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 form adult spinal cord (SC), postnatal day 21 (P21) SC, and P21 brain. We found that (1) cultured OLGs exhibited a heterogeneous responese to norepinephrine, carbachol, ATP, histamine, and glutamate; (2) receptor‐mediated Ca i increases were derived from both Ca 2+ influx and intracellular Ca 2+ 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 Ca 2+ 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 of differences in the maturation stage of OLGs. © 1995 Wiley‐Liss, Inc.