Development of a potent inhibitor of 2-arachidonoylglycerol hydrolysis with antinociceptive activity in vivo.
Biochim Biophys Acta. 2008 Nov 5;
Authors: Bisogno T, Ortar G, Petrosino S, Morera E, Palazzo E, Nalli M, Maione S, Di Marzo V,
Although inhibitors of the enzymatic hydrolysis of the endocannabinoid 2-arachidonoylglycerol are available, they are either rather weak in vitro (IC(50)>30 muM) or their selectivity towards other proteins of the endocannabinoid system has not been tested. Here we describe the synthesis and activity in vitro and in vivo of a tetrahydrolipstatin analogue, OMDM169, as a potent inhibitor of 2-AG hydrolysis, capable of enhancing 2-AG levels and of exerting analgesic activity via indirect activation of cannabinoid receptors. OMDM169 exhibited 0.13 muM<IC(50)<0.41 muM towards 2-AG hydrolysing activities in COS-7 cells and rat cerebellum, and inhibited (IC(50)=0.89 muM) the human recombinant MAGL, whilst being inactive (K(i)>10 muM) at human CB(1) and CB(2) receptors. However, OMDM169 shared with tetrahydrolipstatin the capability of inhibiting the human pancreatic lipase (IC(50)=0.6 muM). OMDM169 inhibited fatty acid amide hydrolase and diacylglycerol lipase only at higher concentrations (IC(50)=3.0 and 2.8 muM, respectively), and, accordingly, it increased by approximately 1.6-fold the levels of 2-AG, but not anandamide, in intact ionomycin-stimulated N18TG2 neuroblastoma cells. Acute intraperitoneal (i.p.) administration of OMDM169 to mice inhibited the second phase of the formalin-induced nocifensive response with an IC(50) of approximately 2.5 mg/kg, and concomitantly elevated 2-AG, but not anandamide, levels in both the brain and ipsilateral paw of formalin-treated mice. The antinociceptive effect of OMDM169 was antagonized by antagonists of CB(1) and CB(2) receptors, AM251 and AM630, respectively (1 mg/kg, i.p.). OMDM69 might represent a template for the development of selective and even more potent inhibitors of 2-AG hydrolysis.
PMID: 19027877 [PubMed - as supplied by publisher]