Brain research bulletin
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Brain research bulletin · May 2013
Long-term effects of selective immunolesions of cholinergic neurons of the nucleus basalis magnocellularis on the ascending cholinergic pathways in the rat: a model for Alzheimer's disease.
Alzheimer's disease is associated with a significant decrease in the cholinergic input to the neocortex. In a rat model of this depletion, we analyzed the subsequent long-term changes in cholinergic fiber density in two well-defined areas of the frontal and parietal cortices: Fr1, the primary motor cortex, and HL, the hindlimb area of the somatosensory (parietal) cortex, two cortical cholinergic fields that receive inputs from the nucleus basalis magnocellularis (nBM). A specific cholinergic lesion was induced by the intraparenchymal injection of 192 IgG-saporin into the nBM. ⋯ The cholinergic fiber densities in cortical areas Fr1 and HL remained similarly decreased (to 62% and 68% of the control values, respectively) up to 20 weeks. No significant rebound in AChE activity occurred either in the nBM or in the cortices during the period investigated. This study therefore demonstrated that, similarly to the very extensive reduction in the number of ChAT-positive neurons in the nBM, cortical areas Fr1 and HL underwent long-lasting reductions in the number of AChE-positive fibers in response to specific cholinergic lesioning of the nBM.