdrawal, and by taurine, an ingredient of certain 'energy drinks' often imbibed with ethanol. These findings identify extrasynaptic GlyRs as critical regulators of DR excitability and a novel molecular target for ethanol.
|Central circuits regulating the sympathetic outflow to lumbar muscles in spinally transected mice by retrograde transsynaptic transport. |
Xiang, HB; Liu, C; Liu, TT; Xiong, J
International journal of clinical and experimental pathology 7 2987-97 2014
Despite considerable interest in the mechanisms that control the hyperalgesia associated with muscle inflammation, the CNS descending pathways that coordinate autonomic circuits regulating lumbar muscles are not adequately understood. Here we used both pseudorabies virus (PRV)-614 retrograde transsynaptic tracing and spinally transected method in 33 C57BL/6J mice to map the polysynaptic pathways between lumbar muscle and CNS. Tissues were processed for dual-label immunocytochemical detection between PRV-614 and tryptophan hydroxylase (TPH) or tyrosine hydroxylase (TH)-expressing neurons in CNS. In intact mice, PRV-614 was transported to the intermediolateral column (IML) and ventral horn (VH) of spinal cord, with subsequent transport to many brain regions, including the medullary raphe nuclei, rostral ventrolateral medulla (RVLM), A5 cell group regions (A5), locus coeruleus (LC), the medullary and pontine reticular formation nucleus (MRN and PRN), paraventricular nucleus of the hypothalamus (PVN), and other central sites. However, PRV-614 in spinally transected mice produced retrograde infection of IML, with subsequent transport to main brain regions that have been shown to contribute to regulating sympathetic circuits, including RVLM, Lateral paragigantocellular reticular nucleus (LPGi), A5, LC, and PVN, whereas PRV-614 labeling in VH and MRN was eliminated in almost every case. In above five brain regions, dual-labeling immunocytochemistry showed coexpression of PRV-614/TPH and PRV-614/TH immunoreactive (IR) neurons involved in these regulatory circuits. Our results reveal a hierarchical organization of central autonomic circuits controlling the lumbar muscles, thus providing neuroanatomical substrates for the central catecholaminergic and serotonergic system to regulate the lumbar muscles.
|Raphe GABAergic neurons mediate the acquisition of avoidance after social defeat. |
Challis, C; Boulden, J; Veerakumar, A; Espallergues, J; Vassoler, FM; Pierce, RC; Beck, SG; Berton, O
The Journal of neuroscience : the official journal of the Society for Neuroscience 33 13978-88, 13988a 2013
Serotonin (5-HT) modulates neural responses to socioaffective cues and can bias approach or avoidance behavioral decisions, yet the cellular mechanisms underlying its contribution to the regulation of social experiences remain poorly understood. We hypothesized that GABAergic neurons in the dorsal raphe nucleus (DRN) may participate in socioaffective regulation by controlling serotonergic tone during social interaction. We tested this hypothesis using whole-cell recording techniques in genetically identified DRN GABA and 5-HT neurons in mice exposed to social defeat, a model that induces long-lasting avoidance behaviors in a subset of mice responsive to serotonergic antidepressants. Our results revealed that social defeat engaged DRN GABA neurons and drove GABAergic sensitization that strengthened inhibition of 5-HT neurons in mice that were susceptible, but not resilient to social defeat. Furthermore, optogenetic silencing of DRN GABA neurons disinhibited neighboring 5-HT neurons and prevented the acquisition of social avoidance in mice exposed to a social threat, but did not affect a previously acquired avoidance phenotype. We provide the first characterization of GABA neurons in the DRN that monosynaptically inhibit 5-HT neurons and reveal their key role in neuroplastic processes underlying the development of social avoidance.
