Figure 5.
α-PHP is an antagonist/inverse agonist of M1R-inositol phosphate signaling with low micromolar potency. (A) Oxotremorine dose-dependently stimulated inositol phosphate 1 (IP1) production. (B) α-PHP blocked effects of oxotremorine (EC80 concentration) at M1Rs and, moreover, decreased IP1 production below basal levels, suggesting inverse agonist activity. Data are expressed as normalized means (±SEM) of three, independent determinations, with oxotremorine tested at each concentration in duplicate and α-PHP tested at each concentration in triplicate.