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Ornelas LC, Besheer J. Predator odor stress reactivity, alcohol drinking and the endocannabinoid system. Neurobiol Stress 2024; 30:100634. [PMID: 38623398 PMCID: PMC11016807 DOI: 10.1016/j.ynstr.2024.100634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 03/26/2024] [Accepted: 03/30/2024] [Indexed: 04/17/2024] Open
Abstract
Post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD) are highly comorbid and individual differences in response to stress suggest resilient and susceptible populations. Using animal models to target neurobiological mechanisms associated with individual variability in stress coping responses and the relationship with subsequent increases in alcohol consumption has important implications for the field of traumatic stress and alcohol disorders. The current review discusses the unique advantages of utilizing predator odor stressor exposure models, specifically using 2,5-dihydro-2,4,5-trimethylthiazoline (TMT) on better understanding PTSD pathophysiology and neurobiological mechanisms associated with stress reactivity and subsequent increases in alcohol drinking. Furthermore, there has been increasing interest regarding the role of the endocannabinoid system in modulating behavioral responses to stress with an emphasis on stress coping and individual differences in stress-susceptibility. Therefore, the current review focuses on the topic of endocannabinoid modulation of stress reactive behaviors during and after exposure to a predator odor stressor, with implications on modulating distinctly different behavioral coping strategies.
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Affiliation(s)
- Laura C. Ornelas
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Joyce Besheer
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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Finn DA, Clark CD, Ryabinin AE. Traumatic stress-enhanced alcohol drinking: Sex differences and animal model perspectives. CURRENT ADDICTION REPORTS 2024; 11:327-341. [PMID: 38915732 PMCID: PMC11196023 DOI: 10.1007/s40429-023-00540-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/27/2023] [Indexed: 06/26/2024]
Abstract
Purpose of review Stress is associated with alcohol drinking, and epidemiological studies document the comorbidity of alcohol use disorder (AUD) and post-traumatic stress disorder (PTSD), with higher comorbid prevalence in females than in males. The aim of this paper is to highlight information related to sex differences in stress-enhanced alcohol drinking from clinical studies and from preclinical studies utilizing an animal model of traumatic stress. Recent findings Stress is associated with alcohol drinking and relapse in males and females, but there are sex differences in the alcohol-related adaptation of stress pathways and in the association of different prefrontal regions with stress-induced anxiety. The predator stress model of traumatic stress produced enhanced alcohol drinking in a subgroup of stress-sensitive male and female animals, which could be associated with sex and subgroup differences in stress axis responsivity, behavioral responses to predator odors, and epigenetic mechanisms engaged by traumatic experiences. Summary While additional studies in females are necessary, existing clinical and preclinical evidence suggests that biological mechanisms underlying stress-enhanced drinking likely differ between males and females. Thus, effective treatment strategies may differ between the sexes.