|Identification of unique release kinetics of serotonin from guinea-pig and human enterochromaffin cells. |
Raghupathi, R; Duffield, MD; Zelkas, L; Meedeniya, A; Brookes, SJ; Sia, TC; Wattchow, DA; Spencer, NJ; Keating, DJ
The Journal of physiology 591 5959-75 2013
The major source of serotonin (5-HT) in the body is the enterochromaffin (EC) cells lining the intestinal mucosa of the gastrointestinal tract. Despite the fact that EC cells synthesise ∼95% of total body 5-HT, and that this 5-HT has important paracrine and endocrine roles, no studies have investigated the mechanisms of 5-HT release from single primary EC cells. We have developed a rapid primary culture of guinea-pig and human EC cells, allowing analysis of single EC cell function using electrophysiology, electrochemistry, Ca(2+) imaging, immunocytochemistry and 3D modelling. Ca(2+) enters EC cells upon stimulation and triggers quantal 5-HT release via L-type Ca(2+) channels. Real time amperometric techniques reveal that EC cells release 5-HT at rest and this release increases upon stimulation. Surprisingly for an endocrine cell storing 5-HT in large dense core vesicles (LDCVs), EC cells release 70 times less 5-HT per fusion event than catecholamine released from similarly sized LDCVs in endocrine chromaffin cells, and the vesicle release kinetics instead resembles that observed in mammalian synapses. Furthermore, we measured EC cell density along the gastrointestinal tract to create three-dimensional (3D) simulations of 5-HT diffusion using the minimal number of variables required to understand the physiological relevance of single cell 5-HT release in the whole-tissue milieu. These models indicate that local 5-HT levels are likely to be maintained around the activation threshold for mucosal 5-HT receptors and that this is dependent upon stimulation and location within the gastrointestinal tract. This is the first study demonstrating single cell 5-HT release in primary EC cells. The mode of 5-HT release may represent a unique mode of exocytosis amongst endocrine cells and is functionally relevant to gastrointestinal sensory and motor function.
|Activation patterns of cells in selected brain stem nuclei of more and less stress responsive rats in two animal models of PTSD - predator exposure and submersion stress. |
Robert Adamec,Mate Toth,Jozsef Haller,Jozsef Halasz,Jacqueline Blundell
Neuropharmacology 62 2012
This study had two purposes. First: compare predator and water submersion stress cFos activation patterns in dorsal raphe (DR), locus coeruleus (LC) and periaqueductal gray (PAG). Second: identify markers of vulnerability to stressors within these areas. Rats were either predator or submersion stressed and tested 1.75 h later for anxiety-like behavior. Immediately thereafter, rats were sacrificed and cFos expression examined. In DR, serotonergic cells expressing or not expressing cFos were also counted. Predator and submersion stress increased anxiety-like behavior (in the elevated plus maze- EPM) equally over controls. Moreover, stressed rats spent equally less time in the center of the hole board than handled controls, another indication of increased anxiety-like behavior. To examine vulnerability, rats which were less anxious (LA) and more (highly) anxious (MA) in the EPM were selected from among handled control and stressed animals. LA rats in the stressed groups were considered stress non-responsive and MA stressed rats were considered stress responsive. LA and MA rats did not differ in cFos expression in any brain area, though stressors did increase cFos cell counts in all areas over controls. Intriguingly, the number of serotonergic DR neurons not activated by stress predicted degree of anxiety response to submersion stress only. LA submersion stressed rats had more serotonergic cells than all other groups, and MA submersion stressed rats had fewer serotonergic cells than all other groups, which did not differ. Moreover, these cell counts correlated with EPM anxiety. We conclude that a surplus of such cells protects against anxiogenic effects of submersion, while a paucity of such cells enhances vulnerability to submersion stress. Other data suggest serotonergic cells may exert their effects via inhibition of dorsolateral PAG cells during submersion stress. Findings are discussed with respect to serotonergic transmission in vulnerability to predator stress and relevance of findings for post traumatic stress disorder (PTSD). This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.
|Reduction of serotonergic neurons in the dorsal raphe due to chronic prenatal administration of a tryptophan-free diet. |
Guadalupe M Flores-Cruz,Alfonso Escobar
International journal of developmental neuroscience : the official journal of the International Society for Developmental Neuroscience 30 2012
Serotonin (5-HT) is a widely studied neurotransmitter which plays an important role in the development and proper functioning of the organism throughout life. The appearance of 5-HT system early in ontogeny suggests the hypothesis that 5-HT plays a regulatory role in neurodevelopment. This study investigated the effect of administration of a tryptophan deficient diet during prenatal development on the morphology and cell population of the dorsal raphe. The experimental diet, containing balanced amounts of carbohydrates, lipids and proteins, was provided to a time-mated group of rats from gestational day 5 until delivery. Control groups were fed with (i) the experimental diet formulation with 0.2% tryptophan added to the mixture, or (ii) a regular chow diet. At delivery, five pups per dam were euthanized. Body and brain weight was measured and brain sections were processed for immunohistochemistry for tryptophan hydroxylase (TrpH) and whole brain 5-HT analysis. Sections containing dorsal raphe were photographed with a light microscope and TrpH positive neurons quantified. Brain weights in the tryptophan deprived group showed no difference as compared with controls while body weights were reduced by 25%. Total numbers of serotonergic neurons at the dorsal raphe in the prenatal tryptophan deficient pups were reduced by 35%. A regional analysis of the dorsal raphe indicated a marked cellular reduction in the medial and caudal sections of the nucleus, which contains the majority of serotonergic neurons, in the tryptophan deprived condition. Quantitative 5-HT analysis showed that the brain concentration was similar among conditions. In conclusion, gestational tryptophan deprivation exerts adverse effects on the development of the 5-HT system, particularly in the dorsal raphe, manifested by decreased numbers of serotonergic neurons as well as altered topography in this important nucleus.
