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Morton RA, Valenzuela CF. Third Trimester Equivalent Alcohol Exposure Reduces Modulation of Glutamatergic Synaptic Transmission by 5-HT1A Receptors in the Rat Hippocampal CA3 Region. Front Neurosci 2016; 10:266. [PMID: 27375424 PMCID: PMC4896948 DOI: 10.3389/fnins.2016.00266] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/26/2016] [Indexed: 01/05/2023] Open
Abstract
Fetal alcohol exposure has been associated with many neuropsychiatric disorders that have been linked to altered serotonin (5-hydroxytryptamine; 5-HT) signaling, including depression and anxiety. During the first 2 weeks of postnatal life in rodents (equivalent to the third trimester of human pregnancy) 5-HT neurons undergo significant functional maturation and their axons reach target regions in the forebrain (e.g., cortex and hippocampus). The objective of this study was to identify the effects of third trimester ethanol (EtOH) exposure on hippocampal 5-HT signaling. Using EtOH vapor inhalation chambers, we exposed rat pups to EtOH for 4 h/day from postnatal day (P) 2 to P12. The average serum EtOH concentration in the pups was 0.13 ± 0.04 g/dl (legal intoxication limit in humans = 0.08 g/dl). We used brain slices to assess the modulatory actions of 5-HT on field excitatory postsynaptic potentials in the hippocampal CA3 region at P13-P15. Application of the GABAA/glycine receptor antagonist, picrotoxin, caused broadening of field excitatory postsynaptic potentials (fEPSPs), an effect that was reversed by application of 5-HT in slices from air exposed rats. However, this effect of 5-HT was absent in EtOH exposed animals. In slices from naïve animals, application of a 5-HT1A receptor antagonist blocked the effect of 5-HT on the fEPSPs recorded in presence of picrotoxin, suggesting that third trimester ethanol exposure acts by inhibiting the function of these receptors. Studies indicate that 5-HT1A receptors play a critical role in the development of hippocampal circuits. Therefore, inhibition of these receptors by third trimester ethanol exposure could contribute to the pathophysiology of fetal alcohol spectrum disorders.
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Affiliation(s)
- Russell A Morton
- Department of Neurosciences, School of Medicine, University of New Mexico Health Sciences Center Albuquerque, NM, USA
| | - C Fernando Valenzuela
- Department of Neurosciences, School of Medicine, University of New Mexico Health Sciences Center Albuquerque, NM, USA
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2
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Ishiguro T, Sakata-Haga H, Fukui Y. A 5-HT2A/2C receptor agonist, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane, mitigates developmental neurotoxicity of ethanol to serotonergic neurons. Congenit Anom (Kyoto) 2016; 56:163-71. [PMID: 26714672 DOI: 10.1111/cga.12152] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 12/10/2015] [Accepted: 12/23/2015] [Indexed: 11/27/2022]
Abstract
Prenatal ethanol exposure causes the reduction of serotonergic (5-HTergic) neurons in the midbrain raphe nuclei. In the present study, we examined whether an activation of signaling via 5-HT2A and 5-HT2C receptors during the fetal period is able to prevent the reduction of 5-HTergic neurons induced by prenatal ethanol exposure. Pregnant Sprague-Dawley rats were given a liquid diet containing 2.5 to 5.0% (w/v) ethanol on gestational days (GDs) 10 to 20 (Et). As a pair-fed control, other pregnant rats were fed the same liquid diet except that the ethanol was replaced by isocaloric sucrose (Pf). Each Et and Pf group was subdivided into two groups; one of the groups was treated with 1 mg/kg (i.p.) of 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI), an agonist for 5-HT2A/2C receptors, during GDs 13 to 19 (Et-DOI or Pf-DOI), and another was injected with saline vehicle only (Et-Sal or Pf-Sal). Their fetuses were removed by cesarean section on GD 19 or 20, and fetal brains were collected. An immunohistological examination of 5-HTergic neurons in the fetuses on embryonic day 20 using an antibody against tryptophan hydroxylase revealed that the number of 5-HTergic neurons in the midbrain raphe nuclei was significantly reduced in the Et-Sal fetuses compared to that of the Pf-Sal and Pf-DOI fetuses, whereas there were no significant differences between Et-DOI and each Pf control. Thus, we concluded that the reduction of 5-HTergic neurons that resulted in prenatal ethanol exposure could be alleviated by the enhancement of signaling via 5-HT2A/2C receptors during the fetal period.
