Effect of chlorpromazine, imipramine and lithium on MAO-A and MAO-B activity in rat brain mitochondria

941-944Drugs with efficacy in psychiatric disorders affect the function of central neurotransmitter amines, which are inactivated primarily by monoamine oxidase (MAO). Effect of these drugs on the two types of MAO (MAO-A and MAO-B) has been studied in rat brain. The result showed that chlorpromazine (CPZ) and imipramine (IMI) at concentrations of 1×10-2 , 5×10-3 and 2.5×10-3 M inhibited rat brain mitochondrial MAO-A activity in vitro by 82, 50, 39 and 86, 74, 38%, respectively. CPZ at concentrations of 5×10-3, 2.5×10-3 ,1×10-3 M inhibited rat brain mitochondrial MAO-B activity in vitro by 83, 55,39 %, respectively, while IMI at concentrations of 5×10-4, 2.5×10-4, 1×10-4 M inhibited the in vitro enzyme activity by 43, 35, 21%, respectively. Lithium at concentration of 5×10-3M could not either inhibit MAO-A or MAO-B in the mitochondrial fraction of rat brain