Subject 5-hydroxytryptamine

Scarr E, Pavey G, Copolov D, Dean B. 2004. Hippocampal 5-hydroxytryptamine receptors Abnormalities in postmortem brain from schizophrenic subjects. Schizophr Res 71 383-392. 

Indolealkylamines. GC-MS methods applied in studies of the biochemical pharmacology of indoleamines parallel work on the catecholamines. SIM assays for serotonin (5-hydroxytryptamine), 5-methoxytryptamine, JV-acetylserotonin and melatonin (5-methoxy-N-acetyltryptamine) in rat pineal and brain tissue have been described [453,469]. Pentafluoro-propionyl derivatives and structural homologue standardisation were employed with detection limits in the subpicomole range. Estimation of central indoleamine turnover in man currently depends upon metabolite determination in CSF. Ion monitoring determination of indole-3-acetic acid [454] a metabolite of tryptamine, and isotope dilution assays for 5-hydroxyindoleacetic acid (5-HIAA) [455,458] have been reported. Serotonin is converted by central monoamine oxidase to 5-HIAA and the measurement of this metabolite, formerly by fluorimetry, is of interest in patients with CNS disorders [470]. GC-MS has also contributed to the identification of N,N-dimethyltryptamine in vitro [471] and isotope dilution technique has been applied to the measurement of this metabolite in control subjects and in psychiatric patients [472]. 

Noradrenaline is transported by uptake systems that have been extensively studied. On release of noradrenaline from sympathetic nerve varicosities in the peripheral nervous system, it is subject to two uptake systems. Uptake 1 (UJ is a reuptake process where the noradrenaline is recovered by the nerve via a process that has a high affinity but relatively low maximum rate, whereas a second process, uptake 2 (Uj), clears noradrenaline from the tissues into extraneuronal sites by a low affinity, but fast, process (which is inhibited by GLUCOCORTICOIDS, phenoxybenzamine and normetanephrine). The first - the neuronal system - has been studied in detail, and is essentially the same process as used for dopamine and 5-hydroxytryptamine in the CNS. The U transport protein has now been cloned, and is one of a famiiy of transporter proteins which act as co-transporters for Na, Cl and the amine, driven by the ATP-generated electrochemical gradient for Na . This Ui noradrenaline reuptake process is inhibited by cocaine and amphetamine (thus accounting for some of their actions, particularly within the CNS), phenoxybenzamine and the extensive class of tricyclic and related compounds that are used as ANTIDEPRESSANTS (e.g. desipramine). 

For a long time, the major interest in tryptophan metabolism has been focused on the well-known neurotransmitter 5-hydroxytryptamine which, however, accounts for only 1% of dietary tryptophan metabolism in peripheral human tissues, more than 95% being transformed via the kynurenine pathway. Nowadays, a renewed interest arises as far as kynurenine and related substances is concerned, for example as potential targets for pharmacological therapies [5]. Therefore, it seems well worthwhile to carry out a somewhat detailed discussion about some aspects of the kynurenine pathway enzymology. The whole subject has been recently reviewed [5]. 

Blood pressure can be regulated by receptor, enzyme, endogerous substance, and cell, such as bradykinin B2-receptor, ACE, 5-Hydroxytryptamine, and endothelia cell. Based on these facts, the human plasma assay [131], pulmonary hypertension assay [132], coronary arteries (CA) constriction assay [133], MCAO and HSPG assay [134], and temperature assay in awake subjects [135] are established. 

Stone RA, Barnes PJ, Chung KF (1993a) Effect of frusemide on cough responses to chloride-deflcient solution in normal and mild asthmatic subjects. Eur Respir J 6 862-867 Stone RA, WorsdeU YM, Fuller RW, Barnes PJ (1993b) Effects of 5-hydroxytryptamine and 5-hydroxytryptophan infusion on the human cough reflex. J Appl Physiol 74 396 01 Studham J, Fuller RW (1992) The effect of oral terfenadine on the sensitivity of the cough reflex in normal volunteers. Pulm Pharmacol 5 51-52... 

Taking a concentration of 5-hydroxytryptamine of 0-05 jug/ml in the blood and an excretion of 3-6 mg per day of 5-hydroxyindole acetic acid as a basis, Erspamer estimated that the amount of 5-hydroxytryptamine contained in the total blood volume is metabolized every 2-3 hr. Heissel " found that C-marked serotonin in the thrombocytes of eleven healthy subjects had a half-life of 5-6 days. Sjoerdsma et found a pool of 2800 mg 5-hydroxytryptamine with a half-life of 5 days in a patient with a metastasized carcinoid of the small intestine after intravenous injections of C-marked hydroxytryptophane. Zucker et found a half-life of 1-7-2-8... 

The effect of 5-hydroxytryptamine on the blood pressure has been the subject of numerous investigations. The results have varied according to the doses given, the manner of their administration, the rate of injection, vasomotor tone, species, and other experimental conditions. A discussion of findings resulting from animal experiments will be omitted, ... 

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