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Affiliation(s)
- Tsukasa Ishiguro
- Department of Anatomy and Developmental Neurobiology, Tokushima University Graduate School of Biomedical Science, Tokushima, Japan
| | - Hiromi Sakata-Haga
- Department of Anatomy and Developmental Neurobiology, Tokushima University Graduate School of Biomedical Science, Tokushima, Japan
| | - Yoshihiro Fukui
- Department of Anatomy and Developmental Neurobiology, Tokushima University Graduate School of Biomedical Science, Tokushima, Japan
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3
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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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4
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Parker MO, Annan LV, Kanellopoulos AH, Brock AJ, Combe FJ, Baiamonte M, Teh MT, Brennan CH. The utility of zebrafish to study the mechanisms by which ethanol affects social behavior and anxiety during early brain development. Prog Neuropsychopharmacol Biol Psychiatry 2014; 55:94-100. [PMID: 24690524 PMCID: PMC4186787 DOI: 10.1016/j.pnpbp.2014.03.011] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/07/2014] [Accepted: 03/21/2014] [Indexed: 01/31/2023]
Abstract
Exposure to moderate levels of ethanol during brain development has a number of effects on social behavior but the molecular mechanisms that mediate this are not well understood. Gaining a better understanding of these factors may help to develop therapeutic interventions in the future. Zebrafish offer a potentially useful model in this regard. Here, we introduce a zebrafish model of moderate prenatal ethanol exposure. Embryos were exposed to 20mM ethanol for seven days (48hpf-9dpf) and tested as adults for individual social behavior and shoaling. We also tested their basal anxiety with the novel tank diving test. We found that the ethanol-exposed fish displayed reductions in social approach and shoaling, and an increase in anxiety in the novel tank test. These behavioral differences corresponded to differences in hrt1aa, slc6a4 and oxtr expression. Namely, acute ethanol caused a spike in oxtr and ht1aa mRNA expression, which was followed by down-regulation at 7dpf, and an up-regulation in slc6a4 at 72hpf. This study confirms the utility of zebrafish as a model system for studying the molecular basis of developmental ethanol exposure. Furthermore, it proposes a putative developmental mechanism characterized by ethanol-induced OT inhibition leading to suppression of 5-HT and up-regulation of 5-HT1A, which leads, in turn, to possible homeostatic up-regulation of 5-HTT at 72hpf and subsequent imbalance of the 5-HT system.
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Affiliation(s)
- Matthew O Parker
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Leonette V Annan
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Alexandros H Kanellopoulos
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Alistair J Brock
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Fraser J Combe
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Matteo Baiamonte
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom
| | - Muy-Teck Teh
- Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AD, United Kingdom
| | - Caroline H Brennan
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, United Kingdom.
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Mikhailenko VA, Butkevich IP, Lavrova YA, Bagaeva TR, Otellin VA. Effect of tonic pain on the corticosterone level in rat pups of various ages subjected to prenatal stress and opportunities for correction of stress-induced impairments. DOKLADY BIOLOGICAL SCIENCES : PROCEEDINGS OF THE ACADEMY OF SCIENCES OF THE USSR, BIOLOGICAL SCIENCES SECTIONS 2013; 450:134-138. [PMID: 23821050 DOI: 10.1134/s0012496613030204] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Indexed: 06/02/2023]
Affiliation(s)
- V A Mikhailenko
- Pavlov Institute of Physiology, Russian Academy of Sciences, St. Petersburg, Russia
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Inflammatory pain and corticosterone response in infant rats: effect of 5-HT1A agonist buspirone prior to gestational stress. Mediators Inflamm 2013; 2013:915189. [PMID: 23606797 PMCID: PMC3628187 DOI: 10.1155/2013/915189] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 03/06/2013] [Indexed: 01/18/2023] Open
Abstract
Our researches have shown that gestational stress causes exacerbation of inflammatory pain in the offspring; the maternal 5-HT1A agonist buspirone before the stress prevents the adverse effect. The serotonergic system and hypothalamo-pituitary-adrenal (HPA) axis are closely interrelated. However, interrelations between inflammatory pain and the HPA axis during the hyporeactive period of the latter have not been studied. The present research demonstrates that formalin-induced pain causes a gradual and prolonged increase in plasma corticosterone level in 7-day-old male rats; twenty-four hours after injection of formalin, the basal corticosterone level still exceeds the initial basal corticosterone value. Chronic treatments of rat dams with buspirone before restraint stress during gestation normalize in the offspring pain-like behavior and induce during the acute phase in the formalin test the stronger corticosterone increase as compared to the stress hormonal elevation in animals with other prenatal treatments. Negative correlation between plasma corticosterone level and the number of flexes+shakes is revealed in buspirone+stress rats. The new data enhance the idea about relativity of the HPA axis hyporeactive period and suggest that maternal buspirone prior to stress during gestation may enhance an adaptive mechanism of the inflammatory nociceptive system in the infant male offspring through activation of the HPA axis peripheral link.
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Butkevich IP, Mikhailenko VA, Vershinina EA, Otellin VA, Aloisi AM. Buspirone before prenatal stress protects against adverse effects of stress on emotional and inflammatory pain-related behaviors in infant rats: age and sex differences. Brain Res 2011; 1419:76-84. [PMID: 21937026 DOI: 10.1016/j.brainres.2011.08.068] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 08/23/2011] [Accepted: 08/27/2011] [Indexed: 12/29/2022]
Abstract
Prenatal stress strengthens tonic pain and provokes depression. The serotoninergic system is involved in these processes. We recently showed that maternal buspirone, a 5-HT1A receptor agonist, protects against the adverse effects of in utero stress on depression and pain in adult rat offspring. Using a similar maternal treatment with buspirone, we focus here on the infant stage, which is important for the correction of prenatal abnormalities. Maternal buspirone before restraint stress during the last week of pregnancy decreased the time of immobility in the forced swim test in the infant offspring. Prenatal stress increased formalin-induced pain in the second part of the time-course of the response to formalin in males of middle infancy but in the first part of the response in males of late infancy. The effect was reversed by maternal buspirone. Pain dominated in males of both middle and late infancy but the time-course of formalin pain in infant females revealed a slower development of the processes. The results show that the time-course of formalin-induced pain in infant rats reacts to prenatal stress in an age-dependent and sexually dimorphic manner. Our finding of opposite influences of prenatal stress and buspirone before prenatal stress on formalin-induced pain during the interphase indicates that functional maturity of the descending serotonergic inhibitory system occurs in late infancy males (11-day-olds), and 5-HT1A receptors participate in this process. The data provide evidence that maternal treatment with buspirone prior to stress during pregnancy alleviates depression-like and tonic pain-related behaviors in the infant offspring.
