Influence of Strychnine on Catecholamine Release Evoked by Activationof Cholineric Receptors from the Perfused Rat Adrenal Gland

Influence of Strychnine on Catecholamine Release Evoked by Activationof Cholineric Receptors from the Perfused Rat Adrenal Gland

The present study was attempted to investigate the effect of strychnine on catecholarnine(CA) secretion evoked by ACh, high K⁺, DMPP and McN-A-343 from the isolated perfused rat adrenal gland. The perfusion of strychinie(10⁴ㅡ) into an adrenal vein for 20 min produced great ingibition in CA secretory responses evoked by ACh(5.32X10^-3M), DMPP(10^-4M for 2 min) and McN-A-343(10^-4M for 2 min), but did not after CA secretion by high K⁺(5.6X10^-2M). Strychinine itself did also fail to affect basal catecholarnine out put. Furthernore, inadrenal glands perloaded simultaneously with strychnine(10^-4M) and glycine(an agonist of glycinergic recepfor, 10^-4M), CA secretory responses evoked by ACh, DMPP and McN-A-343 were considerably recovered to some extent when compared with those evoked by treatment with strychnine only. However, CA secretion by high K⁺(5.6X10^-2M) was not affected. Taken together, these results demonstrate that strychnine inhibits greatly the CA secretory responses evoked by stimulation of cholinergic(both nicotinic and muscarinic) receptors, but does not affect that by menbrane depolarization. It is suggested that strchnine-sensigive glycinergic receptors are localized in ref adrenal medullary chromaffin cells.