Effect of chronic lithium treatment on the turnover of α2-adrenoceptors after chemical inactivation in rats

One of the most effective psychotherapeutic agents in the treatment of bipolar disease is lithium. Chronic lithium treatment affects some signal transduction mechanisms such as cAMP, cGMP, inositol 1,4,5 P3, Gi protein, protein kinase C and can also modify gene expression in rat brain. In a previous study, we observed a greater inhibitory effect of lithium on cAMP production after blockade of α2-adrenoceptors in rat cerebral cortex. Here we examine the influence of chronic lithium treatment on turnover of α2-adrenoceptors after their inactivation by N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ) in rat cerebral cortex. After treatment with lithium for 10 days (120 mg/kg/day, i.p.), there was a significant increase in the appearance and disappearance rate constants of these adrenoceptors and a significant reduction of their half-life. These results suggest that chronic lithium administration alters the α2-adrenoceptor turnover in rat brain.