OLIGODENDROGLIAL LINEAGE CELLS EXPRESS NEUROLIGAND RECEPTORS

This study was designed to determine whether cells of the oligodendrog lial lineage express neuroligand receptors linked to Ca2+ mobilization . Intracellular Ca2+ levels were monitored with a video-based imaging system and cells were characterized with immunocytochemical markers. O -2A progenitor cells (A2B5+/GFAP-) and mature oligodendroglia (GC+/MBP +) responded to norepinephrine, glutamate, ATP, and histamine with inc reased intracellular Ca2+ levels. As O-2A progenitor cells differentia ted into mature oligodendroglia, there was an increase in the percenta ge of cells that responded to ATP and histamine with an increase in in tracellular Ca2+ levels. Both O-2A progenitor cells and mature oligode ndroglia were pharmacologically heterogeneous with respect to their ab ility to respond to neuroligands with an increase in intracellular Ca 2+ . Treatment with bradykinin, carbachol, and substance P also increa sed intracellular Ca 2+ levels in O-2A progenitor cells and mature oli godendroglia. Whereas the percentage of cells that responded to bradyk inin and substance P increased with differentiation of O-2A progenitor cells into mature oligodendroglia, the trend was reversed with respec t to the percentage of cells responding to carbachol. These results su ggest that cells of the oligodendroglial lineage exhibit neuroligand r eceptors linked to Ca2+ mobilization and that the ability of these cel ls to respond to neuroligands is developmentally regulated.