DOXAPRAM STIMULATES DOPAMINE RELEASE FROM THE INTACT RAT CAROTID-BODY IN-VITRO

被引:24
作者
ANDERSONBECK, R
WILSON, L
BRAZIER, S
HUGHES, IE
PEERS, C
机构
[1] UNIV LEEDS,INST CARDIOVASC RES,LEEDS LS2 9JT,W YORKSHIRE,ENGLAND
[2] UNIV LEEDS,DEPT PHARMACOL,LEEDS LS2 9JT,W YORKSHIRE,ENGLAND
关键词
DOXAPRAM; CAROTID BODY; TYPE I CELL; ION CHANNELS; DOPAMINE; NIFEDIPINE;
D O I
10.1016/0304-3940(95)11328-T
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
Hypoxic chemotransduction by the carotid body is believed to involve inhibition of K+ channels in type I cells, leading to depolarization and the opening of Ca2+ channels which triggers catecholamine release. We have investigated whether the clinically used ventilatory stimulant doxapram (which, like hypoxia, blocks K+ channels in isolated type I cells) also stimulates catecholamine release from the intact carotid body in vitro, by pre-incubating tissues with [H-3]tyrosine. H-3 overflow was evoked by raised extracellular [K+] (60 mM) and by cyanide (2 mM). Doxapram (15-150 mu M) also evoked H-3 overflow in a concentration dependent manner; and doxapram-evoked release was inhibited by the Ca2+ channel blocker nifedipine (5 mu M). Analysis of released tritiated compounds suggested that doxapram preferentially stimulated the release of dopamine. Our results indicate that the mechanism of action of doxapram shares similarities with that of hypoxia in the carotid body.
引用
收藏
页码:25 / 28
页数:4
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