CLONED MICROGLIAL CELLS BUT NOT MACROPHAGES SYNTHESIZE BETA-ENDORPHININ RESPONSE TO CRH ACTIVATION

The properties of microglial cell clones, obtained from embryonic mous e brain primary cultures immortalized with recombinant retroviruses, h ave been investigated and compared with the properties of macrophage c lones similarly obtained. Macrophage clones differed from microglial c lones in some functions but shared most of the immunological propertie s. Interestingly, microglial cells were able to produce beta-endorphin , and this production was regulated differently in microglial cell clo nes when compared with macrophage clones. Although lipopolysaccharide (LPS) treatment induces an increase in beta-endorphin concentration in both cell types, only microglial clones and primary microglial cell c ultures respond to the neuroendocrine stimulus corticotropin releasing hormone (CRH). In addition, in these cells, beta-endorphin release is regulated by a classical neurotransmitter, such as noradrenaline, add ing some evidence of communication between neurons and microglial cell s. (C) 1993 Wiley-Liss, Inc.