Effects of voluntary ethanol intake on the expression of Ca(2+) /calmodulin-dependent protein kinase IV and on CREB expression and phosphorylation in the rat nucleus accumbens.

To define the molecular basis of alcohol drinking behaviors, the effects of voluntary ethanol intake on the expression of Ca(2+)/calmodulin-dependent protein kinase IV (CaM kinase IV) and on the expression and phosphorylation of cAMP responsive element binding protein (CREB) [corrected] in the nucleus accumbens (NAc), central amygdala, and frontal cortex of rats were investigated. Voluntary ethanol intake significantly decreased the expression of CaM kinase IV and CREB phosphorylation but not of CREB protein levels [corrected], specifically in the shell of NAc. These changes were not observed in the core of NAc, central amygdala and frontal cortex. Mianserin treatment significantly attenuated ethanol intake and antagonized the voluntary ethanol-induced reduction in expression of CaM kinase IV and CREB phosphorylation in the shell of NAc. This is the first evidence to suggest that decreased CaM kinase IV-dependent CREB phosphorylation in the shell region of NAc may play a role in the reward mechanisms of alcohol drinking.