Blockade of biogenic amine synthesis: its effect on the responses to leptazol and dexamphetamine in rats.

1. The convulsive effects of leptazol in the rat are potentiated by prior treatment with dexamphetamine.2. An intact dopamine synthesis is necessary for the potentiation of the convulsive action of leptazol.3. An intact noradrenaline synthesis is not necessary for this action of amphetamine, as long as the dopamine synthesis is intact.4. An intact 5-hydroxytryptamine synthesis is not necessary for the potentiation to be shown.5. Blockade of either noradrenaline, dopamine or 5-hydroxytryptamine synthesis has no direct effect on leptazol convulsions.6. It is possible that it is an intact 3-4 dihydroxyphenylalanine (dopa) synthesis rather than an intact dopamine synthesis that is involved.