5-Hydroxytryptamine occurrence

Very little is known about the occurrence of 1-hydroxytryptamine and/or 1-hydroxytryptophan derivatives in living organisms. Many 1-methoxyindole derivatives have been isolated as natural products (87MI629, 88BCJ285, 92H1877, 93MI22) for the simple reason that they are stable under isolating processes. 

Fig. 1. Occurrence of H3 receptors inhibiting release of acetylcholine, of amino acid and monoamine neurotransmitters in the mammalian CNS in vitro. The schematic drawing represents a midsagittal section of the human brain three areas with a more lateral position are shown by broken line (substantia nigra and part of the hippocampus and of the striatum). For each of the six regions of the CNS (subregions given in brackets), in which H3 heteroreceptors have been identified, the neurotransmitter(s) and the species are indicated. The superscripts refer to the numbers of the papers as listed under References. Own unpublished data suggest that an H3 receptor-mediated inhibition of noradrenaline release also occurs in the human cerebral cortex and hippocampus and in the guinea-pig cerebral cortex. Note that a presynaptic location has not been verified for each of the H3 heteroreceptors or has been even excluded (for details, see Table 1). Abbreviations ACh, acetylcholine DA, dopamine GABA, y-aminobutyric acid Glu, glutamate 5-HT, 5-hydroxytryptamine, serotonin NA, noradrenaline...

Ribeiro, P. and Webb, R.A. (1 984) The occurrence, synthesis and metabolism of 5-hydroxytryptamine and 5-hydroxytryptophan in the cestode Hymenolepis diminuta. Comparative Biochemistry and Physiology C 79, 159-164. 

Since the discovery of 5-hydroxytryptamine (serotonin, enteramine, thrombocytin) (VII), and the demonstration of its physiological activity and its important function as a neurohormone, the possibility of its occurrence in plants has attracted much attention. It was first shown to be present in Mucuna pruriens DC. (cowhage), and is probably responsible for the intense irritation which results when cowhage comes into contact with the skin (94). This irritation could be a mechanical effect due to the trichomes, but it is more likely to be the result of liberation of... 

T er, VE. and D. Groger 1964A. Occurrence of 5-hydroxytryptamine and 5-hyd-roxytryptophan in Panaeolus sphinctrin-us "Journal of Pharmaceutical Sciences 33 462—463. 

Fig. 3 5-Hydroxytryptamine (5-HT)-induced inhibition and its reactivation by dextromethorphan in a single neuron acutely dissociated from the raphe nucleus. Note that 10 M 5-HT induced hyperpolarization of the membrane potential followed by complete blocking of the occurrence of action potentials. Dextromethorphan at 3 x 10 M reactivated 5-HT-induced inhibition of the...

CoRREALE, P., The occurrence and distribution of 5-hydroxytryptamine (enteramine) in the central nervous system of vertebrates, J. Neurochem. 1, 22 (1956). 

Schizophrenia 20, 128 Serotonin (5-hydroxytryptamine) human brain 57 ff kidney function 73, 74, 80, 102 localization 4, 5, 11 metabolism 17, 18 microcirculation 83, 84, 86 occurrence 41 ff Parkinson s disease 62 pharmacology 67 ff production 3... 

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