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Exercise Training Improves the Arterial Baroreflex Function in Hypertensive Rats
Author(s) -
Pan YanXia,
Hong Lin,
Zhao XiaoLin,
Lin Cheng
Publication year - 2016
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.30.1_supplement.753.9
Subject(s) - baroreflex , blood pressure , medicine , phenylephrine , malondialdehyde , endocrinology , superoxide dismutase , sodium nitroprusside , heart rate , oxidative stress , anesthesia , nitric oxide
Objective To investigate the influence of exercise training on the arterial baroreflex and its central mechanisms in spontaneously hypertensive rats (SHR). Methods Twenty male SHR and 24 normotensive Wistar rats were randomly assigned into control group (C) or exercise training (E) group. All experimental procedures were in conformance with the FASEB Statement of Principles for the use of animals in research and education. Exercise training was performed on a treadmill for 8 weeks. Systolic blood pressure and heart rate were measured by tail‐cuff method. Baroreflex sensitivity(BRS) was determined by intravenous injection of phenylephrine (PE) and sodium nitroprusside (SNP). Alterations in the BRS were evaluated before and after intracerebroventricular administration of superoxide dismutase (SOD) mimetic Tempol or SOD inhibitor DETC. Malondialdehyde (MDA) content, total antioxidant capacity (T‐AOC), superoxide dismutase (SOD) and catalase (CAT) antioxidant enzyme activities in the hypothalamus were measured to assess oxidative state. Results Before exercise training, systolic blood pressure in two groups of SHR was obviously higher than those in normotensive Wistar rats ( P <0.01). Exercise training significantly decreased heart rate in SHR and Wistar rats and systolic blood pressure in SHR alone. The BRS of control SHR was significantly lower than that of normotensive Wistar rats [PE: (0.89 ± 0.22) vs. (1.96 ± 0.23) bpm/mmHg, P <0.001; SNP: (0.62 ± 0.10 ) vs. (1.32 ± 0.23) bpm/mmHg, P <0.001). Exercise training significantly improved the BRS of SHR. Compared with control SHR, the BRS of the trained SHR was significantly increased [PE: (1.31 ± 0.26 ) vs. (0.89±0.22) bpm/mmHg, P <0.001 SNP: (1.22 ± 0.25) vs. (0.62±0.10)bpm/mm Hg, P <0.01). Intracerebroventricular infusion of DETC abolished the beneficial effect of exercise training on the BRS in SHR rats ( P <0.05) and significantly decreased the BRS in two Wistar groups ( P < 0.05). In contrast, Tempol greatly improved the BRS in two SHR groups ( P <0.05) and normalized the BRS of the trained SHR. Exercise training decreased MDA content in the hypothalamus of SHR by 27% ( P <0.05), but increased T‐AOC, SOD and CAT activities by 74%, 41% and 62%, respectively ( P <0.05). In addition, exercise training decreased MDA content in the hypothalamus of Wistar by 40% ( P <0.05), but increased T‐AOC, SOD and CAT activities by 72%, 30% and 51%, respectively ( P <0.05). Conclusions Central oxidative stress depresses the arterial baroreflex, and exercise training –induced reduction of central oxidative stress contributes to improved arterial baroreflex function in SHR by the enhancement of antioxidant enzyme activity and antioxidant capacity in the brain. Support or Funding Information the National Natural Science Foundation of China (No.81372111) the Natural Science Foundation of Fujian Province (No. J01339)