Modulation of multiple ethanol withdrawal-induced anxiety-like behavior by CRF and CRF 1 receptors

Abstract

Previous work demonstrated that rats subjected to multiple withdrawals from chronic ethanol exhibit a sensitization of anxiety-like behavior compared to animals withdrawn from treatment with an equal but continuous amount of ethanol. This study sought to examine whether corticotropin-releasing factor (CRF) could modulate this ethanol-withdrawal-induced anxiety-like behavior. Initially, rats were administered with CRF (1 μg) or vehicle intraventricularly on two occasions 5 days apart while on control diet (CD) followed by exposure to 7% ethanol diet (ED) for 5 days, with social interaction assessed 5 h into withdrawal. Social interaction was significantly reduced in the CRF-treated animals compared to vehicle-treated rats and vehicle- and CRF-treated rats maintained on CD, indicative that CRF given before ethanol exposure was capable of inducing an adaptive change that sensitized withdrawal-induced anxiety-like behavior. Next, the CRF 1 receptor antagonist CRA1000 (3 mg/kg, systemically), the CRF 2 receptor antagonist antisauvagine-30 (20 μg intraventricularly), or vehicle was injected 4 h after the ethanol was removed following the first and second cycles of chronic ethanol exposure and the effect on the multiple-withdrawal-induced anxiety-like behavior determined after the third withdrawal cycle. The CRF 1 receptor antagonist blocked the reduced social interaction behavior, whereas the CRF 2 receptor antagonist was without effect. Similar pretreatment with another CRF 1 receptor antagonist CP-154,526 (10 mg/kg systemically) during the first and second withdrawals also counteracted anxiety-like behavior. These findings indicate that the CRF system and CRF 1 receptors play key roles in the adaptive change responsible for the anxiety-like behavior induced by repeated withdrawals from chronic ethanol.