However, it also ushered in new interest in neuroglia. It also consists of neuroglia cells and unmyelinated axons. Microglia are a type of neuroglia (glial cell) located throughout the brain and spinal cord. This channel which is activated by ATP depletion is found on neurons, neuroglia and endothelium. Neuroglia cells are only affected in severe cases. Microglia (and other neuroglia including astrocytes) are distributed in large non-overlapping regions throughout the CNS. In addition, MDA activates a response of the neuroglia, though this subsides after use. Neuroglia ("glial cells") may play a role in central sensitization. Two types of neuroglia found in the PNS are satellite cells and Schwann cells.