Research article summary (published 30 Aug 1995):

Inhibition of catecholamine synthesis with alpha-methyl-p-tyrosine apparently increases brain serotoninergic activity in the rat: no influence of previous chronic immobilization stress.

Full Abstract

The functional relationship between brain catecholamines and serotoninergic function was studied in stress-naive and chronically immobilized rats after blockade of catecholamine synthesis with alpha-methyl-p-tyrosine (alpha MpT). The levels of noradrenaline (NA), serotonin, and 5-hydroxyindole acetic acid (5-HIAA) in pons plus medulla, brainstem, hypothalamus, hippocampus, and frontal cortex, and those of 3-methoxy, 4-hydroxyphenile-tileneglicol sulphate (MHPG-SO4) in the hypothalamus were measured by HPLC. Chronic immobilization (IMO) resulted in higher NA levels in pons plus medulla and hypothalamus, the latter area (the only one in which the NA metabolite was determined) also showing slightly elevated MHPG-SO4 levels as compared to stress-naive rats. Chronic IMO did not alter either serotonin or 5-HIAA levels, but acute stress consistently increased 5-HIAA levels in all areas, independently of previous chronic stress. Administration of alpha-MpT drastically reduced NA and increased 5-HIAA levels in all brain regions excepting the frontal cortex. The effect of the drug on serotoninergic function was not altered by previous chronic exposure to IMO. These data suggest that the noradrenergic system appears to exert a tonic inhibitory effect on serotoninergic activity in the brain, with the intensity of the effect depending on the brain area studied. In addition, chronic stress does not appear to alter the functional relationship between noradrenergic and serotoninergic activities, although interactions might exist in more restricted brain areas; this deserves further study.

Author information

Author/s: Pol, O (O); Campmany, L (L); Armario, A (A);

Affiliation: Departamento de Biología Celular y Fisiología, Facultad de Ciencias, Universidad Autónoma de Barcelona, Spain.

Journal and publication information

Publication Type: Journal Article

Journal: Pharmacology, biochemistry, and behavior (Pharmacol Biochem Behav), published in UNITED STATES. (Language: eng)

Reference: 1995-Sep; vol 52 (issue 1) : pp 107-12

Dates: Created 1996/01/16; Completed 1996/01/16; Revised 2003/11/14;

PMID: 7501651, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Acute Disease Animals Brain Chemistry - drug effects Catecholamines - biosynthesis Chronic Disease Enzyme Inhibitors - pharmacology Hydroxyindoleacetic Acid - metabolism Immobilization Male

Methoxyhydroxyphenylglycol - metabolism Methyltyrosines - pharmacology Norepinephrine - metabolism Rats Rats, Sprague-Dawley Serotonin - metabolism Stress, Psychological - metabolism Tyrosine 3-Monooxygenase - antagonists & inhibitors alpha-Methyltyrosine

Associated Chemicals: Catecholamines (0) ; Enzyme Inhibitors (0) ; Methyltyrosines (0) ; Serotonin (50-67-9) ; Norepinephrine (51-41-2) ; Methoxyhydroxyphenylglycol (534-82-7) ; Hydroxyindoleacetic Acid (54-16-0) ; alpha-Methyltyrosine (658-48-0) ; Tyrosine 3-Monooxygenase (EC 1.14.16.2)

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