Estrogen Effects on High-Affinity Choline Uptake in Primary Cultures of Rat Basal Forebrain
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Basal forebrain cholinergic neurons (BFCNs) degenerate in aging and Alzheimer’s disease. It has been proposed that estrogen can affect the survival and function of BFCNs. This study characterized primary rat BFCN cultures and investigated the effect of estrogen on high-affinity choline uptake (HACU). BFCNs were identified by immunoreactivity to the vesicular acetylcholine transporter (VAChT) and represented up to 5% of total cells. HACU was measured in living BFCN cultures and differentiated from low-affinity choline uptake by hemicholinium-3 (HC-3) inhibition. A HC-3 concentration curve showed that 0.3 μM HC-3, but not higher concentrations that inhibit LACU, could distinguish the two transport activities. 17-β-Estradiol treatment increased HACU in some culture preparations that contained non-neuronal cells. Elimination of dividing cells using antimitotic treatments resulted in a lack of estrogen effects on HACU. These results suggest that estrogen may have indirect effects on BFCNs that are mediated through non-neuronal cells.
KeywordsAlzheimer’s disease Basal forebrain cholinergic neurons Choline uptake Estrogen Nerve growth factor Antimitotics
Basal forebrain cholinergic neurons
High-affinity choline uptake
Low-affinity choline uptake
Nerve growth factor
Vesicular acetylcholine transporter
This research was supported by NIH RO3 AG21735 (J.S.), the Laura W. Bush Institute for Women’s Health (J.S.), the Achievement Rewards for College Scientists scholarship foundation (K.M.B.), and the Merck/AFAR Summer Research Scholarship in Geriatric Pharmacology (C.H. and C.M.). We would like to thank Dr. Joachim Hartmann for his expertise and Dr. Jochen Klein for providing access to instruments and for critical reading of the manuscript.
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