Cultured glial cells express the SNAP-25 analogue SNAP-23

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Abstract
Astrocytes release glutamate and aspartate in response to elevated intracellular calcium levels, and it has been proposed that this occurs by a vesicular release mechanism, in which SNARE proteins are implicated. Although syntaxin, synaptobrevin, and cellubrevin have been shown to be expressed by cultured astrocytes, SNAP‐25 has not been detected. By using immunocytochemical, immunoblotting, and polymerase chain reaction techniques, the present study demonstrates that SNAP‐23, an analogue of SNAP‐25, is expressed by astrocytes both in culture and in rat cerebellum. These findings provide additional evidence that astrocytes release excitatory amino acids by a vesicular mechanism involving SNARE proteins. SNAP‐23 and also syntaxin 1 and cellubrevin were found to be expressed in glial precursor cells, oligodendrocytes, and microglia. These data suggest that the t‐SNAREs SNAP‐23 and syntaxin 1 and the v‐SNARE cellubrevin participate in general membrane insertion mechanisms involved in diverse glial cell functions such as secretion, phagocytosis, and myelinogenesis. GLIA 27:181–187, 1999.