title: Andrographis paniculata (Ness) induces relaxation of uterus by blocking voltage operated calcium channels and inhibits Ca(+2) influx.
abstract: The possible relaxation of uterine smooth muscle by Andrographis paniculata dried extract via a blockade of voltage operated calcium channels was investigated in rats. Uterine horns pretreated with oestradiol were incubated in Ca(+2) -free Jalon's solution and stimulated with KCl (20-60 mM) in order to produce depolarization of the membrane. The isometric contractile response to 1 mM or cumulative concentrations of CaCl2 were blockaded by 0.2, 0.4 and 0.8 mg/mL of A. paniculata. The maximum contractile response induced by acetylcholine was moderately antagonized by A. paniculata. The possible blockade of Ca(+2) entry by A. paniculata was evaluated with (45)Ca(+2) uptake in uterine rings incubated with free-Ca(+2)-Ringer's solution high in K+ (KCl 40 mM). The influx was completely blockaded with 0.4 mg/mL of A. paniculata. These results strongly suggest that A. paniculata blockades voltage operated calcium channels inhibiting the entry of Ca(+2) from the external medium.
authors.affiliation: Institute of Pharmacology, Faculty of Veterinary Science, Universidad Austral de Chile, P.O. Box 567, Valdivia, Chile. rburgos1@uach.cl
authors.forename: R A
authors.initials: RA
authors.lastname: Burgos
authors.forename: M J
authors.initials: MJ
authors.lastname: Aguila
authors.forename: E T
authors.initials: ET
authors.lastname: Santiesteban
authors.forename: N S
authors.initials: NS
authors.lastname: Sánchez
authors.forename: J L
authors.initials: JL
authors.lastname: Hancke
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D005260:Female; D009126:Muscle Relaxation / Q000187:drug effects*; D010946:Plants, Medicinal; D051381:Rats; D017207:Rats, Sprague-Dawley; D014590:Uterine Contraction / Q000187:drug effects*
chemical_list: D002121:Calcium Channel Blockers; D004365:Drugs, Chinese Herbal