Ligand-Specific Regulation of the Endogenous Mu-Opioid Receptor by Chronic Treatment with Mu-Opioid Peptide Agonists
Figure 3
Stimulation of [35S]GTPγS binding by opioid peptides in crude rat brain membranes. Membrane homogenates (≈10 μg of protein) were incubated with increasing concentrations (10−9–10−4 M) of the indicated ligands and [35S]GTPγS (0.05 nM) as described in Methods except that 30 μM GDP was used. The curves were fit and drawn by Graph Pad Prism 4 computer program. Results are shown as % stimulation of [35S]GTPγS binding over basal values (i.e., binding in the absence of opioid peptides). Each value represents the mean ± S.E.M. of at least three independent experiments performed in triplicate. Nonvisible S.E.M. is within the symbol.
