The role of K+ ions on the response to carbachol of calf coronary artery and cardiac vein during cooling

The role of K+ ions on the vasoconstrictions induced by carbachol during co oling (28 degreesC) in the endothelium of a denuded calf coronary artery an d cardiac vein (noncutaneous vessel) was studied. Carbachol (10(-9) - 3 X 1 0(-4)M) induced concentration-dependent contractions at both 37 degreesC an d 28 degreesC. The sensitivity, but not the maximal response, of carbachol (10(-9) - 3 x 10(-4) M) was significantly lower at 28 degreesC than at 37 d egreesC. Cooling to 28 degreesC after treatment with tetraethylammonium (TE A, 10(-3) M) or ouabain (10(-5) M), or after incubation in K+-free medium, increased the sensitivity to carbachol in both preparations. The results su ggest a role for K+ ions in the cooling-induced changes of noncutaneous ves sels. (C) 2001 Prous Science. All rights reserved.