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Chapp AD, Nwakama CA, Jagtap PP, Phan CMH, Thomas MJ, Mermelstein PG. Fundamental Sex Differences in Cocaine-Induced Plasticity of Dopamine D1 Receptor- and D2 Receptor-Expressing Medium Spiny Neurons in the Mouse Nucleus Accumbens Shell. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2024; 4:100295. [PMID: 38533248 PMCID: PMC10963205 DOI: 10.1016/j.bpsgos.2024.100295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 02/02/2024] [Accepted: 02/11/2024] [Indexed: 03/28/2024] Open
Abstract
Background Cocaine-induced plasticity in the nucleus accumbens shell of males occurs primarily in dopamine D1 receptor-expressing medium spiny neurons (D1R-MSNs), with little if any impact on dopamine D2 receptor-expressing medium spiny neurons (D2R-MSNs). In females, the effect of cocaine on accumbens shell D1R- and D2R-MSN neurophysiology has yet to be reported, nor have estrous cycle effects been accounted for. Methods We used a 5-day locomotor sensitization paradigm followed by a 10- to 14-day drug-free abstinence period. We then obtained ex vivo whole-cell recordings from fluorescently labeled D1R-MSNs and D2R-MSNs in the nucleus accumbens shell of male and female mice during estrus and diestrus. We examined accumbens shell neuronal excitability as well as miniature excitatory postsynaptic currents (mEPSCs). Results In females, we observed alterations in D1R-MSN excitability across the estrous cycle similar in magnitude to the effects of cocaine in males. Furthermore, cocaine shifted estrous cycle-dependent plasticity from intrinsic excitability changes in D1R-MSNs to D2R-MSNs. In males, cocaine treatment produced the anticipated drop in D1R-MSN excitability with no effect on D2R-MSN excitability. Cocaine increased mEPSC frequencies and amplitudes in D2R-MSNs from females in estrus and mEPSC amplitudes of D2R-MSNs from females in diestrus. In males, cocaine increased both D1R- and D2R-MSN mEPSC amplitudes with no effect on mEPSC frequencies. Conclusions Overall, while there are similar cocaine-induced disparities regarding the relative excitability of D1R-MSNs versus D2R-MSNs between the sexes, this is mediated through reduced D1R-MSN excitability in males, whereas it is due to heightened D2R-MSN excitability in females.
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Affiliation(s)
- Andrew D. Chapp
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota
- Medical Discovery Team on Addiction, University of Minnesota, Minneapolis, Minnesota
| | - Chinonso A. Nwakama
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota
- Medical Discovery Team on Addiction, University of Minnesota, Minneapolis, Minnesota
- Medical Scientist Training Program, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Pramit P. Jagtap
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Chau-Mi H. Phan
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Mark J. Thomas
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota
- Medical Discovery Team on Addiction, University of Minnesota, Minneapolis, Minnesota
- Center for Neural Circuits in Addiction, University of Minnesota, Minneapolis, Minnesota
| | - Paul G. Mermelstein
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota
- Medical Discovery Team on Addiction, University of Minnesota, Minneapolis, Minnesota
- Center for Neural Circuits in Addiction, University of Minnesota, Minneapolis, Minnesota
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Proaño SB, Miller CK, Krentzel AA, Dorris DM, Meitzen J. Sex steroid hormones, the estrous cycle, and rapid modulation of glutamatergic synapse properties in the striatal brain regions with a focus on 17β-estradiol and the nucleus accumbens. Steroids 2024; 201:109344. [PMID: 37979822 PMCID: PMC10842710 DOI: 10.1016/j.steroids.2023.109344] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 10/28/2023] [Accepted: 11/15/2023] [Indexed: 11/20/2023]
Abstract
The striatal brain regions encompassing the nucleus accumbens core (NAcc), shell (NAcs) and caudate-putamen (CPu) regulate cognitive functions including motivated behaviors, habit, learning, and sensorimotor action, among others. Sex steroid hormone sensitivity and sex differences have been documented in all of these functions in both normative and pathological contexts, including anxiety, depression and addiction. The neurotransmitter glutamate has been implicated in regulating these behaviors as well as striatal physiology, and there are likewise documented sex differences in glutamate action upon the striatal output neurons, the medium spiny neurons (MSNs). Here we review the available data regarding the role of steroid sex hormones such as 17β-estradiol (estradiol), progesterone, and testosterone in rapidly modulating MSN glutamatergic synapse properties, presented in the context of the estrous cycle as appropriate. Estradiol action upon glutamatergic synapse properties in female NAcc MSNs is most comprehensively discussed. In the female NAcc, MSNs exhibit development period-specific sex differences and estrous cycle variations in glutamatergic synapse properties as shown by multiple analyses, including that of miniature excitatory postsynaptic currents (mEPSCs). Estrous cycle-differences in NAcc MSN mEPSCs can be mimicked by acute exposure to estradiol or an ERα agonist. The available evidence, or lack thereof, is also discussed concerning estrogen action upon MSN glutamatergic synapse in the other striatal regions as well as the underexplored roles of progesterone and testosterone. We conclude that there is strong evidence regarding estradiol action upon glutamatergic synapse function in female NAcs MSNs and call for more research regarding other hormones and striatal regions.
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Affiliation(s)
- Stephanie B Proaño
- Dept. of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Christiana K Miller
- Dept. of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Amanda A Krentzel
- Office of Research and Innovation, North Carolina State University, Raleigh, NC, USA
| | - David M Dorris
- Dept. of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - John Meitzen
- Dept. of Biological Sciences, North Carolina State University, Raleigh, NC, USA; Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA; Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA.
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3
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Johnson CS, Chapp AD, Lind EB, Thomas MJ, Mermelstein PG. Sex differences in mouse infralimbic cortex projections to the nucleus accumbens shell. Biol Sex Differ 2023; 14:87. [PMID: 38082417 PMCID: PMC10712109 DOI: 10.1186/s13293-023-00570-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 11/16/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND The nucleus accumbens (NAc) is an important region in motivation and reward. Glutamatergic inputs from the infralimbic cortex (ILC) to the shell region of the NAc (NAcSh) have been implicated in driving the motivation to seek reward through repeated action-based behavior. While this has primarily been studied in males, observed sex differences in motivational circuitry and behavior suggest that females may be more sensitive to rewarding stimuli. These differences have been implicated for the observed vulnerability in women to substance use disorders. METHODS We used an optogenetic self-stimulation task in addition to ex vivo electrophysiological recordings of NAcSh neurons in mouse brain slices to investigate potential sex differences in ILC-NAcSh circuitry in reward-seeking behavior. Glutamatergic neurons in the ILC were infected with an AAV delivering DNA encoding for channelrhodopsin. Entering the designated active corner of an open field arena resulted in photostimulation of the ILC terminals in the NAcSh. Self-stimulation occurred during two consecutive days of testing over three consecutive weeks: first for 10 Hz, then 20 Hz, then 30 Hz. Whole-cell recordings of medium spiny neurons in the NAcSh assessed both optogenetically evoked local field potentials and intrinsic excitability. RESULTS Although both sexes learned to seek the active zone, within the first day, females entered the zone more than males, resulting in a greater amount of photostimulation. Increasing the frequency of optogenetic stimulation amplified female reward-seeking behavior. Males were less sensitive to ILC stimulation, with higher frequencies and repeated days required to increase male reward-seeking behavior. Unexpectedly, ex vivo optogenetic local field potentials in the NAcSh were greater in slices from male animals. In contrast, female medium-spiny neurons (MSNs) displayed significantly greater intrinsic neuronal excitability. CONCLUSIONS Taken together, these data indicate that there are sex differences in the motivated behavior driven by glutamate within the ILC-NAcSh circuit. Though glutamatergic signaling was greater in males, heightened intrinsic excitability in females appears to drive this sex difference.
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Affiliation(s)
- Caroline S Johnson
- Department of Neuroscience, School of Medicine, University of Minnesota, 4-140 Jackson Hall, 321 Church St SE, Minneapolis, MN, 55455, USA
| | - Andrew D Chapp
- Department of Neuroscience, School of Medicine, University of Minnesota, 4-140 Jackson Hall, 321 Church St SE, Minneapolis, MN, 55455, USA
- Medical Discovery Team on Addiction, University of Minnesota, 3-432 McGuire Translational Research Facility, 2001 6th St SE, Minneapolis, MN, 55455, USA
| | - Erin B Lind
- Department of Neuroscience, School of Medicine, University of Minnesota, 4-140 Jackson Hall, 321 Church St SE, Minneapolis, MN, 55455, USA
- Medical Discovery Team on Addiction, University of Minnesota, 3-432 McGuire Translational Research Facility, 2001 6th St SE, Minneapolis, MN, 55455, USA
| | - Mark J Thomas
- Department of Neuroscience, School of Medicine, University of Minnesota, 4-140 Jackson Hall, 321 Church St SE, Minneapolis, MN, 55455, USA
- Medical Discovery Team on Addiction, University of Minnesota, 3-432 McGuire Translational Research Facility, 2001 6th St SE, Minneapolis, MN, 55455, USA
| | - Paul G Mermelstein
- Department of Neuroscience, School of Medicine, University of Minnesota, 4-140 Jackson Hall, 321 Church St SE, Minneapolis, MN, 55455, USA.
