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 (Cai). We examined mechanisms for Cai signaling and intercellular propagation of Cai 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 Cai 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 Cai responses. Receptor-mediated Cai signaling appears to occur not only in cultured OLGs but also in acutely dissociated OLGs. The heterogeneity in Cai responses as a function of cell origin may reflect the existence of OLG subsets or differences in the maturation stage of OLGs.

Region-Specific Myelin Pathology in Mice Lacking the Golli Products of the Myelin Basic Protein Gene

“…Other evidence supporting the notion of OL heterogeneity include: differences in regional OL cycling times when exposed to PDGF in vitro and differences among OPCs in signaling molecules and transcription factors (for review, see Noble et al, 2003), regional and cellular heterogeneity in morphology (Del RioHortega, 1928;Weruaga-Prieto et al, 1996), and differences in complements of trk receptors (Du et al, 2003) and other receptors (Kettenmann et al, 1984;Takeda et al, 1995). It is possible that some subsets of OLs are more sensitive to golli ablation and others are more refractory because of compensation mechanisms.…”

Calcium and glial cell death

“…However, the amplitude of Ca 2+ currents recorded in oligodendrocytes was lower than that observed in neurons. In situ studies confirmed the presence of Ca 2+ currents in progenitors but not in mature oligodendrocytes [36,37]. It is plausible that VGCCs are not detected in these cells because they are located in the periphery of oligodendrocytes or confined to domains such as the paranodal loops, and thus facilitate axoglial signalling during myelination by detecting electrical activity through changes in [K + ] o [38].…”

Intercellular Ca2+Waves: Mechanisms and Function

“…Subsequently, ICWs have been found to be initiated by a variety of stimuli in a diversity of cell types, including glial cells (246,312,361), neurons (56, 153), various epithelial (171,249) and endothelial (47,129,382) cells, smooth muscle cells (151, 407), cardiomyocytes (352), hepatocytes (122), osteocytes (178), chondrocytes (189), kidney cells (276,402), mammary gland cells (104), mast cells (255), pancreatic acinar cells (409), and keratinocytes (188). FIGURE 1 illustrates typical examples of ICWs in glial and endothelial cells.…”