ABSTRACT
Studies have suggested that 17beta estradiol (E2) can modify apolipoprotein E (apoE) expression. The current study determined if apoE protein varied in different regions of the mouse brain as a function of the estrous cycle and if E2 could increase apoE protein expression. In this study apoE concentration was lowest on estrus in the hippocampus, cingulate cortex and frontal cortex. In contrast, apoE concentration was highest on estrus in the olfactory bulb and cerebellum. There were no differences in the striatal apoE expression throughout the estrous cycle. Exogenous E2 significantly raised tissue levels of apoE in the olfactory bulb and cerebellum at 5 days after treatment. There was a slight, but nonsignificant increase in cortical expression of apoE and no change in striatum. Immunocytochemical localization studies found estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta) in cortical neurons and glia. In the cerebellum and olfactory bulb, ERbeta was seen primarily in glia. ERalpha was not observed in the cerebellum and was rare in the olfactory bulb. Neither ERalpha nor ERbeta was seen in the striatum. Our data show regional differences in the production of apoE throughout the estrous cycle. In addition, exogenous E2 has regionally specific effects on apoE expression. Regional variability in apoE production appears to vary as a function of the estrogen receptor subtype.
Subject(s)
Apolipoproteins E/metabolism , Brain/drug effects , Brain/metabolism , Estradiol/pharmacology , Estrus/metabolism , Animals , Cerebellum/drug effects , Cerebellum/metabolism , Corpus Striatum/drug effects , Corpus Striatum/metabolism , Estrogen Receptor alpha , Estrogen Receptor beta , Female , Frontal Lobe/drug effects , Frontal Lobe/metabolism , Gyrus Cinguli/drug effects , Gyrus Cinguli/metabolism , Hippocampus/drug effects , Hippocampus/metabolism , Immunohistochemistry , Mice , Mice, Inbred C57BL , Olfactory Bulb/drug effects , Olfactory Bulb/metabolism , Receptors, Estrogen/metabolismABSTRACT
The effects of 12 days of continuous monocular occlusion on the stereoscopic acuity and the magnitude of the fixation disparity associated with a given amount of prism-forced vergence were investigated in six adult subjects with normal binocular vision. After the period of occlusion, all six subjects were able to perceive stereopsis, although four of the six subjects demonstrated a slight but reversible elevation in stereothresholds. The general shape of the fixation disparity curve for a given individual was not altered by occlusion, but changes in the magnitude of the fixation disparity were observed for some subjects.
