Stimulant and anxiogenic effects of corticotropin releasing factor.

Corticotropin releasing factor (CRF) injected intracerebroventricularly in doses from 15-150 pmoles (10-1000 nanograms) produced a prolonged locomotor activation in rats previously habituated to a test cage environment. This CRF activation persisted following hypophysectomy, opiate-receptor blockade and low dose dopamine receptor blockade suggesting a unique mechanism of action. In aversive, stressful situations such as a novel open field test and an operant conflict test CRF produced behavioral changes consistent with increased "emotionality." In the rat conflict test, this "anxiogenic" effect of CRF could be reversed by low doses of the anti-anxiety drug chlordiazepoxide. These results suggest that CRF liberated directly into the central nervous system may have an endocoid action important for mobilizing behavioral responses to stress.