Biomaterial Database

[Turnover of brain histamine and its changes by various drugs]. 1988

R Oishi

Department of Pharmacology, Okayama University Medical School, Japan.

Histamine (HA) is synthesized from L-histidine by histidine decarboxylase (HDC), and HA released from neurons is predominantly methylated to tele-methylhistamine (t-MH), which is further metabolized by MAO. Therefore, the HA turnover rate is determined by either a exponential decrease in HA level after treatment with alpha-fluoromethylhistidine (alpha-FMH), a specific HDC inhibitor, or a linear accumulation of t-MH after pargyline treatment. Brain HA and t-MH can be simultaneously assayed using HPLC with fluorometric detection. Care should be given to avoid the contamination by extraencephalic mast-cell HA after microwave irradiation or immersion in liquid nitrogen, and to a marked circadian variation of t-MH level. The HA turnover is the highest in the hypothalamus, low in the pons-medulla oblongata and cerebellum, and nil in the spinal cord in rats, mice and guinea pigs. The half-life of neuronal HA is 8-87 min in various brain regions of these animals. Barbiturates, enflurane, benzodiazepines, GABA-mimetic drugs, ethanol and delta 9-tetrahydrocannabinol significantly decrease the HA turnover, whereas mu-opioid agonists such as morphine and [D-Ala2, MePhe4, Gly(ol)5] enkephalin enhance it. Foot-shock and phencyclidine also enhance it at least partly via mu-opioid receptors. Chlorpromazine, haloperidol, imipramine, methamphetamine or halothane have no influence on the HA turnover.

UI	MeSH Term	Description	Entries
D008761	Methylhistamines	Histamine substituted in any position with one or more methyl groups. Many of these are agonists for the H1, H2, or both histamine receptors.
D010880	Piperidines	A family of hexahydropyridines.
D011619	Psychotropic Drugs	A loosely defined grouping of drugs that have effects on psychological function. Here the psychotropic agents include the antidepressive agents, hallucinogens, and tranquilizing agents (including the antipsychotics and anti-anxiety agents).	Psychoactive Agent,Psychoactive Agents,Psychoactive Drug,Psychopharmaceutical,Psychopharmaceuticals,Psychotropic Drug,Psychoactive Drugs,Agent, Psychoactive,Agents, Psychoactive,Drug, Psychoactive,Drug, Psychotropic,Drugs, Psychoactive,Drugs, Psychotropic
D001921	Brain	The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.	Encephalon
D002940	Circadian Rhythm	The regular recurrence, in cycles of about 24 hours, of biological processes or activities, such as sensitivity to drugs or environmental and physiological stimuli.	Diurnal Rhythm,Nyctohemeral Rhythm,Twenty-Four Hour Rhythm,Nycthemeral Rhythm,Circadian Rhythms,Diurnal Rhythms,Nycthemeral Rhythms,Nyctohemeral Rhythms,Rhythm, Circadian,Rhythm, Diurnal,Rhythm, Nycthemeral,Rhythm, Nyctohemeral,Rhythm, Twenty-Four Hour,Rhythms, Circadian,Rhythms, Diurnal,Rhythms, Nycthemeral,Rhythms, Nyctohemeral,Rhythms, Twenty-Four Hour,Twenty Four Hour Rhythm,Twenty-Four Hour Rhythms
D006207	Half-Life	The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacologic, physiologic, or radiologic activity.	Halflife,Half Life,Half-Lifes,Halflifes
D006632	Histamine	An amine derived by enzymatic decarboxylation of HISTIDINE. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter.	Ceplene,Histamine Dihydrochloride,Histamine Hydrochloride,Peremin
D000431	Ethanol	A clear, colorless liquid rapidly absorbed from the gastrointestinal tract and distributed throughout the body. It has bactericidal activity and is used often as a topical disinfectant. It is widely used as a solvent and preservative in pharmaceutical preparations as well as serving as the primary ingredient in ALCOHOLIC BEVERAGES.	Alcohol, Ethyl,Absolute Alcohol,Grain Alcohol,Alcohol, Absolute,Alcohol, Grain,Ethyl Alcohol
D000777	Anesthetics	Agents capable of inducing a total or partial loss of sensation, especially tactile sensation and pain. They may act to induce general ANESTHESIA, in which an unconscious state is achieved, or may act locally to induce numbness or lack of sensation at a targeted site.	Anesthetic,Anesthetic Agents,Anesthetic Drugs,Anesthetic Effect,Anesthetic Effects,Agents, Anesthetic,Drugs, Anesthetic,Effect, Anesthetic,Effects, Anesthetic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia