anandamide and Airway-Obstruction

(-)-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

In guinea pigs, we found that intravenous 5,8,11,14-eicosatetraenamide (N-2-hydroxyethyl), arachidonylethanolamide (anandamide), 0.3-10.0 mg/kg, did not inhibit leukotriene D(4) (LTD(4))-induced airway obstruction, while inhaled anandamide, 21.8 and 43.6 microg/kg (estimated inhaled doses), significantly reduced this airway obstructive effect by 24.8+/-8.8 and 42.0+/-11.2%, respectively. In contrast, aerosolized anandamide (43.6 microg/kg) was ineffective against histamine-induced bronchoconstriction. Thus, inhaled, but not intravenous anandamide selectively antagonizes the bronchospasm produced by LTD(4).

Topics: Administration, Inhalation; Airway Obstruction; Animals; Arachidonic Acids; Bronchoconstriction; Bronchodilator Agents; Cannabinoid Receptor Modulators; Endocannabinoids; Guinea Pigs; Histamine; Injections, Intravenous; Leukotriene D4; Lung; Polyunsaturated Alkamides

Anandamide (arachidonylethanolamide), 5,8,11,14-eicosatetraenamide, (N-2-hydroxyethyl), was tested for bronchodilator and anti-inflammatory activities. Conscious guinea pigs were given cumulative i.v. doses of anandamide (1.0, 3.0, and 10.0 mg/kg) to assess its effect on dynamic compliance (Cdyn), total pulmonary resistance (RL), tidal volume (VT) and breathing frequency (f). Other guinea pigs were exposed to an aerosol of A23187 (6S-[6alpha(2S*,3S*),8beta(R*),9beta,11alpha]-5- (methylamino)-2-[[3,9,11-trimethyl-8-[1-methyl-2-oxo-2-(1H-pyrrol-2-yl)e thyl]-1,7-dioxaspiro[5.5]undec-2-yl]methyl]-4-benzoxazole carboxylic acid) until Cdyn decreased by 50% (approximately 5 min) and at 20 min, cumulative i.v. doses of anandamide (1.0, 3.0, and 10.0 mg/kg) were administered and reversal of Cdyn examined. After the final dose of anandamide, the animals were killed and excised lung gas volumes (ELGV), i.e., pulmonary gas trapping, measured. Other animals were treated i.v. with anandamide (10.0 mg/kg), exposed to an aerosol of A23187 until labored breathing began, and then killed 1 h later. Anandamide did not significantly affect Cdyn, RL, VT and f. ELGV values of anandamide-treated guinea pigs were not different from those of vehicle-treated animals. Anandamide failed to reverse A23187-induced decreases in Cdyn and to reduce A23187-associated ELGV increases. Also, it did not prevent the prolonged airway obstruction caused by A23187. Histological evaluation revealed that anandamide significantly reduced A23187-related airway epithelial injury and pulmonary leukocytosis. However, it did not prevent A23187-induced peribronchiolar granulocytic accumulation. Our results suggest that in vivo anandamide has minimal direct airway smooth muscle-related actions, however it may possess modest anti-inflammatory properties.

Topics: Aerosols; Airway Obstruction; Airway Resistance; Animals; Anti-Inflammatory Agents; Arachidonic Acids; Bronchodilator Agents; Calcimycin; Endocannabinoids; Guinea Pigs; Injections, Intravenous; Lung; Lung Compliance; Male; Polyunsaturated Alkamides; Pulmonary Ventilation; Receptors, Cannabinoid; Receptors, Drug; Tidal Volume