G proteins are involved in the regulation of transmitter release at an Aplysia cholinergic synapse.
At an identified cholinergic synapse of the Aplysia buccal ganglion, presynaptic injections of guanosine 5'-O-3-thiotriphosphate (GTP-gamma-S) depressed the amplitude of evoked postsynaptic responses. This reduction of acetylcholine (ACh) release by GTP-gamma-S, prevented by pre-injection of guanosine 5'-O-2-thiodiphosphate (GDP-beta-S) in the presynaptic neuron, was due to a reduction of the number of ACh quanta released. The mean amplitude of the evoked miniature postsynaptic current (MPSC) was unchanged. The presynaptic Ca2+ influx was lowered.
Laboratoire de Neurobiologie Cellulaire et Moléculaire, C.N.R.S. Gif-sur-Yvette, France.
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D000109:Acetylcholine / Q000502:physiology*; D000818:Animals; D001048:Aplysia / Q000378:metabolism*; D005071:Evoked Potentials / Q000187:drug effects; D019204:GTP-Binding Proteins / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology*; D007478:Iontophoresis; D018377:Neurotransmitter Agents / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism*
D018377:Neurotransmitter Agents; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D019204:GTP-Binding Proteins; D000109:Acetylcholine