Biomaterial Database

A microassay for simultaneous measurement of in vivo rates of tryptophan hydroxylation and levels of serotonin in discrete brain nuclei. 1982

J B Long, and W W Youngblood, and J S Kizer

A sensitive procedure for simultaneous determination of in vivo rates of tryptophan hydroxylation and levels of serotonin (5-HT) in discrete rat brain nuclei is described. Rates of tryptophan hydroxylation are estimated by 5-hydroxytryptophan (5-HTP) accumulation following l-aromatic amino acid decarboxylase inhibition by R04-4602/1. 5-HTP is separated from 5-HT by liquid cation exchange after which both 5-HTP and 5-HT are measured by a sensitive radioenzymatic assay. Following decarboxylase inhibition, 5-HTP accumulates over 30 min in 6 brain nuclei examined, with negligible levels of 5-HTP being measured in the absence of decarboxylase inhibition. 5-HT levels do not change significantly up to 45 min after decarboxylase inhibition. Comparison of rates of tryptophan hydroxylation determined in 12 different microdissected rat brain areas reveals a greater rate of 5-HT biosynthetic activity in raphe nuclei containing 5-HT cell bodies than in nuclei containing 5-HT terminals. Pretreatment with para-chlorophenylalanine markedly reduces both 5-HTP accumulation and 5-HT levels in the nucleus raphe dorsalis. With this procedure quantities as little as 10 pg of both 5-HTP and 5-HT can be measured, allowing estimation of in vivo serotonin biosynthesis in microgram quantities of brain tissue.

UI	MeSH Term	Description	Entries
D011903	Raphe Nuclei	Collections of small neurons centrally scattered among many fibers from the level of the TROCHLEAR NUCLEUS in the midbrain to the hypoglossal area in the MEDULLA OBLONGATA.	Caudal Linear Nucleus of the Raphe,Interfascicular Nucleus,Nucleus Incertus,Rostral Linear Nucleus of Raphe,Rostral Linear Nucleus of the Raphe,Superior Central Nucleus,Central Nucleus, Superior,Incertus, Nucleus,Nuclei, Raphe,Nucleus, Interfascicular,Nucleus, Raphe,Nucleus, Superior Central,Raphe Nucleus
D011919	Rats, Inbred Strains	Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.	August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D001933	Brain Stem	The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.	Brainstem,Truncus Cerebri,Brain Stems,Brainstems,Cerebri, Truncus,Cerebrus, Truncus,Truncus Cerebrus
D006900	Hydroxylation	Placing of a hydroxyl group on a compound in a position where one did not exist before. (Stedman, 26th ed)	Hydroxylations
D006916	5-Hydroxytryptophan	The immediate precursor in the biosynthesis of SEROTONIN from tryptophan. It is used as an antiepileptic and antidepressant.	5-HTP,Hydroxytryptophan,Oxitriptan,Oxytryptophan,Tryptophan, 5-Hydroxy-,5 Hydroxytryptophan,5-Hydroxy- Tryptophan,Tryptophan, 5 Hydroxy
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
D012701	Serotonin	A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator.	5-HT,5-Hydroxytryptamine,3-(2-Aminoethyl)-1H-indol-5-ol,Enteramine,Hippophaine,Hydroxytryptamine,5 Hydroxytryptamine
D014364	Tryptophan	An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.	Ardeydorm,Ardeytropin,L-Tryptophan,L-Tryptophan-ratiopharm,Levotryptophan,Lyphan,Naturruhe,Optimax,PMS-Tryptophan,Trofan,Tryptacin,Tryptan,Tryptophan Metabolism Alterations,ratio-Tryptophan,L Tryptophan,L Tryptophan ratiopharm,PMS Tryptophan,ratio Tryptophan
D051381	Rats	The common name for the genus Rattus.	Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus