title: The influences of L(+)-lactate and pH on contractile performance in rabbit glycerinated skeletal muscle.
abstract: To know whether L(+)-lactate directly induces the decrease in muscle contractile performance, several parameters of cross-bridge function were measured at various concentrations of lactate and pH in glycerinated rabbit psoas and soleus muscles at three different temperatures (5, 20, 28 degrees C). At all pHs studied (pH 7.0, 6.5, 6.0, and 5.5), isometric tension, unloaded velocity of shortening, and stiffness of a fiber during active and resting state in the presence of 50 mM lactate were not virtually different from those in the absence of lactate, but pH had remarkable effects on these parameters. The active stiffness decreased only slightly, and the small resting stiffness appeared at low pH; they were not affected by the presence of lactate. The present results indicate that the lactate anions may not have marked influence on the interaction between actin and myosin, and the concomitant change in pH with the production of lactate may remarkably affect it, as far as they were examined under the existing conditions of the experimental solutions.
authors.affiliation: Department of Biology, Faculty of Science, Kobe University, Kobe, 657-8501 Japan.
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Miyake
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Ishii
authors.forename: Takashi
authors.initials: T
authors.lastname: Watari
authors.forename: Zhenli
authors.initials: Z
authors.lastname: Huang
authors.forename: Teizo
authors.initials: T
authors.lastname: Tsuchiya
mesh_terms: D000138:Acidosis / Q000503:physiopathology; D000818:Animals; D000838:Anions; D005260:Female; D005990:Glycerol; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000494:pharmacology*; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D011817:Rabbits
chemical_list: D000838:Anions; D019344:Lactic Acid; D005990:Glycerol