THE ACTION OF ACIDS ON TURTLE HEART MUSCLE WITH REFERENCE TO THE PENETRATION OF ANIONS

Abstract

A preparation is devised from excised atrial tissue of turtle which is suitable for examination of action of carbonic and other acids on muscular contraction. It is concluded from physiological methods that this tissue is freely permeable to CO2 and apparently permeable to HCO3-. Under the observed conditions the HCO3- concentration in the cell appears to be some fraction (which is probably near unity) of the sum of the HC03- concentration in the fluid and a constant, or approximately constant, quantity. A-trial tissue is relatively impermeable to primary and secondary phosphate ions, to lactic acid and the lactate ion, and to acetic acid and the acetate ion; it is slowly permeable to valeric acid and apparently permeable to the valerate ion; propionic and butyric acids, and propionate and butyrate ions, occupy intermediate positions between valeric and acetic acids. From the action of HC1, lactates and phosphates, it is concluded that the H+ penetrates atrial tissue provided a sufficient concentration difference between fluid and cell is established; and that the final equilibrium is characterized by a considerable difference in Ph in fluid and cell. It is concluded that the apparent penetration of certain anions is not a consequence of migration of these anions from fluid to cell, and it is suggested that an intracellular concentration of anion is established by a redistribution of H and Cl ion pairs between cell and fluid subsequent to and in consequence of the penetration of the respective acid molecule.