The role of glial cells in influencing neurite extension by dorsal root ganglion cells

Abstract

When pretreated with pertussis toxin (PTX), the neurites of adult rat dorsal root ganglion (DRG) cells in mixed cell cultures retract over a period of 2 h following the initial stimulus of removal from the cell culture incubator for brief periods of observation. The purpose of this investigation was to determine whether this PTX-dependent response was specific to any one of the three subpopulations of DRG neurons. However, no neurite retraction response was observed in neuron-enriched populations of cells, or in cultures enriched in isolectin B 4 (IB4)-positive neurons or in IB4-negative neurons. But, the addition of nonneuronal cells, and/or medium conditioned by non-neuronal cells, was sufficient to restore the PTX-dependent neurite retraction response, but only in large diameter IB4-negative neurons. In conclusion, we have identified a regulatory response, mediated by Gi/o-proteins, which prevents retraction of neurites in large diameter IB4-negative cells of adult rat DRG. The non-neuronal cells of adult rat DRG constitutively release factor/s that can stimulate neurite retraction of a subset of isolated DRG neurons, but this property of non-neuronal cells is only observed when the Gi/o-proteins of large diameter IB4-negative cells are inhibited.

Isolated dorsal root ganglion neurones inhibit receptor‐dependent adenylyl cyclase activity in associated glial cells

“…and the spinal cords were rapidly removed (the total number of rats used was estimated to be 180). The dorsal root ganglia were removed from all levels of the spinal cord of and cultures were prepared as described previously (Ng et al ., ). The cell pellet was resuspended in Ham's F14 medium containing Ultroser G (4%), penicillin (100 U·mL −1 ) and streptomycin (100 μg·mL −1 ), and the morphologically distinct phase‐bright neurones and phase‐dark glial cells were counted using a haemocytometer slide.…”

“…For neurone‐enriched preparations, the mixed DRG cells were plated on poly‐ dl ‐ornithine‐coated tissue culture dishes (cells from two rats per 10 cm dish), as described previously (Ng et al ., ). After overnight incubation, the loosely attached neuronal cells were gently removed from the more firmly attached glial cells.…”

“…However, although the PGE 2 receptor (EP 4 ) subtype and the prostacyclin (IP) receptor are localized to neurones in intact DRG (Oida et al ., ), we have shown that the non‐neuronal cell population in mixed DRG cell cultures also express these receptors (Ng et al ., ). Because the majority of non‐neuronal cells in our DRG cell cultures express glial fibrillary‐acidic protein (GFAP) (Ng et al ., ), we refer to these cells as DRG glial cells. What causes the up‐regulation of EP 4 and IP receptors in isolated DRG glial cells is presently unknown, but up‐regulation of EP 2 and EP 4 receptors in spinal cord microglial cells in vivo occurs in response to chronic, but not acute, inflammatory conditions to provide a negative feedback system regulating neuroinflammation (Noda et al ., ; Brenneis et al ., ).…”

Satellite glial cells: more than just ‘rings around the neuron’

“…Ng et al (2010) report that SGC-neuron interactions include influence on neurite retraction in a subpopulation of dorsal root ganglia (DRG) neurons in culture. This work suggests that non-neuronal cells (presumably SGCs) can control neuronal characteristics in sensory ganglia.…”

Differential Transcriptional Profiling of Damaged and Intact Adjacent Dorsal Root Ganglia Neurons in Neuropathic Pain

“…A pathological neuro-immune communication has also been associated with painful neuropathy [4,5]. This complexity is well reflected by the tissue heterogeneity in DRG: Studies suggest that only 15% of all DRG cells are neurons [6]. The largest numbers of other cells include glia, i.e.…”