- Medical Discovery Team on Addiction, University of Minnesota, 3-432 McGuire Translational Research Facility, 2001 6th St SE, Minneapolis, MN, 55455, USA.
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Seib DR, Tobiansky DJ, Meitzen J, Floresco SB, Soma KK. Neurosteroids and the mesocorticolimbic system. Neurosci Biobehav Rev 2023; 153:105356. [PMID: 37567491 DOI: 10.1016/j.neubiorev.2023.105356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 08/01/2023] [Accepted: 08/08/2023] [Indexed: 08/13/2023]
Abstract
The mesocorticolimbic system coordinates executive functions, such as working memory and behavioral flexibility. This circuit includes dopaminergic projections from the ventral tegmental area to the nucleus accumbens and medial prefrontal cortex. In this review, we summarize evidence that cells in multiple nodes of the mesocorticolimbic system produce neurosteroids (steroids synthesized in the nervous system) and express steroid receptors. Here, we focus on neuroandrogens (androgens synthesized in the nervous system), neuroestrogens (estrogens synthesized in the nervous system), and androgen and estrogen receptors. We also summarize how (neuro)androgens and (neuro)estrogens affect dopamine signaling in the mesocorticolimbic system and regulate executive functions. Taken together, the data suggest that steroids produced in the gonads and locally in the brain modulate higher-order cognition and executive functions.
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Affiliation(s)
- Désirée R Seib
- Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.
| | - Daniel J Tobiansky
- Department of Biology and Neuroscience Program, St. Mary's College of Maryland, St. Mary's City, MD, USA
| | - John Meitzen
- Department of Biological Sciences and Center for Human Health and the Environment, NC State University, Raleigh, NC, USA
| | - Stan B Floresco
- Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Kiran K Soma
- Department of Psychology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
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5
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Knouse MC, Deutschmann AU, Nenov MN, Wimmer ME, Briand LA. Sex differences in pre- and post-synaptic glutamate signaling in the nucleus accumbens core. Biol Sex Differ 2023; 14:52. [PMID: 37596655 PMCID: PMC10439632 DOI: 10.1186/s13293-023-00537-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 08/08/2023] [Indexed: 08/20/2023] Open
Abstract
BACKGROUND Glutamate signaling within the nucleus accumbens underlies motivated behavior and is involved in psychiatric disease. Although behavioral sex differences in these processes are well-established, the neural mechanisms driving these differences are largely unexplored. In these studies, we examine potential sex differences in synaptic plasticity and excitatory transmission within the nucleus accumbens core. Further understanding of baseline sex differences in reward circuitry will shed light on potential mechanisms driving behavioral differences in motivated behavior and psychiatric disease. METHODS Behaviorally naïve adult male and female Long-Evans rats, C57Bl/6J mice, and constitutive PKMζ knockout mice were killed and tissue containing the nucleus accumbens core was collected for ex vivo slice electrophysiology experiments. Electrophysiology recordings examined baseline sex differences in synaptic plasticity and transmission within this region and the potential role of PKMζ in long-term depression. RESULTS Within the nucleus accumbens core, both female mice and rats exhibit higher AMPA/NMDA ratios compared to male animals. Further, female mice have a larger readily releasable pool of glutamate and lower release probability compared to male mice. No significant sex differences were detected in spontaneous excitatory postsynaptic current amplitude or frequency. Finally, the threshold for induction of long-term depression was lower for male animals than females, an effect that appears to be mediated, in part, by PKMζ. CONCLUSIONS We conclude that there are baseline sex differences in synaptic plasticity and excitatory transmission in the nucleus accumbens core. Our data suggest there are sex differences at multiple levels in this region that should be considered in the development of pharmacotherapies to treat psychiatric illnesses such as depression and substance use disorder.
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Affiliation(s)
- Melissa C Knouse
- Department of Psychology, Temple University, Weiss Hall, 1701 North 13th Street, Philadelphia, PA, 19122, USA
| | - Andre U Deutschmann
- Department of Psychology, Temple University, Weiss Hall, 1701 North 13th Street, Philadelphia, PA, 19122, USA
| | - Miroslav N Nenov
- Department of Psychology, Temple University, Weiss Hall, 1701 North 13th Street, Philadelphia, PA, 19122, USA
| | - Mathieu E Wimmer
- Department of Psychology, Temple University, Weiss Hall, 1701 North 13th Street, Philadelphia, PA, 19122, USA
| | - Lisa A Briand
- Department of Psychology, Temple University, Weiss Hall, 1701 North 13th Street, Philadelphia, PA, 19122, USA.
- Neuroscience Program, Temple University, Weiss Hall, 1701 North 13th Street, Philadelphia, PA, 19122, USA.
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Rissman EF, Lynch WJ. Role of Hormones in Substance Use Disorders. Neuroendocrinology 2023; 113:1095-1098. [PMID: 37562372 PMCID: PMC10704930 DOI: 10.1159/000533291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 07/25/2023] [Indexed: 08/12/2023]
Abstract
Addictive drugs, such as cocaine and heroin, have well-documented actions on behavior. The mechanisms that these drugs employ have been under investigation for decades although the investigation of how gonadal and pituitary hormones impact these mechanisms is a relatively new focus. Here we have assembled a group of primary-literature papers solicited from many of the leading addiction laboratories in the world. The papers in this compellation highlight different drug classes, hormones, levels of analysis, and animal models. Our hope is that this “wide angle” approach provides us some overarching conclusions on common mechanisms. In this editorial, we present an overview of each paper and then speculate about general principles.
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Affiliation(s)
- Emilie F. Rissman
- Center for Human Health and the Environment, Department of Biological Sciences, NCSU, Raleigh, NC 27695
| | - Wendy J. Lynch
- Department of Psychiatry and Neurobehavioral Sciences, University of Virginia School of Medicine, Charlottesville VA 22903
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7
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Lewitus VJ, Blackwell KT. Estradiol Receptors Inhibit Long-Term Potentiation in the Dorsomedial Striatum. eNeuro 2023; 10:ENEURO.0071-23.2023. [PMID: 37487741 PMCID: PMC10405883 DOI: 10.1523/eneuro.0071-23.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/25/2023] [Accepted: 06/19/2023] [Indexed: 07/26/2023] Open
Abstract
Estradiol, a female sex hormone and the predominant form of estrogen, has diverse effects throughout the brain including in learning and memory. Estradiol modulates several types of learning that depend on the dorsomedial striatum (DMS), a subregion of the basal ganglia involved in goal-directed learning, cued action-selection, and motor skills. A cellular basis of learning is synaptic plasticity, and the presence of extranuclear estradiol receptors ERα, ERβ, and G-protein-coupled estrogen receptor (GPER) throughout the DMS suggests that estradiol may influence rapid cellular actions including those involved in plasticity. To test whether estradiol affects synaptic plasticity in the DMS, corticostriatal long-term potentiation (LTP) was induced using theta-burst stimulation (TBS) in ex vivo brain slices from intact male and female C57BL/6 mice. Extracellular field recordings showed that female mice in the diestrous stage of the estrous cycle exhibited LTP similar to male mice, while female mice in estrus did not exhibit LTP. Furthermore, antagonists of ERα or GPER rescued LTP in estrous females and agonists of ERα or GPER reduced LTP in diestrous females. In males, activating ERα but not GPER reduced LTP. These results uncover an inhibitory action of estradiol receptors on cellular learning in the DMS and suggest a cellular mechanism underlying the impairment in certain types of DMS-based learning observed in the presence of high estradiol. Because of the dorsal striatum's role in substance use disorders, these findings may provide a mechanism underlying an estradiol-mediated progression from goal-directed to habitual drug use.
