Minami Naoyoshi, Mori Nobuyoshi, Nagasaka Makoto, Ito Osamu, Ogawa Mika, Kurosawa Hajime, Kanazawa Masayuki, Kohzuki Masahiro
Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, Sendai, Japan.
Tohoku J Exp Med. 2007 Apr;211(4):339-45. doi: 10.1620/tjem.211.339.
In men, exercise training attenuates age-related reduction in baroreflex sensitivity, which is related to cardiovascular health. It is unknown, however, if this holds true for post-menopausal women. We examined the effects of exercise training on baroreceptor-heart rate (HR) reflex sensitivity in ovariectomized (OVX) and sham-operated (SO) Wistar-Kyoto rats. At the age of 8 weeks, OVX and SO rats were assigned to either sedentary or exercise-trained group. Exercise training was performed on a treadmill 5 days per week. At the age of 20 weeks, baroreflex sensitivity in response to increases in blood pressure (BRSinc) and decreases in blood pressure (BRSdec) were evaluated by injections of phenylephrine and sodium nitroprusside, respectively. Both BRSinc and BRSdec were significantly reduced in sedentary OVX rats compared with sedentary SO rats. Exercise training decreased resting HR and BRSdec, but had no effect on BRSinc in SO rats. In OVX rats, exercise training decreased resting HR but modified neither BRSdec nor BRSinc. We conclude that withdrawal of female sex hormones in normotensive female rats is associated with reduced baroreflex sensitivity in response to both increase and decrease in blood pressure and that exercise training fails to modulate the decline of BRSinc associated with withdrawal of female sex hormones. To maintain high level of BRSinc in post-menopausal women, hormone replacement therapy may be needed.
在男性中，运动训练可减轻与压力反射敏感性相关的年龄相关性降低，而压力反射敏感性与心血管健康有关。然而，对于绝经后女性是否如此尚不清楚。我们研究了运动训练对去卵巢（OVX）和假手术（SO）的Wistar-Kyoto大鼠压力感受器-心率（HR）反射敏感性的影响。8周龄时，将OVX和SO大鼠分为久坐组或运动训练组。运动训练每周在跑步机上进行5天。20周龄时，分别通过注射去氧肾上腺素和硝普钠评估对血压升高（BRSinc）和血压降低（BRSdec）的压力反射敏感性。与久坐的SO大鼠相比，久坐的OVX大鼠的BRSinc和BRSdec均显著降低。运动训练降低了SO大鼠的静息心率和BRSdec，但对BRSinc没有影响。在OVX大鼠中，运动训练降低了静息心率，但对BRSdec和BRSinc均无影响。我们得出结论，正常血压雌性大鼠体内雌性激素的撤除与血压升高和降低时压力反射敏感性降低有关，并且运动训练无法调节与雌性激素撤除相关的BRSinc下降。为了使绝经后女性维持高水平的BRSinc，可能需要激素替代疗法。
