Estradiol reduction of alpha 2-adrenoceptor binding in female rat cortex is correlated with decreases in alpha 2A/D-adrenoceptor messenger RNA.
We developed a quantitative RNAse protection assay for alpha 2A/D-adrenoceptor messenger RNA in rats to test the hypothesis that decreases in cortical alpha 2-adrenoceptor binding observed following estrogen treatment of ovariectomized rats correlate with reduced levels of messenger RNA encoding the predominant alpha 2-adrenoceptor subtype expressed in cortex. Estradiol treatment for 48 h reduced cortical alpha 2A/D-adrenoceptor messenger RNA by approximately 50% when compared to ovariectomized, oil-treated control animals. Estradiol down-regulation of alpha 2A/D-adrenoceptor messenger RNA was accompanied by a significant decrease in cortical alpha 2-adrenoceptor density, as measured by 3H-RX821002 binding. Estrogen treatment did not alter alpha 2A/D-adrenoceptor messenger RNA or alpha 2-adrenoceptor binding in female rat hypothalamus-preoptic area. This study provides the first evidence that estradiol regulates expression of postsynaptic alpha 2-adrenoceptors in female rat frontal cortex, suggesting a possible molecular substrate for hormonal modulation of cognitive function.
Karkanias
G B
GB
Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Li
C S
CS
Etgen
A M
AM
D000317:Adrenergic alpha-Antagonists / Q000378:metabolism; D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism*; D015536:Down-Regulation; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D019329:Idazoxan / Q000031:analogs & derivatives / Q000378:metabolism; D010052:Ovariectomy; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000235:genetics* / Q000378:metabolism*; D012016:Reference Values
D000317:Adrenergic alpha-Antagonists; D012333:RNA, Messenger; D011942:Receptors, Adrenergic, alpha; D004958:Estradiol; C058525:2-methoxyidazoxan; D019329:Idazoxan