title: Antispasmodic effects of eugenol on rat airway smooth muscle.
abstract: This study was undertaken to assess the effects of eugenol (EUG) on tracheal muscle (TM) and the putative mechanisms underlying these effects. Cumulatively increasing concentrations (1-1000 μm) of EUG did not affect the resting tonus of TM. However, EUG (1-2000 μm) reduced the contractions induced by electrical field stimulation (IC(50) = 842.3 ± 52.7 μm), an effect that was unaltered by either 10 μm montelukast (IC(50) = 816.1 ± 70.1 μm) or 2 μm indomethacin (IC(50) = 693.1 ± 170.8 μm). EUG also completely relaxed the sustained contractile responses to 80 mM K(+) (IC(50)  = 597.3 ± 60.6 μm) and 1 μm carbamoylcholine (IC(50) = 571.3 ± 148.8 μm), an effect that was unaltered by indomethacin (2 μm). Under Ca(2+) -free conditions, EUG reduced the ACh-induced contractions (IC(50) = 703.4 ± 256.1 μm), the CaCl₂ -induced contractions in preparations pretreated with 60 μm ACh in the presence of nifedipine, and the Ba(2+) -induced contractions in preparations depolarized with K(+) . In tracheal preparations maintained in Ca(2+) -containing solution, EUG (300-2000 μm) relaxed the contractile response to phorbol dibutyrate (1 μm), an activator of protein kinase C. It is concluded that in TM, EUG induces a myogenic antispasmodic effect (not modulated by arachidonic acid derivatives) either through various mechanisms almost with the same pharmacological potency or via an action on a step common to all of them. These mechanisms seem to include blockade of voltage- and receptor-operated Ca(2+) channels, IP₃ -induced Ca(2+) release from sarcoplasmic reticulum and reduction of the sensitivity of contractile proteins to Ca(2+) .
authors.affiliation: Electrophysiology Laboratory, Superior Institute of Biomedical Sciences, State University of Ceará, Fortaleza. Av. Paranjana, 1700 - Campus of Itaperi - 60740-903, Fortaleza, CE, Brazil.
authors.forename: Felipe Crescêncio
authors.initials: FC
authors.lastname: Lima
authors.forename: Dieniffer
authors.initials: D
authors.lastname: Peixoto-Neves
authors.forename: Maria Diana Moreira
authors.initials: MD
authors.lastname: Gomes
authors.forename: Andrelina Noronha
authors.initials: AN
authors.lastname: Coelho-de-Souza
authors.forename: Crystianne Calado
authors.initials: CC
authors.lastname: Lima
authors.forename: Walter
authors.initials: W
authors.lastname: Araújo Zin
authors.forename: Pedro Jorge Caldas
authors.initials: PJ
authors.lastname: Magalhães
authors.forename: Lahlou
authors.initials: L
authors.lastname: Saad
authors.forename: José Henrique
authors.initials: JH
authors.lastname: Leal-Cardoso
mesh_terms: D000085:Acetates / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D003521:Cyclopropanes; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D005054:Eugenol / Q000008:administration & dosage / Q000494:pharmacology*; D007213:Indomethacin / Q000008:administration & dosage / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D011804:Quinolines / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D013440:Sulfides; D014132:Trachea / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000085:Acetates; D015220:Calcium Channels; D003521:Cyclopropanes; D011804:Quinolines; D013440:Sulfides; D005054:Eugenol; C093875:montelukast; D002118:Calcium; D007213:Indomethacin