Amiloride-sensitive pressure-induced myogenic contraction in rat cerebral artery.
Fundam Clin Pharmacol
; 14(4): 369-77, 2000.
Article
en En
| MEDLINE
| ID: mdl-11030444
ABSTRACT
The inhibitory action of amiloride on the pressure-induced contraction was assessed in isolated rat cerebral artery. The artery was mounted in an arteriograph, and the change in intracellular Ca2+ concentration ([Ca2+]i) and vessel diameter were simultaneously measured. The contractile response elicited by intraluminal pressurization was independent of endothelium, i.e. myogenic in nature, and abolished by nicardipine, a Ca2+ antagonist or by removal of extracellular Ca2+, and was potentiated by 25 mM KCl. Cyclopiazonic acid and thapsigargin, inhibitors of the Ca2+-ATPase pump of the sarcoplasmic reticulum, and a protein kinase C inhibitor calphostin C did not suppress the pressure-induced contraction. Amiloride, a putative stretch-activated cation channel blocker, attenuated with an IC50 (50% inhibitory concentration) of about 3 microM the increase in [Ca2+]i and contractile activity in response to pressure, whereas the drug showed no apparent effect on the contraction produced by high KCl or 9,11-dideoxy-11alpha,9alpha-epoxymethano prostaglandin F2alpha (U46619). Furthermore, amiloride (100 microM) did not significantly affect intracellular pH in the artery. In spite of its multiple pharmacological actions, it seems possible that amiloride is a useful alternative tool at the cellular or tissue level to study the mechanotransduction mechanisms involved in the pressure-induced contraction in rat cerebral artery.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Arterias Cerebrales
/
Diuréticos
/
Amilorida
/
Canales Iónicos
/
Músculo Liso
Tipo de estudio:
Diagnostic_studies
Límite:
Animals
Idioma:
En
Revista:
Fundam Clin Pharmacol
Asunto de la revista:
FARMACOLOGIA
Año:
2000
Tipo del documento:
Article
País de afiliación:
Japón