n-oleoyldopamine and arachidonyl-dopamine

Mass spectrometric approaches to the identification and quantification of lipid signalling molecules are reviewed. Fatty acid amides are an important new class of lipid signalling molecules which include oleamide, the endocannabinoid anandamide, the endovanilloid/endocannabinoid N-arachidonoyldopamine (NADA) and the endovanilloid N-oleoyldopamine (OLDA) among many others. This diverse group of endogenous compounds comprises combinations of acyl backbones coupled by an amide bond to any of a variety of different small polar molecules such as ethanolamine, various amino acids, and catecholamines. Many fatty acid amides appear to play a role in pain and inflammation. Targeted lipidomics of fatty acid amides aims to identify new members of this diverse class of compounds, of which only a few representative molecules have been characterized to date. This effort has been made feasible by advances in chromatography and mass spectrometry, which permits: (1) identification of compounds present in complex mixtures, (2) astronomical increases in sensitivity due to miniaturization of HPLC components, and (3) novel scanning modes that permit the identification of compounds exhibiting similar structural components. Insofar as lipid signalling molecules such as prostanoids, leukotrienes and endocannabinoids operate via G-protein coupled receptors (GPCR), it appears likely that many of the numerous lipids awaiting identification may serve as ligands for any of the greater than 150 orphan GPCRs.

Topics: Amides; Analgesics; Animals; Arachidonic Acids; Chromatography, High Pressure Liquid; Dopamine; Fatty Acids; Humans; Inflammation; Lipid Metabolism; Lipids; Mass Spectrometry; Models, Chemical; Pain; Receptors, G-Protein-Coupled; Signal Transduction

Topics: Apoptosis; Arachidonic Acids; Caspase 3; Caspase 9; Cell Survival; Cells, Cultured; Dopamine; Endometriosis; Endometrium; Female; Humans; Membrane Potential, Mitochondrial; Reactive Oxygen Species; Signal Transduction; Stromal Cells

Accumulation of ubiquitinated protein aggregates is a common pathology associated with a number of neurodegenerative diseases and selective autophagy plays a critical role in their elimination. Although aging-related decreases in protein degradation properties may enhance protein aggregation, it remains unclear whether proteasome dysfunction is indispensable for ubiquitinated-protein aggregation in neurodegenerative diseases. Here, we show that N-oleoyl-dopamine and N-arachidonyl-dopamine, which are endogenous brain substances and belong to the N-acyldopamine (AcylDA) family, generate cellular inclusions through aggresome formation without proteasome inhibition. Although AcylDA itself does not inhibit proteasome activity in vitro, it activates the rearrangement of vimentin distribution to form a vimentin cage surrounding aggresomes and sequesters ubiquitinated proteins in aggresomes. The gene transcription of p62/SQSTM1 was significantly increased by AcylDAs, whereas the transcription of other ubiquitin-dependent autophagy receptors was unaffected. Genetic depletion of p62 resulted in the loss of ubiquitinated-protein sequestration in aggresomes, indicating that p62 is a critical component of aggresomes. Furthermore, AcylDAs accelerate the aggregation of mutant huntingtin exon 1 proteins. These results suggest that aggresome formation does not require proteasome dysfunction and AcylDA-induced aggresome formation may participate in forming cytoplasmic protein inclusions.

Topics: Arachidonic Acids; Autophagy; Cell Line; Dopamine; Drug Evaluation, Preclinical; Gene Expression Regulation; Humans; Huntingtin Protein; Leupeptins; Mutation; Phosphorylation; Proteasome Endopeptidase Complex; Protein Aggregates; Sequestosome-1 Protein; Transcription, Genetic

The transient receptor potential vanilloid 1 (TRPV1) channel, a nonselective Ca(2+) and Na(+) channel, is a molecular transducer of nociceptive stimuli. N-Arachidonoyl dopamine (NADA) and N-oleoyldopamine (OLDA), two unsaturated N-acyldopamines, are major activating endogenous TRPV1 ligands and their presence in mammalian brain tissue has been reported. However, the biological significance of NADA and OLDA remains unknown. To investigate their biological function in the nervous system, a sensitive and accurate quantitative method for determining endogenous NADA and OLDA in the brain is necessary. Thus, a column-switching liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed to quantify NADA and OLDA in mouse striatum. Mouse cerebellum tissue in which neither NADA nor OLDA were detected was used as a surrogate matrix to prepare calibrators. NADA and OLDA were extracted from mouse brain tissue by solid-phase extraction and then filtered and analyzed by LC-MS-MS with electrospray ionization in the positive ion mode. The selectivity results and comparison of calibration curves prepared with mouse cerebellum and striatum established that the former was acceptable as the surrogate matrix of the latter for analyzing NADA and OLDA. The validation results of the matrix effect, linearity, precision, accuracy, and stability were satisfactory. The limits of detection and limits of quantification were 0.125 pg mg(-1) for both analytes. This method was sensitive and accurate enough to determine endogenous concentrations of these compounds in mouse striatum and will be very useful for further study of the biological functions of NADA and OLDA and other related factors in vivo.

