Perfused skeletal muscle contraction and metabolism improved by angiotensin ii-mediated vasoconstriction. Rattigan, Stephen, Kim A. Dora, Alex C. Y. Tong, and Michael G. Clark. Division of Biochemistry, University of Tasmania, Hobart, Tasmania, 7001, Australia
APStracts 3:0065E, 1996.
In the present study, the effects of Angiotensin II (AII) on tension development and associated metabolism during twitch and tetanic stimulation via the sciatic nerve of the gastrocnemius-plantaris -soleus muscle group of the perfused rat hindlimb was investigated. Rat hindlimbs were perfused at constant flow with an erythrocyte containing medium equilibrated with 95:5 Air:CO2 at 37 degrees C and determinations of oxygen and glucose uptake, lactate and glycerol release and 2-deoxy-D-[1-3H] glucose uptake (R'g) into individual muscles were carried out. AII (1nM) infusion alone caused vasoconstriction with increased oxygen (55%) and glucose uptake (98%), lactate (37%) and glycerol release (64%). AII infusion during muscle contraction gave less vasoconstriction but increased the tension development during tetanic stimulation by 80% and increased the contraction-induced oxygen uptake and R'g by plantaris, gastrocnemius red and white muscles. These effects of AII may have been due to increased nutritive flow to contracting muscles or to redirection of flow from non-contracting and type I fibre muscles to the type II fibre contracting muscles in the hindlimb. The results indicate that the regulation of flow by the vasculature is an important regulator of muscle contraction and metabolism. 

Received 2 June 1995; accepted in final form 19 February 1996.
APS Manuscript Number E251-5.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 27 March 96