AJP - Regulatory, Integrative and Comparative Physiology, Vol 240, Issue 5 301-R309, Copyright © 1981 by American Physiological Society
Effect of acclimation temperature and pH on contraction of frog sartorius muscle
J. M. Renaud and E. D. Stevens
The effect of acclimation temperature and pH on the isometric twitch and
tetanus of sartorius muscle from frog, Rana pipiens, was studied at
different experimental temperatures. Seven variables were measured, namely:
tension, latent period, time to maximum tension, half-relaxation time, mean
rate, maximum rate, and maximum acceleration of tension development. The
effect of experimental temperature was similar to that reported in the
literature. The effects of acclimation temperature were small and were not
compensatory. Different pH's were obtained by varying CO2 in the gas phase,
while the HCO3- concentration was kept constant. The main effects of a
decrease in pH on the isometric twitch and tetanus were a reduction in
tension and rate of tension development and an increase in latent period. A
decrease in pH had no effect on the time to maximum tension or the
half-relaxation time. Analysis of variance showed that the test temperature
had the greatest effect of all three treatments on each variable, the
effects of test and acclimation temperature were dependent on neither the
test nor the acclimation temperatures. The in vivo relationships between
these three treatments are discussed.