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Affiliation(s)
| | - Kim T Blackwell
- Interdisciplinary Neuroscience PhD Program
- Department of Bioengineering, George Mason University, Fairfax, VA 22030
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8
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Catalfio AM, Fetterly TL, Nieto AM, Robinson TE, Ferrario CR. Cocaine-induced sensitization and glutamate plasticity in the nucleus accumbens core: effects of sex. Biol Sex Differ 2023; 14:41. [PMID: 37355656 PMCID: PMC10290362 DOI: 10.1186/s13293-023-00525-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 06/12/2023] [Indexed: 06/26/2023] Open
Abstract
BACKGROUND The development and persistence of addiction is mediated in part by drug-induced alterations in nucleus accumbens (NAc) function. AMPA-type glutamate receptors (AMPARs) provide the main source of excitatory drive to the NAc and enhancements in transmission of calcium-permeable AMPARs (CP-AMPARs) mediate increased cue-triggered drug-seeking following prolonged withdrawal. Cocaine treatment regimens that result in psychomotor sensitization enhance subsequent drug-seeking and drug-taking behaviors. Furthermore, cocaine-induced locomotor sensitization followed by 14 days of withdrawal results in an increase in glutamatergic synaptic transmission. However, very few studies have examined cocaine-induced alterations in synaptic transmission of females or potential effects of experimenter-administered cocaine on NAc CP-AMPAR-mediated transmission in either sex. METHODS Male and female rats were given repeated systemic cocaine injections to induce psychomotor sensitization (15 mg/kg, i.p. 1 injection/day, 8 days). Controls received repeated saline (1 mL/kg, i.p). After 14-16 days of withdrawal brain slices were prepared and whole-cell patch-clamp approaches in the NAc core were used to measure spontaneous excitatory post-synaptic currents (sEPSC), paired pulse ratio, and CP-AMPAR transmission. Additional female rats from this same cohort were also given a challenge injection of cocaine at withdrawal day 14 to assess the expression of sensitization. RESULTS Repeated cocaine produced psychomotor sensitization in both sexes. In males this was accompanied by an increase in sEPSC frequency, but not amplitude, and there was no effect on the paired pulse ratio. Males treated with cocaine and saline had similar sensitivity to Naspm. In contrast, in females there were no significant differences between cocaine and saline groups on any measure, despite females showing robust psychomotor sensitization both during the induction and expression phase. CONCLUSIONS Overall, these data reveal striking sex differences in cocaine-induced NAc glutamate plasticity that accompany the induction of psychomotor sensitization. This suggests that the neural adaptations that contribute to sensitization vary by sex.
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Affiliation(s)
| | | | - Allison M. Nieto
- Pharmacology Department, University of Michigan, Ann Arbor, MI USA
- Neuroscience Graduate Program, University of California, Berkeley, CA USA
| | - Terry E. Robinson
- Psychology Department (Biopsychology Area), University of Michigan, Ann Arbor, MI USA
| | - Carrie R. Ferrario
- Pharmacology Department, University of Michigan, Ann Arbor, MI USA
- Psychology Department (Biopsychology Area), University of Michigan, Ann Arbor, MI USA
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9
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Beeson ALS, Meitzen J. Estrous cycle impacts on dendritic spine plasticity in rat nucleus accumbens core and shell and caudate-putamen. J Comp Neurol 2023; 531:759-774. [PMID: 36756791 PMCID: PMC10994586 DOI: 10.1002/cne.25460] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 12/22/2022] [Accepted: 01/17/2023] [Indexed: 02/10/2023]
Abstract
An important factor that can modulate neuron properties is sex-specific hormone fluctuations, including the human menstrual cycle and rat estrous cycle in adult females. Considering the striatal brain regions, the nucleus accumbens (NAc) core, NAc shell, and caudate-putamen (CPu), the estrous cycle has previously been shown to impact relevant behaviors and disorders, neuromodulator action, and medium spiny neuron (MSN) electrophysiology. Whether the estrous cycle impacts MSN dendritic spine attributes has not yet been examined, even though MSN spines and glutamatergic synapse properties are sensitive to exogenously applied estradiol. Thus, we hypothesized that MSN dendritic spine attributes would differ by estrous cycle phase. To test this hypothesis, brains from adult male rats and female rats in diestrus, proestrus AM, proestrus PM, and estrus were processed for Rapid Golgi-Cox staining. MSN dendritic spine density, size, and type were analyzed in the NAc core, NAc shell, and CPu. Overall spine size differed across estrous cycle phases in female NAc core and NAc shell, and spine length differed across estrous cycle phase in NAc shell and CPu. Consistent with previous work, dendritic spine density was increased in the NAc core compared to the NAc shell and CPu, independent of sex and estrous cycle. Spine attributes in all striatal regions did not differ by sex when estrous cycle was disregarded. These results indicate, for the first time, that estrous cycle phase impacts dendritic spine plasticity in striatal regions, providing a neuroanatomical avenue by which sex-specific hormone fluctuations can impact striatal function and disorders.
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Affiliation(s)
- Anna LS Beeson
- Department of Biological Sciences, NC State University, Raleigh, USA
- Graduate Program in Biology, NC State University, Raleigh, USA
| | - John Meitzen
- Department of Biological Sciences, NC State University, Raleigh, USA
- Comparative Medicine Institute, NC State University, Raleigh, USA
- Center for Human Health and the Environment, NC State University, Raleigh, USA
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10
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Funke JR, Hwang EK, Wunsch AM, Baker R, Engeln KA, Murray CH, Milovanovic M, Caccamise AJ, Wolf ME. Persistent Neuroadaptations in the Nucleus Accumbens Core Accompany Incubation of Methamphetamine Craving in Male and Female Rats. eNeuro 2023; 10:ENEURO.0480-22.2023. [PMID: 36792361 PMCID: PMC10016192 DOI: 10.1523/eneuro.0480-22.2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/06/2023] [Accepted: 01/10/2023] [Indexed: 02/17/2023] Open
Abstract
Relapse is a major problem in treating methamphetamine use disorder. "Incubation of craving" during abstinence is a rat model for persistence of vulnerability to craving and relapse. While methamphetamine incubation has previously been demonstrated in male and female rats, it has not been demonstrated after withdrawal periods greater than 51 d and most mechanistic work used males. Here, we address both gaps. First, although methamphetamine intake was higher in males during self-administration training (6 h/d × 10 d), incubation was similar in males and females, with "incubated" craving persisting through withdrawal day (WD)100. Second, using whole-cell patch-clamp recordings in medium spiny neurons (MSNs) of the nucleus accumbens (NAc) core, we assessed synaptic levels of calcium-permeable AMPA receptors (CP-AMPARs), as their elevation is required for expression of incubation in males. In both sexes, compared with saline-self-administering controls, CP-AMPAR levels were significantly higher in methamphetamine rats across withdrawal, although this was less pronounced in WD100-135 rats than WD15-35 or WD40-75 methamphetamine rats. We also examined membrane properties and NMDA receptor (NMDAR) transmission. In saline controls, MSNs from males exhibited lower excitability than females. This difference was eliminated after incubation because of increased excitability of MSNs from males. NMDAR transmission did not differ between sexes and was not altered after incubation. In conclusion, incubation persists for longer than previously described and equally persistent CP-AMPAR plasticity in NAc core occurs in both sexes. Thus, abstinence-related synaptic plasticity in NAc is similar in males and females although other methamphetamine-related behaviors and neuroadaptations show differences.
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Affiliation(s)
- Jonathan R Funke
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97212
| | - Eun-Kyung Hwang
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97212
| | - Amanda M Wunsch
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97212
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
| | - Raines Baker
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97212
| | - Kimberley A Engeln
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97212
| | - Conor H Murray
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
| | - Mike Milovanovic
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
| | - Aaron J Caccamise
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
| | - Marina E Wolf
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97212
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
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11
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Miller CK, Krentzel AA, Meitzen J. ERα Stimulation Rapidly Modulates Excitatory Synapse Properties in Female Rat Nucleus Accumbens Core. Neuroendocrinology 2023; 113:1140-1153. [PMID: 36746131 PMCID: PMC10623399 DOI: 10.1159/000529571] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 01/30/2023] [Indexed: 02/08/2023]
Abstract
INTRODUCTION The nucleus accumbens core (NAcc) is a sexually differentiated brain region that is modulated by steroid hormones such as 17β-estradiol (estradiol), with consequential impacts on relevant motivated behaviors and disorders such as addiction, anxiety, and depression. NAcc estradiol levels naturally fluctuate, including during the estrous cycle in adult female rats, which is analogous to the menstrual cycle in adult humans. Across the estrous cycle, excitatory synapse properties of medium spiny neurons rapidly change, as indicated by analysis of miniature excitatory postsynaptic currents (mEPSCs). mEPSC frequency decreases during estrous cycle phases associated with high estradiol levels. This decrease in mEPSC frequency is mimicked by acute topical exposure to estradiol. The identity of the estrogen receptor (ER) underlying this estradiol action is unknown. Adult rat NAcc expresses three ERs, all extranuclear: membrane ERα, membrane ERβ, and GPER1. METHODS In this brief report, we take a first step toward addressing this challenge by testing whether activation of ERs via acute topical agonist application is sufficient for inducing changes in mEPSC properties recorded via whole-cell patch clamp. RESULTS An agonist of ERα induced large decreases in mEPSC frequency, while agonists of ERβ and GPER1 did not robustly modulate mEPSC properties. CONCLUSIONS These data provide evidence that activation of ERα is sufficient for inducing changes in mEPSC frequency and is a likely candidate underlying the estradiol-induced changes observed during the estrous cycle. Overall, these findings extend our understanding of the neuroendocrinology of the NAcc and implicate ERα as a primary target for future studies.
