LY2183240

LY2183240 is a highly potent blocker of anandamide uptake with IC50 value of 270 pM, and an inhibitor of fatty acid amide hydrolase (FAAH) activity with IC50 value of 12.4 nM [1].

Fatty acid amide hydrolase (FAAH) belongs to the family of serine hydrolase, which is an integral membrane enzyme. It has esterase and amidase activity that are responsive for the uptake of fatty acid amide (FAA) family signaling lipids, including anandamide. The uptake and metabolic process of anandamide is mainly achieved by FAAH, therefore the inhibition of FAAH may result in the blockage of anadaminde uptake.

LY2183240 is a potent and covalent inhibitor of FAAH, with the effect of blocking anandamide uptake. Biochemical research had identified that LY2183240 inactivate FAAH via carbamylation of the serine nucleophile of FAAH [2]. In RBL cell line containing FAAH, radioactive labeled 3H-LY2183240 exhibited strong binding to FAAH, inhibition of FAAH and thus blockage of anandamide uptake. However, in HeLa cells lacking FAAH, 3H-LY2183240 was less bound, and the blockage of anandamide uptake was very weak. It suggested that the direct interaction between LY2183240 and FAAH was required to block the anandamide uptake. However, it also indicated that there might be uncharacterized pathways of anandamide uptake regulated by LY2183240, independent from FAAH [1]. However, FAAH is not the sole target for LY2183240. Several uncharacterized brain serine hydrolases were also identified as the target of LY2183240, and these might be additional pathway for anandamide uptake [2].

In mouse model, 10 mg/kg injection of LY2183240 would produce analgesic effects in the formalin test of noxious pain which is a phenotype associated with elevated level of anandamide in brain. It indicated LY2183240 might inhibit FAAH in vivo [2]. When mice were administrated with LY2183240 (10 mg/kg, ip) for 90 min, characterization of brain tissues revealed that LY2183240 inactivated FAAH and other brain serine hydrolases ranging from 25-35 kDa [2].

References:
[1] Dickason-Chesterfield A K et al. , Pharmacological characterization of endocannabinoid transport and fatty acid amide hydrolase inhibitors. Cell Mol Neurobiol. 2006, 26(4-6): 407-23.
[2] Alexander J P, Cravatt B F.  The putative endocannabinoid transport blocker LY2183240 is a potent inhibitor of FAAH and several other brain serine hydrolases. J Am Chem Soc. 2006, 128(30): 9699-9704.

The putative endocannabinoid transport blocker LY2183240 is a potent inhibitor of FAAH and several other brain serine hydrolases.[Pubmed:16866524]

J Am Chem Soc. 2006 Aug 2;128(30):9699-704.

How lipid transmitters move within and between cells to communicate signals remains an important and largely unanswered question. Integral membrane transporters, soluble lipid-binding proteins, and metabolic enzymes have all been proposed to collaboratively regulate lipid signaling dynamics in vivo. Assignment of the relative contributions made by each of these classes of proteins requires selective pharmacological agents to perturb their individual functions. Recently, LY2183240, a heterocyclic urea inhibitor of the putative endocannabinoid (EC) transporter, was shown to disrupt the cellular uptake of the lipid EC anandamide and promote analgesia in vivo. Here, we show that LY2183240 is a potent, covalent inhibitor of the EC-degrading enzyme fatty acid amide hydrolase (FAAH). LY2183240 inactivates FAAH by carbamylation of the enzyme's serine nucleophile. More global screens using activity-based proteomic probes identified several additional serine hydrolases that are also inhibited by LY2183240. These results indicate that the blockade of anandamide uptake observed with LY2183240 may be due primarily to the inactivation of FAAH, providing further evidence that this enzyme serves as a metabolic driving force that promotes the diffusion of anandamide into cells. More generally, the proteome-wide target promiscuity of LY2183240 designates the heterocyclic urea as a chemotype with potentially excessive protein reactivity for drug design.

