Microinfusion of corticotropin-releasing factor into the nucleus accumbens shell results in increased behavioral arousal and oral motor activity

Corticotropin-releasing factor (CRF) is a 41 amino acid peptide postulated to be involved in integrating the physiological and behavioral responses to stress. The purpose of this experiment was to determine the effects of CRF microinfused into the nucleus accumbens core (AcbC) and shell (AcbSh) subregions. Rats were tested for general motor activity, cage crossings, and rearing following CRF (0, 125, 250, or 500 ng). Behavioral observations were also made to determine the profile of activity caused by CRF infusion into the Acb. CRF in the AcbSh but not the AcbC regions elicited an increase in general motor activity that lasted approximately 2 h. When compared with ventricular injections, CRF in the AcbSh had greater activating effects. The CRF-induced behavioral profile consisted of increases in grooming, sniffing, and oral behavior. Results are discussed as they pertain to the involvement of the AcbSh in stress, motivated behavior, and drug sensitization.