Type A and B monoamine oxidase in glial cells in long-term culture

Monoamine oxidase (MAO) in astroglial primary cultures increased during cell development. The enzyme activity towards type B substrate was further enhanced in cultures treated with 0.25 mM dibutyl cyclic AMP (dBcAMP), although dBcAMP (1 mM) does not effect MAO activity in vitro. It has been estimated that the dBcAMP treated cultures contain 70% type A and 30% type B MAO, while in the untreated one, there was virtually only type A MAO. Following the application of Percoll density gradient centrifugation, MAO associated with different subcellular fractions was obtained. The dBcAMP treated fractions were slightly heavier than the untreated ones.