FC29-05 - Season, sunlight, and brain serotonin function

2011 ◽  
Vol 26 (S2) ◽  
pp. 1981-1981 ◽  
Author(s):  
N. Praschak-Rieder ◽  
M. Willeit ◽  
H. Sitte ◽  
J.H. Meyer ◽  
S. Kasper
Keyword(s):  
Seasonal Variations ◽  
Seasonal Changes ◽  
Healthy Subjects ◽  
Seasonal Affective Disorder ◽  
Light Therapy ◽  
Brain Serotonin ◽  
Winter Depression ◽  
Positron Emission ◽  
Outward Transport ◽  
And Function

IntroductionMany experience low mood and energy during winter. Brain serotonin is involved in the regulation of many physiologic and pathologic functions that vary with season. Seasonal variations in peripheral serotonergic markers have been described in clinical and nonclinical populations, and a postmortem study shows seasonal differences in hypothalamic serotonin concentration.AimWe investigated the molecular background of seasonal changes in serotonin function by conducting a series of studies on serotonin transporter (5-HTT) density and function in depression and health.MethodsIn a large study in drug-free patients with seasonal affective disorder (SAD) we aimed at detecting state-related alterations in 5-HTT-mediated inward and outward transport in platelets. Another study in healthy subjects aimed at detecting seasonal variations in 5-HTT binding in the living human brain using [11C] DASB positron emission tomography. Regional 5-HTT binding, an index of 5-HTT density, was assessed in a large sample of drug-naïve healthy volunteers, and was related to meteorological and astronomical data.ResultsIn patients with SAD we showed that the 5-HTT is in a hyperfunctional state during winter depression, and normalizes after light therapy and in natural summer remission. In healthy subjects, 5-HTT binding was higher in autumn/winter as compared to spring/summer. Regional 5-HTT binding correlated negatively with daily sunshine, such that higher values occurred at times of lesser light.ConclusionsSince high 5-HTT density is associated with low synaptic serotonin levels, regulation of 5-HTT density and 5-HTT function by light is a mechanism that may explain seasonal changes in normal and pathologic behaviours.

scholarly journals Light therapy and the management of winter depression

2004 ◽  
Vol 10 (3) ◽  
pp. 233-240 ◽  
Author(s):  
John M. Eagles
Keyword(s):  
Affective Disorder ◽  
Seasonal Affective Disorder ◽  
Antidepressant Medication ◽  
Light Therapy ◽  
Significant Degree ◽  
Winter Depression ◽  
Effectiveness Prediction ◽  
Clinically Significant ◽  
General Aspects ◽  
The Uk

Much the most common type of seasonal affective disorder at temperate latitudes is recurrent winter depression, which probably affects around 3% of adults in the UK to a clinically significant degree. In this article, diagnosis and presentation are discussed and symptoms are contrasted with those of non-seasonal depression. Aetiology and epidemiology, with regard to age, gender and latitude of residence, are described. Sufferers are often treated with light therapy, and this is described in some detail, with mention of effectiveness, prediction of outcome, timescales of response, side-effects, use of lightboxes and alternatives to lightboxes. Other general aspects of the management of seasonal affective disorder, including the use of antidepressant medication, are also outlined.

Effects of rapid tryptophan depletion in patients with seasonal affective disorder in natural summer remission

2000 ◽  
Vol 30 (1) ◽  
pp. 79-87 ◽  
Author(s):  
R. W. LAM ◽  
T. A. BOWERING ◽  
E. M. TAM ◽  
A. GREWAL ◽  
L. N. YATHAM ◽  
...  
Keyword(s):  
Affective Disorder ◽  
Repeated Measures ◽  
Seasonal Affective Disorder ◽  
Bright Light ◽  
Light Therapy ◽  
Brain Serotonin ◽  
Tryptophan Depletion ◽  
Control Session ◽  
Double Blind ◽  
Plasma Tryptophan

