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Fidalgo S, Yeoman MS. Age-Related Changes in Central Nervous System 5-Hydroxytryptamine Signalling and Its Potential Effects on the Regulation of Lifespan. Subcell Biochem 2023; 102:379-413. [PMID: 36600141 DOI: 10.1007/978-3-031-21410-3_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Serotonin or 5-hydroxytryptamine (5-HT) is an important neurotransmitter in the central nervous system and the periphery. Most 5-HT (~99%) is found in the periphery where it regulates the function of the gastrointestinal (GI) tract and is an important regulator of platelet aggregation. However, the remaining 1% that is found in the central nervous system (CNS) can regulate a range of physiological processes such as learning and memory formation, mood, food intake, sleep, temperature and pain perception. More recent work on the CNS of invertebrate model systems has shown that 5-HT can directly regulate lifespan.This chapter will focus on detailing how CNS 5-HT signalling is altered with increasing age and the potential consequences this has on its ability to regulate lifespan.
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Affiliation(s)
| | - Mark S Yeoman
- Centre for Stress and Age-Related Disease, School of Applied Sciences, University of Brighton, Brighton, United Kingdom.
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Belmer A, Patkar OL, Pitman KM, Bartlett SE. Serotonergic Neuroplasticity in Alcohol Addiction. Brain Plast 2016; 1:177-206. [PMID: 29765841 PMCID: PMC5928559 DOI: 10.3233/bpl-150022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Alcohol addiction is a debilitating disorder producing maladaptive changes in the brain, leading drinkers to become more sensitive to stress and anxiety. These changes are key factors contributing to alcohol craving and maintaining a persistent vulnerability to relapse. Serotonin (5-Hydroxytryptamine, 5-HT) is a monoamine neurotransmitter widely expressed in the central nervous system where it plays an important role in the regulation of mood. The serotonin system has been extensively implicated in the regulation of stress and anxiety, as well as the reinforcing properties of all of the major classes of drugs of abuse, including alcohol. Dysregulation within the 5-HT system has been postulated to underlie the negative mood states associated with alcohol use disorders. This review will describe the serotonergic (5-HTergic) neuroplastic changes observed in animal models throughout the alcohol addiction cycle, from prenatal to adulthood exposure. The first section will focus on alcohol-induced 5-HTergic neuroadaptations in offspring prenatally exposed to alcohol and the consequences on the regulation of stress/anxiety. The second section will compare alterations in 5-HT signalling induced by acute or chronic alcohol exposure during adulthood and following alcohol withdrawal, highlighting the impact on the regulation of stress/anxiety signalling pathways. The third section will outline 5-HTergic neuroadaptations observed in various genetically-selected ethanol preferring rat lines. Finally, we will discuss the pharmacological manipulation of the 5-HTergic system on ethanol- and anxiety/stress-related behaviours demonstrated by clinical trials, with an emphasis on current and potential treatments.
