TH and Parkinson disease: Administration of sinomenine (i.p., 20 mg/kg, 5 days before treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and for another 4 days) can suppress the MPTP-induced decline in rotarod time, pounds for grip strength, and forepaw stride length in mice, which was accompanied by an increase in tyrosine hydroxylase (TH)-positive cells in the substantia nigra pars compacta (Bao et al., 2022) (Table 2), suggesting that sinomenine administration improves motor skills in mice with PD by promoting the survival of dopaminergic neurons.