CALCIUM SIGNALING IN CULTURED RAT OLIGODENDROCYTES

The syntax of neuronal-glial or axonal-glial interaction is frequently communicated through transient changes in internal calcium (Ca-i). We examined mechanisms for Ca-i signaling and intercellular propagation of Ca-i responses in cultured oligodendrocytes (OLGs) derived from adult spinal cord (SC), postnatal day 21 (P21) SC, and P21 brain. We found that (1) cultured OLGs exhibited a heterogeneous response to norepinephrine, carbachol, ATP, histamine, and glutamate; (2) receptor-mediated Ca-i increases were derived from both Ca2+ influx and intracellular Ca2+ release; (3) the percentage of responders to neuroligands varied as a function of cell origin; (4) cultured OLGs exhibited a thapsigargin-sensitive, but not a caffeine-sensitive, intracellular Ca2+ pool; and (5) gap junctional contacts between OLGs permitted limited intercellular propagation of mechanically stimulated Ca-i responses. Receptor-mediated Ca-i signaling appears to occur not only in cultured OLGs but also in acutely dissociated OLGs. The heterogeneity in Ca-i responses as a function of cell origin may reflect the existence of OLG subsets or differences in the maturation stage of OLGs. (C) 1995 Wiley-Liss, Inc.