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TRH injected into the nucleus accumbens shell releases dopamine and reduces feeding motivation in rats.
- Source :
-
Behavioural brain research [Behav Brain Res] 2016 Jun 01; Vol. 306, pp. 128-36. Date of Electronic Publication: 2016 Mar 19. - Publication Year :
- 2016
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Abstract
- The thyrotropin-releasing hormone (TRH), an anorexigenic factor that reduces food intake in food-restricted animals, may be involved in motivation for food. Injected centrally, TRH impairs acquisition of food-rewarded behavior. Through the TRH-R1 receptors, TRH injected in the nucleus accumbens increases dopamine content-perhaps the mechanism by which the peptide modulates food motivation. This, however, is still to be demonstrated. We sought to evaluate dopamine release by microdialysis after a TRH injection into the nucleus accumbens shell in free-moving fasted rats. In addition, we assessed dopamine content and turnover by HPLC and the relationship with the motivation for food by analyzing the performance of rats during a progressive-ratio (PR) operant-conditioning test. Finally, we determined serum leptin and triiodothyronine (T3) levels in order to evaluate the animals' metabolic response to food restriction and the impact of intra-accumbal TRH administration on circulating hormones. Intra-accumbal injections of TRH reduced food intake in food-restricted rats-compared to counterparts treated with saline-, without further decreasing T3 or leptin levels, which dropped due to their dietary regime. TRH-injected rats had lower breaking points on the PR schedule, which indicated lower motivation to eat. Accordingly, compared to saline-treated animals, dopamine release and turnover increased in the nucleus accumbens of TRH-injected rats, a finding that suggests a relationship between motivation for food and TRH-induced release of dopamine.<br /> (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Subjects :
- 3,4-Dihydroxyphenylacetic Acid metabolism
Analysis of Variance
Animals
Conditioning, Operant drug effects
Food Deprivation
Leptin blood
Male
Microdialysis
Nucleus Accumbens metabolism
Rats
Rats, Wistar
Reward
Triiodothyronine blood
Dopamine metabolism
Eating drug effects
Motivation drug effects
Nucleus Accumbens drug effects
Thyrotropin-Releasing Hormone pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 1872-7549
- Volume :
- 306
- Database :
- MEDLINE
- Journal :
- Behavioural brain research
- Publication Type :
- Academic Journal
- Accession number :
- 27006143
- Full Text :
- https://doi.org/10.1016/j.bbr.2016.03.031