Young J B, Daly P A, Uemura K, Chaouloff F
Department of Medicine, Northwestern University Medical School, Chicago, Illinois 60611.
Am J Physiol. 1994 Nov;267(5 Pt 2):R1320-8. doi: 10.1152/ajpregu.1994.267.5.R1320.
The level of sympathetic nervous system (SNS) activity in obesity is controversial, with reports claiming either increased or decreased SNS activity. The following studies examined SNS activity in a dietary form of obesity, ingestion of a lard-enriched diet for 4 wk. Plasma norepinephrine (NE) levels were 61% higher in rats fed the lard-enriched diet than in chow-fed controls at 20 degrees C (200 +/- 24 pg/ml vs. 124 +/- 6, P < 0.005) and remained elevated after 1 h of cold exposure (4 degrees C). [3H]NE turnover was markedly increased in heart, but not in interscapular brown adipose tissue (IBAT), kidney, liver, skeletal muscle, or spleen of rats fed the high-fat diet. By contrast, ingestion of a diet similarly enriched with sucrose raised rates of [3H]NE turnover in IBAT as well as in heart. Thus chronic ingestion of a lard-enriched diet induces region-specific stimulation of SNS activity that is greater in heart than in IBAT. Whereas the absence of an SNS response to lard in IBAT may contribute to weight gain in these animals, activation of cardiac sympathetic nerves may promote development of hypertension in this model of obesity.
肥胖状态下交感神经系统（SNS）的活动水平存在争议，有报告称SNS活动增加或减少。以下研究检测了饮食性肥胖（摄入富含猪油的饮食4周）时的SNS活动。在20℃时，喂食富含猪油饮食的大鼠血浆去甲肾上腺素（NE）水平比喂食普通饲料的对照大鼠高61%（200±24 pg/ml对124±6，P<0.005），且在冷暴露（4℃）1小时后仍保持升高。喂食高脂饮食的大鼠心脏中[3H]NE周转率显著增加，但肩胛间棕色脂肪组织（IBAT）、肾脏、肝脏、骨骼肌或脾脏中未增加。相比之下，摄入同样富含蔗糖的饮食会使IBAT以及心脏中的[3H]NE周转率升高。因此，长期摄入富含猪油的饮食会引起SNS活动的区域特异性刺激，心脏中的刺激程度大于IBAT。虽然IBAT对猪油缺乏SNS反应可能导致这些动物体重增加，但在此肥胖模型中，心脏交感神经的激活可能会促进高血压的发展。
