Analysis of the effects of adenosine in skinned bovine coronary artery.
We have investigated the mechanism of adenosine-induced relaxation in relation to its effects on intracellular organelles in Triton X-100- and saponin-skinned bovine coronary arteries. In intact coronary arteries, high K+ and prostaglandin F2 alpha caused sustained contractions, whereas caffeine produced transient contractions. Triton X-100 treatment abolished these contractions. However, Triton X-100-skinned coronary arteries were responsive to added free calcium. There was no significant difference between calcium concentration-response curves obtained in the absence and presence of adenosine (50 microM). Unlike Triton X-100, in saponin-skinned arteries, caffeine produced transient contractions but high K+ and prostaglandin F2 alpha did not. Adenosine had no effect on caffeine-induced contractions in saponin-skinned coronary arteries. These data suggest that adenosine had no direct inhibitory effect on either the contractile apparatus or calcium release from sarcoplasmic reticulum in coronary arteries.
Ramagopal
M V
MV
Department of Pharmacology, School of Medicine, East Carolina University, Greenville, NC 27858-4354.
Mustafa
S J
SJ
D000241:Adenosine / Q000494:pharmacology*; D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D003331:Coronary Vessels / Q000187:drug effects* / Q000378:metabolism; D015237:Dinoprost / Q000494:pharmacology; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000378:metabolism; D017830:Octoxynol; D011092:Polyethylene Glycols / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D012503:Saponins / Q000737:chemistry*
D012503:Saponins; D002110:Caffeine; D011092:Polyethylene Glycols; D017830:Octoxynol; D015237:Dinoprost; D000241:Adenosine; D011188:Potassium; D002118:Calcium