Study of vasodilator effects of papaverine, adenosine and related drugs in isolated cat cerebral arteries.
Papaverine, 1-methyl-3-isobutylxanthine (MIX), adenosine, cyclic-AMP (cAMP),dibutyryl-cAMP (db-cAMP) evoked concentration-dependent vasodilation in cat middle cerebral arteries precontracted with K+. The order of maximal vasodilator responses was: papaverine greater than MIX greater than adenosine = cAMP greater than or equal to db-cAMP, and with regard to their potency (ED50) was: db-cAMP greater than cAMP greater than papaverine = MIX greater than adenosine. The relaxations induced by papaverine, adenosine and cAMP were reduced by MIX. Preincubation with adenosine increased the vasodilation evoked by MIX. It also transformed the relaxation caused by cAMP in contraction. These results suggest that adenosine and related compounds interact with specific purinoreceptors, as well as the existence of two antagonisms between: adenosine and cAMP, papaverine and MIX for the same site or mechanism of action.
M
M
Salaices
A
A
de Gregorio
J
J
Marin
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000241:Adenosine / Q000494:pharmacology; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002415:Cats; D002536:Cerebral Arteries / Q000187:drug effects*; D000242:Cyclic AMP / Q000494:pharmacology; D004347:Drug Interactions; D066298:In Vitro Techniques; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D010208:Papaverine / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
D014665:Vasodilator Agents; D003994:Bucladesine; D010208:Papaverine; D000242:Cyclic AMP; D000241:Adenosine; D015056:1-Methyl-3-isobutylxanthine