Acute Regulation and Long-Term Modulation of Presynaptic Serotonin Output

Huether, Gerald

doi:10.1007/978-1-4615-4709-9_1

Cited by 7 publications

(1 citation statement)

References 43 publications

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“…Previous studies have reported that long-term food restriction decreases the brain density (Huether, 1999) and expression levels of 5-HTT (Haider and Haleem, 2000; Jahng et al, 2007), and that the depletion of brain 5-HT with chronic para-chlorophenylalanine treatment decreases 5-HTT mRNA expression in the raphe nucleus (Linnet et al, 1995; Yu et al, 1995). Also, we have reported that increased 5-HTT mRNA expression in the raphe nucleus by 3 daily 5-HTP injections is accompanied with increased 5-HT levels in the brain regions (Choi et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

5-hydroxy-L-tryptophan Suppressed Food Intake in Rats Despite an Increase in the Arcuate NPY Expression

et al. 2010

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This study was conducted to define the underlying mechanism of hypophagia induced by increased central serotonergic action. Rats received 3 daily injections of 5-hydroxy-L-tryptophan (5-HTP), a serotonin precursor, at a dose of 100 mg/kg/10 ml saline at 1 h before lights off. A significant suppression in food intake was observed shortly after the 5-HTP injection and persisted during 3 daily 5-HTP injections. Neuropeptide Y (NPY) expression in the arcuate nucleus increased after 3 days of 5-HTP treatment, as high as in the pair-fed group. Immunoreactivity of phosphorylated extracellular signal-regulated protein kinase (pERK1/2) in the hypothalamic paraventricular nucleus (PVN) was increased markedly by 3 days of 5-HTP treatment, but not by 3 days of pair-fed. mRNA expression levels of serotonin reuptake transporter (5-HTT) was increased in the dorsal raphe nucleus of the 5-HTP treated rats, but not in the pair-fed group. Results suggest that increased pERK1/2 in the PVN of 5-HTP injected rats may be a part of serotonergic anorectic signaling, perhaps blunting the orectic action of NPY; i.e., 5-HTP injected rats showed hypophagia despite of increased NPY expression in the arcuate nucleus.

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