Lawrence Catherine B, Williams Torrie, Luckman Simon M
School of Biological Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom.
Endocrinology. 2003 Sep;144(9):3977-84. doi: 10.1210/en.2003-0391.
Like galanin, the 60-amino-acid peptide, galanin-like peptide (GALP), has orexigenic actions, demonstrated by an acute increase in feeding after central injection in rodents. However, in contrast to galanin, GALP causes a prolonged rise in core body temperature and a reduction in body weight over 24 h. In an attempt to identify potential explanations for the observed differences between GALP and galanin, this study examined which brain areas were activated by these peptides. Intracerebroventricular injection of GALP into conscious rats significantly stimulated feeding over 0-1 h, increased core body temperature, but reduced body weight gain over 24 h. Immunohistochemistry to detect c-fos demonstrated that intracerebroventricular injection of GALP or galanin activated several brain regions in common, including the dorsomedial nucleus of the hypothalamus, lateral hypothalamus, and nucleus tractus solitarius of the brainstem. However, GALP also induced c-fos expression in the periventricular hypothalamic region and supraoptic hypothalamic nucleus. Cell activation induced by GALP in the supraoptic hypothalamic nucleus and nucleus tractus solitarius was dependent on food intake but independent of food consumption in all other brain regions. Double immunohistochemistry indicated that small cells expressing c-fos in the periventricular hypothalamic region after GALP were astrocytes and not microglia.
与甘丙肽（一种由60个氨基酸组成的肽）一样，甘丙肽样肽（GALP）也具有促食欲作用，这在向啮齿动物中枢注射后进食量急性增加中得到了证实。然而，与甘丙肽不同的是，GALP会导致核心体温长时间升高，并在24小时内体重下降。为了试图找出GALP和甘丙肽之间观察到的差异的潜在解释，本研究检测了这些肽激活哪些脑区。向清醒大鼠脑室内注射GALP在0至1小时内显著刺激进食，升高核心体温，但在24小时内减少体重增加。检测c-fos的免疫组织化学表明，向脑室内注射GALP或甘丙肽共同激活了几个脑区，包括下丘脑背内侧核、下丘脑外侧区和脑干孤束核。然而，GALP还诱导了室旁下丘脑区和视上核中的c-fos表达。GALP在视上核和孤束核中诱导的细胞激活依赖于食物摄入，但在所有其他脑区中与食物消耗无关。双重免疫组织化学表明，GALP注射后在室旁下丘脑区表达c-fos的小细胞是星形胶质细胞而非小胶质细胞。
