pf-3845 and anandamide

The endocannabinoid, anandamide (AEA), stimulates cannabinoid receptors (CBRs) and is enriched in the kidney, especially the renal medulla. AEA infused into the renal outer medulla of mice stimulates urine flow rate and salt excretion. Here we show that these effects are blocked by the CBR type 1 (CB1) inverse agonist, rimonabant. Immunohistochemical analysis demonstrated the presence of CB1 in thick ascending limb (TAL) tubules. Western immunoblotting demonstrated the presence of CB1 (52 kDa) in the cortex and outer medulla of mouse kidney. The effect of direct [CP55940 (CP) or AEA] or indirect [fatty acyl amide hydrolase (FAAH) inhibitor, PF3845 (PF)] cannabinoidimetics on Na

Topics: Amidohydrolases; Animals; Arachidonic Acids; Cannabinoid Receptor Agonists; Cannabinoid Receptor Antagonists; Cyclohexanols; Diuresis; Endocannabinoids; Loop of Henle; Male; Mice; Mice, Inbred C57BL; Natriuresis; Ouabain; Piperidines; Polyunsaturated Alkamides; Pyridines; Rimonabant; Sodium; Sodium-Potassium-Exchanging ATPase

Topics: Amidohydrolases; Animals; Arachidonic Acids; Arterial Pressure; Cyclooxygenase 2 Inhibitors; Diuresis; Endocannabinoids; Enzyme Inhibitors; Kidney Medulla; Male; Mice, Inbred C57BL; Monoacylglycerol Lipases; Piperidines; Polyunsaturated Alkamides; Pyridines

Increasing the available repertoire of effective treatments for mood and anxiety disorders represents a critical unmet need. Pharmacological augmentation of endogenous cannabinoid (eCB) signaling has been suggested to represent a novel approach to the treatment of anxiety disorders; however, the functional interactions between two canonical eCB pathways mediated via anandamide (N-arachidonylethanolamine [AEA]) and 2-arachidonoylglycerol (2-AG) in the regulation of anxiety are not well understood.. We utilized pharmacological augmentation and depletion combined with behavioral and electrophysiological approaches to probe the role of 2-AG signaling in the modulation of stress-induced anxiety and the functional redundancy between AEA and 2-AG signaling in the modulation of anxiety-like behaviors in mice.. Selective 2-AG augmentation reduced anxiety in the light/dark box assay and prevented stress-induced increases in anxiety associated with limbic AEA deficiency. In contrast, acute 2-AG depletion increased anxiety-like behaviors, which was normalized by selective pharmacological augmentation of AEA signaling and via direct cannabinoid receptor 1 stimulation with Δ. Although AEA and 2-AG likely subserve distinct physiological roles, a pharmacological and functional redundancy between these canonical eCB signaling pathways exists in the modulation of anxiety-like behaviors. These data support development of eCB-based treatment approaches for mood and anxiety disorders and suggest a potentially wider therapeutic overlap between AEA and 2-AG augmentation approaches than was previously appreciated.

Topics: Adaptation, Ocular; Animals; Anti-Anxiety Agents; Anxiety; Arachidonic Acids; Benzodioxoles; Brain; Cannabinoid Receptor Agonists; Cyclohexanols; Disease Models, Animal; Dronabinol; Endocannabinoids; Excitatory Postsynaptic Potentials; Glycerides; Heterocyclic Compounds, 1-Ring; Locomotion; Male; Mice; Mice, Inbred ICR; Piperidines; Polyunsaturated Alkamides; Pyridines; Signal Transduction

