Activation of cultured glial cells by amitriptyline and platelet activating factor.

The activation of glial cells in culture by exposure to chemicals proceeds through two stages. The first stage appears to be an activation of oligodendroglial (OG) proliferation and increased activities of 2'3'-cyclic 3'-phosphodiesterase (CNP). This stage frequently leads to a second stage, which is characterized by a transformation of microglia to actively phagocyting cells with increased 5'-nucleotidase (5'-NT) activity. Compounds of heavy metals induce OG proliferation and activation of CNP, but do not activate microglia. In contrast amitriptyline (AT) is a potent activator of microglia cells and stimulates 5'-NT. Exposure of the cells to platelet activated factor (PAF) or AT for 2, 5, 7 or 12 days revealed different effects on the release of prostaglandin E(2) emphasizing the fact that the cells have specific receptors for PAG but not for AT.