Increased magnitude of relaxation to oestrogen in aorta from oestrogen receptor beta knock-out mice.
Micromolar concentrations of the biologically active oestrogen 17beta-oestradiol reduce agonist-induced force in vascular preparations through an unidentified mechanism. The aim of the present study was to investigate the importance of oestrogen receptor beta (ERbeta) for oestrogen-induced vascular relaxation. 17beta-oestradiol was added to aortic rings from ERbeta knock-out (-/-) and wild-type (+/+) mice precontracted with noradrenaline. 17beta-oestradiol caused a concentration-dependent (1-100 microM) relaxation of aortic rings from both -/- and +/+ animals of both sexes. Rings from male and female -/- mice were more sensitive to 17beta-oestradiol than those from +/+ mice. Medial thickness, determined by computerized image analysis, was similar in rings from -/- and +/+ animals. Endothelium, as determined by immuno-cytochemistry, was present in -/- and +/+ aorta. Maximal noradrenaline evoked force and sensitivity to noradrenaline were similar in both groups. In summary ERbeta modulates vascular relaxation to microM concentrations of oestrogen; lack of ERbeta renders the vascular wall supersensitive to 17beta-oestradiol. Lack of ERbeta caused no change in vascular wall morphology suggesting that this ER subtype is not involved in vascular structure development.
Nilsson
B O
BO
Department of Physiological Sciences, Lund University, Sölvegatan 19, S-223 62 Lund, Sweden.
Ekblad
E
E
Heine
T
T
Gustafsson
J  A
J
D000818:Animals; D001011:Aorta; D001835:Body Weight / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology*; D047629:Estrogen Receptor beta; D005260:Female; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008856:Microscopy, Fluorescence; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D011960:Receptors, Estrogen / Q000235:genetics*; D014661:Vasoconstriction / Q000187:drug effects*
D047629:Estrogen Receptor beta; D011960:Receptors, Estrogen; D004958:Estradiol; D009638:Norepinephrine