Tidgren B, Hjemdahl P, Theodorsson E, Nussberger J
Department of Clinical Physiology, Karolinska Hospital, Stockholm, Sweden.
Am J Physiol. 1990 Oct;259(4 Pt 2):F573-9. doi: 10.1152/ajprenal.1990.259.4.F573.
Renal blood flow, renal sympathetic nerve activity, assessed by the renal overflows of norepinephrine (NE), dopamine (DA), and neuropeptide Y-like immunoreactivity (NPY-LI), as well as plasma renin activity and angiotensin II (ANG II) were evaluated during stepwise increases in lower body negative pressure (LBNP) in 10 healthy volunteers. The fractional extraction of epinephrine (Epi) was used to assess renal catecholamine removal (approximately 50%) from arterial plasma. Renal NE, DA, and NPY-LI overflows at rest were 235 +/- 31, 30 +/- 5, and 0.6 +/- 0.2 pmol/min, respectively. LBNP increased renal vascular resistance (RVR) by 52% and renal NE overflow by 31%. Renin release increased by 330% (from 64 +/- 12 units/min) and arterial ANG II levels by 119%, without altering the renal ANG II extraction (which was approximately 50%). Renal DA and NPY-LI overflows were unaffected. A "vaso-vagal" reaction in one subject was associated with cessation of renal NE overflow and marked elevations of arterial Epi, renal renin release, and arterial ANG II. Selective unloading of cardiopulmonary baroreceptors by low-level LBNP did not affect RVR, whereas higher levels of LBNP caused renal vasoconstriction probably mediated in part by increased renal sympathetic nerve activity and in part by ANG II.
在10名健康志愿者中，当逐步增加下体负压（LBNP）时，评估了肾血流量、通过去甲肾上腺素（NE）、多巴胺（DA）和神经肽Y样免疫反应性（NPY-LI）的肾溢出量所评估的肾交感神经活动，以及血浆肾素活性和血管紧张素II（ANG II）。肾上腺素（Epi）的分数提取用于评估从动脉血浆中清除的肾儿茶酚胺（约50%）。静息时肾NE、DA和NPY-LI溢出量分别为235±31、30±5和0.6±0.2 pmol/分钟。LBNP使肾血管阻力（RVR）增加52%，肾NE溢出量增加31%。肾素释放增加330%（从64±12单位/分钟），动脉ANG II水平增加119%，而肾ANG II提取未改变（约为50%）。肾DA和NPY-LI溢出量未受影响。一名受试者的“迷走血管”反应与肾NE溢出停止以及动脉Epi、肾素释放和动脉ANG II显著升高有关。低水平LBNP选择性卸载心肺压力感受器对RVR无影响，而较高水平的LBNP导致肾血管收缩，这可能部分由肾交感神经活动增加介导，部分由ANG II介导。