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Affiliation(s)
- Irina P Butkevich
- Laboratory of Ontogeny of the Nervous System, Pavlov Institute of Physiology, Russian Academy of Sciences, Nab. Makarova 6, St. Petersburg 199034, Russia.
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Schneider ML, Moore CF, Barr CS, Larson JA, Kraemer GW. Moderate prenatal alcohol exposure and serotonin genotype interact to alter CNS serotonin function in rhesus monkey offspring. Alcohol Clin Exp Res 2011; 35:912-20. [PMID: 21294753 DOI: 10.1111/j.1530-0277.2010.01421.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Moderate prenatal alcohol exposure can contribute to neurodevelopmental impairments and disrupt several neurotransmitter systems. We examined the timing of moderate level alcohol exposure, serotonin transporter gene polymorphic region variation (rh5-HTTLPR), and levels of primary serotonin and dopamine (DA) metabolites in cerebrospinal fluid (CSF) in rhesus monkeys. METHODS Thirty-two 30-month old rhesus monkeys (Macaca mulatta) from 4 groups of females were assessed: (i) early alcohol-exposed group (n = 9), in which mothers voluntarily consumed 0.6 g/kg/d alcohol solution on gestational days 0 to 50; (ii) middle-to-late gestation alcohol-exposed group (n = 6), mothers consumed 0.6 g/kg/d alcohol solution on gestational days 50 to 135; (iii) a continuous-exposure group (n = 8), mothers consumed 0.6 g/kg/d alcohol solution on gestational days 0 to 135; and (iv) controls (n = 9), mothers consumed an isocaloric control solution on gestational days 0 to 50, 50 to 135, or 0 to 135. Serotonin transporter promoter region allelic variants (homozygous s/s or heterozygous s/l vs. homozygous l/l) were determined. We examined CSF concentrations of the 5-HT and DA metabolites, 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA), respectively, at baseline and 50 hours after separation from cage-mates, when the monkeys were 30 months old. RESULTS Early- and middle-to-late gestation-alcohol exposed monkeys carrying the short allele had lower concentrations of 5-HIAA in CSF relative to other groups. Concentrations of 5-HIAA in CSF were lower for s allele carriers and increased from baseline relative to pre-separation values, whereas 5-HIAA levels in l/l allele carriers were not affected by separation. Monkeys carrying the short allele had lower basal concentrations of HVA in CSF compared with monkeys homozygous for the long allele. CONCLUSION Carrying the s allele of the 5-HT transporter increased the probability of reduced 5-HIAA in early- and middle-to-late gestation alcohol-exposed monkeys and reduced HVA at baseline. These findings that prenatal alcohol exposure altered central 5-HT activity in genetically sensitive monkeys raise questions about whether abnormal serotonin biological pathways could underlie some of the psychiatric disorders reported in fetal alcohol spectrum disorder.
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Affiliation(s)
- Mary L Schneider
- Department of Kinesiology, University of Wisconsin-Madison, 53706, USA.
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Butkevich I, Mikhailenko V, Vershinina E, Semionov P, Makukhina G, Otellin V. Maternal buspirone protects against the adverse effects of in utero stress on emotional and pain-related behaviors in offspring. Physiol Behav 2010; 102:137-42. [PMID: 21056051 DOI: 10.1016/j.physbeh.2010.10.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2010] [Revised: 10/25/2010] [Accepted: 10/28/2010] [Indexed: 11/19/2022]
Abstract
Previous investigations from our laboratory demonstrated that prenatal stress exacerbates inflammatory pain-related behavior in adult rats and that fetal serotonin (5-HT) is involved in this phenomenon. In the present study we test the hypothesis that injections of buspirone, a 5-HT1A agonist, to rat dams before restraint stress during the last week of pregnancy (between pregnant days 15 and 20) can improve the characteristics of emotional and inflammatory pain-related behaviors in the adult offspring. Buspirone was injected to dams between the 9 and 20 days of pregnancy, during restraint stress, five min before it. The depression-like behavior in the forced swim test, formalininduced pain and body weight were investigated in the adult offspring. Prenatal stress exacerbated the licking behavior, the index of formalin-induced pain, and increased the time of immobility, the index of depression-like behavior. Buspirone normalized the licking behavior and profoundly reduced the time of immobility, which indicates differences in the mechanisms of antinociceptive and antidepressant effects of buspirone. The present new findings demonstrate that adverse influences of prenatal stress on emotional and inflammatory pain-related behaviors can be prevented by using prenatal buspirone, which shows long-term anxiolytic, antidepressant and antinociceptive effects. The new fact of body weight decrease in buspirone+stress males is worth noting in the context of the important problem of body weight gain as a common side effect of treatment with antidepressant drugs.
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Affiliation(s)
- I Butkevich
- Laboratory of Ontogeny of the Nervous System, I.P. Pavlov Institute of Physiology, Russian Academy of Sciences, Nab. Makarova, 6, St. Petersburg 199034, Russia.
