Effect of Repeated Administration of Corticotropin-Releasing Hormone (CRH) in Central Amygdala Nucleus on Feeding Behavior in Adult Male Rats

Background: Corticotrophin-releasing hormone (CRH) is one of the interventional neuropeptides in the hypothalamic-pituitary-adrenal (HPA) axis and one of the important regulatory factors in energy homeostasis. Central amygdala (CeA) is one of the effective factors on feeding behaviors, which has CRH receptors. Previous studies showed that the intracerebroventricular administration of a single dose of CRH had anorectic affect. Therefore, this study investigated the effect of repeated administration of CRH on feeding behavior. Methods: Eighteen male Wistar rat were divided to control, sham and CRH treated groups. CRH (2 µg/kg) was administrated into the central amygdala (CeA) for 7 days. Before measuring the food intake, the injection of the drug and saline were done for related groups. The food consumption was measured for three consecutive hours, after a period of deprivation about 16-18 hours. Findings: Repeated CRH administration significantly increased the food intake at the first hour (P < 0.01) whereas, the food intake decreased compared to control group during the second and third hours which was significant at the third hour (P < 0.05). In addition, repeated administration of CRH in the CeA caused a slight and insignificant increase in total food intake during three-hour consumption compared to control group. Conclusion: Given the downward trend of food intake in consecutive hours, it seems that the CeA nucleus affects food intake likely independent of HPA axis.