FIGURE 7.

VIPR2 agonist protects dopaminergic neurons and diminishes microglial response after 6-OHDA. Lewis rats were administered 10 μg of 6-OHDA in 5 μl of PBS by stereotaxic injection or were injected without infusion (SHAM controls) (n = 6). Immediately after injection, rats began a regimen of either vehicle (0.0 mg/kg) (n = 5) or 0.6 (n = 6), 2.0 (n = 6), or 6.0 (n = 5) mg/kg of LBT-3627 administered as daily injections for 5 days and every other day thereafter. After 14 days, brains were obtained, processed and stained for expression of TH in the substantia nigra (A) and striatum (B), and for Iba1 in the substantia nigra (C). (D) TH⁺Nissl⁺ (red bars) and TH^–Nissl⁺ (blue bars) neurons within the substantia nigra were counted by stereological analysis and the ipsilateral/contralateral ratios of those numbers were determined. No significant differences in TH^–Nissl⁺ neurons were discernible between treatment groups, P = 0.7671. (E) Densities of TH⁺ termini were determined by digital image analysis and ipsilateral/contralateral ratios of those densities calculated. (F) Densities of amoeboid Iba1⁺ microglia were assessed by stereological analysis and ipsilateral/contralateral ratios of those densities were determined. (D–F) Means and SEM were calculated for 5–6 rats/group. Significant differences were assessed by one-way ANOVA followed by Newman-Keuls post hoc tests. P ≤ 0.05 compared to animals treated as ^asham controls or with ^b6-OHDA + vehicle (0 mg/kg). Scale bars, (A,B) 1000 μm and (C) 40 μm.