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A direct vasoaction of inosine in small intramural coronary arteries
Author(s) -
Randall John R.,
Mass Howard J.,
Jones Carl E.
Publication year - 1985
Publication title -
drug development research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.582
H-Index - 60
eISSN - 1098-2299
pISSN - 0272-4391
DOI - 10.1002/ddr.430050407
Subject(s) - inosine , aminophylline , adenosine , nucleoside , vasodilation , chemistry , theophylline , coronary arteries , medicine , pharmacology , endocrinology , stereochemistry , artery
The direct vasoaction of inosine was examined and compared to that of adenosine in small coronary arterial rings (0.3–0.6 mm o.d.) from the dog heart. Rings were contracted with KCI, and relaxation responses to increasing nucleoside concentrations were recorded. Both inosine (16 rings) and adenosine (12 rings) elicited relaxation responses that were linearly related to the logarithm of nucleoside concentration. In eight rings for which both inosine and adenosine responses were obtained, the geometric mean ED 50 for adenosine was 0.54 μM, compared to 242 μM for inosine (p < 0.001). The R max for the two nucleosides were not significantly different (p > 0.05). In four rings studied, aminophylline abolished the response to adenosine. In five rings studied, aminophylline abolished the response to adenosine. In five rings studied, aminophylline abolished the inosine response in only two rings; in the remaining three rings, the inosine response was attenuated but not abolished. These results indicate that inosine exerts a direct vasodilatory action on small coronary arteries and that this vasoaction is in part aminophylline‐sensitive.