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Affiliation(s)
- Deborah A. Finn
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, United States
- Department of Research, VA Portland Health Care System, Portland, OR, United States
| | - Crystal D. Clark
- Department of Research, VA Portland Health Care System, Portland, OR, United States
| | - Andrey E. Ryabinin
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, United States
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Nipper MA, Helms ML, Finn DA, Ryabinin AE. Stress-enhanced ethanol drinking does not increase sensitivity to the effects of a CRF-R1 antagonist on ethanol intake in male and female mice. Alcohol 2024:S0741-8329(24)00001-6. [PMID: 38185336 DOI: 10.1016/j.alcohol.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/28/2023] [Accepted: 01/04/2024] [Indexed: 01/09/2024]
Abstract
Research confirms that stress is associated with alcohol drinking and relapse in males and females and that there are sex differences in the alcohol-related adaptations of stress pathways. The predator stress (PS) model of traumatic stress produces an increase in alcohol drinking or self-administration in a subpopulation of rodents, so it is utilized as an animal model of comorbid alcohol use disorder (AUD) and post-traumatic stress disorder (PTSD). Previous work determined that sensitivity to PS-enhanced drinking produced sex differences in proteins related to stress-regulating systems in the medial prefrontal cortex and hippocampus. The present studies examined whether male and female C57BL/6J mice differ in sensitivity to the ability of the corticotropin releasing factor receptor 1 antagonist CP-376395 to decrease PS-enhanced drinking. In control studies, CP-376395 doses of 5, 10, and 20 mg/kg dose-dependently decreased 4-hour ethanol drinking. Next, CP-376395 doses of 5 and 10 mg/kg were tested for effects on ethanol drinking in mice with differential sensitivity to PS-enhanced drinking. Subgroups of "Sensitive" and "Resilient" male and female mice were identified based on changes in ethanol intake in an unrestricted access ethanol drinking procedure following four exposures to PS (dirty rat bedding). During the first 2 hours post-injection of CP-376395, both doses significantly decreased ethanol licks versus vehicle in the females, with no significant interaction between subgroups, whereas the 10 mg/kg dose significantly decreased ethanol licks versus vehicle in the "Resilient" males. Thus, sensitivity to the suppressive effect of CP-376395 on stress-induced ethanol intake was greater in females versus males, whereas sensitivity and resilience to PS-enhanced drinking produced differential sensitivity to the ability of CP-376395 to decrease ethanol drinking only in male mice. Our results argue against greater efficacy of CRF-R1's ability to decrease ethanol intake in subjects with traumatic stress-enhanced ethanol drinking.
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Affiliation(s)
- Michelle A Nipper
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239
| | - Melinda L Helms
- Department of Research, VA Portland Health Care System, Portland, OR 97239
| | - Deborah A Finn
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239; Department of Research, VA Portland Health Care System, Portland, OR 97239
| | - Andrey E Ryabinin
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239.
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Ornelas LC, Besheer J. Predator Odor Stressor, 2,3,5-Trimethyl-3-Thiazoline (TMT): Assessment of Stress Reactive Behaviors During an Animal Model of Traumatic Stress in Rats. Curr Protoc 2024; 4:e967. [PMID: 38193654 PMCID: PMC10783820 DOI: 10.1002/cpz1.967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
Animal models utilizing predator odor stress are important in understanding implications for post-traumatic stress disorder. 2,5-dihydro-2,4,5-trimethylthiazoline (TMT) has been used to measure stress reactive behaviors during TMT exposure, indicative of stress coping behaviors. In addition, long-term consequences of stress including contextual-induced stress memory, anxiety-like and hyperarousal behaviors, and subsequent increases in alcohol self-administration can also be examined after TMT exposure. In this article, we describe the TMT exposure protocol used in our lab and how we measure different stress-reactive behaviors that rats engage in during the TMT exposure. Rats are placed in Plexiglass chambers that contain white bedding on the bottom of the chamber and a metal basket in the top right corner containing a filter paper that 10 µl of TMT is pipetted onto. During the 10 min exposure, rats can move around the chamber freely. Exposures are recorded by a video camera for later analysis. During TMT exposure, rats engage in a variety of stress-reactive behaviors, including digging and immobility behavior. These are two distinctly different types of stress-induced behavioral coping strategies to measure individual differences in stress responsivity. To examine individual differences, we group rats into TMT-subgroups based on time spent engaging in digging or immobility behavior. We calculate a digging/immobility ratio score in which we divide the total time spent digging by the total time spent immobile. A cut-off strategy is used such that rats with a criterion ratio score <1.0 are classified as TMT-1 (i.e., low digging/high immobility; greater passive coping) and rats with a ratio score >1.0 are classified as TMT-2 (i.e., high digging/low immobility; greater active coping). Here, we provide a detailed description of the TMT exposure protocol and step-by-step process in evaluation of stress-reactive behaviors. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Predator odor stressor exposure using TMT Basic Protocol 2: Description of stress-reactive behaviors during TMT exposure and formation of TMT-subgroups.
