Decreased muscle ACE activity enhances functional response to endurance training in rats, without change in muscle oxidative capacity or contractile phenotype

1 Département des facteurs humains, Centre de Recherches du Service de Santé des Armées, La Tronche, France; 2 University Paris-Sud 11, IFR141, Châtenay-Malabry; and 3 Institut National de la Santé et de la Recherche Médicale U-769, Châtenay-Malabry, France Submitted 3 November 2008 ; accepted in final form 30 April 2009 In the present study, we tested the hypothesis that chronic ANG I-converting enzyme (ACE) inhibition could improve the training-induced improvement in endurance exercise performance and that this could be related to enhanced skeletal muscle metabolic efficiency. Female Wistar rats were assigned to four groups comprising animals either maintained sedentary or endurance trained (Sed and Tr, respectively), and treated or not for 10 wk with an ACE inhibitor, perindopril (2 mg·kg –1 ·day –1 ) (Per and Ct, respectively) ( n = 8 each). Trained rats underwent an 8-wk treadmill training protocol that consisted of 2 h/day running at 30 m/min on a 8% decline. Before the start of and 1 wk before the end of experimental conditioning, the running time to exhaustion of rats was measured on a treadmill. The training program led to an increase in endurance time, higher in Tr-Per than in Tr-Ct group (125% in Tr-Ct vs. 183% in Tr-Per groups, P < 0.05). Oxidative capacity, measured in saponin-permeabilized fibers of slow soleus and fast plantaris muscles, increased with training, but less in Tr-Per than in Tr-Ct rats. The training-induced increase in citrate synthase activity also was less in soleus from Tr-Per than Tr-Ct rats. The training-induced increase in the percentage of the type IIa isoform of myosin heavy chain (MHC) (45%, P < 0.05) and type IIx MHC (25%, P < 0.05) associated with decreased type IIb MHC (34%, P < 0.05) was minimized by perindopril administration. These findings demonstrate that the enhancement in physical performance observed in perindopril-treated animals cannot be explained by changes in mitochondrial respiration and/or MHC distribution within muscles involved in running exercise. mitochondria; myosin heavy chain; angiotensin I-converting enzyme inhibitor; perindopril; running performance Address for reprint requests and other correspondence: X. Bigard, Département des facteurs humains, Centre de Recherches du Service de Santé des Armées, F-38700 La Tronche, France (e-mail: xbigard{at}crssa.net )