ِaim: Tryptophan hydroxylase-2 mRNA (TPH, the rate limiting enzyme in 5-HT synthesis) expression levels display circadian variations in the median and dorsal raphe nuclei. This circadian pattern is under the control of the suprachiasmatic nuclei (SCN), the master clock. Photoperiodic cue is encoded by the SCN which convey the seasonal message to target sites. In the present study, we have investigated the effect of photoperiodic changes on the serotonergic neurons of the raphe nuclei. We have assessed the daily expression of TPH2 mRNA in both median and dorsal raphe nuclei of rats housed either under long photoperiod (18 h light/6 h dark cycle, LP18:6) or short photoperiod (SP6:18). .
Results: Our results demonstrate that under LP18:6, TPH2 mRNA levels display a progressive decrease during the dark period and a maximal expression is reported at the beginning of the light period. The expression pattern of TPH2 mRNA under SP6:18 remains unchanged during the dark period and increases significantly before the light/dark transition. This latter expression pattern is in line with the daily profiles of TPH2 mRNA reported previously under standard lighting regimen (12 h light/12 h dark cycle).
Conclusion: The present results suggest that TPH2 mRNA expression pattern within DR and MR is affected by photoperiod which might in turn affect TPH content and 5-HT release within the circadian structures, but also in all the serotonergic projection areas of the brain.
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http://dx.doi.org/10.1080/00207454.2020.1782903 | DOI Listing |
Psychoneuroendocrinology
January 2025
Departamento de Farmacología, Centro de Investigación y de Estudios Avanzados del IPN, Av. Instituto Politécnico Nacional 2508, La Laguna Ticomán, CP 07360, México. Electronic address:
Neurotoxicology
September 2024
College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China. Electronic address:
1-octyl-3-methylimidazolium bromide ([Cmim]Br), one of the ionic liquids (ILs), has been used in various fields as an alternative green solvent of conventional organic solvents. Increased application and stabilization of imidazole ring structure lead to its release into the aquatic environment and long-term retention. Structure-activity relationship consideration suggested that ILs may be acetylcholinesterase inhibitors; however, neurotoxicity in vivo, especially the underlying mechanisms is rarely studied.
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June 2024
Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia.
At the Institute of Cytology and Genetics (Novosibirsk, Russia) for over 85 generations, gray rats have been selected for high aggression toward humans (aggressive rats) or its complete absence (tame rats). Aggressive rats are an interesting model for studying fear-induced aggression. Benzopentathiepin TC-2153 exerts an antiaggressive effect on aggressive rats and affects the serotonergic system: an important regulator of aggression.
View Article and Find Full Text PDFInt J Mol Sci
June 2024
Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, 56127 Pisa, Italy.
Physiology and behavior are structured temporally to anticipate daily cycles of light and dark, ensuring fitness and survival. Neuromodulatory systems in the brain-including those involving serotonin and dopamine-exhibit daily oscillations in neural activity and help shape circadian rhythms. Disrupted neuromodulation can cause circadian abnormalities that are thought to underlie several neuropsychiatric disorders, including bipolar mania and schizophrenia, for which a mechanistic understanding is still lacking.
View Article and Find Full Text PDFBiol Res
May 2024
Department of Biological Science Laboratory of Cardiovascular Physiology, Campus Morro do Cruzeiro s/n, Ouro Preto, 35400-000, MG, Brazil.
Obesity, associated with the intake of a high-fat diet (HFD), and anxiety are common among those living in modern urban societies. Recent studies suggest a role of microbiome-gut-brain axis signaling, including a role for brain serotonergic systems in the relationship between HFD and anxiety. Evidence suggests the gut microbiome and the serotonergic brain system together may play an important role in this response.
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