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Affiliation(s)
- Arnauld Belmer
- Translational Research Institute, Queensland University of Technology, Brisbane, Australia.,Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - Omkar L Patkar
- Translational Research Institute, Queensland University of Technology, Brisbane, Australia.,Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - Kim M Pitman
- Translational Research Institute, Queensland University of Technology, Brisbane, Australia.,Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - Selena E Bartlett
- Translational Research Institute, Queensland University of Technology, Brisbane, Australia.,Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
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Differential effects of amphetamine and GBR-12909 on orolingual motor function in young vs aged F344/BN rats. Psychopharmacology (Berl) 2014; 231:4695-701. [PMID: 24923981 PMCID: PMC4301607 DOI: 10.1007/s00213-014-3620-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 05/13/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Orolingual motor deficits, such as dysarthria and dysphagia, contribute to increased morbidity and mortality in the elderly. In preclinical studies, we and others have reported age-related decreases in tongue motility in both F344 and F344/BN rats. The fact that these deficits are associated with nigrostriatal dopamine (DA), tissue measures suggest that increasing dopamine function might normalize tongue motility. OBJECTIVE The purpose of the current study was to determine whether two indirect dopamine agonists with locomotor-enhancing effects, d-amphetamine (amphetamine; 1 and 2 mg/kg) and GBR-12909 (5, 10, and 20 mg/kg), can improve tongue motility in aged F344/BN rats. METHODS Young (6 months) and aged (30 months) F344/BN rats licked water from an isometric force disc so that tongue motility (licks/second) and tongue force could be measured as a function of age and drug dose. RESULTS Consistent with our previous studies, tongue force was greater and tongue motility was lower in the aged group. Tongue motility was increased by amphetamine but not by GBR-12909. Amphetamine decreased peak tongue force, primarily in the young group. GBR-12909 did not affect tongue force. GBR-12909 increased the number of licks/session in the young group but not in the aged group, while amphetamine increased this measure in both groups. CONCLUSION These results demonstrate differential effects of these drugs on orolingual motor function and suggest that blocking DA uptake is insufficient to increase tongue motility in aging.
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Hoekzema E, Rojas S, Herance R, Pareto D, Abad S, Jiménez X, Figueiras FP, Popota F, Ruiz A, Flotats N, Fernández FJ, Rocha M, Rovira M, Víctor VM, Gispert JD. [11C]-DASB microPET imaging in the aged rat: Frontal and meso-thalamic increases in serotonin transporter binding. Exp Gerontol 2011; 46:1020-5. [DOI: 10.1016/j.exger.2011.09.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 09/15/2011] [Accepted: 09/21/2011] [Indexed: 10/17/2022]
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Ethanol-induced effects on the dopamine and serotonin systems in adult Wistar rats are dependent on early-life experiences. Brain Res 2011; 1405:57-68. [PMID: 21741625 DOI: 10.1016/j.brainres.2011.06.031] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Revised: 06/10/2011] [Accepted: 06/12/2011] [Indexed: 11/22/2022]
Abstract
Some individuals control their ethanol consumption throughout life, but others escalate their intake to levels that increase the risk for addiction. The early environment influences the individual response to ethanol and affects the underlying physiological processes that lead to a transition from a voluntary to a compulsive use of ethanol. However, the neurobiological substrates for these processes are not understood. The present study aimed to test the hypothesis that early environmental experiences affect the neurobiological effects that are induced by voluntary ethanol consumption. Rat pups were subjected to three different rearing environments: conventional animal facility rearing or separation from dam and littermates for either 15 or 360min. In adulthood, the rats were exposed to a two-bottle free choice between ethanol and water for seven weeks. Tissue levels of dopamine, 5-hydroxytryptamine (5-HT) and their metabolites were measured in brain areas that have been implicated in reward and addiction processes. Differences in ethanol-induced effects were noted in 5-HT-related measurements in the nucleus accumbens and ventral tegmental area and in dopamine-related measurements in the dorsal raphe nucleus (DRN). These results provided evidence of an early environmental impact on interactive neuronal circuits between the DRN and reward pathways. The amygdala, a key area in addiction processes, was particularly sensitive to early-life conditions. The animals that experienced the longest separation differed from the others; they had low basal 5-HT levels and responded with an increase in 5-HT after ethanol. These altered responses to initial ethanol consumption as a result of early environmental factors may affect the transition from habitual to compulsive drinking and contribute to individual vulnerability or resilience to addiction.