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Ohta KI, Sakata-Haga H, Fukui Y. Alteration in anxiety-related behaviors and reduction of serotonergic neurons in raphe nuclei in adult rats prenatally exposed to ethanol. Congenit Anom (Kyoto) 2010; 50:105-14. [PMID: 20156240 DOI: 10.1111/j.1741-4520.2010.00269.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It is known that the developing serotonergic system is one of the targets of ethanol teratogenicity. Because serotonin has multiple functions in both mature and immature brains, disturbance of the serotonergic system by ethanol exposure in utero can be cause of a wide range of psychiatric problems in adulthood. In the present study, we observed serotonergic neurons in the midbrain raphe nuclei and anxiety-like behaviors which would be affected by an altered serotonergic system in adult rats prenatally exposed to ethanol. Pregnant rats were fed a liquid diet containing 2.5-5.0% (w/v) ethanol on gestational days 10-21. Their offspring were examined at 60-70 days of age. A significant decrease in the number of serotonergic cells in the midbrain raphe nuclei was shown in prenatally ethanol-exposed offspring. In an open field test, they spent more time in a central area compared to controls. Also in an elevated plus maze test, prenatally ethanol-exposed offspring spent more time on the open arms than controls. These behavioral results suggested that prenatally ethanol-exposed rats were less sensitive to anxiety. However, 44% of prenatally ethanol-exposed offspring exhibited freezing behavior on the open arms of the elevated plus maze, causing strong anxiety, compared with 0% in intact control and 12.5% in isocaloric sucrose-fed control groups. These findings suggest that prenatal ethanol exposure decreases both susceptibility and resistance of anxiety. Insufficient serotonergic actions caused by reduced serotonergic neurons in the raphe nuclei might contribute to the alterations in anxiety-related behaviors observed in our prenatally ethanol-exposed rats.
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Affiliation(s)
- Ken-ichi Ohta
- Department of Anatomy and Developmental Neurobiology, Institute of Health Biosciences, University of Tokushima Graduate School, Tokushima, Japan
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Rutz S, Riegert C, Rothmaier AK, Jackisch R. Presynaptic modulation of 5-HT release in the rat septal region. Neuroscience 2007; 146:643-58. [PMID: 17383104 DOI: 10.1016/j.neuroscience.2007.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Revised: 02/06/2007] [Accepted: 02/07/2007] [Indexed: 10/23/2022]
Abstract
5-HT released from serotonergic axon terminals in the septal nuclei modulates the activity of septal output neurons (e.g. septohippocampal cholinergic neurons) bearing somatodendritic 5-HT receptors. Therefore, we studied the mechanisms involved in the presynaptic modulation of 5-HT release in the lateral (LS) and medial septum (MS), and the diagonal band of Broca (DB). HPLC analysis showed that tissue concentrations of noradrenaline, dopamine and 5-HT were highest in DB (DB>MS>LS). Slices prepared from LS, MS and DB regions were preincubated with [(3)H]5-HT, superfused in the presence of 6-nitro-2-(1-piperazinyl)-quinoline (6-nitroquipazine) and electrically stimulated up to three times (first electrical stimulation period (S(1)), S(2), S(3); 360 pulses, 3 Hz, 2 ms, 26-28 mA). In all septal regions the Ca(2+)-dependent and tetrodotoxin-sensitive electrically-evoked overflow of [(3)H] was inhibited by the 5-HT(1B) agonist CP-93,129 and the alpha(2)-adrenoceptor agonist 5-bromo-6-(2-imidazolin-2-ylamino)-quinoxaline tartrate (UK-14,304). Also the mu- and kappa-opioid receptor agonists (d-Ala(2), N-Me-Phe(4), glycinol(5))-enkephalin (DAMGO) and [trans-(1S,2S(-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl) cyclohexyl]-benzenacetamide hydro-chloride] (U-50,488H), respectively, acted inhibitory (although less potently), whereas the delta-opioid receptor agonist (d-Pen(2), d-Pen(5))-enkephalin (DPDPE), the dopamine D(2) receptor agonist quinpirole and the adenosine A(1) receptor agonist N(6)-cyclopentyladenosine were all ineffective; the GABA(B) receptor agonist baclofen had weak effects. All inhibitory effects of the agonists were antagonized by the corresponding antagonists (3-[3-(dimethylamino)propyl]-4-hydroxy-N-[4-(4-pyridinyl)phenyl]benzamide dihydrochloride (GR-55,562), idazoxan, naloxone, nor-binaltorphimine), which also significantly enhanced the evoked release of 5-HT at S(1). It is concluded that 5-HT release in septal nuclei of the rat is modulated by presynaptic 5-HT(1B) autoreceptors, as well as by alpha(2)-, mu- and kappa-opioid heteroreceptors. All of these receptors seem to be under a tonic inhibitory influence of the corresponding endogenous agonists and show qualitatively comparable modulatory properties along the dorso-ventral distribution of the 5-HT terminals.
