title: Effect of Gnaphalium conoideum HBK on guinea pig airway smooth muscle: role of L-type Ca2+ channels.
abstract: Plants from the Gnaphalium genus have been used in the Mexican traditional medicine for digestive and respiratory complaints. In the present study, the effect of methanolic extract from Gnaphalium conoideum HBK on the responses to contractile agonists was assessed in guinea pig tracheas, and the possible role of L-type Ca2+ channels was explored in tracheal guinea pig isolated myocytes. Cumulative concentration-response curves to carbachol or histamine, as well as contractile responses to 60 mM KCl were evaluated with or without 30 min preincubation with 20 or 100 microg ml(-1) Gnaphalium conoideum. Likewise, intracellular Ca2+ concentrations were measured by microfluorometric method (fura-2 AM) in isolated tracheal myocytes with or without preincubation with 0.1, 0.31 or 1 microg ml(-1)Gnaphalium conoideum. We found that methanolic extract from Gnaphalium conoideum significantly diminished the contractile responses to histamine, but not to carbachol or KCl. In isolated myocytes, Gnaphalium conoideum significantly reduced the intracellular Ca2+ rise induced by 60 mM KCl. Because histamine contractile responses are largely dependent on extracellular Ca2+, and KCl responses are mainly mediated through L-type Ca2+ channels, our results suggested that methanolic extract from Gnaphalium conoideum might be acting as a partial blocker of these Ca2+ channels.
authors.affiliation: Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social. Av. Cuauhtémoc 330, CP 06720 Mexico DF, Mexico.
authors.forename: Patricia
authors.initials: P
authors.lastname: Campos-Bedolla
authors.forename: Luis M
authors.initials: LM
authors.lastname: Montaño
authors.forename: Edgar
authors.initials: E
authors.lastname: Flores-Soto
authors.forename: Abigail
authors.initials: A
authors.lastname: Aguilar
authors.forename: Ana María
authors.initials: AM
authors.lastname: Puebla
authors.forename: Xavier
authors.initials: X
authors.lastname: Lozoya
authors.forename: Mario H
authors.initials: MH
authors.lastname: Vargas
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects*; D004347:Drug Interactions; D036622:Gnaphalium; D006168:Guinea Pigs; D008297:Male; D008519:Medicine, Traditional; D008800:Mexico; D009119:Muscle Contraction / Q000187:drug effects; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D013154:Spleen / Q000187:drug effects; D014132:Trachea; D014662:Vasoconstrictor Agents / Q000494:pharmacology*; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D015220:Calcium Channels; D010936:Plant Extracts; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D002118:Calcium