ovalbumin and anandamide

Chronic obstructive airway diseases are a global medical burden that is expected to increase in the near future. However, the underlying mechanistic processes are poorly understood so far. Herein, we show that the endocannabinoid anandamide (AEA) induces prominent airway relaxation in vitro and in vivo. In contrast to 2-arachidonlyglycerol-induced airway relaxation, this is mediated by fatty acid amide hydrolase (FAAH)-dependent metabolites. In particular, we identify mouse and also human epithelial and airway smooth muscle cells as source of AEA-induced prostaglandin E2 production and cAMP as direct mediator of AEA-dependent airway relaxation. Mass spectrometry experiments demonstrate reduced levels of endocannabinoid-like compounds in lungs of ovalbumin-sensitized mice indicating a pathophysiological relevance of endocannabinoid signalling in obstructive airway disease. Importantly, AEA inhalation protects against airway hyper-reactivity after ovalbumin sensitization. Thus, this work highlights the AEA/FAAH axis as a critical regulator of airway tone that could provide therapeutic targets for airway relaxation.

Topics: Animals; Arachidonic Acids; Endocannabinoids; Humans; Mice; Ovalbumin; Polyunsaturated Alkamides

(-)-Δ(9)-Tetrahydrocannabinol has been demonstrated to have beneficial effects in the airways, but its psychoactive effects preclude its therapeutic use for the treatment of airways diseases. In the present study we have investigated the effects of (-)-cannabidiol, a non-psychoactive component of cannabis for its actions on bronchial smooth muscle in vitro and in vivo. Guinea-pig bronchial smooth muscle contractions induced by exogenously applied spasmogens were measured isometrically. In addition, contractile responses of bronchial smooth muscle from ovalbumin-sensitized guinea-pigs were investigated in the absence or presence of (-)-cannabidiol. Furthermore, the effect of (-)-cannabidiol against ovalbumin-induced airway obstruction was investigated in vivo in ovalbumin-sensitized guinea-pigs. (-)-Cannabidiol did not influence the bronchial smooth muscle contraction induced by carbachol, histamine or neurokinin A. In contrast, (-)-cannabidiol inhibited anandamide- and virodhamine-induced responses of isolated bronchi. A fatty acid amide hydrolase inhibitor, phenylmethanesulfonyl fluoride reversed the inhibitory effect of (-)-cannabidiol on anandamide-induced contractions. In addition, (-)-cannabidiol inhibited the contractile response of bronchi obtained from allergic guinea-pigs induced by ovalbumin. In vivo, (-)-cannabidiol reduced ovalbumin-induced airway obstruction. In conclusion, our results suggest that cannabidiol can influence antigen-induced airway smooth muscle tone suggesting that this molecule may have beneficial effects in the treatment of obstructive airway disorders.

Topics: Airway Obstruction; Animals; Arachidonic Acids; Bronchi; Cannabidiol; Cannabinoids; Carbachol; Endocannabinoids; Female; Guinea Pigs; Histamine; In Vitro Techniques; Male; Muscle Contraction; Muscle, Smooth; Neurokinin A; Ovalbumin; Phenylmethylsulfonyl Fluoride; Polyunsaturated Alkamides

The temperature dependency of anandamide uptake into cells implies an active mechanism but this is still a matter of considerable debate. We have therefore re-examined the temperature-sensitive uptake of anandamide in ND7/23 mouse neuroblastoma x rat dorsal root ganglion neurone hybrid cells and RBL2H3 rat basophilic leukaemia cells.. Cellular uptake of [(3)H] anandamide was measured in the presence of bovine serum albumin at different incubation temperatures and times. Rates of uptake were also measured in wells alone. Free anandamide concentrations were calculated by published methods.. Anandamide showed a time-dependent saturable uptake into ND7/23 cells. The uptake was greater at 37 degrees C than at 4 degrees C for a given added anandamide concentration following a 5 min incubation. However, this temperature-dependency reflected temperature-dependent effects on the concentration of anandamide available for uptake, rather than the uptake process itself. A similar conclusion could be drawn for the rapid ( approximately 1 min) uptake of anandamide into RBL2H3 cells. In contrast, re-analysis of published data for P19 cells indicated a clear temperature-dependency of the uptake at long (15 min) incubation times. The level of anandamide retained by wells alone provided a better measure of free anandamide concentrations than calculated values.. ND7/23 cells may be a useful model system for the study of anandamide uptake. The temperature-dependent uptake of anandamide may reflect effects on free anandamide concentrations rather than on the uptake process itself.

Topics: Animals; Arachidonic Acids; Basophils; Cell Line; Cell Line, Tumor; Endocannabinoids; Ganglia, Spinal; Hybrid Cells; Kinetics; Mice; Neuroblastoma; Ovalbumin; Polyunsaturated Alkamides; Rats; Regression Analysis; Serum Albumin, Bovine; Temperature

Immunologic activation of mast cells through the cross-linking of high affinity IgE receptors results in the release of inflammatory mediators which are important in the pathogenesis of allergic reactions. Early studies investigating the effects of palmitoylethanolamide on animal models of inflammation and on rat mast cells led to the hypothesis that endogenous cannabinoids might act as local autacoids which suppressed inflammation by reducing the activation of mast cells. However, more recent studies produced contradicting results. In order to evaluate if cannabinoid receptors are present in mast cells, we studied the effects of endocannabinoids (anandamide and palmitoylethanolamide) and synthetic cannabimimetics (CP 55,940, WIN 55,212-2 and HU-210) on histamine release from rat peritoneal mast cells. When incubated with mast cells alone, only anandamide could induce significant level of histamine release at concentrations higher than 10(-6) M. When mast cells were activated with anti-IgE, the histamine release induced was not affected by anandamide, palmitoylethanolamide and CP 55,940. In contrast, both WIN 55,212-2 and HU-210 enhanced anti-IgE-induced histamine release at 10(-5) M and preincubation did not increase the potency. The histamine releasing action of anandamide and the enhancing effects of WIN 55,212-2 and HU-210 on anti-IgE-induced histamine release were not reduced by the cannabinoid receptor antagonists, AM 281 and AM 630. In conclusion, the present study does not support the hypothesis that cannabinoids suppress mast cell activation. Instead, some of the cannabinoid receptor-directed ligands tested enhanced mast cell activation. However, the high concentrations required and the failure of cannabinoid receptor antagonists to reverse such effects also question the existence of functional cannabinoid receptors in mast cells.

Topics: Adjuvants, Immunologic; Amides; Animals; Anti-Inflammatory Agents, Non-Steroidal; Antibodies, Anti-Idiotypic; Arachidonic Acids; Benzoxazines; Cannabinoid Receptor Modulators; Dose-Response Relationship, Drug; Dronabinol; Drug Synergism; Endocannabinoids; Ethanolamines; Histamine Release; Immunoglobulin E; Male; Mast Cells; Morpholines; Naphthalenes; Ovalbumin; Palmitic Acids; Peritoneal Cavity; Polyunsaturated Alkamides; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptors, Cannabinoid; Receptors, Drug