ATP-sensitive potassium channels do not mediate vasorelaxation by acetylcholine or iloprost
Braz. j. med. biol. res
;
24(7): 729-34, 1991. ilus
Article
in English
| LILACS
| ID: lil-99511
RESUMO
The influence of glibenclamide(GBC), a blocker of ATP-sensitive K+ channells, on relaxation caused by cromakalin(CKL), acetylcholine (ACh) and iloprost (ILO) was assessed in aortic rings (AR) with (E+) or without endotheliium (E-) and in the perfused arterial mesentery (MES) of the rat. In AR preconstricted with noradrenaline, CKL(0.03-10 *M) and ILO (5.5 nM) caused graded vasodilations which were not modified by endothelium removal. ACh(0.01-3 *M) only relaxed E+AR preparations. GBC (3*M) markedly reduced responses to CKL in E+AR and E-AR, but did not affect vasodilation induceds by ILO in E-AR and by ACH in E+AR. In MES preconstricted with methoxamine, bolus injections of CKL (10 or 30 nmol) or ACh (0.03-1nmol) caused graded reductions of perfusion pressure. Only the responses to CKL were significantly inhibited by GBC (10 *M). We conclude that AR and MES contain functional ATP-sensitive K+ channels, which, however, do not play a significant role in the endothelium-dependent vasodilation triggered by ACh or in the endothelium-indipendent relaxation induced by ILO
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Index:
LILACS (Americas)
Main subject:
Vasodilation
/
Endothelium, Vascular
/
Potassium Channels
/
Acetylcholine
/
Adenosine Triphosphate
/
Iloprost
/
Glyburide
Type of study:
Diagnostic study
Limits:
Animals
Language:
English
Journal:
Braz. j. med. biol. res
Journal subject:
Biology
/
Medicine
Year:
1991
Type:
Article
/
Congress and conference
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