Evidence for an extraneuronal location of monoamine oxidase in renal tissues

Naunyn Schmiedebergs Arch Pharmacol. 1990 May;341(5):411-3. doi: 10.1007/BF00176332.


(1) Homogenates of renal cortex and renal medulla of control and 6-hydroxydopamine-denervated cat kidneys were prepared. (2) Monoamine oxidase (MAO) activity was determined with [3H]-5-hydroxytryptamine [( 3H]-5HT) and [14C]-beta-phenylethylamine [( 14C]-beta-PEA) as preferential substrates for MAO-A and MAO-B, respectively. (3) The endogenous dopamine and noradrenaline tissue contents of control and chemically-denervated kidneys were compared with the MAO activities. (4) The results show that a 70% depletion of monoamine content by chemical denervation resulted only in a 23% reduction of MAO-A activity in the renal cortex, whereas MAO-B was unaffected either in the cortical or the medullary zones; in the renal medulla MAO-A activity was not changed by denervation. Most of the MAO activity in the cat kidney is of the B type (74%) and is located in the renal cortex.

MeSH terms

  • Animals
  • Cats
  • Dopamine / metabolism
  • Extracellular Space / enzymology*
  • Isoenzymes / metabolism*
  • Kidney / enzymology*
  • Kidney / innervation
  • Kidney Cortex / enzymology
  • Kidney Medulla / enzymology
  • Monoamine Oxidase / metabolism*
  • Neurons / enzymology*
  • Norepinephrine / metabolism


  • Isoenzymes
  • Monoamine Oxidase
  • Dopamine
  • Norepinephrine