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Affiliation(s)
- Laura C. Ornelas
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Joyce Besheer
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
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Clark CD, Li J, Nipper MA, Helms ML, Finn DA, Ryabinin AE. Differential c-Fos Response in Neurocircuits Activated by Repeated Predator Stress in Male and Female C57BL/6J Mice with Stress Sensitive or Resilient Alcohol Intake Phenotypes. Neuroscience 2023; 535:168-183. [PMID: 37944582 PMCID: PMC10841633 DOI: 10.1016/j.neuroscience.2023.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/23/2023] [Accepted: 11/01/2023] [Indexed: 11/12/2023]
Abstract
Comorbidity of post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD) worsens the prognosis for each of these individual disorders. The current study aimed to identify neurocircuits potentially involved in regulation of PTSD-AUD comorbidity by mapping expression of c-Fos in male and female C57BL/6J mice following repeated predator stress (PS), modeled by exposure to dirty rat bedding. In experiment 1, the levels of c-Fos in the paraventricular nucleus of the hypothalamus (PVH) and the nucleus accumbens shell were higher after the second PS vs the first PS, indicating a sensitized response to this stressor. Additional brain regions showed varied sex-dependent and independent regulation by the two consecutive PS exposures. In experiment 2, mice that increased voluntary alcohol consumption following four exposures to PS (Sensitive subgroup) showed higher c-Fos induction in the PVH, piriform cortex and ventromedial hypothalamus than mice that decreased consumption following these exposures (Resilient subgroup). In contrast to these brain regions, c-Fos was higher in the anterior olfactory nucleus of Resilient vs Sensitive mice. Taken together, these data demonstrate that repeated PS exposure and voluntary alcohol consumption increase neuronal activity across neurocircuits in which specific components depend on the vulnerability of individual mice to these stressors. Increased PVH activity observed across both experiments suggests this brain area as a potential mediator of PS-induced increases in alcohol consumption. Future investigations of specific neuronal populations within the PVH activated by PS, and manipulation of these specific neuronal populations, could improve our understanding of the mechanisms leading to PTSD-AUD comorbidity.
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Affiliation(s)
- Crystal D Clark
- Department of Research, VA Portland Health Care System, Portland, OR 97239, USA
| | - Ju Li
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, USA
| | - Michelle A Nipper
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, USA
| | - Melinda L Helms
- Department of Research, VA Portland Health Care System, Portland, OR 97239, USA
| | - Deborah A Finn
- Department of Research, VA Portland Health Care System, Portland, OR 97239, USA; Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, USA
| | - Andrey E Ryabinin
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, USA.
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Van Voorhies KJ, Liu W, Lovelock DF, Lin S, Liu J, Guan D, Gay EA, Jin C, Besheer J. Novel RXFP3 negative allosteric modulator RLX-33 reduces alcohol self-administration in rats. J Neurochem 2023; 167:204-217. [PMID: 37674350 PMCID: PMC10592109 DOI: 10.1111/jnc.15949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/03/2023] [Accepted: 08/05/2023] [Indexed: 09/08/2023]
Abstract
There is much interest in identifying novel pharmacotherapeutic targets that improve clinical outcomes for the treatment of alcohol use disorder (AUD). One promising target for therapeutic intervention is the relaxin family peptide 3 (RXFP3) receptor, a cognate receptor for neuropeptide relaxin-3, which has previously been implicated in regulating alcohol drinking behavior. Recently, we developed the first small-molecule RXFP3-selective negative allosteric modulator (NAM) RLX-33. Therefore, the goal of the present work was to characterize the impact of this novel NAM on affective-related behaviors and alcohol self-administration in rats. First, the effects of RLX-33 were tested on alcohol and sucrose self-administration in Wistar and alcohol-preferring P rats to determine the dose-response profile and specificity for alcohol. Then, we assessed the effects of systemic RLX-33 injection in Wistar rats in a battery of behavioral assays (open-field test, elevated zero maze, acoustic startle response test, and prepulse inhibition) and tested for alcohol clearance. We found that the lowest effective dose (5 mg/kg) reduced alcohol self-administration in both male and female Wistar rats, while in alcohol-preferring P rats, this effect was restricted to males, and there were no effects on sucrose self-administration or general locomotor activity. The characterization of affective and metabolic effects in Wistar rats generally found few locomotor, affective, or alcohol clearance changes, particularly at the 5 mg/kg dose. Overall, these findings are promising and suggest that RXFP3 NAM has potential as a pharmacological target for treating AUD.