|Effect of fluoxetine on the expression of tryptophan hydroxylase and 14-3-3 protein in the dorsal raphe nucleus and hippocampus of rat. |
Mi Ran Choi,Sejin Hwang,Geu Meum Park,Kyung Hwa Jung,Seok Hyeon Kim,Nando Dulal Das,Young Gyu Chai
Journal of chemical neuroanatomy 43 2012
The serotonergic system is one of the major systems targeted in the pharmacological treatment of mood disorders including depression. Fluoxetine, one of the selective serotonin reuptake inhibitors (SSRIs), has been reported to induce the expression of tryptophan hydroxylase (TPH), the rate-limiting enzyme in the biosynthesis of serotonin. The 14-3-3 protein family not only activates neuronal enzymes, including TPH, but also plays a role in a wide variety of cell signaling. The aim of the present study was to determine whether fluoxetine regulates both the interaction of TPH and 14-3-3 proteins as well as the increase of those proteins in the dorsal raphe nucleus and the hippocampus. Sprague-Dawley rats were administered fluoxetine or vehicle for 5 and 14 days and sacrificed at 5 and 14 days after initial treatment. The intensity of immunoreactivity for TPH and 14-3-3 proteins in the dorsal raphe nucleus of the midbrain and in the hippocampus was measured, and the colocalization of both proteins was observed with double-labeling immunofluorescence. At 5 days after initial treatment with fluoxetine, immunoreactivity of 14-3-3 protein increased in both the dorsal raphe nucleus and the hippocampus, while that of TPH did not change in either region. In addition, at 14 days after initial treatment with fluoxetine, immunoreactivity of 14-3-3 protein significantly increased in both the dorsal raphe nucleus and hippocampus, while that of TPH showed few changes in either region. Colocalization of TPH and 14-3-3 proteins was observed in the cell bodies of dorsal raphe nucleus, whereas it was not observed in the hippocampus. These results suggest that the time-dependent regulation of 14-3-3 protein may be one of the various factors associated with delayed pharmacological effects of SSRIs.
|HDAC6 regulates glucocorticoid receptor signaling in serotonin pathways with critical impact on stress resilience. |
Espallergues, J; Teegarden, SL; Veerakumar, A; Boulden, J; Challis, C; Jochems, J; Chan, M; Petersen, T; Deneris, E; Matthias, P; Hahn, CG; Lucki, I; Beck, SG; Berton, O
The Journal of neuroscience : the official journal of the Society for Neuroscience 32 4400-16 2012
Genetic variations in certain components of the glucocorticoid receptor (GR) chaperone complex have been associated with the development of stress-related affective disorders and individual variability in therapeutic responses to antidepressants. Mechanisms that link GR chaperoning and stress susceptibility are not well understood. Here, we show that the effects of glucocorticoid hormones on socioaffective behaviors are critically regulated via reversible acetylation of Hsp90, a key component of the GR chaperone complex. We provide pharmacological and genetic evidence indicating that the cytoplasmic lysine deacetylase HDAC6 controls Hsp90 acetylation in the brain, and thereby modulates Hsp90-GR protein-protein interactions, as well as hormone- and stress-induced GR translocation, with a critical impact on GR downstream signaling and behavior. Pet1-Cre-driven deletion of HDAC6 in serotonin neurons, the densest HDAC6-expressing cell group in the mouse brain, dramatically reduced acute anxiogenic effects of the glucocorticoid hormone corticosterone in the open-field, elevated plus maze, and social interaction tests. Serotonin-selective depletion of HDAC6 also blocked the expression of social avoidance in mice exposed to chronic social defeat and concurrently prevented the electrophysiological and morphological changes induced, in serotonin neurons, by this murine model of traumatic stress. Together, these results identify HDAC6 inhibition as a potential new strategy for proresilience and antidepressant interventions through regulation of the Hsp90-GR heterocomplex and focal prevention of GR signaling in serotonin pathways. Our data thus uncover an alternate mechanism by which pan-HDAC inhibitors may regulate stress-related behaviors independently of their action on histones.
