Synthesis and metabolism of dopamine in the kidney. Effects of sodium chloride, monoamine oxidase inhibitors and alpha-human atrial natriuretic peptide.
The synthesis of dopamine (DA) and the extent of its deamination to dihydroxyphenylacetic acid (DOPAC) in rat kidney slices loaded with L-DOPA, under in vitro conditions, has been studied. Inhibition of MAO-A increased the accumulation of newly-formed DA and reduced DOPAC formation; by contrast, the inhibition of monoamine oxidase, MAO-B, only resulted in a decrease in DOPAC formation. Raising the sodium chloride concentration in the incubation medium increases DA formation and reduces DOPAC accumulation. The addition of alpha-human atrial natriuretic peptide (alpha-hANP; 3.3 and 330 nmol/L) to the incubation medium decreases DA formation; this effect was potentiated by the cGMP phosphodiesterase inhibitor M&B 22,948 and antagonized by a raise in the sodium chloride concentration to 157 mmol/L.
Soares-da-Silva
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Laboratório de Farmacologia, Faculdade de Medicina, Porto, Portugal.
Fernandes
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MH
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D046508:Culture Techniques; D003641:Deamination; D004298:Dopamine / Q000096:biosynthesis / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology*
D008996:Monoamine Oxidase Inhibitors; D012965:Sodium Chloride; D009320:Atrial Natriuretic Factor; D004298:Dopamine