Fig. 4.

In vitro murine CD4 cell intracellular cAMP concentration. cAMP concentrations were measured by ELISA in 2 × 10⁶ CD4 cells that were homogenized after 30 min of drug exposure in vitro. Cotreatment of CD4 cells exposed to prostaglandin E2 (PGE₂; Gαs-coupled receptor agonist) with 10–25 µM 6-shogaol (6-S) led to dose-dependent increases in cAMP concentrations over cells treated with PGE₂ alone. 6-Shogaol alone did not increase cAMP above DMSO (0.2%) vehicle control. These results are consistent with 6-shogaol-mediated inhibition of phosphodiesterase activity. n = 5 mice, ANOVA with matched comparisons and Bonferonni posttest analyses. **P < 0.01, ***P < 0.001.