SEMICARBAZIDE-SENSITIVE AMINE OXIDASE AND MONOAMINE-OXIDASE IN RAT-BRAIN MICROVESSELS, MENINGES, RETINA AND EYE SCLERA

Monoamine oxidase-A and -B (MAO-A and MAO-B) and semicarbazide-sensiti ve amine oxidase (SSAO) activities were assessed in several rat micro- vascular tissues and eyes using selective substrates and inhibitors. I n rat brain microvessels both MAO-A and MAO-B activities are relativel y high and the levels of the two types of MAO's are comparable. Retina possesses a similar ratio of MAO-A and B but the activities are much lower. Eye sclera and meninges exhibit mainly MAO-A and MAO-B, respect ively. Aorta is the only tissue where SSAO is the predominant amine ox idase. Relatively low, but significant amounts of SSAO were also detec ted in brain microvessels, meninges, retina and eye sclera. Methylamin e was observed to be deaminated by SSAO from different tissues. The ph ysiological and toxicological implications of amine oxidases in these tissues are discussed.