How Do Satellite Glial Cells Control Chronic Pain?
Journal of Anesthesia and Perioperative Medicine
Aim of review: Pain afflicts more than 1.5 billion people worldwide, with hundreds of millions suffering from unrelieved chronic pain. Accumulating evidence suggests that satellite glial cells (SGCs) play active roles in the pathogenesis of pain. We review how SGCs interact with nociceptive neurons by secreting neuroactive signaling molecules that modulate pain, which may offer new therapeutic strategies for the prevention and treatment of chronic pain. Methods: According to the available
... the available literature, we first described the morphology and physiology of SGCs in sensory ganglia and then provided an overview of the signaling molecules by which SGCs contribute to the modulation of the neuronal activity in various animal models of acute and chronic pain. Finally, we addressed some outstanding questions about SGCs that remain to be answered in future research and clinical applications. Recent findings: Accumulating evidence has implicated structural and biochemical changes in SGCs in chronic pain: gliosis (i.e. proliferation), increase in expression of glial fibrillary acidic protein (a marker for their activation), modulation of glutamate transporters and ion channels, increases in purinergic and cytokine signaling, as well as aberrant connectivity between neighboring SGCs and sensory neurons. These changes alter the activity of sensory neurons and contribute to the development and maintenance of chronic pain. Remarkably, SGCs also participate in acute pain, and acute opioid treatment activates SGCs to mask opioid analgesia. Summary: SGCs are now recognized players in the pathogenesis of chronic pain through the secretion of neuroactive signaling molecules and controls of nociceptive neurons. Given the inadequate treatment of chronic pain by the current "neurocentric" drugs, these recently recognized roles of SGCs and their neuroactive signaling molecules are exciting as they predict novel approaches for effective control of chronic pain. (