年龄与人体血浆去甲肾上腺素动力学的α-2肾上腺素能调节

Age and alpha-2 adrenergic regulation of plasma norepinephrine kinetics in humans.

作者信息

Featherstone J A, Veith R C, Flatness D, Murburg M M, Villacres E C, Halter J B

出版信息

J Gerontol. 1987 May;42(3):271-6. doi: 10.1093/geronj/42.3.271.

DOI:10.1093/geronj/42.3.271

Abstract

To investigate whether the age-related elevation of plasma norepinephrine (NE) is due to impaired alpha-2 adrenergic inhibition of sympathetic nervous system (SNS) outflow, arterialized plasma NE kinetics were measured before and 120 to 140 min after 1.5 and 5.0 micrograms m/kg oral clonidine in 6 old (57 to 78 years) and 8 young (25 to 39 years) normotensive male volunteers. Baseline plasma NE levels were higher in old compared with young men (M +/- SEM, 355 +/- 58 vs. 197 +/- 22 pg/ml, p less than .02). Clonidine produced significant (p less than .05) dose-related reductions in plasma NE, NE appearance rate, NE clearance, and mean arterial blood pressure (MAP) in both groups. There was no difference between old and young men in response to low dose clonidine. Following the higher dose, both groups had similar suppression of plasma NE (-51 +/- 7% vs. -58 +/- 2%, p greater than .05) and NE appearance (-60 +/- 6% vs. -62 +/- 2%, p greater than .05), but older men had a greater fall in NE clearance (-20 +/- 2% vs. -10 +/- 1%, p less than .003) and MAP (-28 +/- 3% vs. -10 +/- 4%, p less than .006). These findings suggest that sensitivity to alpha-2 receptor-mediated suppression of plasma NE and NE appearance is not diminished in elderly men.

摘要

为研究血浆去甲肾上腺素（NE）随年龄增长而升高是否是由于交感神经系统（SNS）传出神经的α-2肾上腺素能抑制受损，在6名老年（57至78岁）和8名年轻（25至39岁）血压正常的男性志愿者中，测量了口服1.5微克/千克和5.0微克/千克可乐定前以及服药后120至140分钟时的动脉化血浆NE动力学。老年男性的基线血浆NE水平高于年轻男性（M±SEM，355±58对197±22皮克/毫升，p<0.02）。可乐定使两组的血浆NE、NE出现率、NE清除率和平均动脉血压（MAP）均出现显著（p<0.05）的剂量相关降低。低剂量可乐定给药后，老年和年轻男性之间没有差异。高剂量给药后，两组血浆NE（-51±7%对-58±2%，p>0.05）和NE出现率（-60±6%对-62±2%，p>0.05）的抑制程度相似，但老年男性的NE清除率下降幅度更大（-20±2%对-10±1%，p<0.003），MAP下降幅度也更大（-28±3%对-10±4%，p<0.006）。这些发现表明，老年男性对α-2受体介导的血浆NE和NE出现抑制的敏感性并未降低。