No description available.

No description available.

No description available.

N-acylethanolamines (NAEs) including anandamide are lipid derivative molecules, which play vital roles in physiological and developmental processes in plants and animals and mediate stress responses. In mammals, NAEs are synthesized from hydrolysis of their precursor molecule N-acylphosphatidylethanolamine (NAPE) by NAPE-specific phospholipaseD (NAPE-PLD). All NAEs including anandamide (NAE20:4) are hydrolyzed by fatty acid amide hydrolase (FAAH) into free fatty acid and ethanolamine. To date, different NAEs including anandamide have been identified in Physcomitrella patens but its metabolic pathway remains undiscovered. It is hypothesized that NAE metabolic pathway in P. patens is conserved and is similar to that of other eukaryotic systems. To this extent, putative PpNAPE-PLD and PpFAAH were identified and cloned for heterologous expression and characterization. Expression of PpFAAH was further verified by Western blot analysis. Future studies will involve biochemical characterization of putative PpNAPE-PLD and PpFAAH, to establish the evolutionarily conserved nature of NAE functions in early land plants.

N-acylethanolamines (NAEs) with C12-C18 acyl chain are ubiquitous in seed plants and play a role in mediating abscisic acid (ABA)-dependent or -independent responses to stress. In moss Physcomitrella patens, using selective lipidomics approach, we recently identified the occurrence of anandamide or N-arachidonylethanolamide (NAE 20:4) and its precursors that were previously not reported in plants. Occurrence of anandamide in moss provides us with a unique opportunity to address if early land plants retained NAE-mediated signaling mechanism that is akin to animals but not to vascular plants. It is hypothesized that a distinctive NAE profile and metabolic pathway occurs in P. patens. To this extent, putative genes that might be responsible for anandamide metabolic pathway were identified and their expression levels were determined for three developmental stages of moss. The NAE metabolite levels and transcript levels for putative genes were higher in protonema stage and anandamide showed higher growth inhibitory effects, chlorophyll reduction, and putative gene induction than NAE 12:0, compared to ABA, when applied exogenously.

N-Acylethanolamines (NAEs) are bioactive acylamides that are present in a wide range of organisms. Because NAE levels in seeds decline during imbibition similar to ABA, a physiological role was predicted for these metabolites in Arabidopsis thaliana seed germination and seedling development. There is also a corresponding increase of AtFAAH (fatty acid amide hydrolase), transcript levels and activity, which metabolizes NAE to ethanolamine and free fatty acids. Based on whole genome microarray studies it was determined that a number of up-regulated genes that were responsive to NAE were also ABA responsive. NAE induced gene expression in these ABA responsive genes without elevating endogenous levels of ABA. It was also determined that many of these NAE/ABA responsive genes were associated with an ABA induced secondary growth arrest, including ABI3. ABI3 is a transcription factor that regulates the transition from embryo to seedling growth, the analysis of transcript levels in NAE treated seedlings revealed a dose dependent, inverse relationship between ABI3 transcript levels and growth, high ABI3 transcript levels were associated with growth inhibition. Similar to ABA, NAE negatively regulated seedling growth within a narrow window of early seedling establishment. When seedlings are exposed to NAE or ABA within the window of sensitivity, the induction of genes normally associated with the ungerminated desiccation tolerant state resumed. The NAE tolerant FAAH overexpressor and the NAE sensitive FAAH knockout both had a NAE/ABA sensitive window similar to the wild type A. thaliana. The abi3-1 ABA insensitive mutant does not undergo growth arrest upon exposure to ABA, but NAE did induce growth arrest when treated within the sensitivity window. This evidence showed that although NAE functions within an ABA dependent pathway, it also functions in an ABA independent signaling pathway. The FAAH overexpressor is tolerant to NAE through its ability to quickly metabolize NAE from the growth media, yet it is hypersensitive to ABA. The FAAH overexpressor also displayed hypersensitivity to GA, which improved its delayed germination in non-stratified seed, while the FAAH knock out showed GA insensitivity. Overall, these results showed that NAE functions as a negative regulator of germinating seed and seedling growth in ABA dependent and independent signaling pathways, and that altered NAE metabolism may interfere with ABA/GA perception in germinating seed.

No description available.

Classically, endogenous fatty acid ethanolamides and their derivatives that bind to the cannabinoid receptors and trigger a signalling pathway are referred to as endocannabinoids. Although derivatives of arachidonic acid, including arachidonylethanolamine or anandamide, are the known endogenous ligands for cannabinoid receptors, other fatty acid ethanolamides or N-acylethanolamines (NAE) that vary in carbon chain length and saturation occur ubiquitously in eukaryotic organisms and play an important role in their physiology and development. The metabolic pathway for NAEs is highly conserved among eukaryotes and well characterised in mammalian systems. Although NAE pathway is only partly elucidated in plants, significant progress has been made in the past 20 years in understanding the implications of the metabolism of saturated and unsaturated endocannabinoid-like molecules in plant development and growth. The latest advancements in the field of plant endocannabinoid research are reviewed. Key Concepts Endocannabinoids are endogenous ligands of cannabinoid receptors in mammalian systems. Endocannabinoids belong to a class of small bioactive lipid molecules that are derivatives of fatty acids including their ethanolamides, referred to as N-acylethanolamines. N-Acylethanolamines are ubiquitous and their metabolic pathway is highly conserved among eukaryotes. In higher plants, only 12–18C N-acylethanolamines have been identified and their metabolic pathway is partly elucidated. The endocannabinoid-like lipids play an important role in seed germination, seedling development, flowering and cellular organisation. In plants, N-acylethanolamines also participate in mediating responses to biotic and abiotic stress.

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

Fatty acid amide hydrolase (FAAH) is a widely conserved amidase in eukaryotes, best known for inactivating the signal of N-acylethanolamine (NAE) lipid mediators. In the plant Arabidopsis thaliana, FAAH-mediated hydrolysis of NAEs has been associated with numerous biological processes. Recently, the phylogenetic distribution of FAAH into two major branches (group I and II FAAHs) across angiosperms outside of Arabidopsis (and in other Brassicaceae), suggests a previously unrecognized complexity of this enzyme. Although A. thaliana has long been used to assess biological questions for plants, in this case it will fall short in understanding the significance of multiple FAAHs in other plant systems. Thus, in this study, I examined the role (s) of six FAAH isoforms in upland cotton (Gossypium hirsutum L.) and two FAAHs in the legume Medicago truncatula.