[Effect of carbacholine on proximal and distal regions of motor nerve terminals in the frog].
Carbacholine depressed postsynaptic currents in the frog m. sartorius leaving intact presynaptic currents in proximal and distal portions of the motor nerve ending. The carbacholine depressing action was followed by an increase in the time gap between the beginning of presynaptic depolarisation and subsequent quantal release. This effect was considerably more obvious in the distal portions of the nerve endings. Effect of extracellular potassium was evident in a diminishing of presynaptic currents due to membrane depolarisation. The data obtained suggest that carbacholine presynaptically depresses synaptic transmission via metabotropic cholinergic receptors controlling the time course of the transmitter release.
Giniatullin
R A
RA
Kazan State Medical University, Kazan, Butlerov St., 49, 420012.
Samigullin
D V
DV
Grishin
S N
SN
Bukharaeva
E A
EA
D000818:Animals; D002217:Carbachol / Q000494:pharmacology*; D018678:Cholinergic Agents / Q000494:pharmacology*; D018679:Cholinergic Agonists / Q000494:pharmacology*; D066298:In Vitro Techniques; D009411:Nerve Endings / Q000187:drug effects / Q000502:physiology*; D011188:Potassium / Q000378:metabolism; D011895:Rana ridibunda; D013569:Synapses / Q000187:drug effects / Q000502:physiology
D018678:Cholinergic Agents; D018679:Cholinergic Agonists; D002217:Carbachol; D011188:Potassium