Alcoholism is a devastating condition that represents a progression from initial alcohol use to dependence. Although most individuals are capable of consuming alcohol in a limited fashion, the development of alcohol dependence in a subset of individuals is often associated with negative emotional states (including anxiety and depression).
Since the alleviation of this negative motivational state via excessive alcohol consumption often becomes a central goal of alcoholics, the transition from initial use to dependence is postulated to be associated with a transition from positive to negative reinforcement mechanisms.
Vasopressin is a neuropeptide known to potentiate the effects of CRF on the HPA axis, and emerging evidence also suggests a role for centrally located vasopressin acting on V1b receptors in the regulation of stress- and anxiety-like behaviors in rodents.
The present study determined state-dependent alterations in vasopressin/V1bR signaling in an animal model of ethanol dependence.
The V1bR antagonist SSR149415 dose-dependently reduced excessive levels of ethanol self-administration observed in dependent animals without affecting the limited levels of ethanol drinking in non-dependent animals.
Ethanol self-administration reduced V1b receptor levels in the basolateral amygdala of non-dependent animals, a neuroadaptation that could theoretically facilitate the positive reinforcing effects of alcohol.
In contrast, V1bR levels were seemingly restored in ethanol-dependent rats, a switch that may in part underlie a transition from positive to negative reinforcement mechanisms with dependence.
Together, our data suggest a key role for vasopressin/V1bR signaling in the transition to ethanol dependence.
Request Reprint E-Mail:
