[Muscarinic agonists do not alter the process of spontaneous quantum secretion of the mediator from motor nerve endings in the frog].
The action of carbacholine (Cch) and muscarinic agonists--methylfurmethide, oxotremorine, metacholine, L- and D-F-2268 isomers on spontaneous quantum transmitter release was investigated in experiments on the frog sartorius muscle of R. temporaria. Cch decreased the frequency of miniature and plate potentials (mEEP) by 48%. The muscarinic agonists at a wide concentration range had no effect on mEEP frequency both in normal ionic medium and with potassium concentration increase to 10 mmol/l. The data obtained confirm the assumption that the inhibitory action of Cch on spontaneous transmitter release is unrelated to its muscarinic activity. It was concluded that muscarinic cholinoreceptors controlling spontaneous transmitter release are absent in the frog motor nerve terminals.
D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009045:Motor Endplate / Q000187:drug effects* / Q000378:metabolism; D009469:Neuromuscular Junction / Q000187:drug effects*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D010277:Parasympathomimetics / Q000494:pharmacology*; D011789:Quantum Theory; D011896:Rana temporaria; D011976:Receptors, Muscarinic / Q000187:drug effects; D013329:Structure-Activity Relationship
D018377:Neurotransmitter Agents; D010277:Parasympathomimetics; D011976:Receptors, Muscarinic; D000109:Acetylcholine
Muskarinovye agonisty na izmeniaiut protsess spontannoĭ kvantovoĭ sekretsii mediatora iz dvigatel'nykh nervnykh okonchaniĭ liagushki.