N-acylethanolamines (NAEs) such as N-palmitoylethanolamine and anandamide are endogenous bioactive lipids having numerous functions, including the control of inflammation. Their levels and therefore actions can be controlled by modulating the activity of two hydrolytic enzymes, N-acylethanolamine-hydrolyzing acid amidase (NAAA) and fatty acid amide hydrolase (FAAH). As macrophages are key to inflammatory processes, we used lipopolysaccharide-activated J774 macrophages, as well as primary mouse alveolar macrophages, to study the effect of FAAH and NAAA inhibition, using PF-3845 and AM9053 respectively, on macrophage activation and NAE levels measured by HPLC-MS. Markers of macrophage activation were measured by qRT-PCR and ELISA. Activation of macrophages decreased NAAA expression and NAE hydrolytic activity. FAAH and NAAA inhibition increased the levels of the different NAEs, although with different magnitudes, whether in control condition or following LPS-induced macrophage activation. Both inhibitors reduced several markers of macrophage activation, such as mRNA expression of inflammatory mediators, as well as cytokine and prostaglandin production, with however some differences between FAAH and NAAA inhibition. Most of the NAEs tested - including N-docosatetraenoylethanolamine and N-docosahexaenoylethanolamine - also reduced LPS-induced mRNA expression of inflammatory mediators, again with differences depending on the marker and the NAE, thus offering a potential explanation for the differential effect of the inhibitors on macrophage activation markers. In conclusion, we show different and complementary effects of NAE on lipopolysaccharide-induced macrophage activation. Our results support an important role for inhibition of NAE hydrolysis and NAAA inhibition in particular in controlling macrophage activation, and thus inflammation.

Topics: Amides; Amidohydrolases; Animals; Arachidonic Acids; Endocannabinoids; Ethanolamines; Gene Expression Regulation, Enzymologic; Humans; Inflammation; Lipopolysaccharides; Macrophage Activation; Macrophages, Alveolar; Mice; Palmitic Acids; Piperidines; Polyunsaturated Alkamides; Pyridines

Recent studies have shown that inhibition of fatty acid amide hydrolase (FAAH), the major degradative enzyme of the endocannabinoid N-arachidonoylethanolamine (AEA), produced antidepressant behavioral responses, but its underlying mechanism is not clear. Here we find that a systemic administration of the FAAH inhibitor PF3845 or an intra-CA1 application of AEA elicits an in vivo long-term depression (LTD) at excitatory glutamatergic CA3-CA1 synapses of the hippocampus. The PF3845- and/or AEA-elicited LTD are abolished by the LTD-blocking peptide Tat-GluR2. PF3845 significantly decreases passive behavioral coping of naïve mice to acute inescapable stress, which is also abolished by Tat-GluR2 peptide. However, PF3845 does not significantly affect sucrose assumption ratio of mice receiving chronic administration of corticosterone. These results suggest that FAAH inhibitors are able to produce antidepressant effects in naïve animals in response to acute stress through LTD at hippocampal glutamatergic CA3-CA1 synapses.

Topics: Adaptation, Psychological; Amidohydrolases; Animals; Antidepressive Agents; Arachidonic Acids; Astrocytes; Depression; Endocannabinoids; Hippocampus; Long-Term Synaptic Depression; Male; Mice; Mice, Inbred C57BL; Motor Activity; Piperidines; Polyunsaturated Alkamides; Pyridines; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Stress, Psychological

Autism spectrum disorders are a group of neurodevelopmental disorders characterised by impaired social interaction, deficits in communication and repetitive stereotyped behaviours. The endocannabinoid system plays an important role in modulating emotionality and social responding, however there have been a paucity of studies investigating this system in autistic animal models. This study investigated the effect of inhibiting fatty acid amide hydrolyase (FAAH), the anandamide catabolic enzyme, on behavioural responding in the valproic acid (VPA) rat model of autism. Male rats prenatally exposed to VPA exhibit an autistic-like behavioural phenotype exemplified as thermal hypoalgesia, reduced social and exploratory behaviour, and enhanced repetitive behaviour. Systemic administration of the FAAH inhibitor PF3845 (10mg/kg) attenuated the deficit in social behaviour observed in VPA exposed male animals without altering nociceptive, repetitive or exploratory behaviour. In comparison, female VPA exposed rats displayed enhanced repetitive and reduced exploratory behaviour, but no change in social behaviour or thermal nociceptive responding. PF3845 did not alter social, repetitive or thermal nociceptive responding, but reduced exploratory behaviour in a social context in VPA-, but not saline-, exposed females. These data indicate that FAAH inhibition elicits sexual dimorphic effects on behavioural responding in VPA exposed rodents, and support an important role for FAAH in the regulation of social behavioural deficits in autistic males.

