A study of the action of caffeine, halothane, potassium chloride and procaine on normal human skeletal muscle

Abstract

SUMMARY 1. The effects of caffeine, halothane, potassium chloride and procaine have been studied on normal human skeletal muscle in vitro. Particular emphasis has been given to the role played by extracellular calcium ions in producing these effects. 2. Caffeine produces a concentration-dependent contracture probably by stimulating the release of calcium ions from the calcium storing membranes of the muscle cell. 3. Halothane potentiates the contractures produced by caffeine and potassium chloride probably by facilitating the release of calcium from the storage membranes. 4. Potassium chloride produces a contracture only in the presence of caffeine or halothane. 5. Procaine inhibits all the contractures studied.