在自发性运动活动期间,高血压大鼠的肾交感神经和升压反应被夸大。

Exaggerated renal sympathetic nerve and pressor responses during spontaneously occurring motor activity in hypertensive rats.

机构信息

Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States.

Department of Integrative Physiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.

出版信息

Am J Physiol Regul Integr Comp Physiol. 2023 Apr 1;324(4):R497-R512. doi: 10.1152/ajpregu.00271.2022. Epub 2023 Feb 13.

Abstract

Stimulation of the mesencephalic locomotor region elicits exaggerated sympathetic nerve and pressor responses in spontaneously hypertensive rats (SHR) as compared with normotensive Wistar-Kyoto rats (WKY). This suggests that central command or its influence on vasomotor centers is augmented in hypertension. The decerebrate animal model possesses an ability to evoke intermittent bouts of spontaneously occurring motor activity (SpMA) and generates cardiovascular responses associated with the SpMA. It remains unknown whether the changes in sympathetic nerve activity and hemodynamics during SpMA are altered by hypertension. To test the hypothesis that the responses in renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) during SpMA are exaggerated with hypertension, this study aimed to compare the responses in decerebrate, paralyzed SHR, WKY, and normotensive Sprague-Dawley (SD) rats. In all strains, an abrupt increase in RSNA occurred in synchronization with tibial motor discharge (an index of motor activity) and was followed by rises in MAP and heart rate. The centrally evoked increase in RSNA and MAP during SpMA was much greater (306 ± 110%) in SHR than WKY (187 ± 146%) and SD (165 ± 44%). Although resting baroreflex-mediated changes in RSNA were not different across strains, mechanically or pharmacologically induced elevations in MAP attenuated or abolished the RSNA increase during SpMA in WKY and SD but had no effect in SHR. It is likely that the exaggerated sympathetic nerve and pressor responses during SpMA in SHR are induced along a central command pathway independent of the arterial baroreflex and/or result from central command-induced inhibition of the baroreflex.

摘要

刺激中脑运动区会引起自发性高血压大鼠(SHR)交感神经和升压反应过度,而与正常血压的 Wistar-Kyoto 大鼠(WKY)相比。这表明中枢命令或其对血管运动中枢的影响在高血压中增强。去大脑动物模型具有诱发间歇性自发运动活动(SpMA)的能力,并产生与 SpMA 相关的心血管反应。尚不清楚 SpMA 期间交感神经活动和血液动力学的变化是否因高血压而改变。为了检验高血压时 SpMA 期间肾交感神经活动(RSNA)和平均动脉压(MAP)反应过度的假设,本研究旨在比较去大脑、麻痹的 SHR、WKY 和正常血压 Sprague-Dawley(SD)大鼠的反应。在所有品系中,RSNA 突然增加与胫骨运动放电同步(运动活动的指标),随后 MAP 和心率升高。在 SpMA 期间,中枢诱发的 RSNA 和 MAP 增加在 SHR 中比 WKY(187 ± 146%)和 SD(165 ± 44%)大得多。尽管静息压力反射介导的 RSNA 变化在各品系之间没有差异,但机械或药物引起的 MAP 升高会减弱或消除 WKY 和 SD 中 SpMA 期间的 RSNA 增加,但对 SHR 没有影响。很可能是 SHR 在 SpMA 期间交感神经和升压反应过度是通过独立于动脉压力反射的中枢命令途径引起的,或者是由于中枢命令引起的压力反射抑制引起的。

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