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Affiliation(s)
- Kalynn J. Van Voorhies
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Wen Liu
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Dennis F. Lovelock
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Sophia Lin
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Jiaqi Liu
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Dongliang Guan
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Elaine A. Gay
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Chunyang Jin
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, North Carolina 27709, United States
| | - Joyce Besheer
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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Finn DA. Stress and gonadal steroid influences on alcohol drinking and withdrawal, with focus on animal models in females. Front Neuroendocrinol 2023; 71:101094. [PMID: 37558184 PMCID: PMC10840953 DOI: 10.1016/j.yfrne.2023.101094] [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: 04/07/2023] [Revised: 07/06/2023] [Accepted: 08/06/2023] [Indexed: 08/11/2023]
Abstract
Sexually dimorphic effects of alcohol, following binge drinking, chronic intoxication, and withdrawal, are documented at the level of the transcriptome and in behavioral and physiological responses. The purpose of the current review is to update and to expand upon contributions of the endocrine system to alcohol drinking and withdrawal in females, with a focus on animal models. Steroids important in the hypothalamic-pituitary-gonadal and hypothalamic-pituitary-adrenal axes, the reciprocal interactions between these axes, the effects of chronic alcohol use on steroid levels, and the genomic and rapid membrane-associated effects of steroids and neurosteroids in models of alcohol drinking and withdrawal are described. Importantly, comparison between males and females highlight some divergent effects of sex- and stress-steroids on alcohol drinking- and withdrawal-related behaviors, and the distinct differences in response emphasize the importance of considering sex in the development of novel pharmacotherapies for the treatment of alcohol use disorder.
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Affiliation(s)
- Deborah A Finn
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, United States; Department of Research, VA Portland Health Care System, Portland, OR, United States.
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Becker HC, Lopez MF, King CE, Griffin WC. Oxytocin Reduces Sensitized Stress-Induced Alcohol Relapse in a Model of Posttraumatic Stress Disorder and Alcohol Use Disorder Comorbidity. Biol Psychiatry 2023; 94:215-225. [PMID: 36822933 PMCID: PMC10247903 DOI: 10.1016/j.biopsych.2022.12.003] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 11/29/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022]
Abstract
BACKGROUND There is high comorbidity of posttraumatic stress disorder (PTSD) and alcohol use disorder with few effective treatment options. Animal models of PTSD have shown increases in alcohol drinking, but effects of stress history on subsequent vulnerability to alcohol relapse have not been examined. Here we present a mouse model of PTSD involving chronic multimodal stress exposure that resulted in long-lasting sensitization to stress-induced alcohol relapse, and this sensitized stress response was blocked by oxytocin (OT) administration. METHODS Male and female mice trained to self-administer alcohol were exposed to predator odor (TMT) + yohimbine over 5 consecutive days or left undisturbed. After reestablishing stable alcohol responding/intake, mice were tested under extinction conditions, and then all mice were exposed to TMT or context cues previously associated with TMT before a reinstatement test session. Separate studies examined messenger RNA expression of Oxt and Oxtr in hypothalamus following chronic stress exposure. A final study examined the effects of systemic administration of OT on stress-induced alcohol relapse in mice with and without a history of chronic stress experience. RESULTS Chronic stress exposure produced long-lasting sensitization to subsequent stress-induced alcohol relapse that also generalized to stress-related context cues and transcriptional changes in hypothalamic OT system. OT injected before the reinstatement test session completely blocked the sensitized stress-induced alcohol relapse effect. CONCLUSIONS Collectively, these results provide support for the therapeutic potential of OT, along with highlighting the value of utilizing this model in evaluating other pharmacological interventions for treatment of PTSD/alcohol use disorder comorbidity.
