Effect of heavy metal salts on rat brain and liver monoamine oxidase activity.

In experiments on male Wistar albino rats was studied the effect of Co, Cd, Ni, Zn, Hg and Pb on the activity of rat liver and brain monoamine oxidase (MAO) using tyramine, serotonin and beta-phenylethylamine as substrates. It was established that ZnSO4 significantly increased the activity of liver MAO with all substrates studied, Co(NO3)2 increased it when tyramine and serotonin were used while NiSO4 increased MAO activity when serotonin was used as a substrate. All metals studied did not change MAO activity in the brain except for Co(NO3)2 which significantly increased the enzyme activity with tyramine as a substrate. The activity of liver MAO proved to be more susceptible to heavy metals after subchronic exposure than that in the whole brain.