Effects of two years of estrogen loss or replacement on nucleus basalis cholinergic neurons and cholinergic fibers to the dorsolateral prefrontal and inferior parietal cortex of monkeys.
The present study examined the long-term (2 years) effects of estrogen loss or estrogen replacement therapy (ERT) on cholinergic neurons in the nucleus basalis of Meynert and on cholinergic fibers in the prefrontal and parietal cortex of adult female cynomolgus monkeys. Cholinergic fiber density in layer II of the prefrontal cortex was decreased in monkeys who were ovariectomized and treated with placebo for 2 years. In contrast, ovariectomized monkeys receiving ERT for 2 years had fiber densities that were comparable to those of intact controls. No differences in parietal cholinergic fiber density or nucleus basalis cholinergic neuron number or volume were found among intact, ovariectomized, or ERT monkeys. Our results suggest that ERT is effective in preventing region-specific changes in cortical cholinergic fibers that result from the loss of circulating ovarian hormones. These modest but appreciable effects on cholinergic neurobiology following long-term estrogen loss and ERT may contribute to changes in visuospatial attention function that is mediated by the prefrontal cortex.
Tinkler
Gregory Paul
GP
Interdisciplinary Neuroscience Program, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
Tobin
Joseph Raphael
JR
Voytko
Mary Lou
ML
D000109:Acetylcholine / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D020532:Basal Nucleus of Meynert / Q000166:cytology*; D002352:Carrier Proteins / Q000378:metabolism; D002452:Cell Count; D002799:Cholinergic Fibers / Q000378:metabolism*; D015914:Estrogen Replacement Therapy / Q000379:methods; D004967:Estrogens / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry / Q000379:methods; D008252:Macaca fascicularis; D026901:Membrane Transport Proteins; D009474:Neurons / Q000378:metabolism*; D010052:Ovariectomy / Q000379:methods; D010296:Parietal Lobe / Q000033:anatomy & histology / Q000378:metabolism*; D017397:Prefrontal Cortex / Q000033:anatomy & histology / Q000378:metabolism*; D020800:Receptor, Nerve Growth Factor / Q000378:metabolism; D013995:Time; D050494:Vesicular Acetylcholine Transport Proteins; D033921:Vesicular Transport Proteins
D002352:Carrier Proteins; D004967:Estrogens; D026901:Membrane Transport Proteins; D020800:Receptor, Nerve Growth Factor; D050494:Vesicular Acetylcholine Transport Proteins; D033921:Vesicular Transport Proteins; D000109:Acetylcholine