|Quantitative analysis of glutamatergic innervation of the mouse dorsal raphe nucleus using array tomography. |
Soiza-Reilly, M; Commons, KG
The Journal of comparative neurology 519 3802-14 2011
Serotonin (5-hydroxytryptamine, 5-HT) containing neurons located in the dorsal raphe nucleus (DR) comprise the main source of forebrain 5-HT and regulate emotional states in normal and pathological conditions including affective disorders. However, there are many features of the local circuit architecture within the DR that remain poorly understood. DR neurons receive glutamatergic innervation from different brain areas that selectively express three different types of the vesicular glutamate transporter (VGLUT). In this study we used a new high-resolution imaging technique, array tomography, to quantitatively analyze the glutamatergic innervation of the mouse DR. In the same volumetric images, we studied the distribution of five antigens: VGLUT1, VGLUT2, VGLUT3, the postsynaptic protein PSD-95, and a marker for 5-HT cells, the enzyme tryptophan hydroxylase (TPOH). We found that all three populations of glutamatergic boutons are present in the DR; however, the density of paired association between VGLUT2 boutons and PSD-95 was ≈2-fold higher than that of either VGLUT1- or VGLUT3-PSD-95 pairs. In addition, VGLUT2-PSD-95 pairs were more commonly found associated with 5-HT cells than the other VGLUT types. These data support a prominent contribution of glutamate axons expressing VGLUT2 to the excitatory drive of DR neurons. The current study also emphasizes the use of array tomography as a quantitative approach to understand the fine molecular architecture of microcircuits in a well-preserved neuroanatomical context.
|Age-dependent effects of initial exposure to nicotine on serotonin neurons. |
Bang, SJ; Commons, KG
Neuroscience 179 1-8 2011
Adolescence is a critical vulnerable period during which exposure to nicotine greatly enhances the possibility to develop drug addiction. Growing evidence suggests that serotonergic (5-HT) neurotransmission may contribute to the initiation and maintenance of addictive behavior. As the dorsal raphe (DR) and median raphe (MnR) nuclei are the primary 5-HT source to the forebrain, the current study tested the hypothesis that there are age-dependent effects of acute nicotine administration on activation of 5-HT neurons within these regions. Both adolescent (Postnatal day 30) and adult (Postnatal day 70) male Sprague-Dawley rats received subcutaneous injection of either saline or nicotine (0.2, 0.4, or 0.8 mg/kg). Subsequently, the number of 5-HT cells that were double-labeled for Fos and tryptophan hydroxylase was counted in seven subregions within the DR and the entire MnR. The results show that acute nicotine injection induces Fos expression in 5-HT neurons in a region-specific manner. In addition, adolescents show broader regional activations at either a lower (0.2 mg/kg) and a higher (0.8 mg/kg) dose of nicotine, displaying a unique U-shape response curve across doses. In contrast, 5-HT cells with activated Fos expression were restricted to fewer regions in adults, and the patterns of expression were more consistent across doses. The results reveal dose-dependent effects of nicotine during adolescence with apparent sensitization at different ends of the dosage spectrum examined compared to adults. These data indicate that initial exposure to nicotine may have unique effects in adolescence on the ascending 5-HT system, with the potential for consequences on the affective-motivational qualities of the drug and the subsequent propensity for repeated use.
|Shifting topographic activation and 5-HT1A receptor-mediated inhibition of dorsal raphe serotonin neurons produced by nicotine exposure and withdrawal. |
Sperling, R; Commons, KG
The European journal of neuroscience 33 1866-75 2011
Nicotine activates serotonin [5-hydroxytryptamine (5-HT)] neurons innervating the forebrain, and this is thought to reduce anxiety. Nicotine withdrawal has also been associated with an activation of 5-HT neurotransmission, although withdrawal increases anxiety. In each case, 5-HT1A receptors have been implicated in the response. To determine whether there are different subgroups of 5-HT cells activated during nicotine administration and withdrawal, we mapped the appearance of Fos, a marker of neuronal activation, in 5-HT cells of the dorsal raphe nucleus (DR) and median raphe nucleus (MR). To understand the role of 5-HT1A receptor feedback inhibitory pathways in 5-HT cell activity during these conditions, we administered a selective 5-HT1A receptor antagonist and measured novel disinhibited Fos expression within 5-HT cells. Using these approaches, we found evidence that acute nicotine exposure activates 5-HT neurons rostrally and in the lateral wings of the DR, whereas there is 5-HT1A receptor-dependent inhibition of cells located ventrally at both the rostral level and mid-level. Previous chronic nicotine exposure did not modify the pattern of activation produced by acute nicotine exposure, but increased 5-HT1A receptor-dependent inhibition of 5-HT cells in the caudal DR. This pattern was nearly reversed during nicotine withdrawal, when there was evidence for caudal activation and mid-level and rostral 5-HT1A receptor-dependent inhibition. These results suggest that the distinct behavioral states produced by nicotine exposure and withdrawal correlate with reciprocal rostral-caudal patterns of activation and 5-HT1A receptor-mediated inhibition of DR 5-HT neurons. The complementary patterns of activation and inhibition suggest that 5-HT1A receptors may help to shape distinct topographic patterns of activation within the DR.
