title: The action of chlorpromazine at an isolated cholinergic synapse.
abstract: The effects of chlorpromazine (CPZ) on cholinergic transmission were studied at the isolated neuromuscular synapse of the frog. It was found that 5 x 10(-6) M CPZ produces the following effects: (1) a reduction in end-plate potential amplitude, mainly through inhibition of transmitter release at presynaptic nerve terminals; (2) a reduction in amplitude of focally recorded end-plate current without detectable change in nerve terminal potential: (3) a decrease in amplitude of miniature end-plate potentials; and (4) an increase in the frequency of spontaneous liberation of transmitter both in normal and calcium-free Ringer's solution. It is concluded that CPZ inhibits cholinergic transmission by a complex action on presynaptic and postsynaptic elements. The relation of these findings to central cholinergic activities of CPZ is discussed.
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D001001:Anura; D002746:Chlorpromazine / Q000494:pharmacology*; D003864:Depression, Chemical; D005071:Evoked Potentials / Q000187:drug effects; D008564:Membrane Potentials / Q000187:drug effects; D009045:Motor Endplate / Q000187:drug effects; D009469:Neuromuscular Junction / Q000187:drug effects; D011898:Ranidae; D011950:Receptors, Cholinergic / Q000187:drug effects*; D013569:Synapses / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects
chemical_list: D011950:Receptors, Cholinergic; D000109:Acetylcholine; D002746:Chlorpromazine