Ng A V, Callister R, Johnson D G, Seals D R
Department of Exercise and Sport Sciences, School of Health Related Professions and College of Medicine, University of Arizona Health Sciences Center, Tucson.
Hypertension. 1993 Apr;21(4):498-503. doi: 10.1161/01.hyp.21.4.498.
Muscle sympathetic nerve activity at rest increases with age in humans. The respective influences of the aging process per se and gender on this increase and whether age and gender effects on muscle sympathetic nerve activity can be identified with plasma norepinephrine concentrations, however, have not been established. To examine these issues, nine young women (aged 24 +/- 1 years; mean +/- SEM), eight young men (aged 26 +/- 1 years), seven older women (aged 63 +/- 1 years), and eight older men (aged 66 +/- 1 years) were studied. All were healthy, normotensive (blood pressure < 140/90 mm Hg), nonobese (< 20% above ideal weight), unmedicated, nonsmokers engaged in minimal to recreational levels of chronic physical activity. Arterial blood pressure (manual sphygmomanometry, brachial artery), heart rate, muscle sympathetic nerve activity (peroneal microneurography), and antecubital venous plasma norepinephrine concentrations (radioenzymatic assay) were determined during quiet supine resting conditions. Body weight was higher in men, but there were no age-related differences, whereas estimated body fat (sum of skinfolds) was higher in women and in the older groups (p < 0.05). Estimated daily energy expenditure, arterial blood pressure, and heart rate were not different among the groups. Both muscle sympathetic nerve activity burst frequency and burst incidence at rest were progressively higher in the young women, young men, older women, and older men (10 +/- 1 versus 18 +/- 2 versus 25 +/- 3 versus 39 +/- 5 bursts/min and 16 +/- 1 versus 30 +/- 4 versus 40 +/- 3 versus 61 +/- 6 bursts/100 heartbeats, respectively; all p < 0.05 versus each other).(ABSTRACT TRUNCATED AT 250 WORDS)
在人类中，静息状态下的肌肉交感神经活动随年龄增长而增加。然而，衰老过程本身和性别对这种增加的各自影响，以及年龄和性别对肌肉交感神经活动的影响是否可以通过血浆去甲肾上腺素浓度来识别，尚未明确。为了研究这些问题，对9名年轻女性（年龄24±1岁；平均值±标准误）、8名年轻男性（年龄26±1岁）、7名老年女性（年龄63±1岁）和8名老年男性（年龄66±1岁）进行了研究。所有受试者均健康、血压正常（血压<140/90 mmHg）、非肥胖（比理想体重高<20%）、未用药、不吸烟，从事最少到适度的休闲水平的慢性体育活动。在安静仰卧休息状态下，测定动脉血压（手动血压计，肱动脉）、心率、肌肉交感神经活动（腓神经微神经图）和肘前静脉血浆去甲肾上腺素浓度（放射酶法）。男性体重较高，但无年龄相关差异，而估计体脂（皮褶厚度总和）在女性和老年组中较高（p<0.05）。各组间估计的每日能量消耗、动脉血压和心率无差异。年轻女性、年轻男性、老年女性和老年男性静息时的肌肉交感神经活动爆发频率和爆发发生率均逐渐升高（分别为10±1次/分钟对18±2次/分钟对25±3次/分钟对39±5次/分钟和16±1次/100次心跳对30±4次/100次心跳对40±3次/100次心跳对61±6次/100次心跳；相互比较时p均<0.05）。（摘要截短于250字）
