One of the most important locations of calcium channels is in neurons. Housed within subcellular compartments, they mediate voltage-dependent Ca2+ influx, thereby integrating synaptic response, regulating gene expression and initiating synaptic transmission. These channels are classified as PQ type (class A), N-Type (class B), L-type (class C and D), or R-type (class E). Due to their neuronal functions, Ca2+ channels play a critical role in several neuromuscular diseases. In Lambert-Eaton myasthenic syndrome, circulating antibodies against presynaptic Ca2+ channels reduce the level of the presynaptic Ca2+ current and therefore the efficiency of neurotransmitter release.