Therapeutic potential of histamine H3 receptor antagonists in dementias.

Selective antagonism of centrally localized histamine H(3) receptors has been shown to enhance the release of a wide spectrum of important neurotransmitters including acetylcholine, gamma-aminobutyric acid, dopamine and noradrenalin, among others, which play fundamental roles in cognitive processes, in an output-dependent manner. The cognitive-enhancing effects of H(3) receptor antagonists across multiple cognitive domains in a wide number of preclinical cognition models also endow confidence in this therapeutic strategy for the treatment of Alzheimer's disease, attention deficit hyperactivity disorder and the cognitive deficits often expressed in schizophrenia. Recent positive clinical reports are beginning to reinforce this optimism.