Depressing effects of calcium antagonists on oxygen consumption in isolated skeletal muscle during potassium depolarization.
The effects of two Ca2+-antagonizing drugs, dantrolene sodium (DAN) and TMB-8, on subcontracture, K+-induced increased oxygen consumption were studied in isolated frog sartorius muscles. Incubation in Ringer's solution +18 mM KCl caused a marked increase in averaged resting oxygen uptake (52.8 +/- 4.1 to 278.2 +/- 20.0 mm3.g-1.h-1). Incubation in Ringer's +18 mM KCl containing either 0.116 mM TMB-8 or 0.035 mM DAN resulted in a significant reduction in the averaged metabolic response (264.4 +/- 30.8 (control) vs. 142.3 +/- 19.0 (TMB-8) vs. 72.2 +/- 3.4 (DAN]. The results suggest that the enhanced metabolic rate observed upon elevating extracellular [K+] to just below contracture levels is due to increased intracellular Ca2+ release.
Barnes
W S
WS
Department of Health, Texas A & M University, College Station 77843.
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D003620:Dantrolene / Q000494:pharmacology*; D004558:Electric Stimulation; D005707:Gallic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009132:Muscles / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects*; D011188:Potassium / Q000378:metabolism; D011894:Rana pipiens
D002121:Calcium Channel Blockers; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid; D003620:Dantrolene; D011188:Potassium