Ki: 0.35 pM and 21 nM for CB1 and CB2 receptor, respectively.

NESS 0327 is an extremely potent cannabinoid (CB) receptor antagonist.

Cannabinoid CB1 receptors are present in the central nervous system with the highest densities in the hippocampus, and to a lesser extent in some peripheral tissues. Cannabinoid CB2 receptors are predominantly located in peripheral tissues. Both receptors can negatively regulate adenylate cyclase and control the release of arachidonic acid.

In vitro: Previous study found that NESS 0327 exhibited a stronger selectivity for CB1 receptor compared with SR 141716A, showing a much higher affinity for CB1 receptor and a higher affinity for the CB2 receptor. Affinity ratios demonstrated that NESS 0327 was more than 60,000-fold selective for the CB1 receptor. NESS 0327 alone did not produce concentration-dependent stimulation of guanosine 5'-O-(3-[35S]thio)-triphosphate binding in rat cerebella membranes. Conversely, NESS 0327 antagonized WIN 55,212-2-stimulated guanosine 5'-O-(3-[35S]thio)-triphosphate binding. In functional assay, NESS 0327 could antagonize the inhibitory effects of WIN 55,212-2 on electrically evoked contractions in mouse isolated vas deferens preparations [1].

In vivo: In vivo studies showed that NESS 0327 could antagonize the antinociceptive effect produced by WIN 55,212-2 in both tail-flick and hot-plate test, suggesting that NESS 0327 was a novel cannabinoid antagonist with high selectivity for the cannabinoid CB1 receptor [1].

Clinical trial: So far, no clinical study has been conducted.

Reference:
[1] Ruiu, S. ,Pinna, G.A.,Marchese, G., et al. Synthesis and characterization of NESS 0327: A novel putative antagonist of the CB1 cannabinoid receptor. Journal of Pharmacology and Experimental Therapeutics 306(1), 363-370 (2003).