REGIONAL BINDING TO CORTICOTROPIN-RELEASING FACTOR RECEPTORS IN BRAINOF RATS EXPOSED TO CHRONIC COCAINE AND COCAINE WITHDRAWAL

Cocaine, as does exposure to other physiological stressors, releases b rain corticotropin releasing factor (CRF), and this release habituates during the course of repeated cocaine administration in animals. Due to the many signs of anxiety and responses to stress that are produced by cocaine withdrawal in humans, the present study was designed to as sess the effects of chronic cocaine and its withdrawal on regional I-1 25-Tyr-oCRF binding to the CRF(1) receptor in brains of male Lewis rat s. Cocaine or saline was intravenously infused for 10 days in a regime n that resembled a self-administration paradigm (1 mg/kg every 12 min for 2 h each day). Tissues were harvested either 15 min after or 10 da ys after the last cocaine infusion, and the brains were sectioned and prepared for CRF(1) receptor autoradiography. Compared with findings i n saline controls, there was a 31% lower level of CRF binding sites in the basolateral nucleus of the amygdala immediately after the last co caine infusion, but not 10 days later. Neuroendocrine and non-neuroend ocrine mechanisms associated with CRF(1) receptors do not appear to co ntribute to long-term withdrawal effects. (C) 1997 Wiley-Liss, Inc.