title: Changes in serotonin (5-HT) and brain-derived neurotrophic factor (BDFN) expression in frontal cortex and hippocampus of aged rat treated with high tryptophan diet.
abstract: Age-related cognitive decline is accompanied by an alteration in neurotransmitter synthesis and a dysregulation of neuroplasticity-related molecules such as serotonin (5-HT) and brain-derived neurotrophic factor (BDFN). It has been previously demonstrated that hyperserotonemia induced by l-Tryptophan (TrP) enriched diet protect against memory deficits during physiological aging. Since 5-HT is closely associated to BDNF, we aimed to investigate the effect of high TrP diet on 5-HT levels and BDNF expression in Frontal Cortex (FC) and Hippocampus (Hp) of aged rats. We found that the raising of systemic 5-HT levels by chronic diet (1 month) containing high TrP significantly prevents age-related decline of BDNF protein expression in both brain areas as indicated by ELISA and Western Blot analyses. Interestingly, immunohistochemical analyses confirmed that high TrP diet significantly elevates the number of 5-HT immunoreactive fibers in both brain areas tested and this correlated with BDNF increase in the FC and hippocampal regions CA1, CA2, CA3 and a strikingly down-regulation of neurotrophin levels in the dentate gyrus (DG) of aged rats. Altogether, these finding provide evidence that enhanced TrP intake and the consequent increase in 5-HT neurotransmission may act as a modulator of BDNF system suggesting a possible mechanism for the protective role of serotonergic system on memory impairment occurring along normal aging process.
authors.affiliation: Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology section, University of Catania, Catania, Italy. Electronic address: giumusu@gmail.com.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Musumeci
authors.affiliation: Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology section, University of Catania, Catania, Italy. Electronic address: pacastro@unict.it.
authors.forename: Paola
authors.initials: P
authors.lastname: Castrogiovanni
authors.affiliation: Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology section, University of Catania, Catania, Italy. Electronic address: sergio.castorina@unict.it.
authors.forename: Sergio
authors.initials: S
authors.lastname: Castorina
authors.affiliation: Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology section, University of Catania, Catania, Italy. Electronic address: roimbesi@unict.it.
authors.forename: Rosa
authors.initials: R
authors.lastname: Imbesi
authors.affiliation: Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology section, University of Catania, Catania, Italy. Electronic address: marta.sz@hotmail.it.
authors.forename: Marta Anna
authors.initials: MA
authors.lastname: Szychlinska
authors.affiliation: Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology section, University of Catania, Catania, Italy; Yale Child Study Center, Yale School of Medicine, New Haven, CT, USA. Electronic address: sorayascuderi@yahoo.it.
authors.forename: Soraya
authors.initials: S
authors.lastname: Scuderi
authors.affiliation: Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology section, University of Catania, Catania, Italy. Electronic address: carla.loreto@unict.it.
authors.forename: Carla
authors.initials: C
authors.lastname: Loreto
authors.affiliation: Department of Biomedical and Biotechnological Sciences, Human Anatomy and Histology section, University of Catania, Catania, Italy. Electronic address: salvatore.giunta15@virgilio.it.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Giunta
mesh_terms: D000375:Aging / Q000378:metabolism* / Q000473:pathology; D000818:Animals; D015153:Blotting, Western; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism*; D004032:Diet; D004035:Diet Therapy; D004797:Enzyme-Linked Immunosorbent Assay; D005625:Frontal Lobe / Q000378:metabolism* / Q000473:pathology; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology; D007150:Immunohistochemistry; D011897:Random Allocation; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D014364:Tryptophan / Q000008:administration & dosage*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D012701:Serotonin; D014364:Tryptophan
keywords: Aging; BDNF; Brain; Serotonin; Tryptophan