Calcium signaling in cultured rat oligodendrocytes

Abstract

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 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 of differences in the maturation stage of OLGs.