Serotonin(2C) receptors and serotonin(2C) receptor-mediated phosphoinositide hydrolysis in the brain of alcohol-preferring and alcohol-nonpreferring rats

To examine the role of serotonin(2C) (5HT(2C)) receptors in alcohol drinking behavior, the binding indices of 5HT(2C) receptors were determined in various brain regions of alcohol-preferring (P) and alcohol-nonpreferring (NP) rats. 5HT(2C) receptor-mediated phosphoinositide hydrolysis in the choroid plexus of P and NP rats was also determined. It was observed that the densities of 5HT(2C) receptors are significantly higher in the hippocampus, the amygdala, and the choroid plexus, but not in the cortex of P rats compared with NP rats. The K-d values of [H-3]mesulergine binding to 5HT(2C) receptors were not different in these brain regions of P rats compared with tip rats. It was also observed that 5HT-stimulated [H-3]inositol 1-phosphate formation was significantly higher in the choroid plexus of P rats compared with NP rats. The results of this study indicate that the numbers of 5HT(2C) receptors are higher in the hippocampus, the amygdala, and the choroid plexus, and that 5HT(2C) receptor-mediated phosphoinositide hydrolysis is more elevated in the choroid plexus of P rats compared with NP rats. Thus, it seems from these results that increased 5HT(2C) receptors may be involved in the genetic vulnerability to alcohol drinking behavior.