|Serotonin depletion hampers survival and proliferation in neurospheres derived from adult neural stem cells. |
Benninghoff J, Gritti A, Rizzi M, Lamorte G, Schloesser RJ, Schmitt A, Robel S, Genius J, Moessner R, Riederer P, Manji HK, Grunze H, Rujescu D, Moeller HJ, Lesch KP, Vescovi AL
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology 35 893-903 2010
Serotonin (5-HT) and the serotonergic system have recently been indicated as modulators of adult hippocampal neurogenesis. In this study, we evaluated the role of 5-HT on the functional features in neurospheres derived from adult neural stem cells (ANSC). We cultured neurospheres derived from mouse hippocampus in serum-free medium containing epidermal (EGF) and type-2 fibroblast growth factor (FGF2). Under these conditions ANSC expressed both isoforms of tryptophane-hydroxylase (TPH) and produced 5-HT. Blocking TPH function by para-chlorophenylalanine (PCPA) reduced ANSC proliferation, which was rescued by exogenous 5-HT. 5-HT action on ANSC was mediated predominantly by the serotonin receptor subtype 5-HT1A and, to a lesser extent, through the 5-HT2C (receptor) subtype, as shown by selectively antagonizing these receptors. Finally, we documented a 5-HT-induced increase of ANSC migration activity. In summary, we demonstrated a powerful serotonergic impact on ANSC functional features, which was mainly mediated by 5-HT1A receptors.
|Phasic responses in dorsal raphe serotonin neurons to noxious stimuli. |
J V Schweimer,M A Ungless
Neuroscience 171 2010
Serotonin is widely implicated in aversive processing. It is not clear, however, whether serotonin neurons encode information about aversive stimuli. We found that, in the dorsal raphe of anesthetized rats, most neurochemically-identified clocklike serotonin neurons were phasically excited by noxious footshocks, whereas most bursting serotonin neurons were inhibited. These results suggest that discrete groups of serotonin neurons differentially code for aversive stimuli.
|Afferents to the GABAergic tail of the ventral tegmental area in the rat. |
Kaufling, Jennifer, et al.
J. Comp. Neurol., 513: 597-621 (2009) 2009
We previously showed that chronic psychostimulant exposure induces the transcription factor DeltaFosB in gamma-aminobutyric acid (GABA)ergic neurons of the caudal tier of the ventral tegmental area (VTA). This subregion was defined as the tail of the VTA (tVTA). In the present study, we showed that tVTA can also be visualized by analyzing FosB/DeltaFosB response following acute cocaine injection. This induction occurs in GABAergic neurons, as identified by glutamic acid decarboxylase (GAD) expression. To characterize tVTA further, we mapped its inputs by using the retrograde tracers Fluoro-Gold or cholera toxin B subunit. Retrogradely labeled neurons were observed in the medial prefrontal cortex, the lateral septum, the ventral pallidum, the bed nucleus of the stria terminalis, the substantia innominata, the medial and lateral preoptic areas, the lateral and dorsal hypothalamic areas, the lateral habenula, the intermediate layers of the superior colliculus, the dorsal raphe, the periaqueductal gray, and the mesencephalic and pontine reticular formation. Projections from the prefrontal cortex, the hypothalamus, and the lateral habenula to the tVTA were also shown by using the anterograde tracer biotinylated dextran amine (BDA). We showed that the central nucleus of the amygdala innervates the anterior extent of the VTA but not the tVTA. Moreover, the tVTA mainly receives non-aminergic inputs from the dorsal raphe and the locus coeruleus. Although the tVTA has a low density of dopaminergic neurons, its afferents are mostly similar to those targeting the rest of the VTA. This suggests that the tVTA can be considered as a VTA subregion despite its caudal location.
