Contraction and Metabolism Traits in Skeletal Muscle Biopsies from Halothane Positive Pigs as Studied by Mechanical Measurements and 31p NMR

Abstract

The effects of caffeine and A23187 ionophore (calcimycine) on some traits of contraction and metabolism in skeletal muscle biopsies from halothane positive (HP) and halothane negative (HN) piglets were studied using simultaneous mechanical and NMR measurements on the same sample. Before applying caffeine or A23187, pH and CP level were much lower in HP pig muscle than in HN pig muscle. Two Pi peaks were observed, although not constantly, in HP pig muscle, indicating two pH compartments. Both caffeine and A23187 provoked in HP pig muscle, as compared to HN pig muscle, a stronger contracture, a decrease in twitch tension (increased in HN muscle), a faster pH decrease and a faster depletion of creatine phosphate. It is proposed that, in HP pig muscle, the mechanical response could be affected not only by the changes in free intracellular Ca2+ but also by acidosis and CP depletion induced by caffeine and A23187.