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Sağlam E, Uzbay IT, Kayir H, Celik T, Beyazyürek M. Effects of venlafaxine on ethanol withdrawal syndrome in rats. Fundam Clin Pharmacol 2004; 18:693-8. [PMID: 15548241 DOI: 10.1111/j.1472-8206.2004.00281.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The present study was designed to investigate the effects of venlafaxine, a serotonin and noradrenaline reuptake inhibitor (SNRI), on ethanol withdrawal syndrome in rats. Adult male Wistar rats (187-319 g) were used for the study. Ethanol (7.2%, v/v) was given to rats by a liquid diet for 21 days. Control rats were pair-fed an isocaloric liquid diet containing sucrose as a caloric substitute to ethanol. Venlafaxine (5, 10, 20 and 40 mg/kg) and saline were injected to rats intraperitoneally just before ethanol withdrawal. After the 2nd, 4th and 6th hour of ethanol withdrawal, rats were observed for 5 min, and withdrawal signs that included locomotor hyperactivity, agitation, stereotyped behaviour and wet dog shakes were recorded or rated. A second series of injections was given at the 6th hour after the first one, and rats were then tested for audiogenic seizures. Venlafaxine produced some inhibitory effects on locomotor hyperactivity, stereotypic behaviours and wet dog shakes. However, a two-way anova of the data did not indicate any significant effect. It reduced the incidence of the audiogenic seizures at the 6th hour of ethanol withdrawal. Venlafaxine (20 mg/kg) also prolonged the latency of the seizures significantly. Our results suggest that acute venlafaxine treatment has limited beneficial effects on ethanol withdrawal syndrome in rats.
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Affiliation(s)
- Esra Sağlam
- Department of Pharmacology, Maltepe University 81530, Istanbul, Turkey
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Birthelmer A, Lazaris A, Schweizer T, Jackisch R, Cassel JC. Presynaptic regulation of neurotransmitter release in the cortex of aged rats with differential memory impairments. Pharmacol Biochem Behav 2003; 75:147-62. [PMID: 12759123 DOI: 10.1016/s0091-3057(03)00065-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cluster analysis of water-maze reference-memory performances of 25-27-month-old (compared to 3-5-month-old) rats distinguished subpopulations of young adult rats (YOUNG), aged rats with no significant impairment (AU), aged rats with moderate impairment (AMI), and aged rats with severe impairment (ASI). In the frontoparietal cortex, we subsequently assessed the electrically evoked release of tritium in slices preloaded with [3H]choline, [3H]noradrenaline (NA), or [3H]serotonin (5-HT) and the effects of an agonist (oxotremorine, UK 14,304, and CP 93,129) of the respective autoreceptors. Cholinergic and monoaminergic markers were measured in homogenates. Overall, aged rats exhibited reduced accumulation of [3H]choline (-25%) and weaker evoked transmitter release (in % of accumulated tritium: -44%, -20%, and -34%, for [3H]acetylcholine, [3H]NA, and [3H]5-HT, respectively). In all rats, the inhibitory effects of the autoreceptor agonists on the evoked release of [3H] were comparable. Acetylcholinesterase (AChE), not choline acetyltransferase (ChAT), activity was reduced. The results suggest age-related modifications in the cholinergic, noradrenergic, and serotonergic innervation of the frontoparietal cortex, alterations of evoked transmitter release, but no interference with presynaptic autoinhibition of the release. Neither of these alterations seemed to account for the cognitive impairment assessed.
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Affiliation(s)
- A Birthelmer
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Universität Freiburg, Neuropharmakologisches Labor, Hansastrasse 9A, D-79104 Freiburg, Germany
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Abstract
Although the role of serotonin (5-hydroxytryptamine or 5-HT) in pre-natal craniofacial growth and development has been studied, no research has been done on the effects of serotonin on post-natal craniofacial growth and development. The following experimental question was tested: What effect does increasing in vivo serotonin levels adjacent to trigeminal motoneurons have on post-natal craniofacial structures in young, actively growing rats? Forty male Sprague-Dawley rats were divided into 4 experimental groups (10% serotonin microspheres, 15% serotonin microspheres, blank microspheres, sham surgeries) and underwent stereotactic neurosurgery at post-natal day 35; 5 rats of each group were killed at 14 and 21 post-surgical days for data collection. Statistical analyses by mixed-model, 4 x 2 repeated-measures ANOVA, and post hoc Fisher LSD tests revealed significant (P < or = 0.05, 0.01) differences between groups and sides for muscle weight, cranial dimension, and TMJ dimension data. Data described here indicate that significant alterations of post-natal craniofacial structures can be caused by altered in vivo levels of serotonin adjacent to trigeminal motoneurons.