|Vesicular glutamate transporter 3-immunoreactive pericellular baskets ensheath a distinct population of neurons in the lateral septum. |
Riedel, A; Westerholz, S; Braun, K; Edwards, RH; Arendt, T; Härtig, W
Journal of chemical neuroanatomy 36 177-90 2008
The lateral septum (LS) plays a role in the adjustment of behavioral responses according to environmental demands. This is a complex integrative process wherein a variety of modulatory systems, i.e. cholinergic, dopaminergic and serotonergic projections forming pericellular baskets around LS neurons, are involved. Recently, vesicular glutamate transporter 3 (VGLUT3)-immunoreactive (-ir) structures outlining unlabeled somata and their proximal dendrites were described in the LS. However, the vesicular transporters for acetylcholine and GABA were not or only rarely co-expressed with VGLUT3. In this study, the morphology and distribution of these VGLUT3-ir structures were systematically analyzed revealing that (1) they form distinct pericellular baskets (PBs) displaying variable shapes, (2) they are arranged in a layer-like pattern similar to the terminals of other modulatory systems, (3) beside a few exceptions (e.g., choline acetyltransferase), they are generally not or very sparsely co-localized with other neurochemical markers characterizing major neuron populations or afferent systems of the LS, i.e. calcium-binding proteins, tyrosine hydroxylase, tryptophan hydroxylase, vesicular glutamate transporters 1 (VGLUT1) and 2 (VGLUT2) and the vesicular GABA transporter. Thus, in the LS, a separate population of neurons is covered by VGLUT3-ir PBs. The distribution pattern and the lack of co-localization indicate that the VGLUT3-expressing cells of origin are located in the brainstem and that they could be pure glutamatergic projection neurons-different from the well-defined canonical VGLUT1- and VGLUT2-expressing neurons. Alternatively, they could simultaneously express VGLUT3 and second transmitter, but use different release sites inside the LS for both.
|Regulation of pseudosexual behavior in the parthenogenetic whiptail lizard, Cnemidophorus uniparens. |
Dias, BG; Crews, D
Endocrinology 149 4622-31 2008
Neuroendocrine mechanisms underlying complementary behaviors like male-typical mounting and female-typical receptivity are most often studied independently in males and females, respectively. Cnemidophorus uniparens is a unisexual lizard species consisting only of females that alternately express male- and female-like pseudosexual behavior across the ovarian cycle. Intact, postovulatory (PostOv), and ovariectomized (OVX), androgen-implanted animals [OVX plus testosterone (T)] exhibit male-like mounting, but not receptivity, whereas intact, preovulatory (PreOv), and OVX lizards injected with estradiol [OVX plus estrogen (E)] express receptivity, but not mounting. We tested whether the serotonergic system in the preoptic area (POA) and ventromedial nucleus of the hypothalamus (VMN) gates the reciprocal inhibition characterizing this alternating expression of mounting and receptivity. Serotonergic signaling at the POA appears to be key to gating male-like behavior. Postovulatory and OVX plus T animals have lower intracellular serotonin (5-HT) levels, and greater abundance of inhibitory 5-HT1A receptor mRNA in the POA compared with both PreOv and OVX plus E lizards. Moreover, injecting 5-HT into the POA of OVX plus T animals suppresses mounting, whereas injection into VMN of OVX plus E lizards suppresses receptivity. Although 5-HT levels in the VMN do not differ across the ovarian cycle or between hormonally manipulated animals, PreOv and OVX plus E lizards have a lower abundance of 5-HT2A mRNA in the VMN. Stimulating 5-HT1A receptors using systemic drug administration inhibits mounting, whereas activating 5-HT2A receptors facilitates receptivity. This study illuminates how male- and female-typical sexual behaviors share common neural circuits, and that 5-HT regulates these naturally complementary, and mutually exclusive, behaviors.Full Text Article
|Depletion of putative chemosensitive respiratory neurons in the ventral medullary surface in multiple system atrophy. |
Benarroch, Eduardo E, et al.