Topics: Animals; Arachidonic Acids; Brain; Calibration; Cerebellum; Chromatography, Liquid; Corpus Striatum; Dopamine; Limit of Detection; Male; Mice, Inbred ICR; Reproducibility of Results; Sensitivity and Specificity; Tandem Mass Spectrometry

Plant-derived and endogenous vanilloid-like agents exert their effects on cells through transient receptor potential vanilloid-1 (TRPV1). Little is known about the effects of these agents on platelet aggregation. We investigated the effect of various vanilloid-like agents on in-vitro platelet aggregation and tested whether this action is mediated through TRPV1. Understanding the mechanism of action of these compounds in platelets is important in that these compounds may be developed as novel anti-platelet agents.. The effects of plant-derived (capsaicin; dihydrocapsaicin, DHC) and endogenous vanilloid-like agents (N-oleoyldopamine, OLDA; N-arachidonoyl-dopamine, NADA) on platelet aggregation were investigated using ADP (5, 10μM), collagen (4, 8μg/mL) and arachidonic acid (AA, 300, 400μg/mL) as agonists. The direct effects of these agents on platelet viability were also determined using an LDH release assay.. Capsaicin, OLDA and NADA inhibited ADP-induced platelet aggregation in a concentration-dependent manner. OLDA and NADA, but not capsaicin and DHC, inhibited collagen-induced aggregation, whereas AA-induced aggregation was inhibited by capsaicin, DHC and NADA, but not OLDA. Inhibition of aggregation was not due to direct toxicity of these agents towards platelets. The TRPV1 antagonist, SB-452533, did not affect inhibition of ADP-induced platelet aggregation by capsaicin and OLDA.. These results demonstrate that the endovanilloids, OLDA and NADA, and plant-derived vanilloid, capsaicin, inhibit ADP-induced platelet aggregation. Collagen-induced aggregation was inhibited only by endovanilloids, whereas AA-induced aggregation was inhibited by capsaicin, DHC and NADA. This inhibition was not due to direct toxic effects of these agents, nor was inhibition of ADP-induced aggregation TRPV1 mediated.

Topics: Adenosine Diphosphate; Adolescent; Adult; Aged; Arachidonic Acids; Blood Platelets; Capsaicin; Dopamine; Humans; Middle Aged; Plants; Platelet Aggregation; Platelet Aggregation Inhibitors; TRPV Cation Channels; Young Adult

N-Acyldopamines were recently described as putative endogenous substances in the rat brain. Among them, N-arachidonoyldopamine (AADA) was characterized as cannabinoid CB1 and vanilloid TRPV1 receptor ligand. The physiological significance of such compounds is yet poorly understood. In this study, we describe the novel properties of AADA as antioxidant and neuroprotectant. Antioxidant potential of AADA and its analogs were first tested in the galvinoxyl assay. It was found that N-acyldopamines are potent antioxidants and that the number of free hydroxyl groups in the phenolic moiety of dopamine is essential for the activity. AADA dose dependently (0.1-10 microM) protected cultured cerebellar granule neurons (CGN) in the model of oxidative stress induced by hydrogen peroxide. N-Oleoyldopamine, another endogenous substance, was much less potent in these conditions while the natural antioxidant alpha-tocopherol was inactive. In this test, AADA decreased the peroxide level in CGN preparations and its neuroprotection was independent of cannabinoid/vanilloid receptors blockade. AADA (10 microM) also protected CGN from death induced by K(+)/serum deprivation and glutamate exitotoxicity. These data indicate that AADA may act as endogenous antioxidant in different pathological conditions.

Topics: Animals; Animals, Newborn; Antioxidants; Arachidonic Acids; Biological Assay; Brain; Cell Survival; Cells, Cultured; Culture Media, Serum-Free; Cytoprotection; Dopamine; Dose-Response Relationship, Drug; Excitatory Amino Acid Antagonists; Glutamic Acid; Molecular Structure; Neurons; Neuroprotective Agents; Peroxides; Rats; Rats, Wistar

Four long-chain, linear fatty acid dopamides (N-acyldopamines) have been identified in nervous bovine and rat tissues. Two unsaturated members of this family of lipids, N-arachidonoyl-dopamine (NADA) and N-oleoyl-dopamine, were shown to potently activate the transient receptor potential channel type V1 (TRPV1), also known as the vanilloid receptor type 1 for capsaicin. However, the other two congeners, N-palmitoyl- and N-stearoyl-dopamine (PALDA and STEARDA), are inactive on TRPV1. We have investigated here the possibility that the two compounds act by enhancing the effect of NADA on TRPV1 ('entourage' effect). When pre-incubated for 5 min with cells, both compounds dose-dependently enhanced NADA's TRPV1-mediated effect on intracellular Ca(2+) in human embryonic kidney cells overexpressing the human TRPV1. In the presence of either PALDA or STEARDA (0.1-10 microm), the EC(50) of NADA was lowered from approximately 90 to approximately 30 nm. The effect on intracellular Ca(2+) by another endovanilloid, N-arachidonoyl-ethanolamine (anandamide, 50 nm), was also enhanced dose-dependently by both PALDA and STEARDA. PALDA and STEARDA also acted in synergy with low pH (6.0-6.7) to enhance intracellular Ca(2+) via TRPV1. When co-injected with NADA (0.5 micrograms) in rat hind paws, STEARDA (5 micrograms) potentiated NADA's TRPV1-mediated nociceptive effect by significantly shortening the withdrawal latencies from a radiant heat source. STEARDA (1 and 10 micrograms) also enhanced the nocifensive behavior induced by carrageenan in a typical test of inflammatory pain. These data indicate that, despite their inactivity per se on TRPV1, PALDA and STEARDA may play a role as 'entourage' compounds on chemicophysical agents that interact with these receptors, with possible implications in inflammatory and neuropathic pain.

Topics: Animals; Arachidonic Acids; Calcium; Carrageenan; Cell Line; Disease Models, Animal; Dopamine; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Drug Synergism; Drug Therapy, Combination; Endocannabinoids; Hindlimb; Humans; Hyperalgesia; Inflammation; Italy; Kidney; Male; Pain Measurement; Palmitates; Polyunsaturated Alkamides; Rats; Rats, Sprague-Dawley; Receptors, Drug; Stearates; TRPV Cation Channels