title: Quantal release of acetylcholine examined by current fluctuation analysis at an identified neuro-neuronal synapse of Aplysia.
abstract: Quantal events have been analyzed at a neuro-neuronal synapse of Aplysia where the nature of the transmitter is established and both presynaptic and postsynaptic neurons are identified and can be voltage-clamped. Prolonged depolarizations were applied to the presynaptic neuron, which gave rise in the postsynaptic cell to a current response characterized by current fluctuations or noise. Acetylcholine was also applied ionophoretically on the same postsynaptic cell. Amplitude and time course of miniature currents and acetylcholine-activated chloride channels of the same cell were examined by using a current fluctuation analysis. It was estimated that one presynaptic spike releases about 180 quanta, each opening 500 chloride channels.
mesh_terms: D000109:Acetylcholine / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001048:Aplysia; D002712:Chlorides / Q000378:metabolism; D004553:Electric Conductivity; D007473:Ion Channels / Q000502:physiology; D013570:Synaptic Membranes / Q000378:metabolism*; D009435:Synaptic Transmission
chemical_list: D002712:Chlorides; D007473:Ion Channels; D000109:Acetylcholine