PT - JOURNAL ARTICLE AU - OLIVER CARRIER, JR. AU - HELGA A. JUREVICS TI - THE ROLE OF CALCIUM IN "NONSPECIFIC" SUPERSENSITIVITY OF VASCULAR MUSCLE DP - 1973 Jan 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - 81--94 VI - 184 IP - 1 4099 - http://jpet.aspetjournals.org/content/184/1/81.short 4100 - http://jpet.aspetjournals.org/content/184/1/81.full SO - J Pharmacol Exp Ther1973 Jan 01; 184 AB - The development in vascular muscle of supersensitivity to calcium, potassium, acetylcholine, isoproterenol and norepinephrine was studied in rabbit aortic strips after pretreatment with reserpine, either 3 mg/kg 24 hours or 0.3 mg/kg/day for three days before testing. Supersensitivity of the aortae to calcium was obtained in a 60 mM potassium Ringer's solution. Supersensitivity of the aortae to potassium and acetylcholine was obtained only in the presence of calcium. Responses of aortae from reserpine-treated rabbits to isoproterenol and norepinephrine were potentiated both in normal Ringer's solution and in a calcium-free 60 mM potassium Ringer's solution. Aortic strips from reserpinetreated rabbits had a slower rate of tension decline in a calcium-free solution than did the strips from untreated animals. 45Ca efflux was delayed after reserpine with a decrease in the rate of the slow component. It is concluded from these results that reserpine increases the permeability of the muscle to calcium and acts in addition at some other calcium site to increase calcium's availability for contraction. © 1973 by The Williams & Wilkins Company