Fig. 1.
The ghrelin receptor is able to cause constitutive activation of Gαo1: substance P analog is an inverse agonist; HEK293 cells were transfected to express Gαo1 (open bars) or Gαo1 and the ghrelin receptor (filled bars). The binding of [35S]GTPγS in membranes of these cells in the absence of ligand or the presence of ghrelin or SPA (both 1 μM) was then assessed. Data are presented as the percentage of the effect of ghrelin in membranes coexpressing Gαo1 and the ghrelin receptor (means ± S.E.M., n = 3). ***, p < 0.001; **, p < 0.01 (one-way ANOVA with Tukey's multiple comparison test).