Amyloid-β1-42 Treatment Does Not Have a Specific Effect on Cholinergic Neurons in in vitro Basal Forebrain Neuronal Cultures of Rat

The neurotoxic effect of amyloid-beta peptide (1–42) was investigated in cultures of neuronal tissue derived from the basal forebrain of embryonic rat. The axonal varicosities of the cholinergic cells were revealed by vesicular acetylcholine transporter staining, and the axonal varicosities in general by synap-tophysin immunohistochemistry. The results demonstrate that the treatment of in vitro neuronal cultures with 20 μM amyloid-beta peptide (1–42) for 2 days on day 5, 12 or 15 exerted a neurotoxic effect on both the cholinergic and the non-cholinergic neurons. In the same cultures, the absolute number of synapto-physin-positive axon varicosities was reduced to greater extent (control: 203 ± 37/field vs treated: 101 ± 16/field) than the number of vesicular acetylcholine transporter-immunoreactive (control: 48 ± 4/field vs treated: 0/field) structures. It is concluded that amyloid-beta peptide (1–42) does not have a specific effect only on the cholinergic neurons, but affects non-cholinergic neurons as well.