Kramer J M, Beatty J A, Little H R, Plowey E D, Waldrop T G
Department of Molecular and Integrative Physiology and College of Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
Am J Physiol Regul Integr Comp Physiol. 2001 Feb;280(2):R389-97. doi: 10.1152/ajpregu.2001.280.2.R389.
Previous studies have documented a deficit in the GABA neurotransmitter system within the caudal hypothalamus (CH) of spontaneously hypertensive rats (SHR). The reduction in inhibitory influence on this cardiovascular excitatory brain region is associated with an increased neuronal activity and resting blood pressure. The purpose of this study was to determine if chronic treadmill and wheel-running activities alter the ability of the CH to regulate cardiovascular function. SHR were exercised on a treadmill (5 times/wk) at moderate intensity or allowed free access to running wheels (7 days/wk) for a period of 10 wk. Resting blood pressures were obtained before and after the exercise training periods. After the exercise period, rats were anesthetized and microinjection experiments were performed. Treadmill-trained SHR exhibited a significantly blunted developmental rise in resting blood pressure after 10 wk of exercise. A similar yet less marked effect was observed in wheel-run rats. Microinjection of the GABA synthesis inhibitor 3-mercaptopropionic acid (3-MP) into the CH of nonexercised SHR did not produce any change in arterial pressure. In contrast, microinjection of 3-MP into the CH produced significant increases in blood pressure and heart rate in exercised SHR. These results demonstrate that exercise training can alter CH cardiovascular regulation in hypertensive rats and therefore may play a role in increasing cardiovascular health.
先前的研究已证明，自发性高血压大鼠（SHR）尾侧下丘脑（CH）内的γ-氨基丁酸（GABA）神经递质系统存在缺陷。对这个心血管兴奋性脑区抑制作用的减弱与神经元活动增加和静息血压升高有关。本研究的目的是确定慢性跑步机运动和自由轮转运动是否会改变CH调节心血管功能的能力。将SHR以中等强度在跑步机上运动（每周5次），或允许其自由使用转轮（每周7天），持续10周。在运动训练期前后测量静息血压。运动期结束后，将大鼠麻醉并进行微量注射实验。经过10周运动训练的SHR静息血压的发育性升高明显减弱。在自由轮转运动的大鼠中观察到了类似但不太明显的效果。向未运动的SHR的CH中微量注射GABA合成抑制剂3-巯基丙酸（3-MP）不会使动脉血压发生任何变化。相比之下，向运动后的SHR的CH中微量注射3-MP会使血压和心率显著升高。这些结果表明，运动训练可以改变高血压大鼠CH的心血管调节功能，因此可能在增强心血管健康方面发挥作用。
