Author/Editor		Kalesnykas, Giedrius; Miettinen, Riitta
Title		The effect of ovariectomy and estrogen replacement therapy on cholinergic neurons of basal forebrain of aged mice
Type		članek
Source		Image Anal Stereol
Vol. and No.		Letnik 20, št. Suppl 1
Publication year		2001
Volume		str. 157-62
Language		eng
Abstract		Cholinergic neurons of the medial septum (MS) and vertical diagonal band (VDB) provide the main cholinergic innervation to the hippocampus. Recent experimental studies have suggested that estrogens modulate the activity of these neurons. In the present study we investigated whether the experimental manipulation of circulating estrogens affects the cholinergic neurons in the MS/VDB complex of aged mice. We used four different treatment groups of female C57BL/6J (129/Sv x DBA/2J) 21-month-old mice: I) Sham-operated, 2) ovariectomized at 17 months, 3) ovariectomized at 18 months, and 4) ovariectomized at 18 months and treated with 17beta-estradiol for 3 months. At the age of 21 months animals were deeply anaesthetized and perfused transcardially. Brain sections were double immunostained for choline acetyltransferase (Chat) and estrogen receptor alpha (ERalpha) and embedded in Durcupan. Our analyses using the optical fractionator revealed that there was no statistically significant difference in the total number of Chat-immunoreactive (Chat-ir) neurons between the individual treatment groups. However, the number of Chat-ir neurons that also contain ERalpha was the highest in mice ovariectomized at age of 17 months. We conclude that whilst neither ovariectomy nor estrogen replacement therapy affect the total number of Chat-ir cells in the MS/VDB of aged mice, long-term ovariectomy induces an upregulation of the ERalpha receptors in these neurons.
Descriptors		OVARIECTOMY ESTROGEN REPLACEMENT THERAPY CHOLINERGIC FIBERS BRAIN ESTRADIOL MICE, INBRED C57BL MICE, INBRED DBA IMMUNOHISTOCHEMISTRY CHOLINE ACETYLTRANSFERASE RECEPTORS, ESTROGEN