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Affiliation(s)
- Christiana K. Miller
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Amanda A. Krentzel
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - John Meitzen
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC, USA
- Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA
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12
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Nieto AM, Catalfio AM, Papacostas Quintanilla H, Alonso‐Caraballo Y, Ferrario CR. Transient effects of junk food on NAc core MSN excitability and glutamatergic transmission in obesity-prone female rats. Obesity (Silver Spring) 2023; 31:434-445. [PMID: 36575127 PMCID: PMC9877139 DOI: 10.1002/oby.23613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 08/25/2022] [Accepted: 09/19/2022] [Indexed: 12/29/2022]
Abstract
OBJECTIVE The nucleus accumbens (NAc) plays critical roles in eating and food seeking in rodents and humans. Diets high in fats and sugars ("junk food") produce persistent increases in NAc function in male obesity-prone rats. This study examines effects of junk food and junk food deprivation on NAc core medium spiny neuron (MSN) excitability and glutamate transmission in females. METHODS Obesity-prone female rats were given access to ad libitum junk food for 10 days, and recordings were made from MSNs in the NAc core immediately or after a short (27-72 hours) or long (14-16 days) junk food deprivation period in which rats were returned to ad libitum standard chow. Controls remained on chow throughout. Whole-cell slice electrophysiology was used to examine MSN intrinsic membrane and firing properties and glutamatergic transmission. RESULTS The study found that intrinsic excitability was reduced, whereas glutamatergic transmission was enhanced, after the short, but not long, junk food deprivation period. A brief junk food deprivation period was necessary for increases in NAc calcium-permeable-AMPA receptor transmission and spontaneous excitatory postsynaptic current (sEPSC) frequency, but not for increases in sEPSC amplitude. CONCLUSIONS This study reveals that females are protected from long-lasting effects of sugary fatty foods on MSN neuronal function and provides evidence for sex-specific effects on plasticity in brain centers that influence food-seeking and feeding behavior.
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Affiliation(s)
- Allison M. Nieto
- Department of PharmacologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Amanda M. Catalfio
- Department of PharmacologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
| | - Helena Papacostas Quintanilla
- Department of PharmacologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
- Department of Biological SciencesUniversité du Québec à MontréalMontrealQuébecCanada
| | - Yanaira Alonso‐Caraballo
- Department of PharmacologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
- Neuroscience DepartmentUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Carrie R. Ferrario
- Department of PharmacologyUniversity of Michigan Medical SchoolAnn ArborMichiganUSA
- Department of Psychology, Biopsychology AreaUniversity of MichiganAnn ArborMichiganUSA
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13
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Hilz EN, Lee HJ. Estradiol and progesterone in female reward-learning, addiction, and therapeutic interventions. Front Neuroendocrinol 2023; 68:101043. [PMID: 36356909 DOI: 10.1016/j.yfrne.2022.101043] [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: 06/06/2022] [Revised: 09/24/2022] [Accepted: 10/28/2022] [Indexed: 11/09/2022]
Abstract
Sex steroid hormones like estradiol (E2) and progesterone (P4) guide the sexual organization and activation of the developing brain and control female reproductive behavior throughout the lifecycle; importantly, these hormones modulate functional activity of not just the endocrine system, but most of the nervous system including the brain reward system. The effects of E2 and P4 can be seen in the processing of and memory for rewarding stimuli and in the development of compulsive reward-seeking behaviors like those seen in substance use disorders. Women are at increased risk of developing substance use disorders; however, the origins of this sex difference are not well understood and therapeutic interventions targeting ovarian hormones have produced conflicting results. This article reviews the contribution of the E2 and P4 in females to functional modulation of the brain reward system, their possible roles in origins of addiction vulnerability, and the development and treatment of compulsive reward-seeking behaviors.
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Affiliation(s)
- Emily N Hilz
- The University of Texas at Austin, Department of Pharmacology, USA.
| | - Hongjoo J Lee
- The University of Texas at Austin, Department of Psychology, USA; The University of Texas at Austin, Institute for Neuroscience, USA
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14
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Krentzel AA, Proaño SB, Dorris DM, Setzer B, Meitzen J. The estrous cycle and 17β-estradiol modulate the electrophysiological properties of rat nucleus accumbens core medium spiny neurons. J Neuroendocrinol 2022; 34:e13122. [PMID: 35365910 PMCID: PMC9250601 DOI: 10.1111/jne.13122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 02/02/2022] [Accepted: 02/22/2022] [Indexed: 12/03/2022]
Abstract
The nucleus accumbens core is a key nexus within the mammalian brain for integrating the premotor and limbic systems and regulating important cognitive functions such as motivated behaviors. Nucleus accumbens core functions show sex differences and are sensitive to the presence of hormones such as 17β-estradiol (estradiol) in normal and pathological contexts. The primary neuron type of the nucleus accumbens core, the medium spiny neuron (MSN), exhibits sex differences in both intrinsic excitability and glutamatergic excitatory synapse electrophysiological properties. Here, we provide a review of recent literature showing how estradiol modulates rat nucleus accumbens core MSN electrophysiology within the context of the estrous cycle. We review the changes in MSN electrophysiological properties across the estrous cycle and how these changes can be mimicked in response to exogenous estradiol exposure. We discuss in detail recent findings regarding how acute estradiol exposure rapidly modulates excitatory synapse properties in nucleus accumbens core but not caudate-putamen MSNs, which mirror the natural changes seen across estrous cycle phases. These recent insights demonstrate the strong impact of sex-specific estradiol action upon nucleus accumbens core neuron electrophysiology.
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Affiliation(s)
- Amanda A. Krentzel
- Department of Biological SciencesNorth Carolina State UniversityRaleighNCUSA
| | - Stephanie B. Proaño
- Neurobiology LaboratoryNational Institute of Environmental Health Sciences, NIHResearch Triangle ParkNCUSA
| | - David M. Dorris
- Department of Biological SciencesNorth Carolina State UniversityRaleighNCUSA
| | - Beverly Setzer
- Graduate Program for Neuroscience and Department of Biomedical EngineeringBoston UniversityBostonMAUSA
| | - John Meitzen
- Department of Biological SciencesNorth Carolina State UniversityRaleighNCUSA
- Comparative Medicine InstituteNorth Carolina State UniversityRaleighNCUSA
- Center for Human Health and the EnvironmentNorth Carolina State UniversityRaleighNCUSA
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15
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Almey A, Milner TA, Brake WG. Estrogen receptors observed at extranuclear neuronal sites and in glia in the nucleus accumbens core and shell of the female rat: Evidence for localization to catecholaminergic and GABAergic neurons. J Comp Neurol 2022; 530:2056-2072. [PMID: 35397175 PMCID: PMC9167786 DOI: 10.1002/cne.25320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 02/17/2022] [Accepted: 03/07/2022] [Indexed: 11/08/2022]
Abstract
Estrogens affect dopamine-dependent diseases/behavior and have rapid effects on dopamine release and receptor availability in the nucleus accumbens (NAc). Low levels of nuclear estrogen receptor (ER) α and ERβ are seen in the NAc, which cannot account for the rapid effects of estrogens in this region. G-protein coupled ER 1 (GPER1) is observed at low levels in the NAc shell, which also likely does not account for the array of estrogens' effects in this region. Prior studies demonstrated membrane-associated ERs in the dorsal striatum; these experiments extend those findings to the NAc core and shell. Single- and dual-immunolabeling electron microscopy determined whether ERα, ERβ, and GPER1 are at extranuclear sites in the NAc core and shell and whether ERα and GPER1 were localized to catecholaminergic or γ-aminobutyric acid-ergic (GABAergic) neurons. All three ERs are observed, almost exclusively, at extranuclear sites in the NAc, and similarly distributed in the core and shell. ERα, ERβ, and GPER1 are primarily in axons and axon terminals suggesting that estrogens affect transmission in the NAc via presynaptic mechanisms. About 10% of these receptors are found on glia. A small proportion of ERα and GPER1 are localized to catecholaminergic terminals, suggesting that binding at these ERs alters release of catecholamines, including dopamine. A larger proportion of ERα and GPER1 are localized to GABAergic dendrites and terminals, suggesting that estrogens alter GABAergic transmission to indirectly affect dopamine transmission in the NAc. Thus, the localization of ERs could account for the rapid effects of estrogen in the NAc.
