Effect of inhibitors of monoamine oxidase on various enzymes and on the storage of monoamines

The potentiation of the anti akinetic effect after L-dopa treatment by an inhibitor of MAO-B, Deprenil

The potentiation of the anti akinetic effect after L-Dopa treatment by an inhibitor of monoamine oxidase (MAO) "B", Deprenil, has been demonstrated in parkinsonian patients with or without previous L-Dopa theapy. Application of the drug has been performed orally, intravenously and intramuscularly. Excellent kinetic effects resulted when combined with Madopar. The combined treatment with L-Dopa was highly effective when applicated i.v. or i.m. Deprenil is an inhibitor of MAO-B and is characterized by less frequent side effects. These are predominantly involuntary movements and confusion, which can be eliminated by lowering the dosage of Deprenil. A daily rhythm of MAO could be demonstrated in several areas of human brains as well as in a control group as in parkinsonian patients with or without L-Dopa therapy. Maximal activity of MAO occurs between noon and 6p.m. The clinical and biochemical data are discussed regarding the off-phenomenons as Deprenil is an excellent drug for preventing these.

Interaction between histamine and monoamine oxidase inhibitors

The monoamine oxidase inhibitors tranylcypromine, nialamide and iproniazid potentiated the actions of histamine on the blood pressure of the cat and on the tracheo-bronchial muscle of the guinea-pig. These findings may have relevance to side-effects of treatment with monoamine oxidase inhibitors.

MODIFICATION OF THE HYPOGLYCAEMIC RESPONSE TO TOLBUTAMIDE AND INSULIN BY MEBANAZINE--AN INHIBITOR OF MONOAMINE OXIDASE

Following reports of clinical changes in the carbohydrate metabolism of diabetic patients receiving mebanazine, possible interactions between mebanazine, adrenaline, tolbutamide and insulin have been studied in rats. Mebanazine had no activity on blood sugar levels and was found to have no effect on the metabolic actions of injected adrenaline. In acute experiments, mebanazine appeared to reduce the net hypoglycaemic action of tolbutamide but had no effect on the response to insulin. In chronic experiments, mebanazine pre-treatment led to a significant potentiation of the hypoglycaemic responses both to tolbutamide and insulin. The possible mechanisms of action and the clinical implications are discussed.