title: The relaxant activity of the methanolic extract of Acanthus montanus on intestinal smooth muscles.
abstract: The effects of the methanolic extract of Acanthus montanus on different smooth muscle preparations have been investigated. The extract (6.25-100 microg/ml) produced a concentration-dependent relaxation and inhibition of the spontaneous contraction of the rabbit jejunum which was reversed by CaCl2 (0.1-1mM). This effect of the extract was not blocked by propranolol (3 x 10(-7) M) but partially antagonised by phentolamine (10(-6)-3 x 10(-6) M), procaine (10(-3) M) and methylene blue (10(-5) M). The extract also caused a concentration-dependent relaxation of the KCl-precontracted taenia coli of the guinea-pig which was partially blocked by propranolol (3 x 10(-5) M) that completely blocked isoprenaline (10(-8)-3 x 10(-4) M) relaxation of the tissue. Methylene blue (10(-5) M) and procaine (10(-3) M) completely blocked the direct relaxant effects of the extract and isoprenaline on the guinea-pig taenia coli. The extract (0.1-1mg/ml) shifted the concentration-response curves of CaCl2 to the right in a concentration-dependent manner on the guinea-pig taenia coli. These effects of the extract suggest a non specific smooth muscle relaxant activity.
authors.affiliation: Department of Pharmacology, College of Medicine, University of Lagos, Nigeria.
authors.forename: O O
authors.initials: OO
authors.lastname: Adeyemi
authors.forename: S O
authors.initials: SO
authors.lastname: Okpo
authors.forename: C C
authors.initials: CC
authors.lastname: Young-Nwafor
mesh_terms: D000818:Animals; D003106:Colon / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D006168:Guinea Pigs; D007422:Intestines / Q000187:drug effects*; D007545:Isoproterenol / Q000494:pharmacology; D007583:Jejunum / Q000187:drug effects; D008297:Male; D008751:Methylene Blue / Q000494:pharmacology; D009126:Muscle Relaxation / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D010646:Phentolamine / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D011343:Procaine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011817:Rabbits
chemical_list: D010936:Plant Extracts; D011343:Procaine; D011189:Potassium Chloride; D011433:Propranolol; D007545:Isoproterenol; D008751:Methylene Blue; D010646:Phentolamine