The effects of corticoptropin-releasing factor and the urocortins on striatal dopamine release induced by electrical stimulation-an in vitro superfusion study.

The members of the CRF peptide family, corticotropin-releasing factor (CRF), urocortin I (Ucn I), urocortin II (Ucn II) and urocortin III (Ucn III) coordinate endocrine and behavioral responses to stress. CRF has also been demonstrated to stimulate dopamine (DA) synthesis. In our study, a superfusion system was used to investigate the effects of this peptide family on striatal DA release following electrical stimulation. The involvement of the CRF receptors was studied by pretreatment of rat striatal slices with selective CRF antagonists. CRF and Ucn I increased the release of [(3)H]DA while Ucn II and Ucn III were ineffective. The CRFR1 antagonist antalarmin inhibited the [(3)H]DA release induced by electrical stimulation and enhanced by CRF and Ucn I. The CRFR2 antagonist astressin-2B was ineffective. These results suggest that CRF and Ucn I mediate DA release through the activation of CRFR1. Ucn II and Ucn III are not involved in this process.