Journal of Applied Physiology, Vol 73, Issue 3 806-811, Copyright © 1992 by American Physiological Society
Differences in metabolic response of dog and goat latissimus dorsi muscle to chronic stimulation
J. F. Glatz, Y. F. de Jong, W. A. Coumans, C. M. Lucas, F. H. van der Veen and G. J. van der Vusse
Department of Physiology, University of Limburg, Maastricht, The Netherlands.
The latissimus dorsi (LD) muscle is considered suitable to assist
ventricular mechanical function in either cardiomyoplasty or
extra-aortic-assist devices. Such application requires that this mixed-type
skeletal muscle be transformed into a fatigue-resistant muscle, the
adaptation of which can be elicited by chronic stimulation. In this study
the LD muscles of dog and goat were subjected in situ to 12 wk of
continuous electrical stimulation through intramuscular electrodes, and
their myofibrillar and metabolic adaptations were compared. A gradual
increase in the contraction rate of the muscle (in 10 wk from 30 to 80
contractions/min) caused the proportion of immunohistochemically identified
type I fibers to increase in dog muscle from 30 to 74% and in goat muscle
from 21 to 99%. Correspondingly, the anaerobic-glycolytic activity
(fructose-6-phosphate kinase and lactate dehydrogenase activities)
decreased by approximately 75% in both dog and goat muscles, whereas the
oxidative capacity (fatty acid oxidation and citrate synthase activity)
increased two- to threefold in goat LD muscle but remained unaltered in dog
LD muscle. Muscular contents of high-energy phosphates and endogenous
substrates were maintained, but the L-carnitine content decreased by 43% in
both dog and goat. Our data further indicate that, for the monitoring of
the metabolic adaptation of skeletal muscle, the ratio of activities of the
oxidative and anaerobic-glycolytic pathways (e.g., citrate synthase to
fructose-6-phosphate kinase activities) is a useful parameter in both dog
and goat.(ABSTRACT TRUNCATED AT 250 WORDS)
