Low temperature augments the endothelium-dependent relaxation in isolated rat aorta.
The norepinephrine-induced contraction in isolated rat aorta was relaxed (by approximately 35%) by a decrease in bath temperature from 37 to 35 degrees C and was augmented (by approximately 30%) by an increase to 39 degrees C. The effect of temperature was inhibited by endothelium removal, methylene blue or hemoglobin. The carbachol-induced, endothelium-dependent relaxation and the sodium nitroprusside-induced relaxation were decreased at 39 degrees C and increased at 35 degrees C. These results suggest that low temperature augments the effect of inhibitory substances released from vascular endothelium, possibly by a change in the sensitivity of smooth muscle cells to this substance.
Department of Veterinary Pharmacology, Faculty of Agriculture, University of Tokyo, Japan.
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Karaki
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Nagase
D000818:Animals; D001011:Aorta / Q000502:physiology; D002217:Carbachol / Q000494:pharmacology; D003080:Cold Temperature; D004730:Endothelium, Vascular / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
D002217:Carbachol; D009638:Norepinephrine