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Affiliation(s)
- Anne Almey
- Department of Psychology, Centre for Studies in Behavioral Neurobiology (CSBN), Concordia University, Montreal, Canada
| | - Teresa A Milner
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York City, New York, USA.,Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York City, New York, USA
| | - Wayne G Brake
- Department of Psychology, Centre for Studies in Behavioral Neurobiology (CSBN), Concordia University, Montreal, Canada
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16
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Wright KN, Johnson NL, Dossat AM, Wilson JT, Wesson DW. Reducing local synthesis of estrogen in the tubular striatum promotes attraction to same-sex odors in female mice. Horm Behav 2022; 140:105122. [PMID: 35101702 DOI: 10.1016/j.yhbeh.2022.105122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 01/14/2022] [Accepted: 01/19/2022] [Indexed: 11/17/2022]
Abstract
Brain-derived 17β-estradiol (E2) confers rapid effects on neural activity. The tubular striatum (TuS, also called the olfactory tubercle) is both capable of local E2 synthesis due to its abundant expression of aromatase and is a critical locus for odor-guided motivated behavior and odor hedonics. TuS neurons also contain mRNA for estrogen receptors α, β, and the G protein-coupled estrogen receptor. We demonstrate here that mRNA for estrogen receptors appears to be expressed upon TuS dopamine 1 receptor-expressing neurons, suggesting that E2 may play a neuromodulatory role in circuits which are important for motivated behavior. Therefore, we reasoned that E2 in the TuS may influence attraction to urinary odors which are highly attractive. Using whole-body plethysmography, we examined odor-evoked high-frequency sniffing as a measure of odor attaction. Bilateral infusion of the aromatase inhibitor letrozole into the TuS of gonadectomized female adult mice induced a resistance to habituation over successive trials in their investigatory sniffing for female mouse urinary odors, indicative of an enhanced attraction. All males displayed resistance to habituation for female urinary odors, indicative of enhanced attraction that is independent from E2 manipulation. Letrozole's effects were not due to group differences in basal respiration, nor changes in the ability to detect or discriminate between odors (both monomolecular odorants and urinary odors). Therefore, de novo E2 synthesis in the TuS impacts females' but not males' attraction to female urinary odors, suggesting a sex-specific influence of E2 in odor hedonics.
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Affiliation(s)
- Katherine N Wright
- University of Florida, Department of Pharmacology & Therapeutics, Center for Smell and Taste, Center for Addiction Research and Education, 1200 Newell Dr., Gainesville, FL 32610, USA.
| | - Natalie L Johnson
- University of Florida, Department of Pharmacology & Therapeutics, Center for Smell and Taste, Center for Addiction Research and Education, 1200 Newell Dr., Gainesville, FL 32610, USA
| | - Amanda M Dossat
- University of Florida, Department of Pharmacology & Therapeutics, Center for Smell and Taste, Center for Addiction Research and Education, 1200 Newell Dr., Gainesville, FL 32610, USA
| | - Jamie T Wilson
- University of Florida, Department of Pharmacology & Therapeutics, Center for Smell and Taste, Center for Addiction Research and Education, 1200 Newell Dr., Gainesville, FL 32610, USA
| | - Daniel W Wesson
- University of Florida, Department of Pharmacology & Therapeutics, Center for Smell and Taste, Center for Addiction Research and Education, 1200 Newell Dr., Gainesville, FL 32610, USA
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17
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Krizman J, Rotondo EK, Nicol T, Kraus N, Bieszczad KM. Sex differences in auditory processing vary across estrous cycle. Sci Rep 2021; 11:22898. [PMID: 34819558 PMCID: PMC8613396 DOI: 10.1038/s41598-021-02272-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022] Open
Abstract
In humans, females process a sound's harmonics more robustly than males. As estrogen regulates auditory plasticity in a sex-specific manner in seasonally breeding animals, estrogen signaling is one hypothesized mechanism for this difference in humans. To investigate whether sex differences in harmonic encoding vary similarly across the reproductive cycle of mammals, we recorded frequency-following responses (FFRs) to a complex sound in male and female rats. Female FFRs were collected during both low and high levels of circulating estrogen during the estrous cycle. Overall, female rodents had larger harmonic encoding than male rodents, and greater harmonic strength was seen during periods of greater estrogen production in the females. These results argue that hormonal differences, specifically estrogen, underlie sex differences in harmonic encoding in rodents and suggest that a similar mechanism may underlie differences seen in humans.
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Affiliation(s)
- Jennifer Krizman
- Auditory Neuroscience Laboratory, Northwestern University, Evanston, IL, 60208, USA
- Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, 60208, USA
| | - Elena K Rotondo
- Department of Psychology-Behavioral and Systems Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
| | - Trent Nicol
- Auditory Neuroscience Laboratory, Northwestern University, Evanston, IL, 60208, USA
- Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, 60208, USA
| | - Nina Kraus
- Auditory Neuroscience Laboratory, Northwestern University, Evanston, IL, 60208, USA.
- Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, 60208, USA.
- Department of Neurobiology, Northwestern University, Evanston, IL, 60208, USA.
- Department of Otolaryngology, Northwestern University, Chicago, IL, 60611, USA.
| | - Kasia M Bieszczad
- Department of Psychology-Behavioral and Systems Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ, 08854, USA
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18
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Krentzel AA, Kimble LC, Dorris DM, Horman BM, Meitzen J, Patisaul HB. FireMaster® 550 (FM 550) exposure during the perinatal period impacts partner preference behavior and nucleus accumbens core medium spiny neuron electrophysiology in adult male and female prairie voles, Microtus ochrogaster. Horm Behav 2021; 134:105019. [PMID: 34182292 PMCID: PMC8403633 DOI: 10.1016/j.yhbeh.2021.105019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/27/2021] [Accepted: 06/11/2021] [Indexed: 11/23/2022]
Abstract
One of the most widely used flame retardant (FR) mixtures in household products is Firemaster 550 (FM 550). FM 550 leaches from items such as foam-based furniture and infant products, resulting in contamination of the household environment and biota. Previous studies indicate sex-specific behavioral deficits in rodents and zebrafish in response to developmental FM 550 exposure. These deficits include impacts on social and attachment behaviors in a prosocial rodent: the prairie vole (Microtus ochrogaster). The prairie vole is a laboratory-acclimated rodent that exhibits spontaneous attachment behaviors including pair bonding. Here we extend previous work by addressing how developmental exposure to FM 550 impacts pair bonding strength via an extended-time partner preference test, as well as neuron electrophysiological properties in a region implicated in pair bond behavior, the nucleus accumbens (NAcc) core. Dams were exposed to vehicle or 1000 μg of FM 550 via subcutaneous injections throughout gestation, and female and male pups were directly exposed beginning the day after birth until weaning. Pair bond behavior of adult female and male offspring was assessed using a three hour-long partner preference test. Afterwards, acute brain slices of the NAcc core were produced and medium spiny neuron electrophysiological attributes recorded via whole cell patch-clamp. Behavioral impacts were sex-specific. Partner preference behavior was increased in exposed females but decreased in exposed males. Electrophysiological impacts were similar between sexes and specific to attributes related to input resistance. Input resistance was decreased in neurons recorded from both sexes exposed to FM 550 compared to vehicle. This study supports the hypothesis that developmental exposure to FM 550 impacts attachment behaviors and demonstrates a novel FM 550 effect on neural electrophysiology.
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Affiliation(s)
- Amanda A Krentzel
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Laney C Kimble
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - David M Dorris
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Brian M Horman
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - John Meitzen
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA; Center for Human Health and the Environment, North Carolina State University, Raleigh, NC 27695, USA; Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27695, USA.
| | - Heather B Patisaul
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA; Center for Human Health and the Environment, North Carolina State University, Raleigh, NC 27695, USA
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19
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Doncheck EM, Anderson EM, Konrath CD, Liddiard GT, DeBaker MC, Urbanik LA, Hearing MC, Mantsch JR. Estradiol Regulation of the Prelimbic Cortex and the Reinstatement of Cocaine Seeking in Female Rats. J Neurosci 2021; 41:5303-5314. [PMID: 33879537 PMCID: PMC8211550 DOI: 10.1523/jneurosci.3086-20.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 03/10/2021] [Accepted: 04/08/2021] [Indexed: 11/21/2022] Open
Abstract
Relapse susceptibility in women with substance use disorders (SUDs) has been linked to the estrogen, 17β-estradiol (E2). Our previous findings in female rats suggest that the influence of E2 on cocaine seeking can be localized to the prelimbic prefrontal cortex (PrL-PFC). Here, we investigated the receptor mechanisms through which E2 regulates the reinstatement of extinguished cocaine seeking. Sexually mature female rats underwent intravenous cocaine self-administration (0.5 mg/inf; 14 × 2 h daily) and extinction, and then were ovariectomized before reinstatement testing. E2 (10 µg/kg, i.p.) alone did not reinstate cocaine seeking, but it potentiated reinstatement when combined with an otherwise subthreshold priming dose of cocaine. A similar effect was observed following intra-PrL-PFC microinfusions of E2 and by systemic or intra-PrL-PFC administration of the estrogen receptor (ER)β agonist, DPN, but not agonists at ERα or the G-protein-coupled ER1 (GPER1). By contrast, E2-potentiated reinstatement was prevented by intra-PrL-PFC microinfusions of the ERβ antagonist, MPP, or the GPER1 antagonist, G15, but not an ERα antagonist. Whole-cell recordings in PrL-PFC layer (L)5/6 pyramidal neurons revealed that E2 decreases the frequency, but not amplitude, of GABAA-dependent miniature IPSCs (mIPSC). As was the case with E2-potentiated reinstatement, E2 reductions in mIPSC frequency were prevented by ERβ and GPER1, but not ERα, antagonists and mimicked by ERβ, but not GPER1, agonists. Altogether, the findings suggest that E2 activates ERβ and GPER1 in the PrL-PFC to attenuate the GABA-mediated constraint of key outputs that mediate cocaine seeking.
