Abolishment of non-quantal release of acetylcholine from the mouse phrenic nerve endings by toosendanin.
The hyperpolarizing effect (H-effect) of d-tubocurarine on the end-plate of the isolated diaphragm pretreated with an anticholinesterase was irreversibly abolished by toosendanin (1 X 10(-5) g/ml), indicating the blockade of spontaneous non-quantal release of acetylcholine (ACh). The H-effect was also inhibited, but temporarily, when toosendanin (a dose of 0.6 LD50) was subcutaneously injected into the mouse and the diaphragm was isolated 40-120 min after injection. During such an inhibitory period, however, spontaneous release of ACh remained facilitated. It is concluded that the effect of toosendanin on non-quantal release of ACh was different from its effect on quantal release not only at the direction but also at the time course.
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D003964:Diaphragm / Q000294:innervation; D004365:Drugs, Chinese Herbal; D004594:Electrophysiology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D009045:Motor Endplate / Q000187:drug effects / Q000378:metabolism; D010791:Phrenic Nerve / Q000187:drug effects* / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology*; D014403:Tubocurarine / Q000494:pharmacology; D014315:Triterpenes
D000109:Acetylcholine; D004365:Drugs, Chinese Herbal; D010936:Plant Extracts; D014403:Tubocurarine; C036454:toosendanin; D014315:Triterpenes