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. 2009 Jan 21;106(4):1285–1290. doi: 10.1073/pnas.0806720106

Fig. 2.

Fig. 2.

Pretreatment with GLP-1 or Ex-4 protects TH(IR) of VM primary neurons from 6-OHDA treatment and likewise protects SH-SY5Y cells from 6-OHDA–induced cell death. (A) TH(IR) of primary VM cells pretreated with vehicle (Veh), 0.1 μM GLP-1, or 0.1 μM Ex-4 for 3 h before administration of PBS or 6-OHDA for 90 min. TH-immunostaining was performed 24 h after 6-OHDA. TH(IR) was significantly different versus PBS-treated controls (P < .05; Dunnett's t-test with SNK, n = 5). (B) In a parallel study, SH-SY5Y cells were treated with vehicle (Veh), GLP-1, or Ex-4 (0.1 uμM) for 2 h and then subjected to 6-OHDA (30 μM) for 24 h. Subsequently, cell survival was quantified by MTS assay. Whereas 6-OHDA reduced cell survival to 83% (*P < .05 vs. control), GLP-1 and Ex-4 protected against this 6-OHDA loss of cell viability (*P < .05 vs. vehicle plus 6-OHDA; Dunnett's t-test, n = 6/group). (C and D) In SH-SY5Y cells, markers of apoptosis were elevated by 6-OHDA (30 μM) and lowered by Ex-4 (0.1 μM) after 2 h of pretreatment. This protection was lost in cells treated with inhibitors of PKA (H89; 10 μM) or PI3K (LY294002; 10 μM) and was retained with insulin (0.01 μM; positive control) (*P < .05, Dunnett's t-test, n = 5 vs. vehicle plus 6-OHDA).