Figure 2.

Effect of compounds on receptor signalling in Saccharomyces cerevisiae stably expressing recombinant human CB₁ receptors. Antagonism of 100 nM CP55,940-induced signalling by SR141716A and PSNCBAM-1 (a). Effect of SR141716A and PSNCBAM-1 on constitutive hCB₁ signalling (b). Yeast cells were incubated with compounds at 30°C and reporter gene expression was measured by a fluorescent readout. Agonist concentrations used were determined by their EC₉₀ values in the assay. Data points are mean±s.e.m. from three experiments and curves are fitted to a four parameter, one-site, dose–response equation. PSNCBAM-1, 1-(4-chlorophenyl)-3-[3-(6-pyrrolidin-1-ylpyridin-2-yl)phenyl]urea; SR141716A, N-(piperidin-1-yl)-5-(4-cholrophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide.