Relaxation by adenosine and its analogs of potassium-contracted human coronary arteries.

Autor: Sabouni, Majd, Ramagopal, Mudumbi, Jamal Mustafa, S.
Zdroj: Naunyn-Schmiedeberg's Archives of Pharmacology; 1990, Vol. 341 Issue 4, p388-390, 3p
Abstrakt: The present study was an attempt to characterize the adenosine receptor in human coronary arteries, and to establish the dependence of the relaxations mediated by this receptor on a functional endothelium. Human coronary arteries were obtained from organ donors. Adenosine and its analogs (5′-N-ethyl-carboxamido-adenosine, NECA; N- l-phenylisopropyladenosine, LPIA; 2-chloroadenosine, CAD), all inhibited the contraction induced by 25 mmol/l KCl in a concentration-dependent manner and the order of potency was found to be NECA > CAD > L-PIA > adenosine. These relaxations were antagonized by 8-phenyltheophylline (8PT). At higher concentrations of KCl, the relaxations were attenuated. In rings which relaxed in response to endothelium-dependent relaxing agents (bradykinin and A23187), NECA and CAD produced relaxations similar to those produced in rings which did not show endothelium-dependent responses. The results suggest that the coronary adenosine receptor (probably A) mediates relaxations which may not be dependent on the relaxing function of the endothelium. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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