Background. Serotonergic mechanisms have been proposed for the pathophysiology of seasonal affective disorder (SAD) and the therapeutic effect of bright-light treatment. Previously, we showed that SAD patients, in clinical remission with light therapy during the winter, experienced transient depressive relapses after a rapid tryptophan depletion (RTD) technique, which results in decreased brain serotonin levels. The objective of this study was to investigate the effect of RTD in SAD patients who were in natural summer remission.Methods. Twelve drug-free patients with SAD by DSM-IV criteria and 10 normal subjects participated in this double-blind, placebo-controlled, crossover study. SAD patients were in natural summer remission for at least 8 weeks. Behavioural ratings and plasma tryptophan levels were obtained before, and 5 h after, ingesting an amino acid (AA) mixture±tryptophan. Experimental RTD and control sessions were scheduled 1 week apart.Results. The RTD session resulted in significant reduction in total and free plasma tryptophan levels compared to the control session. The behavioural data were analysed using repeated measures analysis of variance. This analysis found significant main effects of time (higher scores after AA ingestion) and diagnosis (higher scores in SAD patients), but no main effect of session or significant interaction effects between the three factors. Thus, there were no significant behavioural effects of RTD compared to the sham depletion control session.Conclusions. The summer remission experienced by SAD patients is not dependent on plasma tryptophan levels (and presumably brain serotonin function) in the same manner as that of remission after light therapy. These results conflict with those of other laboratories, perhaps because of differences in study samples.

scholarly journals Photoperiodic regulation of dopamine signaling regulates seasonal changes in retinal photosensitivity in mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kousuke Okimura ◽  
Yusuke Nakane ◽  
Taeko Nishiwaki-Ohkawa ◽  
Takashi Yoshimura
Keyword(s):  
Seasonal Changes ◽  
Molecular Basis ◽  
Seasonal Affective Disorder ◽  
Winter Season ◽  
Light Therapy ◽  
Therapeutic Interventions ◽  
Pharmacological Intervention ◽  
Short Day ◽  
Photoperiodic Regulation ◽  
Dopamine Signaling

AbstractAt high latitudes, approximately 10% of people suffer from depression during the winter season, a phenomenon known as seasonal affective disorder (SAD). Shortened photoperiod and/or light intensity during winter season are risk factors for SAD, and bright light therapy is an effective treatment. Interestingly, reduced retinal photosensitivity along with the mood is observed in SAD patients in winter. However, the molecular basis underlying seasonal changes in retinal photosensitivity remains unclear, and pharmacological intervention is required. Here we show photoperiodic regulation of dopamine signaling and improvement of short day–attenuated photosensitivity by its pharmacological intervention in mice. Electroretinograms revealed dynamic seasonal changes in retinal photosensitivity. Transcriptome analysis identified short day-mediated suppression of the Th gene, which encodes tyrosine hydroxylase, a rate-limiting enzyme for dopamine biosynthesis. Furthermore, pharmacological intervention in dopamine signaling through activation of the cAMP signaling pathway rescued short day–attenuated photosensitivity, whereas dopamine receptor antagonists decreased photosensitivity under long-day conditions. Our results reveal molecular basis of seasonal changes in retinal photosensitivity in mammals. In addition, our findings provide important insights into the pathogenesis of SAD and offer potential therapeutic interventions.

Functional characterization of human brown adipose tissue metabolism

2020 ◽  
Vol 477 (7) ◽  
pp. 1261-1286 ◽  
Author(s):  
Marie Anne Richard ◽  
Hannah Pallubinsky ◽  
Denis P. Blondin
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Functional Characterization ◽  
Human Infants ◽  
Positron Emission ◽  
Brown Adipose ◽  
Treatment Of Obesity ◽  
And Function

