Differential Virtual Screening (DVS) with Active and Inactive Molecular Models for Finding and Profiling GPCR Modulators: Case of the CCK1 Receptor.

We discovered a constitutively activating mutation (CAM) V308E for the neurotensin NT1 receptor. Molecular dynamics (MD) performed for the CAM NT1-V308E exhibiting a high spontaneous activity, and for the wild-type NT1 without basal activity, show dramatic conformational changes for the CAM. To test if the two MD models could be valuable active and inactive templates for building molecular models for other class-A GPCR, supposed active and inactive models were built by homology for the cholecystokinin CCK1 receptor.

An antagonistic monoclonal antibody (B-N6) specific for the human neurotensin receptor-1.

The neuropeptide neurotensin (NT) interacts with two types of human receptors (hNTR) termed hNTR-1 and hNTR-2. This study describes a monoclonal antibody (MAb) specific for hNTR-1, B-N6. This MAb binds specifically to hNTR-1, but not to hNTR-2 transfected CHO cells.

SR 144528, an antagonist for the peripheral cannabinoid receptor that behaves as an inverse agonist.

In the present report, we investigated in detail the effects of SR 144528, a selective antagonist of the peripheral cannabinoid receptor (CB2), on two well-characterized functions mediated by CB2: the induction of the early response gene krox24 and the inhibition of adenylyl cyclase. We generated Chinese hamster ovary cells doubly transfected with human CB2 and a luciferase reporter gene linked to either the murine krox24 regulatory sequence or multiple cAMP responsive elements. Our results show that (1) SR 144528 antagonizes the effect of receptor agonists-it inhibits the krox24 reporter activity and prevents the inhibition of forskolin-induced cAMP reporter activity mediated by CP 55,940; (2) CB2 is autoactivated-CB2 mediates signaling in the absence of ligand, and this basal activity is reduced by pretreating the cells with pertussis toxin; (3) SR 144528 is an inverse agonist-it reproduces the effects of pertussis toxin; and (4) inhibition of precoupled CB2 by a long-term pretreatment of cells with SR 144528 potentiates krox24 response to cannabinoid receptor agonists and restores activation of adenylyl cyclase.

A selective inverse agonist for central cannabinoid receptor inhibits mitogen-activated protein kinase activation stimulated by insulin or insulin-like growth factor 1. Evidence for a new model of receptor/ligand interactions.

In the present study, we showed that Chinese hamster ovary (CHO) cells transfected with human central cannabinoid receptor (CB1) exhibit high constitutive activity at both levels of mitogen-activated protein kinase (MAPK) and adenylyl cyclase. These activities could be blocked by the CB1-selective ligand, SR 141716A, that functions as an inverse agonist. Moreover, binding studies showed that guanine nucleotides decreased the binding of the agonist CP-55,940, an effect usually observed with agonists, whereas it enhanced the binding of SR 141716A, a property of inverse agonists.

Biochemical and pharmacological activities of SR 142948A, a new potent neurotensin receptor antagonist.

SR 142948A, 2-[[5-(2,6-dimethoxyphenyl)-1-(4-(N-(3-dimethylaminopropyl)-N-methylc arbamoyl)-2-isopropylphenyl)-1H-pyrazole3-carbonyl]amino] adamantane-2-carboxylic acid, hydrochloride, a new and extremely potent neurotensin (NT) receptor antagonist, has been characterized in comparison with SR 48692. This selective compound possesses nanomolar affinities for NT receptors, recognizes the two binding sites described for the NT receptor and fully displaces [3H]SR 48692 specific binding. SR 142948A antagonizes the classical in vitro NT effects, i.