EFFECTS OF PERIPHERALLY ADMINISTERED CORTICOTROPIN-RELEASING FACTOR (CRF) AND A CRF ANTAGONIST - DOES PERIPHERAL CRF ACTIVITY MEDIATE BEHAVIOR OF GUINEA-PIG PUPS DURING ISOLATION

Guinea pig pups vocalized and ambulated when first isolated in a test cage; at 1 and 24 hr, levels of these behaviors had waned, and pups fr equently exhibited a crouched stance, eye-closing, and piloerection. I njection (SC) of corticotropin-releasing factor (CRF) prior to isolati on diminished the initial vocalization and locomotor responses and ind uced pups to exhibit the crouched stance, eye-closing, and piloerectio n at the beginning of the isolation period. Pretreatment with a CRF-re ceptor antagonist reversed the behavioral effects of CRF. CRF had no e ffect on blood pressure. Thus, SC CRF produced the same behavioral pro file as seen with the passage of time in untreated isolated pups. The behavioral effects appeared to be CRF-receptor-mediated events and wer e not secondary to hypotension. These results support the hypothesis t hat during prolonged isolation, high or sustained peripheral CRF activ ity modulates behavior.