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Intracerebroventricular losartan increases metabolic cost during exercise reducing mechanical efficiency and running performance in rats
Author(s) -
Leite Laura Hora Rios,
Lacerda Ana Cristina Rodrigues,
Balthazar Cláudio Heitor,
Marubayashi Umeko,
Coimbra Cândido Celso
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a927-d
Subject(s) - losartan , metabolic cost , medicine , physical medicine and rehabilitation , renin–angiotensin system , blood pressure
The effect of central angiotensin AT 1 receptor blockade on metabolic rate and running performance in rats during exercise on a treadmill (18 m.min −1 , 5% inclination) was investigated. Oxygen consumption (VO 2 ) was measured, using the indirect calorimetry system, in rats while they were exercising until fatigue after injection of 2 μL of losartan (Los; 60 nmol, n=9), an angiotensin II AT 1 receptor antagonist, or 2 μL of 0.15 M NaCl (Sal, n=9) into the right lateral cerebral ventricle. Mechanical efficiency (ME) and Workload (W) were calculated. The W of Los‐treated animals were 30% lower than in Sal‐treated animals (p<0.02). During the first 10 minutes of exercise (dynamic state of exercise), there was a similar increase in VO 2 while ME remained the same in both groups. Thereafter (steady state of exercise), VO 2 remained stable in the Sal group but continued to increase and stabilized at a higher level in Los‐treated animals until fatigue. During the steady state of exercise there was a sharper reduction in ME in Los‐treated rats compared to Sal‐treated animals (p<0.01). Our data showed that AT 1 receptor blockade increases metabolic cost during exercise, reducing mechanical efficiency. These results indicate that central angiotensinergic transmission modulates heat production, improving ME during the steady state of exercise. Supported by: CNPq, FAPEMIG, and CAPES