Serotonin, inhibition, and negative mood.
Ontology highlight
ABSTRACT:
SUBMITTER: Dayan P
PROVIDER: S-EPMC2222921 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Serotonin receptor 4 (5‑HT4R) plays an important role in regulating mood, anxiety, and cognition, and drugs that activate this receptor have fast-acting antidepressant (AD)-like effects in preclinical models. However, 5‑HT4R is widely expressed throughout the central nervous system (CNS) and periphery, making it difficult to pinpoint the cell types and circuits underlying its effects. Therefore, we generated a Cre-dependent 5‑HT4R knockout mouse line to dissect the function of 5‑HT4R in specific brain regions and cell types. We show that the loss of functional 5‑HT4R specifically from excitatory neurons of hippocampus led to robust AD-like behavioral responses and an elevation in baseline anxiety. 5‑HT4R was necessary to maintain the proper excitability of dentate gyrus (DG) granule cells and cell type specific molecular profiling revealed a dysregulation of genes necessary for normal neural function and plasticity in cells lacking 5‑HT4R. These adaptations were accompanied by an increase in the number of immature neurons in ventral, but not dorsal, dentate gyrus, indicating a broad impact of 5‑HT4R loss on the local cellular environment. This study is the first to use conditional genetic targeting to demonstrate a direct role for hippocampal 5‑HT4R signaling in modulating mood and anxiety. Our findings also underscore the need for cell type-based approaches to elucidate the complex action of neuromodulatory systems on distinct neural circuits.
2021-01-08 | GSE157607 | GEO
Project description:Serotonin receptor 4 (5-HT4R) plays an important role in regulating mood, anxiety, and cognition, and drugs that activate this receptor have fast-acting antidepressant (AD)-like effects in preclinical models. However, 5-HT4R is widely expressed throughout the central nervous system (CNS) and periphery, making it difficult to pinpoint the cell types and circuits underlying its effects. Therefore, we generated a Cre-dependent 5-HT4R knockout mouse line to dissect the function of 5-HT4R in specific brain regions and cell types. We show that the loss of functional 5-HT4R specifically from excitatory neurons of hippocampus led to robust AD-like behavioral responses and an elevation in baseline anxiety. 5-HT4R was necessary to maintain the proper excitability of dentate gyrus (DG) granule cells and cell type-specific molecular profiling revealed a dysregulation of genes necessary for normal neural function and plasticity in cells lacking 5-HT4R. These adaptations were accompanied by an increase in the number of immature neurons in ventral, but not dorsal, dentate gyrus, indicating a broad impact of 5-HT4R loss on the local cellular environment. This study is the first to use conditional genetic targeting to demonstrate a direct role for hippocampal 5-HT4R signaling in modulating mood and anxiety. Our findings also underscore the need for cell type-based approaches to elucidate the complex action of neuromodulatory systems on distinct neural circuits.
| S-EPMC8275670 | biostudies-literature
Project description:The majority of individuals who suffer an episode of depression go on to experience recurrences. We have proposed, based upon the observation that reducing serotonin via acute tryptophan depletion (ATD) is more likely to induce negative mood in recovered depressed individuals than never depressed individuals, that this may be because associations form between negative mood and reduced serotonin during an episode of depression (Robinson and Sahakian, Psychol Med 38:315-318, 2008b). Such associations would mean that subsequent reductions in serotonin are more likely to provoke depressed mood and hence trigger an episode of depression.In this study, we tested this hypothesis by manipulating the mood state of healthy females undergoing ATD (or balanced placebo) on two separate testing sessions. On the first session, subjects received either negative or neutral mood induction, while on the second session all subjects received neutral mood induction.Our findings demonstrate significant ATD-induced negative mood exclusively on the second visit of subjects who received both ATD and negative mood induction procedure on their first visit.These findings may be explained by the formation of an association between the negative mood and reduced serotonin states during the first visit. As such, these findings provide preliminary support for the associative hypothesis of recurrence in depression.Such associations might therefore explain the discrepancy between the effects of ATD in recovered- and never-depressed individuals and may, in turn, explain why an episode of depression increases the risk of subsequent episodes.
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Project description:The short (S) allele of the serotonin transporter gene (5-HTTLPR) is associated with reduced serotonin turnover compared to the long (L) allele in Caucasians. Few studies have examined its impact on memory and brain structure in healthy young adults.Participants included 51 healthy young adults (25 female; ages 18-25). Multiple regressions examined the independent contribution of 5-HTTLPR biomarker genotype and its interactions with gender and sub-clinical depressive symptoms on hippocampal volumes and memory.The 5-HTTLPR genotype significantly interacted with gender in predicting larger left hippocampal volumes in S-carrying females and smaller hippocampal volumes in males (p<.03). Gender also moderated the impact of the 5-HTTLPR on neurocognition. In females, S allele carriers had poorer visual recall compared to L carriers (p<.05). A three-way interaction between 5-HTTLPR, gender, and depressive symptoms was also observed (p<.04). In females, larger left hippocampal volumes were associated with increased depressive symptoms while the opposite was seen in males. Finally, in male and female S carriers, increased depressive symptoms were marginally associated with poorer verbal memory (p<.09).In females, the 5-HTTLPR S allele was associated with poorer memory performance, increased depressive symptoms and larger hippocampal volumes. In males, the S allele predicted smaller hippocampal volumes and increased depressive symptoms. The opposite morphometric patterns likely reflect gender differences in adolescent hippocampal development. Larger longitudinal studies are needed to examine whether the impact of 5-HTTLPR genotype on neurocognition across development differs according to extent of mood symptoms and gender.
