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No description available.

Multiple sclerosis (MS) is a demyelinating neurodegenerative disease that typically has a relapsing-remitting pattern of progression superimposed on a gradual worsening of disease symptoms. Experimental autoimmune encephalomyelitis (EAE) is a model of MS where animals develop relapses, demyelination and accumulate neurological deficits. Studies using the EAE model have provided evidence that cannabinoids are beneficial in reducing disease symptoms and may impact long term neurodegeneration, but side-effects of exogenous cannabinoid receptor agonists may limit their potential as therapeutic agents for MS. Targeting enzymes involved in degradation of endocannabinoids such as the anandamide-degrading enzyme fatty acid amide hydrolase (FAAH) may be an attractive alternative strategy. Using experimental allergic encephalomyelitis (EAE) as a mouse model of MS, two complementary approaches were used to assess FAAH as a potential therapeutic target. The FAAH deficient (ABH.FAAH-/-) developed similar paralytic relapsing disease of similar severity of disease compared to the wild-type, but showed a poorer recovery following the acute phase. However, following a relapsing-remitting disease course, the FAAH deficient mice showed a substantial improvement in clinical score, improved motor control, and lost less neurofilament compared to wild-type mice. These findings indicate that fatty acid amides may be neuroprotective in EAE. Secondly, a selective FAAH inhibitor (PF-3845; 10 mg/kg) was used to treat mice during the relapse phase of the disease course. Treatment with PF-3845 caused an elevation of anandamide in the CNS. This treatment resulted in a small reduction in neurofilament loss, but no reduction in clinical score or improvement in motor control was observed compared to the vehicle treated group. To investigate at a cellular level how FAAH might affect disease progression in the EAE model, immunohistochemistry was used to analyse FAAH expression in the CNS. Employing novel antibodies to FAAH in combination with neuronal and glial cell markers, it was found that, in addition to previously reported neuronal expression of FAAH, FAAH is highly expressed 3 in oligodendrocytes, but not in other glial cell types. Thus, genetic deletion or pharmacological inhibition of FAAH may affect both neuronal activity and oligodendroglial function (e.g. myelination). The role of FAAH in oligodendrocytes was investigated in vitro. An oligodendrocyte precursor cell (OPC) monoculture was used to monitor differentiation, and a co-culture comprising neurons and OPCs was used to monitor myelination. During the differentiation of OPCs, FAAH expression was detected in the entire oligodendroglia lineage, but with high expression only in mature myelin basic protein (MBP) expressing cells. Treatment with the FAAH inhibitor PF-3845 (0.1 μM to 1 μM) increased differentiation of OPCs into mature oligodendrocytes. However, the same treatment of co-cultures had no effect on the myelination of neurites. In conclusion, this study has: i) obtained evidence that genetic deletion of FAAH is neuroprotective in a mouse model of MS and ii) provided new insights on FAAH expression in the CNS. Further investigation of FAAH, in particular its role(s) in oligodendrocytes, will be required to fully unlock the therapeutic potential of FAAH inhibition in the treatment of MS.

N-acylethanolamines (NAEs) are derived from a minor membrane lipid constituent N-acylphosphatidylethanolamine and are hydrolyzed by fatty acid amide hydrolases (FAAH) into free fatty acid (FFA) and ethanolamine in both plants and animals. In Arabidopsis, NAE plays an important physiological role in growth/development and response to stress. Although NAEs are reported in tomato, their metabolic pathway remains undiscovered. It is hypothesized that there is a functional FAAH in tomato that hydrolyzes NAEs. To this extent, a putative gene that likely encodes for putative SlFAAH1 protein was identified, cloned, and heterologously expressed. Amidase activity was tested using radiolabeled NAE substrates. Furthermore, expression of putative SlFAAH1 transcripts and protein activity was quantified at different developmental stages to demonstrate endogenous amidase activity in tomato seedlings. In future, molecular and biochemical characterization of tomato FAAH will further test the conserved nature of NAE metabolic pathway in plants.

Recent evidence suggesting that the endogenous cannabinoid (ECB) system can be selectively manipulated to facilitate or impair the extinction of learned behaviours — specifically regarding drug-induced aversive memories — has important consequences for research on opiate withdrawal and abstinence. Data presented here support and expand previous findings that the ECB system has an important function in the extinction of aversively motivated behaviors and is mediated by i) an increase in available endogenous CB1 receptor agonists, primarily anandamide, and ii) the exogenous CB1 receptor agonist Δ9-THC, in a manner that is dependent upon both the dose and route of administration. Experiments demonstrated that the fatty acid amide hydrolase (FAAH) inhibitor, URB597, which blocks deactivation of endogenous CB1 ligands, such as anandamide, significantly facilitated extinction of naloxone-precipitated morphine withdrawal-induced conditioned cue aversion, whereas the CB1 receptor antagonist/inverse agonist SR141716 significantly impaired extinction. Several experiments demonstrated that neither the CB1 antagonist AM251 nor the FAAH inhibitor URB597 had any effect on extinction learning for morphine-induced conditioned cue preference. A method was developed for analysing cannabinoid levels in blood by liquid chromatography/mass spectrometry (LC/MS) to compare bioavailable levels of Δ9-THC and its primary psychoactive metabolite. Experiments were designed to meet three primary objectives: 1) to provide further support for the role of the ECB system in the extinction of aversively-motivated behaviours, 2) to compare bioavailable levels of Δ9-THC and its primary psychoactive metabolite, 11-OH-Δ9-THC, after pulmonary and parenteral administration, and 3) to demonstrate that the route of administration of Δ9-THC can have a significant impact on whether or not it facilitates or impairs extinction learning. Results showed that inhaled Δ9-THC dose- and time-dependently facilitated rates of extinction learning of the conditioned aversion whereas injected Δ9-THC significantly impaired extinction. These data suggest that the route of administration of Δ9-THC has important consequences for its resulting pharmacokinetic and behavioural effects, specifically, that pulmonary exposure facilitates, whereas parenteral exposure impairs, rates of extinction learning for conditioned cue aversion. Thus, pulmonary administration of Δ9-THC may prove more beneficial for pharmacological potentiation of extinction learning for aversive memories, such as those supporting drug-craving/seeking in opiate withdrawal-syndrome. / NSERC and OGS