title: Bronchodilatory effect of Acorus calamus (Linn.) is mediated through multiple pathways.
abstract: OBJECTIVE
  This study was undertaken to provide a pharmacological basis for traditional use of Acorus calamus in airways disorders.
  
  
  METHODS
  Isolated guinea-pig trachea and atria were suspended in organ baths bubbled with carbogen and mechanisms were found using different parameters.
  
  
  RESULTS
  In isolated guinea-pig tracheal segments, crude extract of Acorus calamus was more effective than carbachol in causing relaxation of high K(+) (80 mM) precontractions, similar to verapamil, suggesting blockade of calcium channels. The n-hexane fraction was equipotent against both precontractions, similar to papaverine, while ethylacetate fraction was more potent against carbachol precontractions but had a negligible dilator effect against K(+), similar to atropine and or rolipram. Pretreatment of tracheal preparations with n-hexane or ethylacetate fractions potentiated isoprenaline-induced inhibitory concentration-response curves, similar to papaverine or rolipram. Pretreatment of tracheal preparations with ethylacetate fraction caused a rightward parallel shift in carbachol response curve at lower concentration (0.003 mg/mL) similar to atropine and a non-parallel shift at higher concentrations (0.01 mg/mL), with reduction of maximum response, similar to rolipram. In isolated guinea-pig atrial preparations, crude extracts, its fractions and papaverine inhibited force and rate of contractions at higher concentrations than the smooth muscle while verapamil was equipotent.
  
  
  CONCLUSIONS
  These data indicate the presence of unique combination of airways relaxant constituents in crude extract of Acorus calamus, a papaverine-like dual inhibitor of calcium channels and phosphodiesterase in n-hexane fraction and a novel combination of anticholinergic, rolipram-like phosphodiesterase4 inhibitor in ethylacetate fraction and associated cardiac depressant effect, provide a pharmacological basis for traditional use of Acorus calamus in disorders of airways.
authors.affiliation: Department of Biological and Biomedical Sciences, Aga Khan University Medical College, Karachi, Pakistan.
authors.forename: Abdul Jabbar
authors.initials: AJ
authors.lastname: Shah
authors.forename: Anwarul-Hassan
authors.initials: AH
authors.lastname: Gilani
mesh_terms: D029023:Acorus; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001993:Bronchodilator Agents / Q000494:pharmacology*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002217:Carbachol / Q000494:pharmacology; D005260:Female; D006168:Guinea Pigs; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D010208:Papaverine / Q000494:pharmacology; D058988:Phosphodiesterase 4 Inhibitors / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology*; D011188:Potassium; D027343:Rhizome; D020889:Rolipram / Q000494:pharmacology; D014132:Trachea / Q000187:drug effects; D014700:Verapamil / Q000494:pharmacology
chemical_list: D001993:Bronchodilator Agents; D002121:Calcium Channel Blockers; D058988:Phosphodiesterase 4 Inhibitors; D010936:Plant Extracts; D001285:Atropine; D002217:Carbachol; D014700:Verapamil; D010208:Papaverine; D020889:Rolipram; D007545:Isoproterenol; D011188:Potassium