Satellite glial cell
Also known as: satellite cells (glial), satellite glia, amphicytes, capsular cells
Flattened glial cells of the PNS that form a capsule around each neuronal cell body in sensory and autonomic ganglia. They regulate the neurons' microenvironment, in a role analogous to that of astrocytes.
Overview
Satellite glial cells form a thin, complete sheath around the soma of each pseudounipolar neuron in the dorsal root and cranial sensory ganglia. In autonomic ganglia, where the neurons are multipolar and receive synapses, the covering is less complete. Several satellite cells, coupled by gap junctions, envelop each neuron, and the neuron–glia unit is enclosed by a common basal lamina. They should not be confused with the satellite cells of skeletal muscle, which are myogenic stem cells responsible for muscle repair and are unrelated despite the shared name.
Satellite cells control the composition of the fluid around the neuronal soma. They take up and recycle glutamate and buffer K⁺, supply nutrients, and separate neurons from each other and from the blood. After nerve injury or inflammation they proliferate, upregulate GFAP and increase their gap-junction coupling. This activation increases the excitability of sensory neurons and is thought to contribute to chronic neuropathic pain.
- Location
Sensory ganglia of spinal and cranial nerves (DRG, trigeminal, geniculate, glossopharyngeal and vagal ganglia) and autonomic (sympathetic and parasympathetic) ganglia.
Anatomy
- Histology
A ring of small, flattened nuclei closely surrounding each large round ganglion cell body, best seen in DRG sections. Coverage is incomplete in autonomic ganglia.
- Development
Derived from the neural crest, like Schwann cells and ganglion neurons.
Function
- Structurally support and electrically insulate ganglionic neurons.
- Regulate ions (K⁺ buffering), neurotransmitter uptake and the nutrient supply around the soma.
- Respond to injury and modulate sensory neuron excitability.
Clinical significance
Herpesvirus latency and neuropathic pain
VZV and HSV establish latency in sensory ganglion neurons. Satellite glia surround these neurons and take part in the local immune response on reactivation. Satellite glial activation is implicated in post-herpetic neuralgia and other chronic pain states.
Compiled from standard anatomy and physiology references — see the Nervous System sources. For education only; not medical advice.