Calcium-Binding Protein (Calbindin D-28k) Immunoreactive Neurons in the Basal Forebrain of the Monkey and the Rat: Relationship with the Cholinergic Neurons

Abstract

A previous study has shown that many neurons in the monkey nucleus basalis of Meynert (NBM) are immunoreactive for calbindin-D-28k (CaBP), a Vitamin D-dependent calcium binding protein (Celio and Norman, 1985). More recently, it has been shown that many cholinergic neurons (i.e., immunoreactive for choline acetyltransferase, ChAT) in the human NBM are immunoreactive for CaBP, and that these neurons are adversely affected in Alzheimer’s patients (Ichimiya et al., 1989), thus suggesting that CaBP may play an important role in the normal functions of human NBM cholinergic neurons. However, whether cholinergic NBM neurons in other species also express CaBP immunoreactivity has remained unclear. It is also not clear whether all cholinergic neurons in the primate NBM are immunoreactive for CaBP. We report here that most, but not all, of the cholinergic NBM neurons in the Rhesus monkey are immunoreactive for CaBP. On the other hand, none of the rat cholinergic NBM neurons express CaBP immunoreactivity.