Neurofibrillary tangles and histamine-containing neurons in Alzheimer hypothalamus

The location of histamine-immunoreactive (IR) cell bodies in normal aged human brain and in cases of Alzheimer's disease (AD) were compared to the distribution of neurofibrillary tangles (NFT). Cryostat sections were fixed with carbodiimide and processed for histamine-immunohistochemistry using the PAP technique. NFT were visualized in the same sections using thioflavin. Histamine-IR cell bodies in human brain were concentrated in the tuberomammillary (TM) nucleus that embodied a major part of the hypothalamus. Although located in similar large profiles and mainly concentrated in the TM area, the numerous hypothalamic NFT in AD were seldom found within the histamine-IR neurons.