title: Phenylephrine-induced vasoconstriction of the rat superior mesenteric artery is decreased after repeated swimming.
abstract: This study was performed to determine the effect of forced swimming on the vascular responsiveness of the rat superior mesenteric artery to phenylephrine, focusing on the involvement of locally produced substances. Repeated but not single sessions of forced swimming exercise reduced the vasoconstrictor potency of phenylephrine in the studied arteries, regardless of the presence of intact endothelium. No significant changes were observed in the maximal response to phenylephrine. Treatment with indomethacin (1 microM) did not affect the exercise-induced reduction in vascular responsiveness to phenylephrine. However, the reduction of vascular reactivity to phenylephrine due to repeated exercise was no longer observed after treatment with N(G)-monomethyl-L-arginine (L-NMMA, 100 microM). The results suggest that repeated exercise reduces vasomotor responses to phenylephrine in rat superior mesenteric arteries through a non-endothelial nitric oxide (NO)-related mechanism.
authors.affiliation: Laboratory of Pharmacology, School of Medicine of Marília, SP, Brazil.
authors.forename: Agnaldo B
authors.initials: AB
authors.lastname: Chies
authors.forename: Ana M
authors.initials: AM
authors.lastname: de Oliveira
authors.forename: Fabiana C
authors.initials: FC
authors.lastname: Pereira
authors.forename: Claudia R
authors.initials: CR
authors.lastname: de Andrade
authors.forename: Fernando M A
authors.initials: FM
authors.lastname: Corrêa
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000502:physiology; D010656:Phenylephrine / Q000494:pharmacology*; D005082:Physical Exertion / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013550:Swimming / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology; D014662:Vasoconstrictor Agents / Q000494:pharmacology*
chemical_list: D014662:Vasoconstrictor Agents; D010656:Phenylephrine