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Affiliation(s)
- S Rutz
- Institute of Experimental and Clinical Pharmacology and Toxicology, Laboratory of Neuropharmacology, University of Freiburg, Hansastrasse 9A, D-79104 Freiburg, Germany
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Hofmann CE, Ellis L, Yu WK, Weinberg J. Hypothalamic?Pituitary?Adrenal Responses to 5-HT1Aand 5-HT2A/CAgonists Are Differentially Altered in Female and Male Rats Prenatally Exposed to Ethanol. Alcohol Clin Exp Res 2007; 31:345-55. [PMID: 17250628 DOI: 10.1111/j.1530-0277.2006.00316.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Prenatal ethanol exposure alters the development of the hypothalamic-pituitary-adrenal (HPA) axis, resulting in HPA hyper-responsiveness to stressors in adulthood. Prenatal ethanol exposure also alters the development and activity of the serotoninergic (5-HT) system. We have previously shown that 5-HT(1A) and 5-HT(2A/C) receptor-mediated behavioral and physiological function are altered in fetal ethanol-exposed offspring. As there are extensive interactions between the HPA axis and the 5-HT system, the present study tested the hypothesis that prenatal ethanol exposure would alter 5-HT(1A) and 5-HT(2A/C) receptor-mediated HPA function. METHODS The 5-HT(1A) agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT; 0.2 mg/kg), and the 5-HT(2A/C) agonist, (+)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI; 0.3 mg/kg), or vehicle (1 mL/kg) were administered to adult female and male offspring from prenatal ethanol-exposed (E), pair-fed control (PF), and ad libitum-fed control (C) dams. The plasma concentration of adrenocorticotropin (ACTH) and corticosterone (CORT) were determined at 0, 15, 30, 60, and 120 minutes postinjection. In addition, corticotropin releasing hormone (CRH) mRNA expression in the paraventricular nucleus of the hypothalamus, and 5-HT(1A) and 5-HT(2A/C) receptor mRNA expression in the hippocampus and prefrontal cortex, respectively, were determined by in situ hybridization. RESULTS Ethanol-exposed females showed a blunted ACTH response to 8-OH-DPAT at 15 and 30 minutes, and conversely, an increased ACTH response to DOI at all time points postinjection, compared with PF and C females. Differences among E, PF, and C males failed to reach significance. Centrally, however, DOI resulted in a trend toward lower CRH mRNA levels in E and PF compared with C females, but higher CRH mRNA levels in E compared with control males. There were no differences among prenatal groups in 5-HT(2A) receptor expression in the prefrontal cortex following either 8-OH-DPAT or DOI treatment. However, following 8-OH-DPAT, hippocampal 5-HT(1A) receptor expression was higher in E than in PF females in CA1, with a trend toward higher expression in E than in C females in CA2, whereas following DOI, a prenatal group by subfield interaction suggests lower 5-HT(1A) mRNA levels in E and PF compared with C females in CA1 and the dentate gyrus. CONCLUSIONS These data are the first to demonstrate that prenatal ethanol exposure has differential long-term effects on 5-HT(1A)-mediated and 5-HT(2A)-mediated neuroendocrine function in females and males, and suggest a sex-specific ethanol-induced alteration in the interaction between the HPA axis and the serotonin system.
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MESH Headings
- Adrenocorticotropic Hormone/blood
- Animals
- Central Nervous System Depressants/pharmacology
- Corticosterone/blood
- Corticotropin-Releasing Hormone/genetics
- Corticotropin-Releasing Hormone/metabolism
- Ethanol/pharmacology
- Female
- Hypothalamo-Hypophyseal System/drug effects
- Hypothalamo-Hypophyseal System/physiology
- Male
- Paraventricular Hypothalamic Nucleus/drug effects
- Paraventricular Hypothalamic Nucleus/metabolism
- Pituitary-Adrenal System/drug effects
- Pituitary-Adrenal System/physiology
- Prefrontal Cortex/drug effects
- Prefrontal Cortex/metabolism
- Pregnancy
- Prenatal Exposure Delayed Effects/physiopathology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptor, Serotonin, 5-HT1A/genetics
- Receptor, Serotonin, 5-HT1A/metabolism
- Receptor, Serotonin, 5-HT2A/genetics
- Receptor, Serotonin, 5-HT2A/metabolism
- Serotonin Receptor Agonists/pharmacology
- Sex Characteristics
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Affiliation(s)
- Candace E Hofmann
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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13
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Yoshinaga T, Hashimoto E, Ukai W, Toki S, Saito S, Saito T. Neural stem cell transplantation in a model of fetal alcohol effects. JOURNAL OF NEURAL TRANSMISSION. SUPPLEMENTUM 2007:331-337. [PMID: 17982911 DOI: 10.1007/978-3-211-73574-9_41] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Neural stem cell (NSC) transplantation has been investigated and developed in areas such as brain injury, stroke and neurodegenerative diseases. Recently, emerging evidence suggest that many of clinical symptoms observed in psychiatric disease are likely related to neural network disruptions including neurogenesis dysfunction. In the present study, we transplanted NSCs into a model of fetal alchol effects (FAE) for the purpose of investigating the possibility of regenerative therapy for the FAE. We labeled NSCs with fluorescent dye and radioisotope which were transplanted into FAE rats by intravenous injection. The transplanted cells were detected in wide areas of brain and were greater in number in the brains of the FAE group compared to the control group. Furthermore NSC transplantation attenuated behavioral abnormalities in FAE animals. These results suggest NSC transplantation as a potental new therapy for human FAE.
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Affiliation(s)
- T Yoshinaga
- Department of Neuropsychiatry, Sapporo Medical University, Sapporo, S-1, W-16, Chuo-ku 060-8543, Japan
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14
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Evrard SG, Duhalde-Vega M, Tagliaferro P, Mirochnic S, Caltana LR, Brusco A. A low chronic ethanol exposure induces morphological changes in the adolescent rat brain that are not fully recovered even after a long abstinence: An immunohistochemical study. Exp Neurol 2006; 200:438-59. [PMID: 16631170 DOI: 10.1016/j.expneurol.2006.03.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2005] [Revised: 02/25/2006] [Accepted: 03/01/2006] [Indexed: 10/24/2022]
Abstract
Little is known about the morphological effects of alcoholism on the developing adolescent brain and its consequences into adulthood. We studied here the relationship between two neurotransmitter systems (the serotoninergic and nitrergic) and the astrocytic and neuronal cytoskeleton immediately and long after drinking cessation of a chronic, but low, ethanol administration. Adolescent male Wistar rats were exposed to ethanol 6.6% (v/v) in drinking water for 6 weeks and studied after ending exposure or after a 10-week recovery period drinking water. Control animals received water. Brain sections were processed by immunohistochemistry using antibodies to serotonin (5-HT); glial fibrillary acidic protein (GFAP); astroglial S-100b protein; microtubule associated protein-2 (MAP-2); 200 kDa neurofilaments (Nf-200); and neuronal nitric oxide synthase (nNOS). The mesencephalic dorsal and median raphe nucleus (DRN; MRN) and three prosencephalic areas closely related to cognitive abilities (CA1 hippocampal area, striatum and frontal cortex) were studied by digital image analysis. 5-HT immunoreactivity (-ir) decreased in the DRN and recovered after abstinence and was not changed in the MRN. In the three prosencephalic areas, astrocytes' cell area (GFAP-ir cells) increased after EtOH exposure and tended to return to normality after abstinence, while cytoplasmic astroglial S100b protein-ir, relative area of MAP-2-ir and Nf-200-ir fibers decreased, and later partially recovered. In the striatum and frontal cortex, nNOS-ir decreased only after abstinence. In conclusion, in the adolescent brain, drinking cessation can partially ameliorate the ethanol-induced morphological changes on neurons and astrocytes but cannot fully return it to the basal state.
