Development of a potent inhibitor of 2-arachidonoylglycerol hydrolysis with antinociceptive activity in vivo.
Although inhibitors of the enzymatic hydrolysis of the endocannabinoid 2-arachidonoylglycerol are available, they are either rather weak in vitro (IC(50)>30 microM) 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 microM<IC(50)<0.41 microM towards 2-AG hydrolysing activities in COS-7 cells and rat cerebellum, and inhibited (IC(50)=0.89 microM) the human recombinant MAGL, whilst being inactive (K(i)>10 microM) 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 microM). OMDM169 inhibited fatty acid amide hydrolase and diacylglycerol lipase only at higher concentrations (IC(50)=3.0 and 2.8 microM, 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 the 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.
Bisogno
Tiziana
T
Institute of Biomolecular Chemistry, C.N.R., Pozzuoli (Naples), Italy.
Ortar
Giorgio
G
Petrosino
Stefania
S
Morera
Enrico
E
Palazzo
Enza
E
Nalli
Marianna
M
Maione
Sabatino
S
Di Marzo
Vincenzo
V
D000700:Analgesics / Q000138:chemical synthesis* / Q000494:pharmacology*; D000818:Animals; D001095:Arachidonic Acids / Q000037:antagonists & inhibitors* / Q000378:metabolism; D019556:COS Cells; D002522:Chlorocebus aethiops; D063388:Endocannabinoids; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000494:pharmacology*; D005559:Formamides / Q000138:chemical synthesis* / Q000494:pharmacology*; D005989:Glycerides / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis / Q000187:drug effects; D020128:Inhibitory Concentration 50; D008071:Lipoprotein Lipase / Q000378:metabolism; D051379:Mice; D008994:Monoacylglycerol Lipases / Q000378:metabolism; D011420:Propiolactone / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D051381:Rats
D000700:Analgesics; D001095:Arachidonic Acids; D063388:Endocannabinoids; D004791:Enzyme Inhibitors; D005559:Formamides; D005989:Glycerides; C538985:OMDM 169; D011420:Propiolactone; C094503:glyceryl 2-arachidonate; D008994:Monoacylglycerol Lipases; D008071:Lipoprotein Lipase