Three experiments were conducted to test the role of the brain corticotropin- releasing factor (CRF) system in mediating stress-induced behaviors and regulating food intake by using CRF receptor antagonists (a-helical CRF9_41 and astressin) in chicks. In Experiment 1, birds were intracerebroventricularly (i.c.v.) injected with 10 /ug of a-helical CRF9-41 or saline and placed individually into an acrylic glass recording chamber 20 min postinjection and automatically monitored by an audio analysis application for 60 seconds. The number of distress vocalizations (DVs) induced by isolation was significantly suppressed by a-helical CRF9-41 compared to the control group. Chicks were similarly treated with astressin in doses of 0, and 10 pg in Experiment 2, but no significant difference of DVs was observed. In Experiment 3, after a 3h fast, birds were i.c.v. injected with either saline, 0.1 µg of CRF, 0.1 µg of CRF + 5 µg of a-helical CRF9-41 or 0.1 µg of CRF + 10 µg of a-helical CRF9-41 and food intake was measured for 2h. CRF suppressed food intake and a-helical CRF9-41 partially blocked such effect. The results suggested that 1) a-helical CRF9-41 attenuated the behavior changes induced by isolation and exogenous CRF; 2) CRF receptors in avian species may be somewhat different from that in mammals.
All Science Journal Classification (ASJC) codes
- Animal Science and Zoology