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Acute Effects of Conjugate Equine Estrogen and Selective Estrogen Receptor‐α Agonist PPT on Postischemic Pial Arteriole Response in Rats
Author(s) -
Zeynalov Emil,
Ma Li,
Rezvani Niloofar,
Littleton-Kearney Marguerite T
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.685.36
Subject(s) - agonist , ovariectomized rat , medicine , vasodilation , arteriole , estrogen , endocrinology , ischemia , estrogen receptor , receptor , circulatory system , cancer , breast cancer
Study Objective We explored the effects of acute administration of conjugated equine estrogens (CEE), on postischemic pial arteriole dilatory capacity. Additionally, we determined determined if the beneficial effects of estrogen are mediated through estrogen receptor‐α (ER‐α) using the specific a specific agonist, propyl pyrazole triol (PPT). Methods Ovariectomized (OVX) female or male rats were anesthetized, and after placement of a closed cranial window over the parietal cortex, rats were subjected to 15‐min reversible forebrain ischemia, followed by 2 hr. reperfusion. OVX rats received intravenous CEE (1 mg/kg) or vehicle at the onset of reperfusion. Separate cohorts of OVX female or male rats were treated with the ER‐α agonist PPT intraperitoneally (2 mg/kg) 3 hours prior to ischemia. Pial artery dilatory capacity was tested before and after ischemia. Results Administration of CEE improved vasodilatory response from −1.7 ± 4.43% to 15.31± 6.63% (p=0.0002). PPT augmented postischemic vasodilatory response in females from −2.63 ± 1.42% to 23.57 ± 11.3% (p= 0.005), and in male rats from −0.38 ± 2.88% to 30.84 ± 11.66% (p=0.007). Conclusion Acute administration of CEE or PPT restores postischemic pial arteriole vasodilatory reactivity to Ach. These findings suggest that the effects acute estrogen treatment after ischemic cerebral injury may be modulated via ER‐α.