title: Albaconol from the mushroom Albatrellus confluens induces contraction and desensitization in guinea pig trachea.
abstract: The contraction and desensitization induced by albaconol and the influence of capsazepine, capsaicin and extracellular Ca2+ were investigated to see whether the actions were mediated via a specific VR receptor in guinea pig trachea spiral strips in vitro. Both albaconol and capsaicin were contractors of tracheal smooth muscle, but albaconol was not so potent as capsaicin, with -log (M) EC50 values of 4.23 +/- 0.18 (n = 10) and 7.33 +/- 0.21 (n = 10) respectively. 2.5 microM capsazepine competitively antagonized the contractile response to albaconol and capsaicin. Albaconol increased the contraction induced by a low dose of capsaicin (10(-10) to 10(-9) M), but non-competitively antagonized the contraction induced by a high dose of capsaicin (10(-8) to 10(-3) M). Either albaconol (1 or 100 mM) or capsaicin (3 or 10 microM) was able to desensitize the isolated guinea pig bronchi to subsequent addition of albaconol. Capsazepine (5.0 microM) significantly prevented the desensitization induced by either albaconol (1 or 100mM) or capsaicin (3 or 10 microM). Extracellular Ca2+ was essential for albaconol to induce excitation, but it did not affect albaconol- or capsaicin-induced desensitization. In summary, the results from the present study suggest that albaconol induces contraction and desensitization of guinea pig trachea in vitro as a partial agonist for VR.
authors.affiliation: Kunming Institute of Botany, The Chinese Academy of Science, Kunming, PR China.
authors.forename: Wei-Min
authors.initials: WM
authors.lastname: Yang
authors.forename: Ji-Kai
authors.initials: JK
authors.lastname: Liu
authors.forename: Chen
authors.initials: C
authors.lastname: Qing
authors.forename: Yi-Dan
authors.initials: YD
authors.lastname: Liu
authors.forename: Zhi-Hui
authors.initials: ZH
authors.lastname: Ding
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Shen
authors.forename: Zhi-He
authors.initials: ZH
authors.lastname: Chen
mesh_terms: D000363:Agaricales; D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001643:Bridged Bicyclo Compounds / Q000008:administration & dosage / Q000494:pharmacology*; D002118:Calcium / Q000502:physiology; D002211:Capsaicin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism; D010636:Phenols / Q000008:administration & dosage / Q000494:pharmacology*; D008517:Phytotherapy; D011955:Receptors, Drug / Q000187:drug effects; D014132:Trachea / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000700:Analgesics; D001643:Bridged Bicyclo Compounds; D010636:Phenols; D011955:Receptors, Drug; C478999:albaconol; C071423:capsazepine; D002211:Capsaicin; D002118:Calcium