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Affiliation(s)
- Sergio Gustavo Evrard
- Instituto de Biología Celular y Neurociencias, Prof. Eduardo De Robertis, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155 3rd fl., C1121ABG, Buenos Aires, Argentina
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15
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Hofmann CE, Patyk IA, Weinberg J. Prenatal ethanol exposure: Sex differences in anxiety and anxiolytic response to a 5-HT1A agonist. Pharmacol Biochem Behav 2005; 82:549-58. [PMID: 16359722 DOI: 10.1016/j.pbb.2005.10.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Revised: 10/12/2005] [Accepted: 10/20/2005] [Indexed: 11/19/2022]
Abstract
This study utilized a novelty-induced suppression of feeding task to examine anxiety-like behaviour and the anxiolytic effects of the 5-HT1A agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), in rats prenatally exposed to ethanol. Adult offspring from ethanol exposed (E), pair-fed control (PF) and ad libitum-fed control (C) dams were habituated to a novel palatable food for 21 days and measures of baseline feeding obtained. On day 22 (d 22), animals received either 8-OH-DPAT (0.06 mg/kg) or vehicle (0.9% NaCl) and feeding behaviour in the home cage or a novel cage was observed. Factor analyses revealed that feeding behaviour on d 21 (habituation) and d 22 (test day) are reflective of two different affective states, and that the single factor that emerged for novel cage testing on d 22 likely reflects the anxiety evoked by the novel test condition. Analyses of variance on the variables loading significantly onto the factors support the suggestion that the novel environment is anxiogenic for both females and males, and that 8-OH-DPAT acts as an anxiolytic. However, although both females and males showed alterations in behaviours (latency, amount, duration of feeding) reflective of anxiety, 8-OH-DPAT had anxiolytic effects primarily in females. Importantly, prenatal ethanol exposure altered several aspects of behavior in this task. Both E females and males consumed less than their control counterparts on d 21, suggesting a possible delay or deficit in response habituation. During home cage testing on d 22, overall feeding rate was slower in E than in C females, and E males consumed less than PF and C males. In addition, a smaller percentage of E than PF and C females fed in the novel environment, and latency to feed was significantly increased in E compared to control females. These findings indicate that prenatal ethanol exposure results in increased anxiety-like behaviour in adulthood, and that prenatal ethanol-induced hyponeophagia may be, at least in part, mediated by the 5-HT1A receptor. This study is one of the first to demonstrate specific increases in anxiety-like behaviour in animals prenatally exposed to ethanol, and further supports the utility of the novelty-induced suppression of feeding task in assessing anxiety and the effectiveness of anxiolytic agents.
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Affiliation(s)
- Candace E Hofmann
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, 950 West 28th Ave, Vancouver, British Columbia, Canada, V5Z 4H4
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16
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Tajuddin NF, Orrico LA, Eriksen JL, Druse MJ. Effects of ethanol and ipsapirone on the development of midline raphe glial cells and astrocytes. Alcohol 2003; 29:157-64. [PMID: 12798971 DOI: 10.1016/s0741-8329(03)00024-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Previously, results of studies from our laboratory have shown that the offspring of ethanol-fed female rats have a significant decrease in serotonin (5-HT) neurons and glia that contain S100B, an essential trophic factor for the development of 5-HT neurons. The deficiency of S100B-immunopositive glia was detected during the vulnerable period in 5-HT neuron development and in brain areas proximal to these neurons. The reductions of both 5-HT neurons and S100B-positive glia were prevented by maternal treatment with a 5-HT(1A) agonist (i.e., ipsapirone or buspirone). In the current study, we investigated whether the offspring of ethanol-fed rats had a general decrease in the density of glial cells in the brain areas that contain 5-HT neurons, and we determined whether these changes were prevented by maternal treatment with ipsapirone between gestational days (GDs) 13 and 20. We estimated the density of vimentin-positive glia of the midline raphe glial structure (MRGS) at GD 20 and postnatal day (PND) 5 and of glial fibrillary acidic protein (GFAP)-positive astrocytes proximal to the dorsal and median raphe at PNDs 5 and 19. The results of this study provide evidence that in utero ethanol exposure is associated with a reduced density of GFAP-immunopositive astrocytes proximal to the dorsal and median raphe. Maternal ipsapirone treatment significantly increased astroglial density in the dorsal raphe at PNDs 5 and 19 and in the median raphe at PND 5, such that it either prevented (dorsal raphe, PNDs 5 and 19) or blunted (median raphe, PND 5) the effects of ethanol.