Brown adipose tissue (BAT) has long been described according to its histological features as a multilocular, lipid-containing tissue, light brown in color, that is also responsive to the cold and found especially in hibernating mammals and human infants. Its presence in both hibernators and human infants, combined with its function as a heat-generating organ, raised many questions about its role in humans. Early characterizations of the tissue in humans focused on its progressive atrophy with age and its apparent importance for cold-exposed workers. However, the use of positron emission tomography (PET) with the glucose tracer [18F]fluorodeoxyglucose ([18F]FDG) made it possible to begin characterizing the possible function of BAT in adult humans, and whether it could play a role in the prevention or treatment of obesity and type 2 diabetes (T2D). This review focuses on the in vivo functional characterization of human BAT, the methodological approaches applied to examine these features and addresses critical gaps that remain in moving the field forward. Specifically, we describe the anatomical and biomolecular features of human BAT, the modalities and applications of non-invasive tools such as PET and magnetic resonance imaging coupled with spectroscopy (MRI/MRS) to study BAT morphology and function in vivo, and finally describe the functional characteristics of human BAT that have only been possible through the development and application of such tools.

scholarly journals PET evaluation of light-induced modulation of microglial activation and GLP-1R expression in depressive rats

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yu Liu ◽  
Lizhen Wang ◽  
Donghui Pan ◽  
Mingzhu Li ◽  
Yaoqi Li ◽  
...  
Keyword(s):  
Microglial Activation ◽  
Light Therapy ◽  
Emission Tomography ◽  
Noninvasive Evaluation ◽  
Mild Stress ◽  
Positron Emission ◽  
Therapeutic Choice ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
The Brain

AbstractLight therapy has been accepted as a promising therapeutic choice for depression. Positron emission tomography (PET) combined with specific radiotracers has great benefits for revealing pathogenesis and developing therapeutics. This study aimed to investigate the influences of light therapy on microglial activation and glucagon-like peptide-1 receptor (GLP-1R) expression in the brain of depressive rats using [18F]DPA-714 and [18F]exendin-4 PET. The results showed that chronic unpredictable mild stress (CUMS)-induced depressive rats had poorer performance in behavioral tests compared to normal rats (p < 0.05) and the depressive-like behavior could be ameliorated by light therapy. Besides, depressive rats had significantly higher [18F]DPA-714 uptake and lower [18F]FDG uptake compare to normal rats in 11 and 9 regions of interest (ROIs) of the brain, respectively (p < 0.05). After 5 weeks of light therapy, higher [18F]FDG and [18F]exendin-4 uptake was observed in most ROIs of light therapy-treated depressive rats compared to untreated depressive rats (p < 0.05) and no significant differences existed in [18F]DPA-714 uptake between the two groups. This study demonstrated that light therapy can ameliorate depressive-like behavior, improve glucose metabolism, and halt the decline of brain GLP-1R expression of depressive rats, but have no effects on microglial activation caused by CUMS. Besides, this study validated that [18F]DPA-714 and [18F]exendin-4 PET have the potential for noninvasive evaluation of microglial activation and GLP-1R expression in the brain of depression.

Light therapy increases visual contrast sensitivity in seasonal affective disorder

2004 ◽  
Vol 126 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Zoltán Szabó ◽  
Andrea Antal ◽  
Zsolt Tokaji ◽  
János Kálmán ◽  
Szabolcs Kéri ◽  
...  
Keyword(s):  
Affective Disorder ◽  
Contrast Sensitivity ◽  
Seasonal Affective Disorder ◽  
Light Therapy ◽  
Visual Contrast ◽  
Visual Contrast Sensitivity

The timing of light therapy and response assessment in winter depression

1995 ◽  
Vol 7 (2) ◽  
pp. 61-63 ◽  
Author(s):  
Y. Meesters
Keyword(s):  
Affective Disorders ◽  
Response Assessment ◽  
Light Therapy ◽  
Biological Psychiatry ◽  
Light Treatment ◽  
Winter Depression ◽  
Research Centres

Since Rosenthal et al published their first study about the effects of light treatment on mood in patients suffering from winter depression, many research centres have become interested in the study and treatment of seasonal affective disorders (SAD), one of them being the department of Biological Psychiatry in Groningen. In 1987, we started the first experiments under the inspiring direction of Prof. Rudi van den Hoofdakker and hundreds of patients have participated in various investigations ever since.

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