Estimation of the total number of cholinergic neurons containing estrogen receptor-alpha in the rat basal forebrain.

This study was undertaken to estimate the total number of cholinergic cells and the percentage of cholinergic cells that contain estrogen receptor-alpha (ER alpha) in the rat basal forebrain. Double immunostaining for choline acetyltransferase (ChAT) and ER alpha was carried out on 50-microm-thick free-floating sections. Because routine mounting method causes considerable flattening of the sections, we embedded immunostained sections in Durcupan, an epoxy resin known to cause virtually no shrinkage.