After each experimental period, time-matched euglycemic (E) or 4, 8, or 12 week-long diabetic rats (DB) (E4, E8, E12, DB4, DB8, and DB12, respectively) were sacrificed, and SN and dorsal root ganglia (DRG) harvested for analysis of slc5A3 (SMIT1), slcA11 (SMIT2), and slc2A13 (HMIT) mRNA expression by RT-PCR and protein levels by western blot analyses.