Characterization of the Fatty Acid Amide Hydrolase Inhibitor Cyclohexyl Carbamic Acid 3'-Carbamoyl-biphenyl-3-yl Ester (URB597): Effects on Anandamide and Oleoylethanolamide Deactivation (original) (raw)
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Frontiers in Pharmacology
biochemist working in the neurosciences, I was always fascinated with neurotransmitter inactivation. In 1993 we identified an enzyme activity that breaks down anandamide. We called the enzyme anandamide amidase, now called FAAH. We and other laboratories developed FAAH inhibitors that were useful reagents that also proved to have beneficial physiological effects and until recently, new generations of inhibitors were in clinical trials. Nearly all neurotransmitters are water soluble and as such, require a transmembrane protein transporter to pass through the lipid membrane for inactivation inside the cell. However, using model systems, we and others have shown that this is unnecessary for anandamide, an uncharged hydrophobic molecule that readily diffuses across the cellular membrane. Interestingly, its uptake is driven by the concentration gradient resulting from its breakdown mainly by FAAH localized in the endoplasmic reticulum. We identified the FABPs as intracellular carriers that "solubilize" anandamide, transporting anandamide to FAAH. Compounds that bind to FABPs block AEA breakdown, raising its level. The cannabinoids (THC and CBD) also were discovered to bind FABPs and this may be one of the mechanisms by which CBD works in childhood epilepsy, raising anandamide levels. Targeting FABPs may be advantageous since they have some tissue specificity and do not require reactive serine hydrolase inhibitors, as does FAAH, with potential for off-target reactions. At the International Cannabis Research Society Symposium in 1992, Raphe Mechoulam revealed that his laboratory isolated an endogenous lipid molecule that binds to the CB1 receptor (cannabinoid receptor type 1) and this became the milestone paper published in December of that year describing anandamide (AEA, Devane et al., 1992). As to be expected, this discovery raised the issues of AEA's synthesis and breakdown.
Biological Psychiatry, 2008
Background-CB 1 cannabinoid receptors in the brain are known to participate in the regulation of reward-based behaviors, however, the contribution of each of the endocannabinoid transmitters, anandamide and 2-arachidonoylglycerol (2-AG), to these behaviors remains undefined. To address this question, we assessed the effects of URB597, a selective anandamide deactivation inhibitor, as a reinforcer of drug-seeking and drug-taking behavior in squirrel monkeys.
The fatty acid amide hydrolase inhibitor URB 597: interactions with anandamide in rhesus monkeys
British Journal of Pharmacology, 2011
The fatty acid amide hydrolase inhibitor URB 597 increases brain anandamide levels, suggesting that URB 597 could enhance the behavioural effects of anandamide. The goal of the current study was to examine and characterize the in vivo pharmacology of URB 597 alone and in combination with anandamide and D 9 -tetrahydrocannabinol (D 9 -THC) in two drug discrimination assays in rhesus monkeys.
profile, responsiveness to anandamide, and baroreflex sensitivity of mice lacking fatty acid amide hydrolase. The endocannabinoid anandamide exerts neurobehavioral, cardiovascular, and immune-regulatory effects through cannabinoid receptors (CB). Fatty acid amide hydrolase (FAAH) is an enzyme responsible for the in vivo degradation of anandamide. Recent experimental studies have suggested that targeting the endocannabinergic system by FAAH inhibitors is a promising novel approach for the treatment of anxiety, inflammation, and hypertension. In this study, we compared the cardiac performance of FAAH knockout (FAAH Ϫ/Ϫ ) mice and their wild-type (FAAH ϩ/ϩ ) littermates and analyzed the hemodynamic effects of anandamide using the Millar pressure-volume conductance catheter system. Baseline cardiovascular parameters, systolic and diastolic function at different preloads, and baroreflex sensitivity were similar in FAAH Ϫ/Ϫ and FAAH ϩ/ϩ mice. FAAH Ϫ/Ϫ mice displayed increased sensitivity to anandamide-induced, CB 1-mediated hypotension and decreased cardiac contractility compared with FAAH ϩ/ϩ littermates. In contrast, the hypotensive potency of synthetic CB 1 agonist HU-210 and the level of expression of myocardial CB 1 were similar in the two strains. The myocardial levels of anandamide and oleoylethanolamide, but not 2-arachidonylglycerol, were increased in FAAH Ϫ/Ϫ mice compared with FAAH ϩ/ϩ mice. These results indicate that mice lacking FAAH have a normal hemodynamic profile, and their increased responsiveness to anandamide-induced hypotension and cardiodepression is due to the decreased degradation of anandamide rather than an increase in target organ sensitivity to CB 1 agonists. contractility; hypertension; cannabinoids; endocannabinoids TWO TYPES OF CANNABINOID (CB) RECEPTORS, identified by molecular cloning, are responsible for the biological effects of marijuana and its main psychoactive ingredient ⌬ 9 -tetrahydrocannabinol (THC). The CB receptor type 1 (CB 1 ) is most abundant in the central nervous system (31) but can also be found in cardiovascular tissues . The CB 2 receptor is expressed predominantly by hematopoietic and immune cells (34). The primary endogenous ligands of these receptors, the endocannabinoids, comprise arachidonoyl ethanolamide or anandamide (AEA) and 2-arachidonoylglycerol (2-AG) (reviewed in Ref. 32). Besides well-known neurobehavioral and * P. Pacher and S. Bátkai contributed equally to this work.