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Affiliation(s)
- Howard C Becker
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, South Carolina; Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina; Ralph H. Johnson Department of Veterans Affairs Medical Center, Charleston, South Carolina.
| | - Marcelo F Lopez
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, South Carolina
| | - Courtney E King
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, South Carolina
| | - William C Griffin
- Charleston Alcohol Research Center, Department of Psychiatry and Behavioral Sciences, Medical University of South Carolina, Charleston, South Carolina
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Doyle MA, Brown JA, Winder DG. GluN2D expression is regulated by restraint stress and supports active stress coping bouts. Neuropharmacology 2023; 225:109377. [PMID: 36528117 PMCID: PMC9839594 DOI: 10.1016/j.neuropharm.2022.109377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/22/2022] [Accepted: 12/10/2022] [Indexed: 12/15/2022]
Abstract
Stress coping strategies represent critical responses to environmental challenges, and active coping has been linked to stress resilience in humans. Understanding the neuroadaptations that support these strategies may provide insights into adaptive and maladaptive stress responses. NMDA receptors (NMDARs) play key roles in neuroadaptation, and NMDARs have been specifically implicated in stress responsiveness. Constitutive knockout mice have been used to implicate the GluN2D NMDAR subunit in regulation of stress-sensitive and affective behavior, but the brain regions in which GluN2D expression changes drive these effects remain unknown. Here we report that following an acute restraint stressor, GluN2D subunit expression is specifically decreased in the bed nucleus of the stria terminalis (BNST), a key region involved in stress processing, in male but not female mice, with no differences found in the thalamus or ventral hippocampus in either sex. Rodents engage in active struggling events during restraint stress that may represent active coping strategies to stress. Thus, we assessed active coping bouts during acute and chronic restraint stress sessions in GluN2D knockout mice. During the first restraint session, GluN2D knockout mice exhibited a pronounced decrease in struggling bouts during restraint stress relative to wild-type littermates, consistent with a role of GluN2D in active coping responses to stress. Repeated, daily restraint sessions revealed a sex-specific role of GluN2D expression on certain aspects of active coping behaviors, with male GluN2D KO mice exhibiting a decrease in total coping bouts measured across five sessions. However, BNST-specific knockdown of GluN2D in male mice did not alter active coping bouts, suggesting either a multi-synaptic role of GluN2D and/or a developmental role of GluN2D in this behavior. Altogether, these data are consistent with a growing literature suggesting that exploration of GluN2D control of stress circuit actions may lead to a novel therapeutic target to consider for stress-related mood disorders.
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Affiliation(s)
- Marie A Doyle
- Department of Molecular Physiology and Biophysics, Vanderbilt University, USA; Vanderbilt Center for Addiction Research, Vanderbilt University, USA
| | - Jordan A Brown
- Vanderbilt Center for Addiction Research, Vanderbilt University, USA; Department of Pharmacology, Vanderbilt University, USA
| | - Danny G Winder
- Department of Molecular Physiology and Biophysics, Vanderbilt University, USA; Vanderbilt Center for Addiction Research, Vanderbilt University, USA; Department of Pharmacology, Vanderbilt University, USA; Department of Psychiatry, Vanderbilt University Medical Center, USA.
