title: Relaxation of rat tail artery to electrical stimulation.
abstract: Rat tail artery strips relax in response to electrical stimulation (0.1-8Hz, 9V, 1.0msec) following contraction induced by norepinephrine (5.9 X 10(-7)M). The relaxation is not altered by treatment of the strips with atropine, propranolol, tetrodotoxin or indomethacin nor by chemical denervation with 6-hydroxydopamine. Incubation of strips in calcium-free solution reduced the contractile response to norepinephrine and blocked relaxation in response to 4Hz electrical stimulation. Histamine antagonists (H2 receptor subclass: cimetidine, metiamide) inhibited the relaxation to electrical stimulation in a dose-dependent manner. These results suggest that relaxation to electrical stimulation in rat tail artery is modulated by calcium and by the H2 subclass of histamine receptors.
mesh_terms: D000818:Animals; D001158:Arteries / Q000502:physiology; D002118:Calcium / Q000494:pharmacology; D002927:Cimetidine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D006632:Histamine / Q000494:pharmacology; D008297:Male; D008785:Metiamide / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D008785:Metiamide; D002927:Cimetidine; D006632:Histamine; D002118:Calcium; D009638:Norepinephrine