The stainless steel cannula inserting method was used to observe effects of alpha-adrenoceptor agonists, 5-HT and KCl before and after cold storage (3-5 days, at 4 degrees C) in skeletal muscle branches of the simian deep femoral artery. Epinephrine (EPI), norepinephrine (NE), phenylephrine (PE), methoxamine (MT) and 5-hydroxytryptamine (5-HT) induced marked monophasic vasoconstrictions in a dose-dependent manner. 5-HT induced a greater vasoconstriction in larger diameter vessels (old animals) than that in smaller ones (young animals), suggesting age-related responses. A selective alpha 2-stimulant, clonidine (CLO) or xylazine (XYL), produced only a slight vasoconstriction. Tyramine (TYR) also produced only a slight vasoconstrictor response. The order of potencies for inducing vasoconstrictions was EPI greater than or equal to 5-HT greater than or equal to NE greater than MT = PE much greater than KCl greater than CLO = XYL = TYR. The vasoconstrictor responses to all used adrenergic agonists and 5-HT were not significantly influenced by the prolonged cold storage. However, KCI-induced constrictions were significantly suppressed by the cold storage. These results suggest that the postjunctional alpha-adrenoceptor in simian skeletal muscle arteries is mainly of the alpha 1-type. Since cold storage caused a significant suppression of the KCl-induced response but not those of adrenoceptor agonists and 5-HT, it was considered that the mechanism of calcium entry to the vascular smooth muscle of skeletal muscle arteries might be significantly damaged by the cold storage.

Using the cannula inserting method, we investigated the responsiveness of isolated skeletal muscle branches of the dog femoral artery to alpha-adrenoceptor agonists and potassium chloride, and the influence of cold storage (3 days and 5-7 days, at 4 degrees C). Epinephrine (EPI) and norepinephrine (NE) induced a marked vasoconstriction in a dose-related manner. A large dose of EPI and NE usually induced an increase in perfusion pressure of more than 100-200 mm Hg. Phenylephrine (PE) and methoxamine (MT) also induced a marked constriction, but clonidine (CLO) and xylazine (XYL) produced only a slight vasoconstriction, even in large doses. Tyramine (TYR) also induced a small vasoconstrictor response. A large dose of KCl induced a marked vasoconstriction. The order of potency of constriction was EPI greater than or equal to NE greater than PE = MT much greater than KCl greater than CLO greater than or equal to TYR greater than or equal to XYL. The vasoconstrictor responses to EPI and NE were significantly suppressed by 3-7 days of cold storage. Vasoconstrictor responses to MT were slightly suppressed by cold storage. However, XYL-, CLO- and TYR-induced vasoconstrictions were not significantly influenced by cold storage. KCl-induced constriction was clearly suppressed by cold storage. These observations suggest that the postjunctional alpha-adrenoceptor in skeletal muscle branches of the femoral artery is of the alpha 1-type. Moreover, it was shown that prolonged cold storage (3-7 days, at 4 degrees C) resulted in a decrease in sensitivity of these vessels to alpha-adrenoceptor agonists and in a marked decrease in sensitivity to KCl, suggesting a depression of the calcium channel by cold storage.