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Affiliation(s)
- Elizabeth M Doncheck
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53201
| | - Eden M Anderson
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53201
| | - Chaz D Konrath
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53201
| | - Gage T Liddiard
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53201
| | - Margot C DeBaker
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53201
| | - Luke A Urbanik
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53201
| | - Matthew C Hearing
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53201
| | - John R Mantsch
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin 53201
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20
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Cao J, Meitzen J. Perinatal activation of ER α and ER β but not GPER-1 masculinizes female rat caudate-putamen medium spiny neuron electrophysiological properties. J Neurophysiol 2021; 125:2322-2338. [PMID: 33978486 DOI: 10.1152/jn.00063.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Exposure to steroid sex hormones such as 17β-estradiol (estradiol) during early life potentially permanently masculinize neuron electrophysiological phenotype. In rodents, one crucial component of this developmental process occurs in males, with estradiol aromatized in the brain from testes-sourced testosterone. However, it is unknown whether most neuron electrophysiological phenotypes are altered by this early masculinization process, including medium spiny neurons (MSNs) of the rat caudate-putamen. MSNs are the predominant and primary output neurons of the caudate-putamen and exhibit increased intrinsic excitability in females compared to males. Here, we hypothesize that since perinatal estradiol exposure occurs in males, then a comparable exposure in females to estradiol or its receptor agonists would be sufficient to induce masculinization. To test this hypothesis, we injected perinatal female rats with estradiol or its receptor agonists and then later assessed MSN electrophysiology. Female and male rats on postnatal day 0 and 1 were systemically injected with either vehicle, estradiol, the estrogen receptor (ER)α agonist PPT, the ERβ agonist DPN, or the G-protein-coupled receptor 1 (GPER-1) agonist G1. On postnatal days 19 ± 2, MSN electrophysiological properties were assessed using whole cell patch clamp recordings. Estradiol exposure abolished increased intrinsic excitability in female compared to male MSNs. Exposure to either an ERα or ERβ agonist masculinized female MSN evoked action potential firing rate properties, whereas exposure to an ERβ agonist masculinized female MSN inward rectification properties. Exposure to ER agonists minimally impacted male MSN electrophysiological properties. These findings indicate that perinatal estradiol exposure masculinizes MSN electrophysiological phenotype via activation of ERα and ERβ.NEW & NOTEWORTHY This study is the first to demonstrate that estradiol and estrogen receptor α and β stimulation during early development sexually differentiates the electrophysiological properties of caudate-putamen medium spiny neurons, the primary output neuron of the striatal regions. Overall, this evidence provides new insight into the neuroendocrine mechanism by which caudate-putamen neuron electrophysiology is sexually differentiated and demonstrates the powerful action of early hormone exposure upon individual neuron electrophysiology.
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Affiliation(s)
- Jinyan Cao
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina
| | - John Meitzen
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina.,Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina.,Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina
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21
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Wei D, Talwar V, Lin D. Neural circuits of social behaviors: Innate yet flexible. Neuron 2021; 109:1600-1620. [PMID: 33705708 DOI: 10.1016/j.neuron.2021.02.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/31/2020] [Accepted: 02/09/2021] [Indexed: 12/16/2022]
Abstract
Social behaviors, such as mating, fighting, and parenting, are fundamental for survival of any vertebrate species. All members of a species express social behaviors in a stereotypical and species-specific way without training because of developmentally hardwired neural circuits dedicated to these behaviors. Despite being innate, social behaviors are flexible. The readiness to interact with a social target or engage in specific social acts can vary widely based on reproductive state, social experience, and many other internal and external factors. Such high flexibility gives vertebrates the ability to release the relevant behavior at the right moment and toward the right target. This maximizes reproductive success while minimizing the cost and risk associated with behavioral expression. Decades of research have revealed the basic neural circuits underlying each innate social behavior. The neural mechanisms that support behavioral plasticity have also started to emerge. Here we provide an overview of these social behaviors and their underlying neural circuits and then discuss in detail recent findings regarding the neural processes that support the flexibility of innate social behaviors.
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Affiliation(s)
- Dongyu Wei
- Neuroscience Institute, New York University School of Medicine, New York, NY, USA
| | - Vaishali Talwar
- Neuroscience Institute, New York University School of Medicine, New York, NY, USA
| | - Dayu Lin
- Neuroscience Institute, New York University School of Medicine, New York, NY, USA; Department of Psychiatry, New York University School of Medicine, New York, NY, USA; Center for Neural Science, New York University, New York, NY, USA.
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22
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Quigley JA, Logsdon MK, Turner CA, Gonzalez IL, Leonardo NB, Becker JB. Sex differences in vulnerability to addiction. Neuropharmacology 2021; 187:108491. [PMID: 33567305 DOI: 10.1016/j.neuropharm.2021.108491] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 01/27/2021] [Accepted: 02/04/2021] [Indexed: 02/07/2023]
Abstract
This article reviews evidence for sex differences in vulnerability to addiction with an emphasis on the neural mechanisms underlying these differences. Sex differences in the way that the gonadal hormone, estradiol, interacts with the ascending telencephalic dopamine system results in sex differences in motivated behaviors, including drug-seeking. In rodents, repeated psychostimulant exposure enhances incentive sensitization to a greater extent in females than males. Estradiol increases females' motivation to attain psychostimulants and enhances the value of drug related cues, which ultimately increases their susceptibility towards spontaneous relapse. This, along with females' dampened ability to alter decisions regarding risky behaviors, enhances their vulnerability for escalation of drug use. In males, recent evidence suggests that estradiol may be protective against susceptibility towards drug-preference. Sex differences in the actions of estradiol are reviewed to provide a foundation for understanding how future research might enhance understanding of the mechanisms of sex differences in addiction-related behaviors, which are dependent on estradiol receptor (ER) subtype and the region of the brain they are acting in. A comprehensive review of the distribution of ERα, ERβ, and GPER1 throughout the rodent brain are provided along with a discussion of the possible ways in which these patterns differentially regulate drug-taking between the sexes. The article concludes with a brief discussion of the actions of gonadal hormones on the circuitry of the stress system, including the hypothalamic pituitary adrenal axis and regulation of corticotropin-releasing factor. Sex differences in the stress system can also contribute to females' enhanced vulnerability towards addiction.
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Affiliation(s)
- Jacqueline A Quigley
- Psychology Department, Ann Arbor MI, 48109 USA; Michigan Neuroscience Institute, University of Michigan, Ann Arbor MI, 48109 USA
| | - Molly K Logsdon
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor MI, 48109 USA
| | - Christopher A Turner
- Psychology Department, Ann Arbor MI, 48109 USA; Michigan Neuroscience Institute, University of Michigan, Ann Arbor MI, 48109 USA
| | - Ivette L Gonzalez
- Psychology Department, Ann Arbor MI, 48109 USA; Michigan Neuroscience Institute, University of Michigan, Ann Arbor MI, 48109 USA
| | - N B Leonardo
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor MI, 48109 USA
| | - Jill B Becker
- Psychology Department, Ann Arbor MI, 48109 USA; Michigan Neuroscience Institute, University of Michigan, Ann Arbor MI, 48109 USA.
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23
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Sex specific effects of "junk-food" diet on calcium permeable AMPA receptors and silent synapses in the nucleus accumbens core. Neuropsychopharmacology 2021; 46:569-578. [PMID: 32731252 PMCID: PMC8027187 DOI: 10.1038/s41386-020-0781-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 07/02/2020] [Accepted: 07/10/2020] [Indexed: 12/18/2022]
Abstract
CP-AMPARs in the nucleus accumbens (NAc) mediate cue-triggered motivation for food and cocaine. In addition, increases in NAc CP-AMPAR expression and function can be induced by cocaine or sugary, fatty junk-foods. However, the precise nature of these alterations and the degree to which they rely on the same underlying mechanisms is not well understood. This has important implications for understanding adaptive vs. maladaptive plasticity that drives food- and drug-seeking behaviors. Furthermore, effects of junk-foods on glutamatergic plasticity in females are unknown. Here, we use a combination of protein biochemistry and whole-cell patch clamping to determine effects of diet manipulation on glutamatergic plasticity within the NAc of males and females. We found that junk-food consumption increases silent synapses and subsequently increases CP-AMPAR levels in males in the NAc of male rats. In addition, a brief period of junk-food deprivation is needed for the synaptic insertion of CP-AMPARs and the maturation of silent synapses in males. In contrast, junk-food did not induce AMPAR plasticity in females but may instead alter NMDAR-mediated transmission. Thus, these studies reveal sex differences in the effects of junk-food on NAc synaptic plasticity. In addition, they provide novel insights into how essential food rewards alter NAc function.