| S-EPMC4433017 | biostudies-literature
Project description:Abnormal serotonin type 1A (5-HT1A) receptor function and binding have been implicated in the pathophysiology of mood disorders. Preclinical studies have consistently shown that stress decreases the gene expression of 5-HT1A receptors in experimental animals, and that the associated increase in hormone secretion plays a crucial role in mediating this effect. Chronic administration of the mood stabilizers lithium and divalproex (valproate semisodium) reduces glucocorticoid signaling and function in the hippocampus. Lithium has further been shown to enhance 5-HT1A receptor function. To assess whether these effects translate to human subject with bipolar disorder (BD), positron emission tomography (PET) and [18F]trans-4-fluoro-N-(2-[4-(2-methoxyphenyl) piperazino]-ethyl)-N-(2-pyridyl) cyclohexanecarboxamide ([(18)F]FCWAY) were used to acquire PET images of 5-HT1A receptor binding in 10 subjects with BD, before and after treatment with lithium or divalproex. Mean 5-HT1A binding potential (BPP) significantly increased following mood stabilizer treatment, most prominently in the mesiotemporal cortex (hippocampus plus amygdala). When mood state was also controlled for, treatment was associated with increases in BPP in widespread cortical areas. These preliminary findings are consistent with the hypothesis that these mood stabilizers enhance 5-HT1A receptor expression in BD, which may underscore an important component of these agents' mechanism of action.
| S-EPMC3784836 | biostudies-literature
Project description:BackgroundThere is increasing evidence for predictive coding theories of psychosis, which state that hallucinations arise from abnormal perceptual priors or biases. However, psychological processes that foster abnormal priors/biases in patients suffering hallucinations have been largely unexplored. The widely recognized relationship between affective disorders and psychosis suggests a role for mood and emotion.MethodsThirty-six patients with dementia with Lewy bodies (DLB), a representative condition associated with psychosis of neurological origin, and 12 patients with Alzheimer's disease (AD) were enrolled. After an experimental mood induction, the participants underwent the pareidolia test, in which visual hallucination-like illusions were evoked and measured.ResultsIn DLB patients, the number of pareidolic illusions was doubled under negative mood compared to that under neutral mood. In AD patients, there was no significant difference in the number of pareidolic responses between negative and neutral mood conditions. A signal detection theory analysis demonstrated that the observed affective modulation of pareidolic illusions was mediated through heightened perceptual bias, not sensory deterioration.ConclusionsThe current findings demonstrated that abnormal perceptual priors in psychotic false perception have an affective nature, which we suggest are a type of cognitive feeling that arises in association with perception and cognition.
| S-EPMC5983458 | biostudies-literature
Project description:Serotonin (5-hydroxytryptamine; 5-HT) is an ancient signaling molecule that has a conserved role in modulating mood and behavior. Integral to its pleiotropic actions is the existence of multiple receptors, expressed in distinct but often overlapping patterns within the brain and the periphery. The existence of ?14 mammalian receptor subtypes, many of which possess similar pharmacological profiles, has made assigning functional roles for these receptors challenging. This challenge has been further compounded by the revelation that a single receptor can have several different functions depending upon where and when it is expressed and activated, that is, in brain versus periphery, or at different developmental time points. This review highlights the contribution of genetic techniques to dissect the specific function of distinct serotonin receptor populations across the life course, with an emphasis on the contribution of different serotonin 1A receptor populations to mood and behavior. Similar approaches hold the promise to elucidate the functional roles of other receptors, as well as the interaction of serotonin with other neuroendocrine modulators of mood and behavior.
| S-EPMC3652904 | biostudies-literature
Project description:BackgroundAffective disorders are associated with altered cognitive performance. However, the precise interaction between affect and cognition is unclear. The manipulation of serotonin (5-HT), a neurotransmitter implicated in affect, influences performance on "hot" cognitive tasks that require the processing of affective stimuli, but manipulation of affect via mood induction influences performance on "cold" cognitive tasks that do not involve affective stimuli. We attempted to disentangle the influence of affect on cognition by examining the effect of manipulating both serotonin (via acute tryptophan depletion [ATD]) and mood on established hot and cold cognitive tasks.MethodsIn a double blind, placebo-controlled crossover design, 33 healthy mood-induced (positive, negative, or neutral) subjects completed the (hot) affective go/no-go (AGNG) and (cold) one touch tower (OTT) following both placebo and ATD.ResultsMood influenced performance on the OTT but not AGNG; ATD influenced performance on the AGNG but not OTT.ConclusionsA double dissociation was demonstrated between the influence of ATD and mood on cognition, indicating that serotonin and mood are not closely linked. We hypothesize that this is due to the differences between emotions and moods and that aberrant cognition in affective disorders may be provoked through both bottom-up and top-down mechanisms.
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Project description:Whether and to what extent animals experience emotions is crucial for understanding their decisions and behaviour, and underpins a range of scientific fields, including animal behaviour, neuroscience, evolutionary biology and animal welfare science. However, research has predominantly focused on alleviating negative emotions in animals, with the expression of positive emotions left largely unexplored. Therefore, little is known about positive emotions in animals and how their expression is mediated. We used tail handling to induce a negative mood in laboratory mice and found that while being more anxious and depressed increased their expression of a discrete negative emotion (disappointment), meaning that they were less resilient to negative events, their capacity to express a discrete positive emotion (elation) was unaffected relative to control mice. Therefore, we show not only that mice have discrete positive emotions, but that they do so regardless of their current mood state. Our findings are the first to suggest that the expression of discrete positive and negative emotions in animals is not equally affected by long-term mood state. Our results also demonstrate that repeated negative events can have a cumulative effect to reduce resilience in laboratory animals, which has significant implications for animal welfare.
| S-EPMC7482280 | biostudies-literature
Project description:Serotonin receptor 4 in the hippocampus modulates mood and anxiety
| PRJNA662219 | ENA