The anorexic effect of alpha-melanocyte-stimulating hormone is mediated by corticotrophin-releasing factor in chicks
- 作者：Tetsuya Tachibana ; Daichi Oikawa ; Hirokazu Takahashi ; Tim Boswell ; Mitsuhiro Furuse
- 关键词：Agouti-related protein ; Alpha-melanocyte-stimulating hormone ; Chick ; Corticosterone ; Corticotrophin-releasing factor ; Feeding
- 刊名：Comparative Biochemistry and Physiology - Part A ; Molecular & Integrative Physiology
- 出版年：2007
- 期刊代码：23_10956433
- 类别：abs
- 出版时间：May 2007
- 卷：147
- 期：1
- 页码：173-178
- 文件大小：221 K
摘要
Alpha-melanocyte-stimulating hormone (alpha-MSH) is recognized as an anorexic peptide in the brain of vertebrates, but its mechanism of action has not been identified in birds. Therefore, we investigated whether the anorexic effect of alpha-MSH is mediated by corticotrophin-releasing factor (CRF) in the domestic chick. Firstly, we found that intracerebroventricular (ICV) injection of alpha-MSH dose dependently increased plasma corticosterone (CORT) concentration. This effect was partly attenuated by co-injection of astressin, a CRF receptor antagonist, demonstrating that alpha-MSH stimulated CORT secretion by activating CRF neurons. The alpha-MSH-elicited CORT release was not attenuated by the injection of agouti-related protein, an endogenous melanocortin-4 (MC4) receptor antagonist, suggesting that alpha-MSH stimulated CRF neurons through MC4 receptor-independent pathways. Finally, we found that the anorexic effect of alpha-MSH was partly attenuated by astressin. The present results suggest that the anorexic effect of alpha-MSH in the chick brain is mediated in part by activation of CRF neurons.