Fatty acid amide hydrolase (FAAH) is a membrane- bound enzyme activity that degrades neuromodula- tory fatty acid amides, including oleamide and anan- damide. A single 2.5-kb FAAH mRNA is distributed throughout the rat CNS and accumulates progres- sively between embryonic day 14 and postnatal day 10, remains high until postnatal day 30, then decreases into adulthood. FAAH enzymatic activity, as mea- sured in dissected brain regions, was well correlated with the distribution of its messenger RNA. In situ hybridization revealed profound distribution of FAAH mRNA in neuronal cells throughout the CNS. The most prominent signals were detected in the neocor- tex, hippocampal formation, amygdala, and cerebel- lum. The FAAH distribution in the CNS suggests that degradation of neuromodulatory fatty acid amides at their sites of action influences their effects on sleep, euphoria, and analgesia. J. Neurosci. Res. 50:1047- 1052, 1997. r 1997 Wiley-Liss, Inc.
The Journal of Neuroscience, 2003
A number of recent in vitro studies have described a role for endogenous cannabinoids ("endocannabinoids") as transsynaptic modulators of neuronal activity in the hippocampus and other brain regions. However, the impact that endocannabinoid signals may have on activity-dependent neural events in vivo remains mostly unknown and technically challenging to address because of the short half-life of these chemical messengers in the brain. Mice lacking the enzyme fatty acid amide hydrolase [FAAH (Ϫ/Ϫ) mice] are severely impaired in their ability to degrade the endocannabinoid anandamide and therefore represent a unique animal model in which to examine the function of this signaling lipid in vivo. Here, we show that the administration of anandamide dramatically augments the severity of chemically induced seizures in FAAH (Ϫ/Ϫ) mice but not in wild-type mice. Anandamide-enhanced seizures in FAAH (Ϫ/Ϫ) mice resulted in significant neuronal damage in the CA1 and CA3 regions of the hippocampus for the bicuculline and kainate models, respectively. Notably, in the absence of anandamide treatment, FAAH (Ϫ/Ϫ) mice exhibited enhanced seizure responses to high doses of kainate that correlated with greatly elevated endogenous levels of anandamide in the hippocampus of these animals. Collectively, these studies suggest that both exogenously administered and endogenously produced anandamide display FAAH-regulated proconvulsant activity and do not support a general neuroprotective role for this endocannabinoid in response to excitotoxic stimuli in vivo. More generally, these findings demonstrate that the disinhibitory actions of endocannabinoids observed in hippocampal slices in vitro may also occur in vivo.
Biochemical and Biophysical Research Communications, 2000
Treatment of intact human neuroblastoma CHP100 cells with anandamide (arachidonoylethanolamide, AEA) or 2-arachidonoylglycerol (2-AG) inhibits intracellular fatty acid amide hydrolase (FAAH). This effect was not associated with covalent modifications of FAAH, since specific inhibitors of farnesyltransferase, kinases, phosphatases, glycosyltransferase or nitric oxide synthase were ineffective. Electrophoretic analysis of 33 P-labelled proteins, Western blot with antiphosphotyrosine antibodies, and glycan analysis of cellular proteins confirmed the absence of covalent modifications of FAAH. The inhibition by AEA was paralleled by an increased arachidonate release, which was not observed upon treatment of cells with linoleoylethanolamide, palmitoylethanolamide, or oleoylethanolamide. Moreover, cell treatment with AEA or 2-AG increased the activity of cyclooxygenase and 5-lipoxygenase, and the hydro(pero)xides generated from arachidonate by lipoxygenase were shown to inhibit FAAH, with inhibition constants in the low micromolar range. Consistently, inhibitors of 5-lipoxygenase, but not those of cyclooxygenase, significantly counteracted the inhibition of FAAH by AEA or 2-AG.
Role of fatty acid amide hydrolase in the transport of the endogenous cannabinoid anandamide
Molecular pharmacology, 2001
A facilitated transport process that removes the endogenous cannabinoid anandamide from extracellular spaces has been identified. Once transported into the cytoplasm, fatty acid amide hydrolase (FAAH) is responsible for metabolizing the accumulated anandamide. We propose that FAAH contributes to anandamide uptake by creating and maintaining an inward concentration gradient for anandamide. To explore the role of FAAH in anandamide transport, we examined anandamide metabolism and uptake in RBL-2H3 cells, which natively express FAAH, as well as wild-type HeLa cells that lack FAAH. RBL-2H3 and FAAH-transfected HeLa cells demonstrated a robust ability to metabolize anandamide compared with vector-transfected HeLa cells. This activity was reduced to that observed in wild-type HeLa cells upon the addition of the FAAH inhibitor methyl arachidonyl fluorophosphonate. Anandamide uptake was reduced in a dose-dependent manner by various FAAH inhibitors in both RBL-2H3 cells and wild-type HeLa ce...