title: Essential oil of Pterodon polygalaeflorus inhibits electromechanical coupling on rat isolated trachea.
abstract: The present work studied the effects of the essential oil of Pterodon polygalaeflorus (EOPP), a plant used to treat bronchitis and amigdalytis, on rat airway smooth muscle in vitro. In Ca(2+)-containing medium, EOPP (100-1300 microg/ml) inhibited preferentially high KCl- than 5-HT-induced muscle contractions in a concentration-dependent fashion, but did affect neither basal muscle tension nor ACh-induced contractions. In preparations maintained in either 60 mM K(+) or 10 microM ACh in Ca(2+)-free medium, EOPP (100, 600 and 1300 microg/ml) inhibited maximum contractile response induced by cumulative Ca(2+) addition (0.1-20 mM). Verapamil (10, 30 and 100 microg/ml), a Ca(2+) channel blocker, also inhibited Ca(2+)-induced concentration-effect curve in presence of ACh in Ca(2+)-free medium, whilst it was ineffective to decrease cholinergic contractions in Ca(2+)-containing medium. In presence of 150 mM K(+) in Ca(2+)-containing medium, EOPP (1300 microg/ml) did not reversed ACh-induced contractions. In contrast, under similar conditions, EOPP almost fully relaxed cholinergic contractions of tracheal smooth muscle in Ba(2+)-containing medium. In medium containing 10 mM tetraethylammonium and 2 mM Ba(2+) instead of Ca(2+), both EOPP (1300 microg/ml) and verapamil (approximately 5 microg/ml) significantly decreased ACh-induced contractions. Thus, in rat isolated trachea, EOPP induces inhibitor effects on contractions preferentially triggered by an electromechanical coupling mode.
authors.affiliation: Instituto Superior de Ciências Biomédicas, Fundação Universidade Estadual do Ceará, Fortaleza, Ceará, CE, Brazil.
authors.forename: Giovanni L
authors.initials: GL
authors.lastname: Evangelista
authors.forename: Andrelina N
authors.initials: AN
authors.lastname: Coelho-de-Souza
authors.forename: Cláudia F
authors.initials: CF
authors.lastname: Santos
authors.forename: José H
authors.initials: JH
authors.lastname: Leal-Cardoso
authors.forename: Erika A B
authors.initials: EA
authors.lastname: Lopes
authors.forename: Márcio V
authors.initials: MV
authors.lastname: dos Santos
authors.forename: Saad
authors.initials: S
authors.lastname: Lahlou
authors.forename: Pedro J C
authors.initials: PJ
authors.lastname: Magalhães
mesh_terms: D000818:Animals; D001938:Brazil; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D004594:Electrophysiology; D007887:Fabaceae / Q000737:chemistry*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000502:physiology; D010938:Plant Oils / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology; D014132:Trachea / Q000187:drug effects* / Q000502:physiology
chemical_list: D015220:Calcium Channels; D010938:Plant Oils; D012701:Serotonin; D011189:Potassium Chloride