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Metabolic adjustments in response to graded exercise depends on central angiotensin AT1‐receptors
Author(s) -
Leite Laura Hora Rios,
Lacerda Ana Cristina R.,
Balthazar Cláudio H.,
Marubayashi Umeko,
Coimbra Cândido C.
Publication year - 2009
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.23.1_supplement.991.15
Subject(s) - medicine , losartan , endocrinology , angiotensin ii receptor type 1 , chemistry , receptor , angiotensin ii , anaerobic exercise , treadmill , aerobic exercise , blockade , physical exercise , physical therapy
To asses the influence of central angiotensin AT 1 receptors on metabolic adjustments in rats during graded exercise on a treadmill, 2 μL of NaCl (Sal) or losartan (Los; 60 nmol) were intracerebroventricularly injected before running until fatigue (starting at 10 m/min, 1 m/min increment every 3 min until fatigue, 10% inclination). Oxygen consumption (VO 2 ) was measured and mechanical efficiency (ME) calculated (n=6). The same protocol was used to collect blood samples through a jugular catheter (n=7). Plasmatic concentrations of glucose, lactate and free fatty acids (FFAs) were determined. During the first two steps of exercise, a similar increase in VO 2 and equal ME were observed in both groups. Thereafter, VO 2 continued to increase, but at a higher rate in Los‐treated animals, leading to a 34% reduction in ME in these animals (p<0.01). Los‐treated rats also showed a fast hyperglycemic response, already seen at low exercise intensities as 20% of maximal work. Higher lactate and FFAs levels followed this hyperglycemic response. The data shows that AT 1 ‐receptor blockade during graded exercise increases metabolic cost, leading to decreased ME, hyperglycemia and higher FFA mobilization at lower levels of exercise intensities. We conclude that angiotensinergic blockade results in higher and premature sympathetic activation, shifting energy balance during graded exercise. Supported by CNPq, FAPEMIG