Tripartite Synapse
Within the dorsal horn of the spinal cord, activated astrocytes have the ability to respond to almost all neurotransmitters (Haydon, 2001) and, upon activation, release a multitude of neuroactive molecules such as glutamate, ATP, nitric oxide (NO), prostaglandins (PG), and D-serine, which in turn influences neuronal excitability. The close association between astrocytes and presynaptic and postsynaptic terminals as well as their ability to integrate synaptic activity and release neuromodulators has been termed the "tripartite synapse" (Araque et al., 1999). Synaptic modulation by astrocytes takes place because of this 3-part association.
Read more about this topic: Astrocyte