Serotonin and feeding responses of rats to amino acid imbalance

Initial phase

D. W. Gietzen, Quinton Rogers, P. M B Leung, B. Semon, T. Piechota

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The role of serotonin in the anorexic response of rats to an amino acid-imbalanced diet was investigated. After chronic depletion of serotonin with parachlorophenylalanine (PCPA, 300 mg/kg) or 5,7-dihydroxytryptamine (DHT, 200 μg/rat, intracisternally), initial intake of a mild isoleucine-imbalanced diet was reduced by 60% vs. a 17% reduction after saline injection. After acute treatment with the agonist, quipazine (quip, 5 mg/kg ip) or the precursor, tryptophan (TRP, 1% added to the diet), imbalanced diet intake was also exacerbated. PCPA and DHT may have caused receptor sensitivity, such that the food intake depression after serotonin depletion was similar to that seen with the quip and TRP treatments. Injection of the autoreceptor agonist, 8-hydroxy-2(di-n-propylamino)tetralin (8-OH-DPAT, 500 μg/kg sc), to reduce transmission in the serotonergic system resulted in an attenuation of the usual food intake depression of the amino acid-imbalanced diet (only a 7%, nonsignificant reduction). Also measurements made in the absence of pharmacological treatment showed that the ratio 5-hydroxyindole acetic acid-to-serotonin, a putative index of serotonin turnover, was increased 155% in the raphe nuclei and 140% in the hippocampus 3.5 h after ingestion of the mild isoleucine-imbalanced diet. Therefore increased serotonergic activity in some brain areas may be associated with the initial depression of food intake in rats fed an imbalanced amino acid diet.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume253
Issue number5
StatePublished - Dec 1 1987

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Serotonin
Diet
Amino Acids
Eating
8-Hydroxy-2-(di-n-propylamino)tetralin
Isoleucine
Quipazine
5,7-Dihydroxytryptamine
Autoreceptors
Injections
Raphe Nuclei
Tryptophan
Acetic Acid
Hippocampus
Therapeutics
Pharmacology
Brain

ASJC Scopus subject areas

  • Physiology

Cite this

Serotonin and feeding responses of rats to amino acid imbalance : Initial phase. / Gietzen, D. W.; Rogers, Quinton; Leung, P. M B; Semon, B.; Piechota, T.

In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 253, No. 5, 01.12.1987.

Research output: Contribution to journalArticle

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