Brain, 130: 469-75 (2007) 2007
Multiple system atrophy (MSA) is a disorder that may manifest with reduced respiratory chemosensitivity and central sleep apnoea. Chemosensitive glutamatergic and serotonergic neurons located just beneath the ventral medullary surface, corresponding to the human arcuate nucleus (ArcN), have recently been implicated in control of automatic breathing in response to hypercapnia and hypoxia. We sought to determine whether these neurons were affected in MSA. Medullae were obtained at post-mortem from 11 patients (8 men, 3 women, age 64 +/- 3 years) with neuropathologically confirmed MSA and 11 control subjects (6 men and 5 women, age 66 +/- 4 years). Fifty micrometre sections obtained throughout the medulla were processed for vesicular glutamate transporter-2 (VGLUT-2), tryptophan-hydroxylase (TrOH), glial fibrillary acid protein (GFAP) and alpha-synuclein immunoreactivity. Cell counts, GFAP immunoreactivity and presence of glial cytoplasmic inclusions (GCIs) were assessed in the ArcN. In MSA, compared with controls, there was a marked depletion of ArcN neurons immunoreactive for either VGLUT-2 (74 +/- 21 versus 342 +/- 84 cells/section, P < 0.004) or TrOH (5 +/- 1 versus 16 +/- 2 cells/section, P < 0.001). There was also marked astrocytic gliosis and accumulation of alpha-synuclein immunoreactive GCIs in the ventral medullary surface in all cases. Our results indicate that there is severe loss of putative chemosensitive glutamatergic and serotonergic neurons as well as marked astrocytic gliosis in the ventral medullary surface in MSA. This may provide a possible morphological basis for impaired respiratory chemosensitivity and central sleep apnoea in this disorder.
|Neurochemical identification of stereotypic burst-firing neurons in the rat dorsal raphe nucleus using juxtacellular labelling methods. |
Mihály Hajós, Kelly A Allers, Katie Jennings, Trevor Sharp, Guy Charette, Attila Sík, Bernát Kocsis
The European journal of neuroscience 25 119-26 2007
Recent electrophysiological studies have discovered evidence of heterogeneity of 5-hydroxytryptamine (5-HT) neurons in the mesencephalic raphe nuclei. Of particular interest is a subpopulation of putative 5-HT neurons that display many of the electrophysiological properties of presumed 5-HT-containing neurons (regular and slow firing of single spikes with a broad waveform) but fire spikes in short, stereotyped bursts. In the present study we investigated the chemical identity of these neurons in rats utilizing in vivo juxtacellular labelling methods. Of ten dorsal raphe nucleus (DRN) neurons firing short stereotyped bursts within an otherwise regular firing pattern, all exhibited immunoreactivity for either 5-HT (n = 6) or the 5-HT synthesizing enzyme, tryptophan hydroxylase (TRH; n = 2) or both (n = 2). Supporting pharmacological experiments demonstrated that the burst firing DRN neurons demonstrated equal sensitivity to 5-HT(1A) agonism and alpha(1)-adrenoceptor antagonism to single spiking DRN neurons that we have previously identified as 5-HT-containing. Collectively these data provide direct evidence that DRN neurons that exhibit stereotyped burst firing activity are 5-HT containing. The presence of multiple types of electrophysiologically distinct midbrain 5-HT neurons is discussed.
|Circadian phosphorylation of ATF-2, a potential activator of Period2 gene transcription in the chick pineal gland. |
Fumiko Shimizu,Yoshitaka Fukada
Journal of neurochemistry 103 2007
Stimulus-induced transcription of the Period gene is a critical step for phase-shift of vertebrate circadian systems. The promoter region of chicken Period2 contains a canonical calcium/cAMP-responsive element, but its functional relevance is not known. The present study shows that cAMP-responsive element-binding protein (CREB) and activating transcription factor-2 (ATF-2) bind to the promoter region of the Period2 gene in the chick pineal gland. In transient transfection assays, a reporter construct containing 0.7-kbp upstream region of chicken Period2 was transactivated by ATF-2, but it was poorly responsive to CREB. In the chick pineal gland, phosphorylation of CREB protein at the kinase-inducible domain was negatively regulated by light. On the other hand, phosphorylation of ATF-2 at the amino-terminal transactivation domain exhibited a circadian rhythm with a daytime peak, suggesting a role for ATF-2 in circadian rhythmicity in the chick pineal gland.
|Involvement of medullary regions controlling sympathetic output in Lewy body disease. |
Benarroch, Eduardo E, et al.
Brain, 128: 338-44 (2005) 2005
We sought to determine the involvement of medullary regions controlling sympathetic output in pathologically confirmed diffuse Lewy body disease (LBD). We studied eight limbic or neocortical stage LBD and eight multiple system atrophy (MSA) cases, confirmed neuropathologically, and eight age-matched controls. Five of the LBD cases and all MSA cases had orthostatic hypotension. Serial 50-mum sections obtained from the medulla rostral to the obex were immunostained for tyrosine hydroxylase, tryptophan hydroxylase and alpha-synuclein. Analysis was focused on the ventrolateral medulla and medullary raphe nuclei. In LBD cases, there were Lewy bodies and neurites, as well as dystrophic neurons in the ventrolateral medulla, but the number of catecholaminergic and serotonergic neurons was not significantly reduced. All these groups were depleted in MSA. There were Lewy body pathology and dystrophic neurons in the raphe in all LBD cases. Cell numbers were reduced in both the raphe obscurus and raphe pallidus. Our findings suggest that, although LBD affects medullary autonomic areas, it does so less severely than MSA, particularly in the case of the VLM, which controls sympathetic outputs maintaining arterial pressure. In LBD, orthostatic hypotension may be due primarily to involvement of sympathetic ganglion neurons rather than ventrolateral medulla neurons.