Topics: Amidohydrolases; Animals; Arachidonic Acids; Autistic Disorder; Behavior, Animal; Disease Models, Animal; Endocannabinoids; Female; Male; Piperidines; Polyunsaturated Alkamides; Pyridines; Rats; Rats, Sprague-Dawley; Sex Characteristics; Social Behavior; Valproic Acid

Amelioration of neuropathic spinal cord injury (SCI) pain is a clinical challenge. Increasing the endocannabinoid anandamide and other fatty acid amides (FAA) by blocking fatty acid amide hydrolase (FAAH) has been shown to be antinociceptive in a number of animal models of chronic pain. However, an antinociceptive effect of blocking FAAH has yet to be demonstrated in a rat model of neuropathic SCI pain. Four weeks following a SCI, rats developed significantly decreased hind paw withdrawal thresholds, indicative of below-level cutaneous hypersensitivity. A group of SCI rats were systemically treated (i.p.) with either the selective FAAH inhibitor URB597 or vehicle twice daily for seven days. A separate group of SCI rats received a single dose (p.o.) of either the selective FAAH inhibitor PF-3845 or vehicle. Following behavioral testing, levels of the FAA N-arachidonoylethanolamide, N-oleoyl ethanolamide and N-palmitoyl ethanolamide were quantified in brain and spinal cord from SCI rats. Four weeks following SCI, FAA levels were markedly reduced in spinal cord tissue. Although systemic treatment with URB597 significantly increased CNS FAA levels, no antinociceptive effect was observed. A significant elevation of CNS FAA levels was also observed following oral PF-3845 treatment, but only a modest antinociceptive effect was observed. Increasing CNS FAA levels alone does not lead to robust amelioration of below-level neuropathic SCI pain. Perhaps utilizing FAAH inhibition in conjunction with other analgesic mechanisms could be an effective analgesic therapy.

Topics: Amidohydrolases; Analgesics; Animals; Arachidonic Acids; Benzamides; Benzoxazines; Brain; Carbamates; Endocannabinoids; Enzyme Inhibitors; Hindlimb; Male; Morpholines; Naphthalenes; Neuralgia; Pain Measurement; Pain Threshold; Piperidines; Polyunsaturated Alkamides; Pyridines; Rats, Sprague-Dawley; Spinal Cord; Spinal Cord Injuries; Treatment Outcome

Inflammatory pain presents a problem of clinical relevance and often elicits allodynia, a condition in which non-noxious stimuli are perceived as painful. One potential target to treat inflammatory pain is the endogenous cannabinoid (endocannabinoid) system, which is comprised of CB1 and CB2 cannabinoid receptors and several endogenous ligands, including anandamide (AEA). Blockade of the catabolic enzyme fatty acid amide hydrolase (FAAH) elevates AEA levels and elicits antinociceptive effects, without the psychomimetic side effects associated with Δ(9) -tetrahydrocannabinol (THC).. Allodynia was induced by intraplantar injection of LPS. Complementary genetic and pharmacological approaches were used to determine the strategy of blocking FAAH to reverse LPS-induced allodynia. Endocannabinoid levels were quantified using mass spectroscopy analyses.. FAAH (-/-) mice or wild-type mice treated with FAAH inhibitors (URB597, OL-135 and PF-3845) displayed an anti-allodynic phenotype. Furthermore, i.p. PF-3845 increased AEA levels in the brain and spinal cord. Additionally, intraplantar PF-3845 produced a partial reduction in allodynia. However, the anti-allodynic phenotype was absent in mice expressing FAAH exclusively in the nervous system under a neural specific enolase promoter, implicating the involvement of neuronal fatty acid amides (FAAs). The anti-allodynic effects of FAAH-compromised mice required activation of both CB1 and CB2 receptors, but other potential targets of FAA substrates (i.e. µ-opioid, TRPV1 and PPARα receptors) had no apparent role.. AEA is the primary FAAH substrate reducing LPS-induced tactile allodynia. Blockade of neuronal FAAH reverses allodynia through the activation of both cannabinoid receptors and represents a promising target to treat inflammatory pain.. This article is part of a themed section on Cannabinoids in Biology and Medicine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-8. To view Part I of Cannabinoids in Biology and Medicine visit http://dx.doi.org/10.1111/bph.2011.163.issue-7.

