Expression of 3 brain isozymes of phospholipase (PLC-beta, PLC-gamma and PLC-delta) was investigated in relation to cell types found in rat CNS cultures. Immunoreactivity of cultured neurons, astrocytes and oligodendrocytes was demonstrated for all of the 3 isozymes by immunocytochemical staining and immunoblotting, with some differences in reaction intensity. Immunoblotting revealed that the level of expression was neurons greater than oligodendrocytes greater than astrocytes for PLC-beta and PLC-gamma, and astrocytes greater than oligodendrocytes greater than neurons for PLC-delta.