Physiological and behavioural effects of an intracerebroventricular injection of corticotropin releasing hormone in goats

This study investigated the effects of an intracerebroventricular (ICV) injection of corticotropin releasing hormone (CRH) on physiological and behavioural responses in goats. In Experiment 1, saline (control) or saline plus 25 microg of ovine CRH was injected into the third ventricle of castrated male goats. CRH increased plasma cortisol (Cor) levels markedly within 15 min, but had little effect on plasma glucose (Glu). Compared with saline injected goats, CRH decreased the total duration of lying behaviour but increased its frequency, and suppressed rumination and self-grooming. In Experiment 2, the effects of an intravenous (IV) injection of human adrenocorticotropic hormone (ACTH) (1-24) (0.1mg) were examined and an IV injection of saline was used as control. ACTH increased plasma Cor levels markedly, but did not change any behaviour compared with controls. It was concluded that CRH mediated the response of the hypothalamus-pituitary-adrenal (HPA) axis and behaviour following stress in goats, although the CRH-induced behavioural changes were independent of the HPA axis and seemed to be the result of direct action within the central nervous system.