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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Tonic and reflex cardiovascular autonomic control in trained-female rats

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Author(s):
Sanches, I. C. [1] ; Sartori, M. [1, 2] ; Jorge, L. [2] ; Irigoyen, M. C. ; De Angelis, K. [1]
Total Authors: 5
Affiliation:
[1] Univ Sao Judas Tadeu, Lab Movimento Humano, BR-03166000 Sao Paulo - Brazil
[2] Univ Sao Paulo, Inst Coracao, Unidade Hipertensao, Sao Paulo - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Brazilian Journal of Medical and Biological Research; v. 42, n. 10, p. 942-948, OCT 2009.
Web of Science Citations: 13
Abstract

The effects of exercise training on cardiovascular and autonomic functions were investigated in female rats. After an aerobic exercise training period (treadmill: 5 days/week for 8 weeks), conscious female Wistar (2 to 3 months) sedentary (S, N = 7) or trained rats (T, N = 7) were cannulated for direct arterial pressure (AP) recording in the non-ovulatory phases. Vagal (VT) and sympathetic tonus (ST) were evaluated by vagal (atropine) and sympathetic (propranolol) blockade. Baroreflex sensitivity was evaluated by the heart rate responses induced by AP changes. Cardiopulmonary reflex was measured by the bradycardic and hypotensive responses to serotonin. Resting bradycardia was observed in T (332 ± 7 bpm) compared with S animals (357 ± 10 bpm), whereas AP did not differ between groups. T animals exhibited depressed VT and ST (32 ± 7 and 15 ± 4 bpm) compared to S animals (55 ± 5 and 39 ± 10 bpm). The baroreflex and cardiopulmonary bradycardic responses were lower in T (-1.01 ± 0.27 bpm/mmHg and -17 ± 6 bpm) than in the S group (-1.47 ± 0.3 bpm/mmHg and -41 ± 9 bpm). Significant correlations were observed between VT and baroreflex (r = -0.72) and cardiopulmonary (r = -0.76) bradycardic responses. These data show that exercise training in healthy female rats induced resting bradycardia that was probably due to a reduced cardiac ST. Additionally, trained female rats presented attenuated bradycardic responses to baro- and cardiopulmonary receptor stimulation that were associated, at least in part, with exercise training-induced cardiac vagal reduction. (AU)