title: Effects of estrogens on cholinergic neurons in the rat basal nucleus.
abstract: Estrogen replacement in postmenopausal women may help prevent or delay development of Alzheimer's disease. Because loss of basal forebrain cholinergic neurons with reductions in choline acetyltransferase (ChAT) concentration are associated with Alzheimer's disease, we investigated the effect of estradiol (E(2)) and J 861, a non-feminizing estrogen, on cholinergic neurons in the basal forebrain. Ovariectomized rats received E(2), J 861 or vehicle, and basal forebrain sections through the substantia innominata, medial septum, and nucleus of the diagonal band were immunostained for ChAT. ChAT-immunoreactive cells in the basal forebrain were significantly reduced in the ovariectomized rats compared to intact rats, but those ovariectomized rats receiving estrogen replacement with E(2) and J 861 had near normal levels of ChAT-positive neurons. While retrograde tracing experiments with fluorogold injected into the prefrontal cortex showed no significant differences in the number of fluorogold-labeled cells among the groups, ChAT-immunoreactive cells and double-labeled cells were significantly lower in OVX rats than in intact and E(2) rats. Some substantia innominata cells in the J 861 rats were ChAT/estrogen receptor alpha-positive. These results suggest that E(2) and J 861 have positive effects on cholinergic neurons that project from the basal nucleus to the forebrain cortex.
authors.affiliation: Department of Obstetrics and Gynecology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto 602-8566, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Jo
authors.initials: J
authors.lastname: Kitawaki
authors.forename: Noriko
authors.initials: N
authors.lastname: Kikuchi
authors.forename: Tomoharu
authors.initials: T
authors.lastname: Okubo
authors.forename: Koichi
authors.initials: K
authors.lastname: Iwasa
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Kawata
authors.forename: Hideo
authors.initials: H
authors.lastname: Honjo
mesh_terms: D000818:Animals; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D002799:Cholinergic Fibers / Q000187:drug effects* / Q000502:physiology; D004958:Estradiol / Q000494:pharmacology*; D047628:Estrogen Receptor alpha / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010052:Ovariectomy; D016548:Prosencephalon / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D013377:Substantia Innominata / Q000187:drug effects / Q000502:physiology
chemical_list: D047628:Estrogen Receptor alpha; C115405:J861 scavestrogen; D018696:Neuroprotective Agents; D004958:Estradiol; D002795:Choline O-Acetyltransferase