Flechtner-Mors M, Jenkinson C P, Alt A, Adler G, Ditschuneit H H
Department of Internal Medicine, University of Ulm, Germany.
J Pharmacol Exp Ther. 2002 Apr;301(1):229-33. doi: 10.1124/jpet.301.1.229.
The role of alpha(1)-adrenoceptors in lipid mobilization and blood flow was investigated in situ using microdialysis of subcutaneous adipose tissue in severely obese subjects. The lipolysis rate was assessed by determination of interstitial glycerol concentration. The alpha(1)-adrenoceptor agonist norfenefrine caused an increase in glycerol level in adipose tissue that was similar to that observed with the physiologic alpha(1,2)-beta(1)-adrenoceptor agonist norepinephrine, whereas the alpha(1)-adrenoceptor antagonist urapidil showed no effect on basal lipolysis rate. However, the enhanced glycerol concentration due to norfenefrine and norepinephrine was suppressed in the presence of urapidil. The beta-adrenoceptor antagonist propranolol showed no effect on norfenefrine-stimulated glycerol outflow. Blood flow was assessed using the ethanol escape technique. Perfusion with norfenefrine decreased blood flow, whereas urapidil enhanced blood flow significantly. Despite the increase in blood flow, the basal interstitial glycerol concentration remained unchanged. Although norfenefrine at high concentrations could inhibit the urapidil-induced increase in blood flow, the norfenefrine-induced glycerol output was not affected. These results demonstrate that alpha(1)-adrenoceptors are involved in regulation of lipolysis rate and microcirculation of adipose tissue. However, the observed changes in local blood flow were not related to glycerol output.
利用微透析技术对重度肥胖受试者的皮下脂肪组织进行原位研究，以探讨α(1)-肾上腺素能受体在脂质动员和血流中的作用。通过测定间质甘油浓度来评估脂肪分解率。α(1)-肾上腺素能受体激动剂去甲伪麻黄碱可使脂肪组织中的甘油水平升高，这与生理性α(1,2)-β(1)-肾上腺素能受体激动剂去甲肾上腺素所观察到的情况相似，而α(1)-肾上腺素能受体拮抗剂乌拉地尔对基础脂肪分解率无影响。然而，在乌拉地尔存在的情况下，去甲伪麻黄碱和去甲肾上腺素所致的甘油浓度升高受到抑制。β-肾上腺素能受体拮抗剂普萘洛尔对去甲伪麻黄碱刺激的甘油流出无影响。采用乙醇洗脱技术评估血流。用去甲伪麻黄碱灌注可使血流减少，而乌拉地尔可显著增加血流。尽管血流增加，但基础间质甘油浓度保持不变。虽然高浓度的去甲伪麻黄碱可抑制乌拉地尔诱导的血流增加，但去甲伪麻黄碱诱导的甘油输出不受影响。这些结果表明，α(1)-肾上腺素能受体参与脂肪组织脂肪分解率和微循环的调节。然而，观察到的局部血流变化与甘油输出无关。
