Cyclic AMP and the potassium-induced vasodilation.
The cAMP concentration of bovine facial arteries (helical strips) increased from 0.84 +/- 0.14 to 1.51 +/- 0.24 nmole/g wet weight, when the strips were relaxed by exposure to a physiological salt solution containing 10 instead of 2.7 mM KCl. A similar result (increase from 1.13 +/- 0.15 to 2.07 +/- 0.29 nmole cAMP/g wet weight) was obtained in strips pretreated with 10(-7) g/ml beta-methyldigoxin. These strips reacted to 10 mM KCl with a constriction. Addition of the phosphodiesterase activator N-methyl-imidazole (3 - 10(-3)M) did not affect the mechanical response to 10 mM KCl. It is concluded that for the potassium-induced vasodilation cAMP does not have a mediating function comparable to that in beta-adrenergic relaxation of vascular smooth muscle.
D000818:Animals; D001158:Arteries; D002417:Cattle; D000242:Cyclic AMP / Q000378:metabolism*; D004077:Digoxin / Q000031:analogs & derivatives / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D066298:In Vitro Techniques; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D011188:Potassium / Q000378:metabolism*; D014665:Vasodilator Agents
D007093:Imidazoles; D014665:Vasodilator Agents; D004077:Digoxin; D000242:Cyclic AMP; D011188:Potassium