Monoamine oxidase in young and adult rat brain capillaries

Capillaries were isolated from young and adult rat brain and the mitochondrial type A and B monoamine oxidase activities in these endothelial cells were determined. Type A activity was observed to be predominant in both young and adult rats and was increased with maturation while type B activity remained unchanged. The predominance of type A MAO in the rat brain capillaries is consistent with that of the rat aorta and heart tissue.