title: Alterations in perivascular sympathetic and nitrergic innervation function induced by late pregnancy in rat mesenteric arteries.
abstract: OBJECTIVE
  We investigated whether pregnancy was associated with changed function in components of perivascular mesenteric innervation and the mechanism/s involved.
  
  
  METHODS
  We used superior mesenteric arteries from female Sprague-Dawley rats divided into two groups: control rats (in oestrous phase) and pregnant rats (20 days of pregnancy). Modifications in the vasoconstrictor response to electrical field stimulation (EFS) were analysed in the presence/absence of phentolamine (alpha-adrenoceptor antagonist) or L-NAME (nitric oxide synthase-NOS- non-specific inhibitor). Vasomotor responses to noradrenaline (NA), and to NO donor DEA-NO were studied, NA and NO release measured and neuronal NOS (nNOS) expression/activation analysed.
  
  
  RESULTS
  EFS induced a lower frequency-dependent contraction in pregnant than in control rats. Phentolamine decreased EFS-induced vasoconstriction in segments from both experimental groups, but to a greater extent in control rats. EFS-induced vasoconstriction was increased by L-NAME in arteries from both experimental groups. This increase was greater in segments from pregnant rats. Pregnancy decreased NA release while increasing NO release. nNOS expression was not modified but nNOS activation was increased by pregnancy. Pregnancy decreased NA-induced vasoconstriction response and did not modify DEA-NO-induced vasodilation response.
  
  
  CONCLUSIONS
  Neural control of mesenteric vasomotor tone was altered by pregnancy. Diminished sympathetic and enhanced nitrergic components both contributed to the decreased vasoconstriction response to EFS during pregnancy. All these changes indicate the selective participation of sympathetic and nitrergic innervations in vascular adaptations produced during pregnancy.
authors.affiliation: Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Instituto de Investigación Sanitaria IdiPAZ, Madrid, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Sastre
authors.affiliation: Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Instituto de Investigación Sanitaria IdiPAZ, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Blanco-Rivero
authors.affiliation: Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Instituto de Investigación Sanitaria IdiPAZ, Madrid, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Caracuel
authors.affiliation: Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Callejo
authors.affiliation: Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain; Instituto de Investigación Sanitaria IdiPAZ, Madrid, Spain.
authors.forename: Gloria
authors.initials: G
authors.lastname: Balfagón
mesh_terms: D000109:Acetylcholine / Q000378:metabolism; D000818:Animals; D005260:Female; D008638:Mesenteric Arteries / Q000294:innervation* / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D011189:Potassium Chloride / Q000378:metabolism; D011247:Pregnancy; D017207:Rats, Sprague-Dawley; D014661:Vasoconstriction; D014664:Vasodilation; D014666:Vasomotor System / Q000502:physiology*
chemical_list: D009569:Nitric Oxide; D011189:Potassium Chloride; D000109:Acetylcholine; D009638:Norepinephrine