Man P-S, Lawrence C B
Faculty of Life Sciences, University of Manchester, Manchester, UK.
J Neuroendocrinol. 2008 Jan;20(1):128-37. doi: 10.1111/j.1365-2826.2007.01625.x.
Galanin-like peptide (GALP) is a neuropeptide that is thought to act on the galanin receptors GALR1, GALR2 and GALR3. In rats, i.c.v. injection of GALP has dichotomous actions on energy balance, stimulating feeding over the first hour, but reducing food intake and body weight at 24 h, as well as causing an increase in core body temperature. In mice, GALP only induces an anorexic action, and its effects on core body temperature are unknown. One aim of the present study was to determine the effects of GALP on core body temperature in mice. Intracerebroventricular injection of GALP into conscious mice had no effect on feeding over 1 h, but caused a significant reduction in food intake and body weight at 24 h. It also caused an immediate drop in core body temperature, which was followed by an increase in body temperature. To understand these different effects of GALP on energy balance in mice compared to rats, and to determine the involvement of GALR2 and GALR3, immunohistochemistry was performed to localise c-Fos, a marker of cell activation. Intracerebroventricular injection of GALP induced c-Fos expression in the parenchyma surrounding the ventricles, the ventricular ependymal cells and the meninges in mice and rats. GALP also induced c-Fos expression in the supraoptic nucleus, dorsomedial hypothalamic nucleus, lateral hypothalamus and nucleus tractus solitarius in rats but not in mice. Central administration of a GALR2/3 agonist in rats did not induce c-Fos in any of the brain regions that expressed this protein after GALP injection, and had no effect on food intake, body weight and body temperature in rats or mice. These data suggest that GALP induces differential effects on energy balance and brain activity in mice compared to rats, which are unlikely to be due to activation of the GALR2 or GALR3 receptor.
甘丙肽样肽（GALP）是一种神经肽，被认为作用于甘丙肽受体GALR1、GALR2和GALR3。在大鼠中，脑室内注射GALP对能量平衡有二分作用，在最初一小时刺激进食，但在24小时时减少食物摄入量和体重，同时导致核心体温升高。在小鼠中，GALP仅诱导厌食作用，其对核心体温的影响尚不清楚。本研究的一个目的是确定GALP对小鼠核心体温的影响。向清醒小鼠脑室内注射GALP对1小时内的进食没有影响，但在24小时时导致食物摄入量和体重显著降低。它还导致核心体温立即下降，随后体温升高。为了理解与大鼠相比GALP对小鼠能量平衡的这些不同影响，并确定GALR2和GALR3的参与情况，进行了免疫组织化学以定位c-Fos，这是细胞活化的标志物。脑室内注射GALP在小鼠和大鼠的脑室周围实质、脑室室管膜细胞和脑膜中诱导c-Fos表达。GALP还在大鼠的视上核、下丘脑背内侧核、下丘脑外侧和孤束核中诱导c-Fos表达，但在小鼠中未诱导。在大鼠中脑内给予GALR2/3激动剂在GALP注射后未在表达该蛋白的任何脑区诱导c-Fos，并且对大鼠或小鼠的食物摄入量、体重和体温没有影响。这些数据表明，与大鼠相比，GALP对小鼠的能量平衡和脑活动诱导不同的影响，这不太可能是由于GALR2或GALR3受体的激活。