Topics: Amidohydrolases; Animals; Arachidonic Acids; Brain; Endocannabinoids; Enzyme Inhibitors; Female; Glycerides; Hyperalgesia; Inflammation; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Peripheral Nervous System; Piperidines; Polyunsaturated Alkamides; Pyridines; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Spinal Cord

Fatty acid amide hydrolase (FAAH) regulates amidated lipid transmitters, including the endocannabinoid anandamide and its N-acyl ethanolamine (NAE) congeners and transient receptor potential channel agonists N-acyl taurines (NATs). Using both the FAAH inhibitor PF-3845 and FAAH(-/-) mice, we present a global analysis of changes in NAE and NAT metabolism caused by FAAH disruption in central and peripheral tissues. Elevations in anandamide (and other NAEs) were tissue dependent, with the most dramatic changes occurring in brain, testis, and liver of PF-3845-treated or FAAH(-/-) mice. Polyunsaturated NATs accumulated to very high amounts in the liver, kidney, and plasma of these animals. The NAT profile in brain tissue was markedly different and punctuated by significant increases in long-chain NATs found exclusively in FAAH(-/-), but not in PF-3845-treated animals. Suspecting that this difference might reflect a slow pathway for NAT biosynthesis, we treated mice chronically with PF-3845 for 6 days and observed robust elevations in brain NATs. These studies, taken together, define the anatomical and temporal features of FAAH-mediated NAE and NAT metabolism, which are complemented and probably influenced by kinetically distinguishable biosynthetic pathways that produce these lipids in vivo.

Topics: Adipose Tissue, White; Amidohydrolases; Animals; Arachidonic Acids; Brain; Endocannabinoids; Enzyme Inhibitors; Ethanolamines; Kidney; Liver; Male; Mice; Piperidines; Polyunsaturated Alkamides; Pyridines; Substrate Specificity; Taurine; Testis; Tissue Distribution

Endocannabinoids are lipid signaling molecules that regulate a wide range of mammalian behaviors, including pain, inflammation, and cognitive/emotional state. The endocannabinoid anandamide is principally degraded by the integral membrane enzyme fatty acid amide hydrolase (FAAH), and there is currently much interest in developing FAAH inhibitors to augment endocannabinoid signaling in vivo. Here, we report the discovery and detailed characterization of a highly efficacious and selective FAAH inhibitor, PF-3845. Mechanistic and structural studies confirm that PF-3845 is a covalent inhibitor that carbamylates FAAH's serine nucleophile. PF-3845 selectively inhibits FAAH in vivo, as determined by activity-based protein profiling; raises brain anandamide levels for up to 24 hr; and produces significant cannabinoid receptor-dependent reductions in inflammatory pain. These data thus designate PF-3845 as a valuable pharmacological tool for in vivo characterization of the endocannabinoid system.

Topics: Amidohydrolases; Animals; Arachidonic Acids; Brain; Crystallography, X-Ray; Endocannabinoids; Enzyme Inhibitors; Humans; Male; Pain; Piperazine; Piperazines; Piperidines; Polyunsaturated Alkamides; Rats; Rats, Sprague-Dawley; Receptors, Cannabinoid; Structure-Activity Relationship; Urea