HTR1A and Parkinson disease: We also showed that a serotonin 5-HT1A receptor full agonist 8-OH DPAT promotes astrocyte proliferation via S100β secretion and activates the Nrf2-ARE pathway to produce MT in astrocytes by acting on astroglial 5-HT1A receptors, and consequently to prevent dopaminergic neurodegeneration in neuron-astrocyte co-cultures and in PD animal models [17].