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EVIDENCE FOR THE SYNTHESIS AND STORAGE OF 5‐HYDROXYTRYPTAMINE IN TWO SEPARATE POOLS IN THE BRAIN
Author(s) -
Shields P. J.,
Eccleston D.
Publication year - 1973
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1973.tb00048.x
Subject(s) - monoamine oxidase , serotonin , chemistry , tryptophan , monoamine oxidase inhibitor , stimulation , tryptophan hydroxylase , biogenic amine , monoamine neurotransmitter , amine gas treating , adrenalectomy , biochemistry , endocrinology , medicine , amino acid , enzyme , biology , organic chemistry , receptor , serotonergic
— Evidence is presented to support the hypothesis that 5‐hydroxytryptamine (5‐HT) in the rat brain is synthesized by two separate pathways and stored in two or more compartments. Lysergic acid diethylamide in doses down to 50 μg/kg was shown to reduce the formation of 5‐[ 3 H]HT from [ 3 H]tryptophan in the presence of a monoamine oxidase inhibitor, although the total rate of accumulation of 5‐HT was unchanged. Conversely, adrenalectomy was found to increase the total synthesis of 5‐HT measured in the same way, although the amount of 5‐[ 3 H]HT formed suggested that there was no increase in the synthesis of the amine. In a third experiment it was found that electrical stimulation of 5‐HT‐containing nerves following labelling of 5‐HT stores with [ 3 H]tryptophan led to a biphasic disappearance of 5‐[ 3 H]HT. It is suggested that the method of measuring 5‐HT synthesis by measuring 5‐[ 3 H]HT formed from[ 3 H]tryptophan in the presence of a monoamine oxidase inhibitor may be a way of selectively measuring the turnover of the functional pool of 5‐HT.