Effect of oxidized indoles on monoamine oxidase activity in the rat brain mitochondria

: There is increasing evidence, that oxidized indoles, isatin, 5-hydroxyoxindole, 2-oxindole, play important regulatory functions in the brain. Isatin and 5-hydroxyoxindole share some common regulatory properties in cell cultures (Cane et al., 2000, BBRC, 276, 379), however, their effects on brain mitochondrial monoamine oxidases, a potential target for their action, have not been compared yet. Isatin acted as a rather selective monoamine oxidase B inhibitor, whereas 5-hydroxyoxindole was more selective monoamine oxidase A inhibitor, but it was less potent than that of 5-hydroxyisatin, a synthetic analogue of isatin.