title: Effects of apafant on PAF-induced downregulation of beta-adrenoceptors in guinea pigs.
abstract: We examined the effects of platelet-activating factor (PAF) on beta-adrenoceptors and the functional response to isoproterenol in guinea pig parenchymal strips. PAF caused a reduction in the relaxation of guinea pig lung parenchymal strips induced by the beta-adrenoceptor agonist, isoproterenol. In addition, PAF decreased the density of beta-adrenoceptors in guinea pig lung without any change in the affinity. Apafant, a potent PAF antagonist, inhibited the above changes, indicating that it inhibited the downregulation of beta-adrenoceptors. These findings suggest that apafant may be effective in nonspecific airway hyperreactivity in asthma.
authors.affiliation: Department of Pharmacology, Faculty of Pharmaceutical Sciences, Okayama University, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Sugimoto
authors.forename: Y
authors.initials: Y
authors.lastname: Nakayama
authors.forename: H
authors.initials: H
authors.lastname: Kishida
authors.forename: T
authors.initials: T
authors.lastname: Hayakawa
authors.forename: R
authors.initials: R
authors.lastname: Fujiwara
authors.forename: C
authors.initials: C
authors.lastname: Kamei
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D001381:Azepines / Q000494:pharmacology*; D001667:Binding, Competitive; D001980:Bronchi / Q000187:drug effects* / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D006168:Guinea Pigs; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D010972:Platelet Activating Factor / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D014230:Triazoles / Q000494:pharmacology*
chemical_list: D000318:Adrenergic beta-Agonists; D001381:Azepines; D010972:Platelet Activating Factor; D010975:Platelet Aggregation Inhibitors; D011943:Receptors, Adrenergic, beta; D014230:Triazoles; C052518:WEB 2086; D007545:Isoproterenol