Vascular effects of free radicals generated by electrical stimulation.
Electrical field stimulation (9 V, 1.0 ms, 4 Hz) of isolated segments of rat tail arteries and dog coronary arteries inhibits contractile responses to exogenous norepinephrine and elevated potassium concentration. This inhibitory effect of electrical stimulation is blocked by various agents that alter oxygen metabolism: superoxide dismutase, catalase, glutathione, ascorbate, and dimethyl sulfoxide. The observations suggest that the inhibitory effect is due to an action of oxygen free radical metabolites that are generated by the electrical stimulation of the oxygen-rich buffer. These free radical metabolites have two actions: 1) they oxidize drugs in the experimental system, and 2) they exert a direct inhibitory action on vascular smooth muscle.
D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000502:physiology; D001205:Ascorbic Acid / Q000494:pharmacology; D002374:Catalase / Q000494:pharmacology; D003331:Coronary Vessels / Q000187:drug effects / Q000502:physiology; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004285:Dogs; D004558:Electric Stimulation; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D005609:Free Radicals; D005978:Glutathione / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013482:Superoxide Dismutase / Q000494:pharmacology; D013623:Tail / Q000098:blood supply
D005609:Free Radicals; D002374:Catalase; D013482:Superoxide Dismutase; D005978:Glutathione; D001205:Ascorbic Acid; D011188:Potassium; D004837:Epinephrine; D004121:Dimethyl Sulfoxide