Table 3

Amplification factors for mu opioid receptor-stimulated G-protein activation in cultured cell lines and rat thalamus

MembranesBmaxAmplification factor
ReceptorG-Protein
pmol/mg
mMOR-CHO6.783.54 0.52
Rat thalamus0.747.11 9.61
SK-N-SH0.15 1.43 9.53

Receptor and [35S]GTPγS binding assays for saturation analysis were conducted under identical conditions, as described under “Materials and Methods.” The mu receptorBmax was determined by [3H]naloxone binding, and the G-protein Bmax was determined by net DAMGO-stimulated [35S]GTPγS binding. Amplification factor defined by DAMGO-activated G-proteinBmax/mu receptor Bmax.

  •  Data are from Selley et al. (1997).

  •  Data are from Breivogel et al. (1997).