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Baumbach JL, McCormick CM. Nicotine sensitization (part 1): estradiol or tamoxifen is required during the induction phase and not the expression phase to enable locomotor sensitization to nicotine in female rats. Psychopharmacology (Berl) 2021; 238:355-370. [PMID: 33130925 DOI: 10.1007/s00213-020-05685-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 10/19/2020] [Indexed: 11/30/2022]
Abstract
RATIONALE Nicotine sensitization involves two functionally distinct phases: induction and expression. Estradiol enhances nicotine sensitization in female rats, but it is not known whether this enhancement is specific to one or both phases. OBJECTIVES We investigated the effects of estradiol selectively during the induction and the expression of nicotine sensitization. METHODS Ovariectomy (OVX) rats were administered E2 during the induction (2 injection days) and/or the expression phase (9 days later) of nicotine sensitization. The selective estrogen receptor modulator tamoxifen (agonist of ERα and ERß, agonist of the g-coupled estradiol receptor GPER1) also was used to elucidate receptor candidates for the effects of E2 on nicotine sensitization. RESULTS Gonadally intact female rats exhibited expression of nicotine sensitization after a 9-day delay, whereas OVX females did not. Administration of E2 limited to the induction phase of nicotine sensitization rescued expression of nicotine sensitization in OVX females. Tamoxifen during induction did not alter expression of sensitization in gonadally intact female rats, and, like E2, was sufficient to reverse the dampening effects of OVX on expression of sensitization. CONCLUSIONS The enhancing effects of E2 on nicotine sensitization occur during the induction phase of nicotine sensitization, although require a delay to produce the effects on locomotor activity to nicotine, and may involve non-canonical estrogen pathways (e.g., activation of GPER1).
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Affiliation(s)
- Jennet L Baumbach
- Department of Psychology, Centre for Neuroscience, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario, L2S 3A1, Canada
| | - Cheryl M McCormick
- Department of Psychology, Centre for Neuroscience, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario, L2S 3A1, Canada.
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25
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Ferrario CR. Why did I eat that? Contributions of individual differences in incentive motivation and nucleus accumbens plasticity to obesity. Physiol Behav 2020; 227:113114. [DOI: 10.1016/j.physbeh.2020.113114] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 07/16/2020] [Accepted: 07/21/2020] [Indexed: 02/02/2023]
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Tozzi A, Bellingacci L, Pettorossi VE. Rapid Estrogenic and Androgenic Neurosteroids Effects in the Induction of Long-Term Synaptic Changes: Implication for Early Memory Formation. Front Neurosci 2020; 14:572511. [PMID: 33192257 PMCID: PMC7653679 DOI: 10.3389/fnins.2020.572511] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 08/21/2020] [Indexed: 11/17/2022] Open
Abstract
Mounting experimental evidence demonstrate that sex neuroactive steroids (neurosteroids) are essential for memory formation. Neurosteroids have a profound impact on the function and structure of neural circuits and their local synthesis is necessary for the induction of both long-term potentiation (LTP) and long-term depression (LTD) of synaptic transmission and for neural spine formation in different areas of the central nervous system (CNS). Several studies demonstrated that in the hippocampus, 17β-estradiol (E2) is necessary for inducing LTP, while 5α-dihydrotestosterone (DHT) is necessary for inducing LTD. This contribution has been proven by administering sex neurosteroids in rodent models and by using blocking agents of their synthesis or of their specific receptors. The general opposite role of sex neurosteroids in synaptic plasticity appears to be dependent on their different local availability in response to low or high frequency of synaptic stimulation, allowing the induction of bidirectional synaptic plasticity. The relevant contribution of these neurosteroids to synaptic plasticity has also been described in other brain regions involved in memory processes such as motor learning, as in the case of the vestibular nuclei, the cerebellum, and the basal ganglia, or as the emotional circuit of the amygdala. The rapid effects of sex neurosteroids on neural synaptic plasticity need the maintenance of a tonic or phasic local steroid synthesis determined by neural activity but might also be influenced by circulating hormones, age, and gender. To disclose the exact mechanisms how sex neurosteroids participate in finely tuning long-term synaptic changes and spine remodeling, further investigation is required.
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Affiliation(s)
- Alessandro Tozzi
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Laura Bellingacci
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
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Abstract
Gonadal hormones contribute to the sexual differentiation of brain and behavior throughout the lifespan, from initial neural patterning to "activation" of adult circuits. Sexual behavior is an ideal system in which to investigate the mechanisms underlying hormonal activation of neural circuits. Sexual behavior is a hormonally regulated, innate social behavior found across species. Although both sexes seek out and engage in sexual behavior, the specific actions involved in mating are sexually dimorphic. Thus, the neural circuits mediating sexual motivation and behavior in males and females are overlapping yet distinct. Furthermore, sexual behavior is strongly dependent on circulating gonadal hormones in both sexes. There has been significant recent progress on elucidating how gonadal hormones modulate physiological properties within sexual behavior circuits with consequences for behavior. Therefore, in this mini-review we review the neural circuits of male and female sexual motivation and behavior, from initial sensory detection of pheromones to the extended amygdala and on to medial hypothalamic nuclei and reward systems. We also discuss how gonadal hormones impact the physiology and functioning of each node within these circuits. By better understanding the myriad of ways in which gonadal hormones impact sexual behavior circuits, we can gain a richer and more complete appreciation for the neural substrates of complex behavior.
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Affiliation(s)
- Kimberly J Jennings
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California
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28
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Krentzel AA, Willett JA, Johnson AG, Meitzen J. Estrogen receptor alpha, G-protein coupled estrogen receptor 1, and aromatase: Developmental, sex, and region-specific differences across the rat caudate-putamen, nucleus accumbens core and shell. J Comp Neurol 2020; 529:786-801. [PMID: 32632943 DOI: 10.1002/cne.24978] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 12/19/2022]
Abstract
Sex steroid hormones such as 17β-estradiol (estradiol) regulate neuronal function by binding to estrogen receptors (ERs), including ERα and GPER1, and through differential production via the enzyme aromatase. ERs and aromatase are expressed across the nervous system, including in the striatal brain regions. These regions, comprising the nucleus accumbens core, shell, and caudate-putamen, are instrumental for a wide-range of functions and disorders that show sex differences in phenotype and/or incidence. Sex-specific estrogen action is an integral component for generating these sex differences. A distinctive feature of the striatal regions is that in adulthood neurons exclusively express membrane but not nuclear ERs. This long-standing finding dominates models of estrogen action in striatal regions. However, the developmental etiology of ER and aromatase cellular expression in female and male striatum is unknown. This omission in knowledge is important to address, as developmental stage influences cellular estrogenic mechanisms. Thus, ERα, GPER1, and aromatase cellular immunoreactivity was assessed in perinatal, prepubertal, and adult female and male rats. We tested the hypothesis that ERα, GPER1, and aromatase exhibits sex, region, and age-specific differences, including nuclear expression. ERα exhibits nuclear expression in all three striatal regions before adulthood and disappears in a region- and sex-specific time-course. Cellular GPER1 expression decreases during development in a region- but not sex-specific time-course, resulting in extranuclear expression by adulthood. Somatic aromatase expression presents at prepuberty and increases by adulthood in a region- but not sex-specific time-course. These data indicate that developmental period exerts critical sex-specific influences on striatal cellular estrogenic mechanisms.
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Affiliation(s)
- Amanda A Krentzel
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA.,W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina, USA
| | - Jaime A Willett
- Department of Neuroscience, Albert Einstein College of Medicine, New York, New York, USA
| | - Ashlyn G Johnson
- Neuroscience Graduate Program, Emory University, Atlanta, Georgia, USA
| | - John Meitzen
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, USA.,W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina, USA.,Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina, USA
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Kokane SS, Perrotti LI. Sex Differences and the Role of Estradiol in Mesolimbic Reward Circuits and Vulnerability to Cocaine and Opiate Addiction. Front Behav Neurosci 2020; 14:74. [PMID: 32508605 PMCID: PMC7251038 DOI: 10.3389/fnbeh.2020.00074] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 04/22/2020] [Indexed: 12/15/2022] Open
Abstract
Although both men and women become addicted to drugs of abuse, women transition to addiction faster, experience greater difficulties remaining abstinent, and relapse more often than men. In both humans and rodents, hormonal cycles are associated with females' faster progression to addiction. Higher concentrations and fluctuating levels of ovarian hormones in females modulate the mesolimbic reward system and influence reward-directed behavior. For example, in female rodents, estradiol (E2) influences dopamine activity within the mesolimbic reward system such that drug-directed behaviors that are normally rewarding and reinforcing become enhanced when circulating levels of E2 are high. Therefore, neuroendocrine interactions, in part, explain sex differences in behaviors motivated by drug reward. Here, we review sex differences in the physiology and function of the mesolimbic reward system in order to explore the notion that sex differences in response to drugs of abuse, specifically cocaine and opiates, are the result of molecular neuroadaptations that differentially develop depending upon the hormonal state of the animal. We also reconsider the notion that ovarian hormones, specifically estrogen/estradiol, sensitize target neurons thereby increasing responsivity when under the influence of either cocaine or opiates or in response to exposure to drug-associated cues. These adaptations may ultimately serve to guide the motivational behaviors that underlie the factors that cause women to be more vulnerable to cocaine and opiate addiction than men.
