Figure 4.

Occlusion studies suggest a unique mechanism for oxysterols versus other lipophilic positive modulators. A, B, Examples of occlusion protocol. Cells were preincubated for >5 min in 10 μm 24(S)-HC then challenged with 10 μm NMDA plus 50 μm PREGS (A) as a representative nonoccluding potentiator or 0.2 μm SGE-201 (B) as a representative occluding potentiator. C, Summary of results from 6 to 10 cells per bar for the four indicated modulators. Arachidonic acid was used at 5 μm. SGE-301 was used at 0.5 μm. Asterisks indicate a significant reduction in potentiation (p < 0.05).