Relaxation of coronary artery strips by adenosine and acidosis.
Cumulative dose-response curves of Ca2+-induced tension increments were studied in K+-depolarized helical strips of dog coronary arteries. Adenosine 10(-4) M reduced the Ca2+ sensitivity of the strips without altering the maximal tension with full Ca2+ activation. In contrast, acidosis of pH 7.05 significantly diminished the maximal tension with full Ca2+ activation. The relaxing effect of acidosis was almost completely abolished by 10(-4) M adenosine. It is concluded that adenosine inhibits Ca2+ influx, whereas acidosis depresses the contractile process of vascular smooth muscle directly.
D000138:Acidosis / Q000503:physiopathology*; D000241:Adenosine / Q000494:pharmacology / Q000502:physiology*; D000818:Animals; D001808:Blood Vessels / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000494:pharmacology; D003331:Coronary Vessels / Q000187:drug effects / Q000502:physiology; D004285:Dogs; D004347:Drug Interactions; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology
D000241:Adenosine; D002118:Calcium