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Affiliation(s)
- Saurabh S Kokane
- Department of Psychology, University of Texas at Arlington, Arlington, TX, United States
| | - Linda I Perrotti
- Department of Psychology, University of Texas at Arlington, Arlington, TX, United States
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Proaño SB, Meitzen J. Estradiol decreases medium spiny neuron excitability in female rat nucleus accumbens core. J Neurophysiol 2020; 123:2465-2475. [PMID: 32432511 DOI: 10.1152/jn.00210.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The menstrual cycle in humans and its analogous cycle in rodents, the estrous cycle, modulate brain function and behavior. Both cycles are characterized by the cyclical fluctuation of ovarian hormones including estrogens such as estradiol. Estradiol induces cycle- and sex-dependent differences in the phenotype and incidence of many behaviors, including those related to reward and motivation. The nucleus accumbens core (AcbC), a limbic and premotor system nexus region, directly regulates these behaviors. We previously showed that the estrous cycle modulates intrinsic excitability and excitatory synapse properties of medium spiny neurons (MSNs) in the AcbC. The identity of the underlying hormone mechanism is unknown, with estradiol being a prime candidate. The present study tests the hypothesis that estradiol induces estrous cycle-relevant differences in MSN electrophysiology. To accomplish this goal, a time- and dose-dependent estradiol replacement paradigm designed to simulate the rise of circulating estradiol levels across the estrous cycle was employed in ovariectomized adult female rats as well as a vehicle control group. Estradiol replacement decreased MSN excitability by modulating properties such as resting membrane potential, input resistance in both the linear and rectified ranges, and rheobase compared with vehicle-treated females. These differences in MSN excitability mimic those previously described regarding estrous cycle effects on MSN electrophysiology. Excitatory synapse properties were not modulated in response to this estradiol replacement paradigm. These data are the first to demonstrate that an estrous cycle-relevant estradiol exposure modulates MSN electrophysiology, providing evidence of the fundamental neuroendocrine mechanisms regulating the AcbC.NEW & NOTEWORTHY The present study shows, for the first time, that an estrous cycle-relevant estradiol exposure modulates nucleus accumbens neuron excitability. This evidence provides insight into the neuroendocrine mechanisms by which estradiol cyclically alters neuron properties during the estrous cycle. Overall, these data emphasize the significant influence of hormone action in the brain and especially individual neuron physiology.
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Affiliation(s)
- Stephanie B Proaño
- Graduate Program in Biology, North Carolina State University, Raleigh, North Carolina.,W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina.,Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina
| | - John Meitzen
- W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina.,Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina.,Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina
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31
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Proaño SB, Krentzel AA, Meitzen J. Differential and synergistic roles of 17β-estradiol and progesterone in modulating adult female rat nucleus accumbens core medium spiny neuron electrophysiology. J Neurophysiol 2020; 123:2390-2405. [PMID: 32401164 DOI: 10.1152/jn.00157.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Naturally occurring cyclical changes in sex steroid hormones such as 17β-estradiol and progesterone can modulate neuron function and behavior in female mammals. One example is the estrous cycle in rats, which is composed of multiple phases. We previously reported evidence of differences between estrous cycle phases in excitatory synapse and intrinsic electrophysiological properties of rat nucleus accumbens core (AcbC) medium spiny neurons (MSNs). The AcbC is a nexus between the limbic and premotor systems and is integral for controlling motivated and reward-associated behaviors and disorders, which are sensitive to the estrous cycle and hormones. The present study expands our prior findings by testing whether circulating levels of estradiol and progesterone correlate with changes in MSN electrophysiology across estrous cycle phases. As part of this project, the excitatory synapse and intrinsic excitability properties of MSNs in late proestrus of adult female rats were assessed. Circulating levels of estradiol correlate with resting membrane potential, the time constant of the membrane, and rheobase. Circulating levels of progesterone correlate with miniature excitatory postsynaptic current (mEPSC) frequency and amplitude. Circulating levels of estradiol and progesterone together correlate with mEPSC amplitude, resting membrane potential, and input resistance. The late proestrus phase features a prominent and unique decrease in mEPSC frequency. These data indicate that circulating levels of estradiol and progesterone alone or in combination interact with specific MSN electrophysiological properties, indicating differential and synergistic roles of these hormones. Broadly, these findings illustrate the underlying endocrine actions regarding how the estrous cycle modulates MSN electrophysiology.NEW & NOTEWORTHY This research indicates that estradiol and progesterone act both differentially and synergistically to modulate neuron physiology in the nucleus accumbens core. These actions by specific hormones provide key data indicating the endocrine mechanisms underlying how the estrous cycle modulates neuron physiology in this region. Overall, these data reinforce that hormones are an important influence on neural physiology.
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Affiliation(s)
- Stephanie B Proaño
- Graduate Program in Biology, North Carolina State University, Raleigh, North Carolina.,W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina.,Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina
| | - Amanda A Krentzel
- W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina.,Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina
| | - John Meitzen
- W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, North Carolina.,Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina.,Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina
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32
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Mamlouk GM, Dorris DM, Barrett LR, Meitzen J. Sex bias and omission in neuroscience research is influenced by research model and journal, but not reported NIH funding. Front Neuroendocrinol 2020; 57:100835. [PMID: 32070715 PMCID: PMC7225067 DOI: 10.1016/j.yfrne.2020.100835] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/13/2020] [Accepted: 02/14/2020] [Indexed: 12/31/2022]
Abstract
Neuroscience research has historically demonstrated sex bias that favors male over female research subjects, as well as sex omission, which is the lack of reporting sex. Here we analyzed the status of sex bias and omission in neuroscience research published across six different journals in 2017. Regarding sex omission, 16% of articles did not report sex. Regarding sex bias, 52% of neuroscience articles reported using both males and females, albeit only 15% of articles using both males and females reported assessing sex as an experimental variable. Overrepresentation of the sole use of males compared to females persisted (26% versus 5%, respectively). Sex bias and omission differed across research models, but not by reported NIH funding status. Sex omission differed across journals. These findings represent the latest information regarding the complex status of sex in neuroscience research and illustrate the continued need for thoughtful and informed action to enhance scientific discovery.
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Affiliation(s)
- Gabriella M Mamlouk
- Dept. of Biological Sciences, NC State University, Raleigh, NC, United States
| | - David M Dorris
- Dept. of Biological Sciences, NC State University, Raleigh, NC, United States
| | - Lily R Barrett
- Dept. of Psychology, Florida State University, Tallahassee, FL, United States
| | - John Meitzen
- Dept. of Biological Sciences, NC State University, Raleigh, NC, United States; Center for Human Health and the Environment, NC State University, Raleigh, NC, United States.
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Miller CK, Krentzel AA, Patisaul HB, Meitzen J. Metabotropic glutamate receptor subtype 5 (mGlu 5) is necessary for estradiol mitigation of light-induced anxiety behavior in female rats. Physiol Behav 2019; 214:112770. [PMID: 31830486 DOI: 10.1016/j.physbeh.2019.112770] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 11/20/2019] [Accepted: 12/06/2019] [Indexed: 02/07/2023]
Abstract
Anxiety-related behaviors are influenced by steroid hormones such as 17β-estradiol and environmental stimuli such as acute stressors. For example, rats exhibit increased anxiety-related behaviors in the presence, but not the absence, of light. In females, estradiol potentially mitigates these effects. Experiments across behavioral paradigms and brain regions indicate that estradiol action can be mediated via activation of metabotropic glutamate receptors, including Group I subtype five (mGlu5). mGlu5 has been implicated in mediating estradiol's effects upon psychostimulant-induced behaviors, dopamine release and neuron phenotype in striatal regions. Whether estradiol activation of mGlu5 modulates anxiety or locomotor behavior in the absence of psychostimulants is unknown. Here we test if mGlu5 is necessary for estradiol mitigation of light-induced acute anxiety and locomotor behaviors. Ovariectomized adult female rats were pre-treated with either the mGlu5 antagonist MPEP or saline before estradiol or oil treatment. Anxiety and locomotor behaviors were assessed in the presence or absence of white light to induce high and low acute anxiety behavior phenotypes, respectively. In the presence of white light, estradiol treatment mitigated light-induced anxiety-related behaviors but not overall locomotor activity. MPEP treatment blocked estradiol effects upon light-induced anxiety-related behaviors but did not affect overall locomotor activity. In the absence of white light, estradiol or MPEP treatment did not influence anxiety-related behaviors or locomotor activity, consistent with a low anxiety phenotype. These novel findings indicate that mGlu5 activation is necessary for estradiol mitigation of anxiety-related behaviors induced by an acute stressor.
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Affiliation(s)
- Christiana K Miller
- Graduate Program in Biology, North Carolina State University, Raleigh, NC, USA; W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, USA.
| | - Amanda A Krentzel
- W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, USA; Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
| | - Heather B Patisaul
- W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, USA; Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA; Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA
| | - John Meitzen
- W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, USA; Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA; Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, USA
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