Neuroanatomy and glial cells come in many types (see, for example, the nervous system section of the list of distinct cell types in the adult human body). Neurons are the information-processing cells of the nervous system: they sense our environment, communicate with each other via electrical signals and chemicals called neurotransmitters across synapses, and produce our memories, thoughts and movements. Glial cells maintain homeostasis, produce myelin, and provide support and protection for the brain's neurons. Some glial cells (astrocytes) can even propagate intercellular calcium waves over long distances in response to stimulation, and release gliotransmitters in response to changes in calcium
Satellite glial cell tumor necrosis factor α (TNFα) are other cellular factors that work to sensitize neurons to pain. SGCs are present in the PNS in fewer numbers than other more well-known types of glial cells, like astrocytes, but have been determined to affect nociception because of some of their physiological and pharmacological properties. In fact, just like astrocytes, SGCs have the ability to sense and regulate neighboring neuronal activity. First, after a period of nerve cell injury, SGCs are known to up-regulate GFAP and to undergo cell division. They have the ability to release chemoattractants, which are analogous to those released by