TY - JOUR
T1 - Chronic treadmill running in normotensive rats resets the resting blood pressure to lower levels by upregulating the hypothalamic GABAergic system
AU - Hsu, Yuan Chang
AU - Chen, Hsiun Ing
AU - Kuo, Yu Min
AU - Yu, Lung
AU - Huang, Tung Yi
AU - Chen, Shean Jen
AU - Chuang, Jih Ing
AU - Wu, Fong Sen
AU - Jen, Chauying J.
PY - 2011/12
Y1 - 2011/12
N2 - OBJECTIVE: The cardiovascular integration center not only sends out signals to offset the stimulus-induced responses but also resets the resting blood pressure. We hypothesize that GABAergic adaptations in the hypothalamus participate in the chronic exercise-induced cardiovascular resetting effects in conscious normotensive animals. METHODS: Male Wistar rats were subjected to chronic moderate exercise (CME, 8-week treadmill running at moderate intensity). A biotelemetry system was used to measure blood pressure, heart rate, autonomic nervous activities, baroreflex sensitivity and endogenous GABAergic activities in the paraventricular nucleus and the posterior hypothalamic area. Hypothalamic specimens were collected for quantifying GABA-related proteins and GABAergic neurons. RESULTS: CME reduced resting blood pressure, heart rate, sympathetic activity and enhanced parasympathetic activity and baroreflex sensitivity. Additionally, CME elevated the resting level of hypothalamic GABAergic activities, increased the percentage of GABAergic neurons in the hypothalamus and upregulated the hypothalamic protein levels of neuronal nitric oxide synthase, GAD67 and gephyrin, but not GABAA receptor. Moreover, a single bout of moderate exercise transiently elevated blood pressure and heart rate with prolonged high levels of neural controls (sympathetic activity, baroreflex sensitivity and hypothalamic GABAergic activities). CME accelerated the postexercise recovery in cardiovascular parameters and neural control alterations. CONCLUSION: Chronic treadmill running in normotensive rats augmented the GABAergic system in both paraventricular nucleus and posterior hypothalamic area, resulting in lower resting blood pressure, heart rate and sympathetic tone under conscious unrestraint conditions. This study provides insight into mechanisms important for explaining how chronic exercise resets the resting blood pressure.
AB - OBJECTIVE: The cardiovascular integration center not only sends out signals to offset the stimulus-induced responses but also resets the resting blood pressure. We hypothesize that GABAergic adaptations in the hypothalamus participate in the chronic exercise-induced cardiovascular resetting effects in conscious normotensive animals. METHODS: Male Wistar rats were subjected to chronic moderate exercise (CME, 8-week treadmill running at moderate intensity). A biotelemetry system was used to measure blood pressure, heart rate, autonomic nervous activities, baroreflex sensitivity and endogenous GABAergic activities in the paraventricular nucleus and the posterior hypothalamic area. Hypothalamic specimens were collected for quantifying GABA-related proteins and GABAergic neurons. RESULTS: CME reduced resting blood pressure, heart rate, sympathetic activity and enhanced parasympathetic activity and baroreflex sensitivity. Additionally, CME elevated the resting level of hypothalamic GABAergic activities, increased the percentage of GABAergic neurons in the hypothalamus and upregulated the hypothalamic protein levels of neuronal nitric oxide synthase, GAD67 and gephyrin, but not GABAA receptor. Moreover, a single bout of moderate exercise transiently elevated blood pressure and heart rate with prolonged high levels of neural controls (sympathetic activity, baroreflex sensitivity and hypothalamic GABAergic activities). CME accelerated the postexercise recovery in cardiovascular parameters and neural control alterations. CONCLUSION: Chronic treadmill running in normotensive rats augmented the GABAergic system in both paraventricular nucleus and posterior hypothalamic area, resulting in lower resting blood pressure, heart rate and sympathetic tone under conscious unrestraint conditions. This study provides insight into mechanisms important for explaining how chronic exercise resets the resting blood pressure.
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U2 - 10.1097/HJH.0b013e32834c628f
DO - 10.1097/HJH.0b013e32834c628f
M3 - Article
C2 - 22002337
AN - SCOPUS:81355148589
SN - 0263-6352
VL - 29
SP - 2339
EP - 2348
JO - Journal of hypertension
JF - Journal of hypertension
IS - 12
ER -