Fig. 8.

The mechanism of TAL in PD models. Our results demonstrated that TAL administration in hemi-PD rats led to increased expression of TH in the remaining dopaminergic axonal terminals within the striatum. Furthermore, TAL binds to TRHR, which is primarily expressed on GABAergic neurons such as D2-MSNs. Upon TRHR activation, various potential signaling pathways are initiated, leading to increased CREB and p-ERK1/2 activity. This activation further promotes the upregulation of TRHR and RARα expression. RARα, in turn, regulates DRD2 expression. As a result, TAL induces MSNs to express TH