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FEEDBACK CONTROL OF RAT BRAIN 5‐HYDROXYTRYPTAMINE SYNTHESIS 1
Author(s) -
Macon J. B.,
Sokoloff L.,
Glowinski J.
Publication year - 1971
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.1471-4159.1971.tb11961.x
Subject(s) - pargyline , monoamine oxidase , monoamine oxidase inhibitor , serotonin , tryptophan hydroxylase , chemistry , tryptophan , monoamine neurotransmitter , hydroxylation , endocrinology , medicine , endogeny , monoamine oxidase b , pharmacology , biochemistry , serotonergic , biology , enzyme , amino acid , receptor
— The effect of increased levels of 5‐hydroxytryptamine (5‐HT) on the synthesis of [ 3 H]5‐HT from intracisternally injected tracer doses of [ 3 H]tryptophan was studied in the rat brain stem. The [ 3 H]5‐HT which accumulated in the first 15 min after [ 3 H]tryptophan injection was measured at various times after the acute intraperitoneal administration of the monoamine oxidase inhibitors Catron or Pargyline. The 5‐HT levels reached two and three times control values respectively at 20 min and 180 min after monoamine oxidase inhibitor administration but [ 3 H]5‐HT accumulation was decreased (40 per cent) at 180 min when compared with 20 min. These data as well as those obtained after chronic treatment with monoamine oxidase inhibitors revealed that there is an inverse relationship between [ 3 H]5‐HT accumulation and the endogenous 5‐HT level. Monoamine oxidase activity was undetectable during all the intervals in which [ 3 H]5‐HT accumulation was measured. No inhibition of [ 3 H]5‐HT accumulation was detected when [ 3 H]5‐hydroxytryptophan was injected instead of [ 3 H]tryptophan. The results are consistent with a negative feedback of 5‐HT synthesis at the rate‐limiting tryptophan hydroxylation step.