3-(2-hydroxy-4-(1-1-dimethylheptyl)phenyl)-4-(3-hydroxypropyl)cyclohexanol and Cough

Cannabis has been demonstrated to have bronchodilator, anti-inflammatory, and antitussive activity in the airways, but information on the active cannabinoids, their receptors, and the mechanisms for these effects is limited. We compared the effects of Δ(9)-tetrahydrocannabinol, cannabidiol, cannabigerol, cannabichromene, cannabidiolic acid, and tetrahydrocannabivarin on contractions of the guinea pig-isolated trachea and bronchoconstriction induced by nerve stimulation or methacholine in anesthetized guinea pigs following exposure to saline or the proinflammatory cytokine, tumor necrosis factor α (TNF-α). CP55940 (2-[(1R,2R,5R)-5-hydroxy-2-(3-hydroxypropyl) cyclohexyl]-5-(2-methyloctan-2-yl)phenol), a synthetic cannabinoid agonist, was also investigated in vitro. The cannabinoids were also evaluated on TNF-α- and lipopolysaccharide-induced leukocyte infiltration into the lungs and citric acid-induced cough responses in guinea pigs. TNF-α, but not saline, augmented tracheal contractility and bronchoconstriction induced by nerve stimulation, but not methacholine. Δ(9)-Tetrahydrocannabinol and CP55940 reduced TNF-α-enhanced nerve-evoked contractions in vitro to the magnitude of saline-incubated trachea. This effect was antagonized by the cannabinoid 1 (CB(1)) and CB(2) receptor antagonists AM251 [N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-caroxamide] and JTE907 [N-(1,3-benzodioxol-5-ylmethyl)-1,2-dihydro-7-methoxy-2-oxo-8-(pentyloxy)-3-quinolinecarboxamide], respectively. Tetrahydrocannabivarin partially inhibited the TNF-α-enhanced nerve-evoked contractions, whereas the other cannabinoids were without effect. The effect of cannabidiol and Δ(9)-tetrahydrocannabinol together did not differ from that of the latter alone. Only Δ(9)-tetrahydrocannabinol inhibited TNF-α-enhanced vagal-induced bronchoconstriction, neutrophil recruitment to the airways, and citric acid-induced cough responses. TNF-α potentiated contractions of airway smooth muscle in response to nerve stimulation by enhancing postganglionic acetylcholine release. Δ(9)-Tetrahydrocannabinol and CP55940 inhibited the TNF-α-enhanced acetylcholine release, and hence contraction and bronchoconstriction, through activation of presynaptic CB(1) and CB(2) receptors. The other cannabinoids did not influence cholinergic transmission, and only Δ(9)-THC demonstrated effects on airway hyper-responsiveness, anti-inflammatory activity, and antitussive activity in the airways.

Topics: Airway Resistance; Animals; Bronchoalveolar Lavage Fluid; Bronchoconstriction; Cannabinoid Receptor Agonists; Cannabinoids; Cannabis; Citric Acid; Cough; Cyclohexanols; Guinea Pigs; Inflammation; Isometric Contraction; Lipopolysaccharides; Male; Muscle, Smooth; Respiratory Hypersensitivity; Respiratory System; Trachea; Tumor Necrosis Factor-alpha

1. There is considerable interest in novel therapies for cough, since currently used agents such as codeine have limited beneficial value due to the associated side effects. Sensory nerves in the airways mediate the cough reflex via activation of C-fibres and RARs. Evidence suggests that cannabinoids may inhibit sensory nerve-mediated responses. 2. We have investigated the inhibitory actions of cannabinoids on sensory nerve depolarisation mediated by capsaicin, hypertonic saline and PGE2 on isolated guinea-pig and human vagus nerve preparations, and the cough reflex in conscious guinea-pigs. 3. The non-selective cannabinoid (CB) receptor agonist, CP 55940, and the selective CB2 agonist, JWH 133 inhibited sensory nerve depolarisations of the guinea-pig vagus nerve induced by hypertonic saline, capsaicin and PGE2. These responses were abolished by the CB2 receptor antagonist SR144528, and unaffected by the CB1 antagonist SR141716A. Similarly, JWH 133 inhibited capsaicin-evoked nerve depolarisations in the human vagus nerve, and was prevented by SR144528. 4. Using a guinea-pig in vivo model of cough, JWH 133 (10 mg kg-1, i.p., 20 min) significantly reduced citric acid-induced cough in conscious guinea pigs compared to those treated with the vehicle control. 5. These data show that activation of the CB2 receptor subtype inhibits sensory nerve activation of guinea-pig and human vagus nerve, and the cough reflex in guinea-pigs, suggesting that the development of CB2 agonists, devoid of CB1-mediated central effects, will provide a new and safe antitussive treatment for chronic cough.

Topics: Animals; Camphanes; Cannabinoids; Capsaicin; Consciousness; Cough; Cyclohexanols; Dinoprost; Dose-Response Relationship, Drug; Guinea Pigs; Humans; Hypertonic Solutions; In Vitro Techniques; Male; Middle Aged; Neurons, Afferent; Piperidines; Pyrazoles; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Reflex; Rimonabant; Vagus Nerve