Role of monoamine oxidase A and B in the deamination of newly-formed dopamine in the rat kidney
The present study has examined the effects of two selective inhibitors of monoamine oxidase (MAO) type A and B, respectively Ro 41-1049 and Ro 19-6327, on the deamination of newly-synthesized dopamine in kidney slices incubated with exogenous L-DOPA (50 and 100μmol/1). Ro 41-1049 (50, 100 and 250 nmol/l) was found to produce a concentration-dependent increase of newly-formed dopamine (36–56% increase) and reduced DOPAC formation (45–86% reduction). Ro 19-6327 (50, 100 and 250 nmol/1), was found not to affect the accumulation of newly-formed dopamine at 50μmol/1 L-DOPA in the medium, but significantly reduced the formation of DOPAC. At the concentration of 100 μmol/1 of L-DOPA, Ro 19-6327 (100 and 250 nmol/1) significantly increased (by 32% and 132%, respectively), the dopamine tissue levels in kidney slices and decreased DOPAC formation. It is concluded that both MAO-A and MAO-B are important in the metabolism of newly-formed dopamine in kidney slices incubated with exogenous L-DOPA.
KeywordsMonoamine Oxidase Atrial Natriuretic Peptide Tubular Epithelial Cell Krebs Solution Copper Sulphate
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