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Affiliation(s)
- K E Byrd
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis 46202-5120, USA.
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Jeng CH, Chou JR, Hoffer BJ, Wang Y. Serotonergic Modulation of Ethanol-Induced Electrophysiological Depression in Young and Aged Rats. Alcohol Clin Exp Res 2000. [DOI: 10.1111/j.1530-0277.2000.tb01975.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Zafar H, Shelat SG, Redei E, Tejani-Butt S. Fetal alcohol exposure alters serotonin transporter sites in rat brain. Brain Res 2000; 856:184-92. [PMID: 10677625 DOI: 10.1016/s0006-8993(99)02350-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This study examined the effects of fetal alcohol exposure (FAE) on serotonin transporter (5-HTT) binding sites in the brains of developing male and female rat offspring using the technique of quantitative autoradiography. Time-pregnant dams were fed liquid ethanol diet, isocaloric diet without ethanol or normal rat chow. Male and female offspring were sacrificed at 21, 40 and 60 days of age, brains removed and sectioned for analysis of 5-HTT sites. FAE led to distinct effects on 5-HTT sites depending on the age and gender of the offspring. FAE increased 5-HTT binding sites in cortical layers 5, 6, hippocampal layers CA(2,3), lateral nucleus of the amygdala and in the dorsal raphe nucleus. FAE decreased 5-HTT binding sites in the medial nucleus of amygdala, dorsomedial and ventromedial nuclei of the hypothalamus. FAE decreased 5-HTT binding sites temporarily in the ventromedial nucleus of the hypothalamus in the 21-day-old female; this effect was found to disappear by day 40. In contrast, FAE increased 5-HTT sites in the lateral nucleus of the amygdala in the adult animal, suggesting that ethanol exposure in utero may alter serotonin neurotransmission in discrete brain regions permanently.
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Affiliation(s)
- H Zafar
- Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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Tabbaa S, Dlugos C, Pentney R. The number of granule cells and spine density on Purkinje cells in aged, ethanol-fed rats. Alcohol 1999; 17:253-60. [PMID: 10231174 DOI: 10.1016/s0741-8329(98)00059-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The purpose of this study was to determine whether chronic intake of ethanol by aged F344 rats was associated with a reduction in parallel fiber input to cerebellar Purkinje neurons (PN). Previous results from this laboratory provided direct evidence that synaptic density in PN dendritic arbors was significantly decreased and indirect evidence that terminal dendritic segments of PN were deleted during chronic ethanol treatment. From these results, it was hypothesized that an ethanol-related deletion of PN terminal dendritic segments might result from 1) a reduction in parallel fiber input to PN from cerebellar granule neurons or 2) a reduction in dendritic spines, the postsynaptic sites for parallel fiber input to PN dendrites. Measurements of the total number of cerebellar granule neurons (GN) and the volume of the GN layer, and measurements of the density of spines on PN terminal dendritic segments were made in separate groups of aged, ethanol-treated and control rats. There were no significant ethanol-related changes in these parameters after 40-48 weeks of ethanol treatment.
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Affiliation(s)
- S Tabbaa
- Department of Oral Diagnostic Sciences, School of Dental Medicine, SUNY at Buffalo, NY 14214-3000, USA
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Tajuddin NF, Druse MJ. Effects of Chronic Ethanol Consumption and Aging on Proenkephalin and Neurotensin. Alcohol Clin Exp Res 1998. [DOI: 10.1111/j.1530-0277.1998.tb03715.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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