Cannabinoid-Receptor Interacting Protein 1a (CRIP1a) effects ...

Cannabinoid-Receptor Interacting Protein 1a (CRIP1a) effects on CB1 Inverse Agonists Erin Cochran Endocannabinoid System

Pharmacology Terms Basal or Constitutive activity- physiological response in the absence of an agonist or inverse agonist Agonist- ligand that increases basal activity

Inverse Agonist- a ligand that inhibits or eliminates basal activity CB1 CRIP1a

Ahmed et al. 2015 Current Research Full agonist: WIN Partial agonists: MAE and THC Inverse agonist: RIM

Smith et al. 2015 What Triggers CRIP1a Modulation? Extreme ends of stimulation are modulated (full agonists and inverse agonists) Moderate stimulation is not modulated (partial agonists)

Is CRIP1a modulation triggered by the intrinsic efficacy of a ligand or if stimulation caused by the ligand exceeds a range? G-protein Coupled Receptor Activation

Harrison and Traynor 2003 [35S]GTPgS Binding Assay Harrison and Traynor 2003

Background Experiments Transfect Human Embryonic Kidney (HEK) cell lines hCB1-HEK hCB1-HEK-CRIP1a Receptor Density [3H]SR141716A binding assay

Control Basal binding [35S]GTPgS binding assay without ligands present Baseline Inverse Agonists

Pertwee 2005 Experiment Cell Line Reactions hCB1-HEK + inverse agonists + [35S]GTPgS hCB1-HEK-CRIP1a + inverse agonists + [35S]GTPgS

Reaction stopped by vacuum filtration Measure CB1 receptors bound with [35S]GTPgS with scintillation counter Data Analysis Net Stimulation = Ligand Stimulation Basal Binding Percent Stimulation = (Net Stimulation / Basal Binding) X 100

Compare percent stimulation between hCB1-HEK and hCB1-HEK-CRIP1a Compare percent stimulation between the ligands in hCB1-HEK-CRIP1a Triggering CRIP1a Modulation Intrinsic efficacy of ligand All three inverse agonists

stimulation will be reduced to the same degree Reduction of Stimulation SR141716A = AM251 = AM281 Extreme ends of range

Stimulation caused by the less potent inverse agonists will be reduced less than the more potent inverse agonists Reduction of Stimulation SR141716A > AM251 > AM281

Questions?