title: Endothelium-derived factors and k+ channels are involved in the vasorelaxation induced by Sida cordifolia L. in the rat superior mesenteric artery.
abstract: The vasorelaxantion of the aqueous fraction of the hydroalcoholic extract of the Sida cordifolia leaves (AFSC) was evaluated in this work. In rat superior mesenteric artery, AFSC (3-1000 microg/mL) induced relaxation of phenylephrine-induced contractions. This effect was significantly attenuated after removal of the endothelium, after atropine (1 microM), L-NAME (100 microM), indomethacin (10 microM), high K+ (20 mM), tetraethylammonium (1 microM), a K(Ca) blocker, apamin (1 microM), a SK(Ca) blocker and ChTX (0.1 microM), a BK(Ca) blocker, however, it was not affected after glibenclamide (10 microM), an KATP blocker, and 4-aminopyridine (1 microM), a Kv blocker. ChTX (0.1 microM) was able to induce an additional inhibition of the vasorelaxation induced by AFSC in the presence of L-NAME plus indomethacin. The vasorelaxation induced by AFSC in the presence of L-NAME plus indomethacin plus ChTX was not different from that induced by AFSC in rings without endothelium. In conclusion, the results show that endothelium-derived factors (mainly NO, PGI2) and K+ channels (BK(Ca) and SK(Ca)) play a crucial role in the vasorelaxation induced by AFSC in the rat superior mesenteric artery.
authors.affiliation: Universidade Federal de Sergipe, Departamento de Fisiologia, São Cristóvão, SE, Brazil.
authors.forename: M R V
authors.initials: MR
authors.lastname: Santos
authors.forename: N M S
authors.initials: NM
authors.lastname: Nascimento
authors.forename: A R
authors.initials: AR
authors.lastname: Antoniolli
authors.forename: I A
authors.initials: IA
authors.lastname: Medeiros
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D018999:Charybdotoxin / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D066298:In Vitro Techniques; D007213:Indomethacin / Q000494:pharmacology; D019660:Malvaceae / Q000737:chemistry*; D017538:Mesenteric Artery, Superior / Q000187:drug effects / Q000502:physiology*; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D052250:Nitric Oxide Synthase Type III / Q000037:antagonists & inhibitors; D010936:Plant Extracts / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D004791:Enzyme Inhibitors; D010936:Plant Extracts; D015221:Potassium Channels; D018999:Charybdotoxin; D011189:Potassium Chloride; D052250:Nitric Oxide Synthase Type III; D019331:NG-Nitroarginine Methyl Ester; D007213:Indomethacin