Seydoux J, Benzi R H, Shibata M, Girardier L
Department of Physiology, University of Geneva, Switzerland.
Am J Physiol. 1990 Jul;259(1 Pt 2):R61-9. doi: 10.1152/ajpregu.1990.259.1.R61.
The mechanisms involved in brown adipose tissue (BAT) atrophy in obese rats were investigated. In urethan-anesthetized adult obese (fa/fa) and lean (Fa/?) rats, colonic temperature (Tc), interscapular BAT (IBAT) temperature (TIBAT), and the TIBAT-Tc gradient were measured after microknife cut in the prepontine region and during norepinephrine (NE) infusion. The knife cut tests the neural control of IBAT since it suppresses a tonic inhibition of thermogenesis revealing a sustained reflex stimulation of BAT. The NE infusion tests the metabolic capacity of BAT. In 22 degrees C-acclimated lean rats, the cut induced marked hyperthermia, TIBAT that rose faster than Tc, and a reversed temperature gradient. By contrast, in the obese rat, the cut had practically no effect, and NE infusion caused only slight increases in Tc and TIBAT. In cold-acclimated obese rats, an almost complete response to NE infusion and a partial response to knife cut were observed. After adrenalectomy, the responses were similar in lean and obese rats. An operational model to account for these results and for the deficit in diet-induced thermogenesis in fa/fa rats is proposed.
研究了肥胖大鼠棕色脂肪组织（BAT）萎缩的相关机制。在经乌拉坦麻醉的成年肥胖（fa/fa）和瘦（Fa/?）大鼠中，在脑桥前区域进行微刀切割后以及去甲肾上腺素（NE）输注期间，测量结肠温度（Tc）、肩胛间BAT（IBAT）温度（TIBAT）以及TIBAT-Tc梯度。刀割试验用于测试IBAT的神经控制，因为它抑制了对产热的紧张性抑制，揭示了对BAT的持续反射性刺激。NE输注试验用于测试BAT的代谢能力。在适应22摄氏度环境的瘦大鼠中，切割引起明显的体温过高，TIBAT升高速度快于Tc，且温度梯度反转。相比之下，在肥胖大鼠中，切割几乎没有影响，NE输注仅使Tc和TIBAT略有升高。在冷适应的肥胖大鼠中，观察到对NE输注几乎完全的反应以及对刀割的部分反应。肾上腺切除术后，瘦大鼠和肥胖大鼠的反应相似。提出了一个操作模型来解释这些结果以及fa/fa大鼠饮食诱导产热的缺陷。