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Affiliation(s)
- Nuzhath F Tajuddin
- Division of Molecular & Cellular Biochemistry, Department of Cell Biology, Neurobiology, and Anatomy, Loyola University Stritch School of Medicine, Maywood, IL 60153, USA
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17
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Eriksen JL, Gillespie R, Druse MJ. Effects of ethanol and 5-HT1A agonists on astroglial S100B. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2002; 139:97-105. [PMID: 12480124 DOI: 10.1016/s0165-3806(02)00510-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previous studies from this and another laboratory demonstrated that in utero ethanol exposure reduces 5-HT neurons and S100B-immunopositive glia that are proximal to these neurons. Our laboratory also found that these effects are prevented by maternal treatment with a 5-HT(1A) agonist. Because of S100B's important role in the development of 5-HT neurons, the present study used both in vivo and in vitro models to investigate the potential involvement of S100B with the damaging effects of ethanol and with the protective effects of 5-HT(1A) agonists. We used in situ hybridization to address whether a 5-HT(1A) agonist could potentially affect S100B mRNA in vivo. Maternal treatment with buspirone between gestation days 13 and 20 significantly increased S100B mRNA in neuroepithelium of G20 offspring of control (40%) and ethanol-fed dams (20%). However, S100B mRNA was not altered in neuroepithelium from ethanol-exposed offspring. In astroglial cultures, we examined whether ethanol reduces the release of S100B and whether a 5-HT(1A) agonist could stimulate the release of this protein. We also evaluated the effects of ethanol and ipsapirone on astroglial content of S100B. Neither the concentration of S100B in astroglial media nor astroglial content of S100B were affected by ethanol. However, treatment with 100 nM ipsapirone, a 5-HT(1A) agonist, between the 6th and 7th day in vitro, increased astroglial release of S100B 2- to 3-fold. Thus, the protective effects of a 5-HT(1A) agonist on ethanol-treated 5-HT neurons might be associated with the ability of these drugs to release the neurotrophic factor S100B from astrocytes.
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MESH Headings
- Alcohol-Induced Disorders, Nervous System/metabolism
- Alcohol-Induced Disorders, Nervous System/pathology
- Alcohol-Induced Disorders, Nervous System/physiopathology
- Animals
- Astrocytes/drug effects
- Astrocytes/metabolism
- Buspirone/pharmacology
- Cell Differentiation/drug effects
- Cell Differentiation/physiology
- Cells, Cultured
- Disease Models, Animal
- Ethanol/pharmacology
- Female
- Fetus
- Male
- Nerve Growth Factors
- Neurons/drug effects
- Neurons/metabolism
- Pregnancy
- Prenatal Exposure Delayed Effects
- RNA, Messenger/drug effects
- RNA, Messenger/metabolism
- Raphe Nuclei/drug effects
- Raphe Nuclei/embryology
- Raphe Nuclei/metabolism
- Rats
- Receptors, Serotonin/drug effects
- Receptors, Serotonin/metabolism
- Receptors, Serotonin, 5-HT1
- S100 Calcium Binding Protein beta Subunit
- S100 Proteins/genetics
- Serotonin Receptor Agonists/pharmacology
- Stem Cells/drug effects
- Stem Cells/physiology
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Affiliation(s)
- Jason L Eriksen
- The Graduate Program in Neuroscience, Division of Molecular and Cellular Biochemistry, Loyola University Stritch School of Medicine, Maywood, IL 60153, USA
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18
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Othman T, Legare D, Sadri P, Lautt WW, Parkinson FE. A preliminary investigation of the effects of maternal ethanol intake during gestation and lactation on brain adenosine A(1) receptor expression in rat offspring. Neurotoxicol Teratol 2002; 24:275-9. [PMID: 11943515 DOI: 10.1016/s0892-0362(01)00211-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Ethanol exposure during fetal development can result in behavioral and neurological deficits, including reduced cognitive functions, retarded growth, and craniofacial abnormalities. Adenosine is an endogenous neuromodulator that fine-tunes the release and/or synaptic activities of several neurotransmitters, including glutamate, dopamine, and serotonin. Our aim was to determine whether ethanol exposure during early development affects adenosine receptors, particularly the A1 receptor subtype, in adult rats. Female rats were given water or 15% (vol/vol) ethanol in water prior to mating and throughout gestation and lactation. Sixty-day-old male rat offspring from these dams were randomly selected and assayed for adenosine A1 receptor expression in four brain areas: cortex, cerebellum, hippocampus, and striatum. Our results indicate that ethanol intake by dams decreased body and brain weights of offspring and reduced both A1 receptor mRNA and protein density in cortex and cerebellum. These preliminary findings indicate that ethanol intake by dams during pregnancy and lactation can affect adenosine A1 receptor signalling in the offspring. A pair-fed controlled study is warranted to explore these findings further.
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Affiliation(s)
- Timothy Othman
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, MB, Canada
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19
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Abstract
Serotonin is known to play a role in brain development prior to the time it assumes its role as a neurotransmitter in the mature brain. Serotonin regulates both the development of serotonergic neurons (termed autoregulation of development) and the development of target tissues. In both cases, the astroglial-derived protein, S-100beta plays a role. Disruption of serotonergic development can leave permanent alterations in brain function and behavior. This may be the case in such human developmental illnesses as autism and Down Syndrome.
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Affiliation(s)
- P M Whitaker-Azmitia
- Program in Biopsychology, Department of Psychology, SUNY at Stony Brook, 11794-2500, USA.
