Studies on the subcellular localization of monoamine oxidase types A and B and its importance for the deamination of dopamine in the rat brain

摘要: Abstract The distribution of the MAO-forms A and B between intra- extrasynaptosomal rat brain mitochondria was studied with aid their known substrate inhibitor specificities. activities selective substrates serotonin, PEA benzylamine indicated that intrasynaptosomal have about a 3.4-fold higher MAO A:MAO ratio than mitochondria. However, found to be for only at low concentrations (such as 5 × 10 −6 M), whereas −3 M) it both forms MAO. different ratios two enzyme in mitochondrial populations were confirmed when inhibitors clorgyline deprenyl used dopamine or M PEA. With these amines, A: 3–4.5 times In particular, activity measured intact synaptosomes, deamination being preceded by specific uptake into particles, sensitivities clearly showed almost exclusively attributable A-form enzyme. Thus, terminals dopaminergic neurones an even more pronounced enrichment obtained osmotic lysis total synaptosomal preparation. It also inhibitory effect on nerve endings IC 50 values range −5 −4 M. These results are discussed terms possible physiological significancies properties