The human pineal gland in aging and Alzheimer's disease: patterns of cytoskeletal antigen immunoreactivity.

Patients with Alzheimer's disease (AD) and some aged controls may have diminished functions of the pineal gland. In this immunocytochemical study, we stained pineal glands from cases of AD and young and aged controls for cytoskeletal elements and amyloid. We found no evidence of neurofibrillary tangles (NFT) or the accumulation of neurofilaments, tau, A68, or beta/A4 amyloid deposition in pinealocytes or associated structures in cases of AD or controls. In both AD and controls, we observed dense immunoreactivity for phosphorylated neurofilaments in marginal plexuses associated with processes of pinealocytes, boutons, and knob-like endings. The accumulation of phosphorylated neurofilaments in the processes of pinealocytes appears to be a normal morphological characteristic of the pineal gland and may not represent a pathological change.