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20
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Eriksen JL, Druse MJ. Potential involvement of S100B in the protective effects of a serotonin-1a agonist on ethanol-treated astrocytes. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2001; 128:157-64. [PMID: 11412901 DOI: 10.1016/s0165-3806(01)00172-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Previously, this laboratory found that the offspring of rats that consumed ethanol on a chronic basis prior to parturition exhibited a significant reduction in serotonin (5-HT) neurons and in astrocytes proximal to these neurons. This laboratory also showed that maternal treatment with a 5-HT(1A) agonist during the latter part of gestation prevented the reduction of 5-HT neurons and most of the astrocyte abnormalities. The present in vitro studies extended our prior in vivo work by examining the potential involvement of S100B with the protective effects of a 5-HT(1A) agonist, i.e., buspirone, on astrocytes. Astrocyte cultures were either maintained in chemically defined media in the presence and absence of ethanol and buspirone or in conditioned media that was generated by ethanol- and buspirone-treated astrocytes. A mouse monoclonal antibody to S100B was used to assess the potential involvement of S100B with the protective effects of buspirone. Additional in vitro studies measured the direct effects of S100B and ethanol on astrocyte proliferation. These investigations demonstrate that in vitro ethanol exposure reduces the number of astrocytes, and that treatment with the 5-HT(1A) agonist buspirone prevents the ethanol-associated reduction in astrocyte number. The protective effects of buspirone appear to be mediated by factors that are secreted by astrocytes; such factors likely include S100B. In addition, added S100B prevents an ethanol-associated reduction in [(3)H]-thymidine incorporation into proliferating astrocytes.
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Affiliation(s)
- J L Eriksen
- Division of Molecular & Cellular Biochemistry, Department of Cell Biology, Neurobiology, and Anatomy, Loyola University Stritch School of Medicine, Maywood, IL 60153, USA
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21
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Eriksen JL, Gillespie RA, Druse MJ. Effects of in utero ethanol exposure and maternal treatment with a 5-HT(1A) agonist on S100B-containing glial cells. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2000; 121:133-43. [PMID: 10876026 DOI: 10.1016/s0165-3806(00)00029-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
This laboratory previously showed that in utero ethanol exposure severely impairs the development of the cell bodies and projections of serotonin (5-HT) neurons, and that maternal treatment with a 5-HT(1A) agonist prevents many of these abnormalities. Others demonstrated that stimulation of fetal astroglial 5-HT(1A) receptors increases production and release of S100B, a glial trophic factor that is essential for the development of 5-HT neurons. The present study investigated a potential mechanism by which ethanol hinders development of 5-HT neurons, and by which maternal 5-HT(1A) agonist treatment prevents this damage. This study tested the hypothesis that in utero ethanol exposure reduces the number of S100B immunopositive glia and that maternal 5-HT(1A) agonist treatment prevents ethanol-associated changes in S100B. To test our hypothesis, we determined the effects of in utero ethanol exposure and maternal treatments with the 5-HT(1A) agonists ipsapirone and buspirone on S100B immunopositive glial cells. On gestation day 20 (G20), S100B immunopositive cells were quantified in the midline raphe glial structure (MRGS), a large transient structure that contains substantial numbers of S100B-positive glial cells and that spans the dorsal raphe, median raphe, and B9 complex of 5-HT neurons. S100B immunopositive glial cells were also determined in an area proximal to the dorsal raphe in postnatal day 2 (PN2) rats. In utero ethanol exposure significantly reduced S100B immunopositive glial cells in the MRGS at G20 and in the dorsal raphe at PN2. In addition, treatment of pregnant rats with a 5-HT(1A) agonist between G13 and G20 prevented the ethanol-associated reduction in S100B immunopositive glial cells. These studies demonstrated that part of ethanol's damaging effects on developing 5-HT neurons is mediated by a reduction of S100B and that some of the protective effects of maternal 5-HT(1A) agonist treatment are related to the actions of these drugs on glial cells.
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Affiliation(s)
- J L Eriksen
- The Neuroscience Program, Loyola University Stritch School of Medicine, 60153, Maywood, IL, USA
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22
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Tajuddin NF, Druse MJ. In utero ethanol exposure decreased the density of serotonin neurons. Maternal ipsapirone treatment exerted a protective effect. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1999; 117:91-7. [PMID: 10536236 DOI: 10.1016/s0165-3806(99)00102-9] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Prior studies from this laboratory showed that in utero ethanol exposure severely retards the development of the serotonin (5-HT) system; we demonstrated a reduced concentration of 5-HT and 5-HT reuptake sites and alterations in the concentration of 5-HT(1A) receptors in ethanol-exposed offspring. These investigations also found that maternal treatment with a 5-HT(1A) agonist, buspirone, prevented most of the ethanol-associated damage to the developing 5-HT system. In the present investigation, we investigated whether the ethanol-associated changes in the 5-HT system are due to a reduction of 5-HT neurons and whether any changes in the density of 5-HT neurons can be prevented by maternal treatment with another 5-HT(1A) agonist, ipsapirone. Using immunocytochemistry, we found that in utero ethanol exposure reduced the density of 5-HT immunopositive neurons in the dorsal raphe, median raphe and B9 neurons of postnatal day 5 (PN5) rats. In all three brain areas, the offspring of ethanol-fed, saline-treated dams exhibited a 28%-40% reduction in 5-HT neurons. Ipsapirone prevented the ethanol-induced reduction in 5-HT immunopositive neurons in the dorsal raphe, median raphe and B9 neurons. In the dorsal and median raphe of control offspring, ipsapirone did not alter the concentration of 5-HT neurons. However, this drug did reduce 5-HT neurons in the B9 region of the offspring of control-fed rats.
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Affiliation(s)
- N F Tajuddin
- Department of Molecular and Cellular Biochemistry, Loyola University Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA
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