Korean J Physiol Pharmacol.
2001 Jun;5(3):243-251.
Influence of strychnine on catecholamine release evoked by activation of
cholinergic receptors from the perfused rat adrenal gland
- Affiliations
-
- 1Department of Pharmacology, College of Medicine, Chosun University, Gwangju, South Korea. dylim@mail.chosun.ac.kr
Abstract
- The present study was attempted to investigate the effect of
strychnine on catecholamine (CA) secretion evoked by ACh, high K+, DMPP
and McN-A-343 from the isolated perfused rat adrenal gland. The perfusion
of strychnine (10-4 M) into an adrenal vein for 20 min produced great
inhibition in CA secretory responses evoked by ACh (5.32X10-3 M), DMPP
(10-4 M for 2 min) and McN-A-343 (10-4 M for 2 min), but did not alter CA
secretion by high K+ (5.6X10-2 M). Strychnine itself did also fail to
affect basal catecholamine output. Furthermore, in adrenal glands
preloaded simultaneously with strychnine (10-4 M) and glycine (an agonist
of glycinergic receptor, 10-4 M), 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+ (5.6X10-2 M) 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 membrane
depolarization. It is suggested that strychnine-sensitive glycinergic
receptors are localized in rat adrenal medullary chromaffin cells.