Kobayashi A, Osaka T, Namba Y, Inoue S, Lee T H, Kimura S
Showa Women's University Graduate School, Tokyo 154, Japan.
Am J Physiol. 1998 Jul;275(1):R92-8. doi: 10.1152/ajpregu.1998.275.1.R92.
Subcutaneous administration of capsaicin (5 mg/kg) immediately increased the temperature of the tail skin (Tsk) for 2 h in urethan-anesthetized rats, suggesting an increase in heat loss. O2 consumption, an index of heat production, also immediately increased after the capsaicin injection, and this increase lasted for >10 h. Colonic temperature (Tco) decreased within 1 h after the injection, and this decrease was followed by a long-lasting hyperthermic period. Adrenal demedullation largely attenuated the capsaicin-induced increase in O2 consumption, and sympathetic denervation of the interscapular brown adipose tissue partly attenuated the increase in O2 consumption. However, capsaicin-induced heat loss was normal in these rats. In rats with cutaneous vasodilation maximized by warming and administration of hexamethonium, capsaicin did not further increase Tsk but normally induced heat production, and Tco gradually rose without a hypothermic period. Thus capsaicin simultaneously increased heat loss and heat production, and inhibition of one response did not affect the other. These findings suggest that capsaicin simultaneously activates independent networks for heat loss and heat production.
在乌拉坦麻醉的大鼠中，皮下注射辣椒素（5毫克/千克）可使尾皮温度（Tsk）立即升高2小时，这表明散热增加。作为产热指标的耗氧量在注射辣椒素后也立即增加，且这种增加持续超过10小时。注射后1小时内结肠温度（Tco）下降，随后是一个持续时间较长的体温过高期。肾上腺髓质切除在很大程度上减弱了辣椒素诱导的耗氧量增加，肩胛间棕色脂肪组织的交感神经去支配部分减弱了耗氧量的增加。然而，这些大鼠中辣椒素诱导的散热是正常的。在通过升温及给予六甲铵使皮肤血管舒张最大化的大鼠中，辣椒素并未进一步升高Tsk，但正常诱导产热，且Tco逐渐升高而无体温过低期。因此，辣椒素同时增加了散热和产热，抑制一种反应并不影响另一种反应。这些发现表明，辣椒素同时激活了独立的散热和产热网络。
