Dissociation of locomotor activation and suppression of food intake induced by CRF in CRFR1-deficient mice

Corticotropin-releasing factor (CRF) systems are involved in locomotor and feeding behaviors. Two distinct CRF receptor subtypes, CRFR1 and CRFR2, are thought to mediate CRF actions in the central nervous system. However, the role for each receptor in locomotor activity and feeding remains to be det ermined. Using CRFR1 null mutant mice, the present study examined the funct ional significance of this receptor in ambulation and feeding. CRF treatmen t of wild-type mice resulted in increased levels of locomotion whereas no c hange was observed in CRFR1-deficient mice as compared to vehicle-treated m utant mice. In contrast, CRF decreased food-water intake in both wild type and CRFR1-deficient mice equally. These results support an important role f or CRFR1 in mediating CRF-induced locomotor activation, whereas other recep tor subtypes, likely CRFR2, may mediate the appetite-suppressing effects of CRF-like peptides.