Evidence for an extraneuronal location of monoamine oxidase in renal tissues

• Published in: Naunyn-Schmiedeberg's archives of pharmacology 1990-05, Vol.341 (5), p.411-413
• Main Authors: CARAMONA, M. M, SOARES-DA-SILVA, P
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Cats; Dopamine - metabolism; Extracellular Space - enzymology; Fundamental and applied biological sciences. Psychology; Isoenzymes - metabolism; kidney; Kidney - enzymology; Kidney - innervation; Kidney Cortex - enzymology; Kidney Medulla - enzymology; Monoamine Oxidase - metabolism; Neurons - enzymology; Norepinephrine - metabolism; Vertebrates: urinary system
• ISSN: 0028-1298; 1432-1912
• 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.