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. Author manuscript; available in PMC: 2017 Jun 23.
Published in final edited form as: Prog Mol Biol Transl Sci. 2013;115:1–59. doi: 10.1016/B978-0-12-394587-7.00001-4

Figure 1.3.

Figure 1.3

A triple-addition protocol allows for the detection of multiple modes of pharmacology in a single experiment. Calcium assay triple-add traces are shown for an mGlu5 PAM (A), Ago-PAM (B), and NAM (C). The protocol consists of the addition of test compound followed by EC20 and EC80 concentrations of orthosteric agonist to detect agonist, PAM, and NAM activity, respectively. Data shown are expressed as percent of the response of a maximally effective glutamate concentration. (A) The mGlu5 PAM VU0360172 was added to cells expressing a low density of mGlu5 receptors and traces were compared to those of vehicle (vehicle, solid line; VU0360172, dotted line). (B) VU0360172 was added to cells expressing a high level of mGlu5, invoking an Ago-PAM response (note response observed in the “compound addition” window). (C) The mGlu5 NAM, VU0405395, was added to the same cell line as that in panel (A) and results in inhibition of both the EC20 and EC80 peaks. Each data set is from a single representative experiment (P.N. Vinson, previously unpublished data).