Effects of the novel endocannabinoid uptake inhibitor, LY2183240, on fear-potentiated startle and alcohol-seeking behaviors in mice selectively bred for high alcohol preference.[Pubmed:20838777]

Psychopharmacology (Berl). 2010 Dec;212(4):571-83.

RATIONALE: Alcohol-use disorders often occur together with anxiety disorders in humans which may be partly due to common inherited genetic factors. Evidence suggests that the endocannabinoid system (ECS) is a promising therapeutic target for the treatment of individuals with anxiety and/or alcohol-use disorders. OBJECTIVES: The present study assessed the effects of a novel endocannabinoid uptake inhibitor, LY2183240, on anxiety- and alcohol-seeking behaviors in a unique animal model that may represent increased genetic risk to develop co-morbid anxiety and alcohol-use disorders in humans. Mice selectively bred for high alcohol preference (HAP) show greater fear-potentiated startle (FPS) than mice selectively bred for low alcohol preference (LAP). We examined the effects of LY2183240 on the expression of FPS in HAP and LAP mice and on alcohol-induced conditioned place preference (CPP) and limited-access alcohol drinking behavior in HAP mice. RESULTS: Repeated administration of LY2183240 (30 mg/kg) reduced the expression of FPS in HAP but not LAP mice when given prior to a second FPS test 48 h after fear conditioning. Both the 10 and 30 mg/kg doses of LY2183240 enhanced the expression of alcohol-induced CPP and this effect persisted in the absence of the drug. LY2183240 did not alter limited-access alcohol drinking behavior, unconditioned startle responding, or locomotor activity. CONCLUSIONS: These findings suggest that ECS modulation influences both conditioned fear and conditioned alcohol reward behavior. LY2183240 may be an effective pharmacotherapy for individuals with anxiety disorders, such as post-traumatic stress disorder, but may not be appropriate for individuals with co-morbid anxiety and alcohol-use disorders.

Pharmacological characterization of endocannabinoid transport and fatty acid amide hydrolase inhibitors.[Pubmed:16736384]

Cell Mol Neurobiol. 2006 Jul-Aug;26(4-6):407-23.

: 1. The mechanism of anandamide uptake and disposal has been an issue of considerable debate in the cannabinoid field. Several compounds have been reported to inhibit anandamide uptake or fatty acid amide hydrolase (FAAH; the primary catabolic enzyme of anandamide) activity with varying degrees of potency and selectivity. We recently reported the first evidence of a binding site involved in the uptake of endocannabinoids that is independent from FAAH. There are no direct comparisons of purported selective inhibitory compounds in common assay conditions measuring anandamide uptake, FAAH activity and binding activity. 2. A subset of compounds reported in the literature were tested in our laboratory under common assay conditions to measure their ability to (a) inhibit [(14)C]-anandamide uptake in cells containing (RBL-2H3) or cells lacking (HeLa) FAAH, (b) inhibit purified FAAH hydrolytic activity, and (c) inhibit binding to a putative binding site involved in endocannabinoid transport in both RBL and HeLa cell membranes. 3. Under these conditions, nearly all compounds tested inhibited (a) uptake of [(14)C]-anandamide, (b) enzyme activity in purified FAAH preparations, and (c) radioligand binding of [(3)H]-LY2183240 in RBL and HeLa plasma membrane preparations. General rank order potency was preserved within the three assays. However, concentration response curves were right-shifted for functional [(14)C]-anandamide uptake in HeLa (FAAH(-/-)) cells. 4. A more direct comparison of multiple inhibitors could be made in these three assay systems performed in the same laboratory, revealing more information about the selectivity of these compounds and the relationship between the putative endocannabinoid transport protein and FAAH. At least two separate proteins appear to be involved in uptake and degradation of anandamide. The most potent inhibitory compounds were right-shifted when transport was measured in HeLa (FAAH(-/-)) cells suggesting a requirement for a direct interaction with the FAAH protein to maintain high affinity binding of anandamide or inhibitors to the putative anandamide transport protein.