Central histaminergic system and cognition

The neurotransmitter histamine is contained within neurons clustered in the tuberomammillary nuclei of the hypothalamus. These cells give rise to wide spread projections extending through the basal forebrain to the cerebral co rtex, as well as to the thalamus and pontomesencephalic tegmentum. These mo rphological features suggest that the hisraminergic system acts as a regula tory center for whole-brain activity. Indeed, this amine is involved in the regulation of numerous physiological functions and behaviors, including le arning and memory, as indicated by extensive research reviewed in this pape r. Histamine effects on cognition might be explained by the modulation of t he cholinergic system. However, interactions of histamine with any transmit ter system, and/or a putative intrinsic precognitive role cannot be exclude d. Furthermore, although experimental evidence indicates that attention-def icit hyperactivity disorder symptoms arise from impaired dopaminergic and n oradrenergic transmission, recent research suggests that histamine is also involved. The possible relevance of histamine in disorders such as age-rela ted memory deficits, Alzheimer's disease and attention-deficit hyperactivit y disorder is worth of consideration, and awaits validation with clinical t rials that will prove the beneficial effects of histaminergic drugs in the treatment of these diseases. (C) 2000 Published by Elsevier Science Ltd. Al l rights reserved.