Claassen D E, Morgan D A, Hirai T, Kenney M J
Department of Anatomy and Physiology, Kansas State University, Manhattan 66506, USA.
Am J Physiol. 1996 Nov;271(5 Pt 2):R1264-9. doi: 10.1152/ajpregu.1996.271.5.R1264.
We tested the hypothesis that sustained increases in mean arterial pressure (MAP) produce nonuniform changes in regional sympathetic nerve discharges (SND) after the return of MAP to control levels. Renal, adrenal, splanchnic, and lumbar SND were recorded before, during, and after a 30-min elevation in MAP produced by phenylephrine (PE) infusion in alpha-chloralose-anesthetized spontaneously hypertensive (SH) rats. SND remained reduced from control values after PE infusion, despite the return of MAP to control levels. Importantly, the duration of poststimulus sympathoinhibition was significantly less in adrenal and splanchnic SND compared with renal and lumbar SND. In sinoaortic-denervated SH rats, SND remained at control levels during and after PE infusion. Simultaneous recordings of aortic depressor nerve (ADN) activity and SND demonstrated that prolonged renal and lumbar sympathoinhibition occurred even when ADN activity fell below control levels after PE infusion. We conclude that poststimulus responses of efferent SND in SH rats are regionally nonuniform and that renal and lumbar sympathoinhibitory responses are not mediated solely by prolonged increases in afferent baroreceptor nerve activity.
在平均动脉压（MAP）恢复到对照水平后，MAP的持续升高会导致局部交感神经放电（SND）出现不均匀变化。在α-氯醛糖麻醉的自发性高血压（SH）大鼠中，通过输注去氧肾上腺素（PE）使MAP升高30分钟，分别在升高前、升高期间和升高后记录肾、肾上腺、内脏和腰段的SND。尽管MAP恢复到对照水平，但在输注PE后，SND仍低于对照值。重要的是，与肾和腰段SND相比，肾上腺和内脏SND的刺激后交感抑制持续时间明显更短。在去窦弓神经的SH大鼠中，输注PE期间和之后，SND保持在对照水平。同时记录主动脉降压神经（ADN）活动和SND表明，即使在输注PE后ADN活动降至对照水平以下，肾和腰段的交感抑制仍会持续延长。我们得出结论，SH大鼠传出SND的刺激后反应在区域上是不均匀的，并且肾和腰段的交感抑制反应并非仅由传入压力感受器神经活动的持续增加介导。