|The activation of raphe serotonergic neurons in normal and hypoarousal-driven aggression: a double labeling study in rats. |
József Haller, Máté Tóth, József Halász
Behavioural brain research 161 88-94 2005
The serotonergic system is well known for its aggression lowering effects. It has been shown repeatedly, however, that the serotonergic system is activated during fights, and recent data suggested that it is necessary for the expression of aggressive behavior. We investigated the interaction between serotonergic activation and aggressive behavior by assessing the co-localization of the c-Fos signal (marker of neuronal activation) with tryptophan-hydroxylase activity (marker of serotonin secretion) in the raphe. Control rats were compared with rats exposed to visual and olfactory (but not physical) contacts with opponents (psychosocial stimulation) as well as with rats exposed to aggressive encounters. Fights were accompanied by the activation of the raphe; however, the effect was not aggression-specific, as a similar activation was induced by psychosocial contacts. The lack of behavioral specificity in activation suggests that it was related to social arousal rather than to the execution of fights. The activation of serotonergic raphe neurons showed a negative correlation with aggressive behavior, which is in line with the widespread view that serotonin neurotransmission downregulates aggressive behavior. The activation of serotonergic neurons did not show a correlation with measures of hypoarousal-driven abnormal aggression, which indicates that factors other than the raphe control this behavior. The latter finding may explain the low efficacy of serotonergic treatments in conduct and antisocial personality disorders, in which violence correlates with hypoarousal.
|Neural crest stem cells persist in the adult gut but undergo changes in self-renewal, neuronal subtype potential, and factor responsiveness. |
Kruger, Genevieve M, et al.
Neuron, 35: 657-69 (2002) 2002
We found neural crest stem cells (NCSCs) in the adult gut. Postnatal gut NCSCs were isolated by flow-cytometry and compared to fetal gut NCSCs. They self-renewed extensively in culture but less than fetal gut NCSCs. Postnatal gut NCSCs made neurons that expressed a variety of neurotransmitters but lost the ability to make certain subtypes of neurons that are generated during fetal development. Postnatal gut NCSCs also differed in their responsiveness to lineage determination factors, affecting cell fate determination in vivo and possibly explaining their reduced neuronal subtype potential. These perinatal changes in gut NCSCs parallel perinatal changes in hematopoietic stem cells, suggesting that stem cells in different tissues undergo similar developmental transitions. The persistence of NCSCs in the adult PNS opens up new possibilities for regeneration after injury or disease.
|Neural connections of the anterior hypothalamus and agonistic behavior in golden hamsters. |
Y Delville, G J De Vries, C F Ferris
Brain, behavior and evolution 55 53-76 2000
In male golden hamsters, offensive aggression is regulated by an interaction between arginine-vasopressin and serotonin at the level of the anterior hypothalamus. The present studies were conducted to study a neural network underlying this interaction. The connections of the anterior hypothalamus were examined by retrograde and anterograde tracing in adult male hamsters. Several limbic areas were found to contain both types of tracing suggesting reciprocal connections with the anterior hypothalamus. Their functional significance relating to the consummation of aggression was tested by comparing neuronal activity (examined through quantification of c-Fos-immunolabeling) in two groups of animals. Experimental animals were sacrificed after attacking an intruder. Control animals were sacrificed after exposure to a woodblock carrying the odor of an intruder that elicited behaviors related to offensive aggression without its consummation. An increased density of Fos-immunoreactivity was found in experimental animals within the medial amygdaloid nucleus, ventrolateral hypothalamus, bed nucleus of the stria terminalis and dorsolateral part of the midbrain central gray. These data suggest that these areas are integrated in a neural network centered on the anterior hypothalamus and involved in the consummation of offensive aggression. Finally, c-Fos-immunoreactivity was combined with labeling of serotonin and vasopressin neurons to identify sub-populations particularly associated with offensive aggression. Vasopressin neurons in the nucleus circularis and medial division of the supraoptic nucleus showed increased neuronal activity in the fighters, supporting their role in the control of offensive aggression. Copyright (R) 2000 S. Karger AG, Basel
|Anti-Tryptophan Hydroxylase - Data Sheet|