Scott Victoria, McDade Donna M, Luckman Simon M
Faculty of Life Science, University of Manchester, Stopford Building, Oxford Road, Manchester, M13 9PT, UK.
Physiol Behav. 2007 Jan 30;90(1):180-5. doi: 10.1016/j.physbeh.2006.09.026. Epub 2006 Oct 31.
Ghrelin, the endogenous ligand for the growth hormone secretagogue (GHS) receptor, stimulates feeding and increases body weight. Systemic ghrelin administration induces the immediate-early gene protein product, c-Fos, in the arcuate nucleus of the hypothalamus (ARC) of satiated rats and this increase is potentiated in fasted rats. The aim of this study was to determine whether potentiation was seen in fasted animals after intracerebroventricular (i.c.v) administration of ghrelin and to identify the hypothalamic nuclei activated by this peptide. In addition we investigated if allowing fasted animals to re-feed for 1 h prior to i.c.v. ghrelin injection affected the c-Fos response. Using c-Fos immunocytochemistry, we demonstrated that i.c.v. ghrelin activated several hypothalamic nuclei, including the ARC, paraventricular nucleus (PVH) and the lateral hypothalamus (LH). The c-Fos response was greater in fasted animals compared with satiated animals. Fasted rats allowed access to food for 1 h prior to central ghrelin administration showed an attenuated response in the ARC, similar to the response seen in fed animals. However, the response in the LH (including in the orexin neurons) was further potentiated. The latter may reflect a connection between the hypothalamus and regions of the brain responding to the reward value of the meal.
胃饥饿素是生长激素促分泌素（GHS）受体的内源性配体，可刺激进食并增加体重。对饱腹大鼠全身注射胃饥饿素可在下丘脑弓状核（ARC）诱导即刻早期基因蛋白产物c-Fos，而禁食大鼠的这种增加更为明显。本研究的目的是确定脑室注射（i.c.v.）胃饥饿素后禁食动物是否会出现增强效应，并确定被该肽激活的下丘脑核团。此外，我们还研究了在i.c.v.注射胃饥饿素前让禁食动物重新进食1小时是否会影响c-Fos反应。通过c-Fos免疫细胞化学方法，我们证明i.c.v.注射胃饥饿素可激活多个下丘脑核团，包括ARC、室旁核（PVH）和下丘脑外侧区（LH）。与饱腹动物相比，禁食动物的c-Fos反应更强。在中枢注射胃饥饿素前允许禁食大鼠进食1小时，ARC的反应减弱，类似于进食动物的反应。然而，LH（包括食欲素神经元）的反应进一步增强。后者可能反映了下丘脑与大脑中对食物奖励价值有反应的区域之间的联系。
