Neurotransmitters of the major striatal output pathways
What are the neurotransmitters of the two major striatal output pathways?
Medium spiny neurons (MSN), the principal neurons of the striatum, are GABAergic and project to the GPe, GPi, and SNr.
Approximately 50% of MSN also contain substance P and dynorphin and project to the SNr and GPi.
The other half of the neurons expresses enkephalin and projects their axons to the GPe.
These pathways are, respectively, called striatonigral or direct pathway and striatopallidal or indirect pathway .
The direct and indirect pathways are thought to have opposing actions: direct pathway activation may inhibit GPi/SNr activity, thereby disinhibiting thalamocortical interactions, while indirect pathway activates thalamocortical interactions.