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Ornelas LC, Boero G, Van Voorhies K, O’Buckley TK, Besheer J, Morrow AL. Pharmacological administration of 3α,5α-THP into the nucleus accumbens core increases 3α,5α-THP expression and reduces alcohol self-administration. ALCOHOL, CLINICAL & EXPERIMENTAL RESEARCH 2023; 47:459-469. [PMID: 36587947 PMCID: PMC10234128 DOI: 10.1111/acer.15008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 11/16/2022] [Accepted: 12/23/2022] [Indexed: 01/03/2023]
Abstract
BACKGROUND Alcohol affects multiple circuits in the brain, mainly disrupting the delicate balance between inhibitory γ-aminobutyric acid (GABA) transmission and excitatory glutamate signaling in brain areas involved in reward circuits. These include the amygdala, nucleus accumbens (Acb), and ventral tegmental area (VTA). This action impairs circuits that regulate behavioral control of craving and alcohol seeking and intake. Studies in both rodent models and postmortem human brain of patients with alcohol use disorder (AUD) have highlighted the association between the loss of GABAergic inhibition and the development of addiction. The neurosteroid (3α,5α)-3-hydroxypregnan-20-one (3α,5α-THP) is a potent positive modulator of GABAA receptors. Chronic alcohol consumption reduces 3α,5α-THP levels, resulting in decreased GABA inhibition. We previously demonstrated that enhancing neurosteroid biosynthesis by overexpression of the cholesterol side-chain cleavage enzyme P450scc decreased alcohol intake in male alcohol-preferring rats (P-rats). While most of the evidence of alcohol-induced alterations comes from studies in male subjects, some data show that females are more vulnerable to alcohol's effects than males. METHODS In this study, we investigated the ability of 3α,5α-THP direct infusions in two brain regions that contribute to alcohol reinforcement, the VTA and Acb core (AcbC), to regulate alcohol self-administration in female P-rats. RESULTS Administration of 3α,5α-THP into the AcbC increased 3α,5α-THP-positive cell expression in this area and reduced alcohol self-administration. By contrast, 3α,5α-THP infusion into the VTA did not significantly affect alcohol self-administration, though trends for a reduction were found. CONCLUSIONS Our results show that local increases in 3α,5α-THP in the AcbC may alter mesolimbic activity that drives a reduction in alcohol self-administration.
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Affiliation(s)
- Laura C. Ornelas
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Giorgia Boero
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Kalynn Van Voorhies
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Todd K. O’Buckley
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Joyce Besheer
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - A. Leslie Morrow
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
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Giffin KA, Lovelock DF, Besheer J. Toll-like receptor 3 neuroimmune signaling and behavior change: A strain comparison between Lewis and Wistar rats. Behav Brain Res 2023; 438:114200. [PMID: 36334783 PMCID: PMC10123804 DOI: 10.1016/j.bbr.2022.114200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 10/18/2022] [Accepted: 11/01/2022] [Indexed: 11/05/2022]
Abstract
There are many unanswered questions about the interaction between the immune system and behavior change, including the contributions of individual differences. The present study modeled individual differences in the immune system by comparing inbred Lewis rats, which have dysregulated stress and immune systems, to their genetically diverse parent strain, Wistar rats. The objective was to examine the consequences of an immune challenge on behavior and neuroimmune signaling in both strains. Peripheral administration of the toll-like receptor 3 (TLR3) agonist and viral memetic polyinosinic-polycytidylic acid (poly(I:C)) induced behavior changes in both strains, reducing locomotor activity and increasing avoidance behavior (time on the dark side of the light-dark box). Furthermore, poly(I:C) induced hyperarousal and increased avoidance behavior more in female Lewis than female Wistar rats. Baseline strain differences were also observed: Lewis rats had higher avoidance behavior and lower startle response than Wistars. Lewis rats also had lower levels of peripheral inflammation, as measured by spleen weight. Finally, poly(I:C) increased expression of genes in the TLR3 pathway, cytokine genes, and CD11b, a gene associated with proinflammatory actions of microglia, in the prelimbic cortex and central amygdala, with greater expression of cytokine genes in male rats. Lewis rats had lower baseline expression of some neuroimmune genes, particularly CD11b. Overall, we found constitutive strain differences in immune profiles and baseline differences in behavior, yet poly(I:C) generally induced similar behavior changes in males while hyperarousal and avoidance behavior were heightened in female Lewis rats.
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Affiliation(s)
| | | | - Joyce Besheer
- Bowles Center for Alcohol Studies, USA; Department of Psychiatry, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
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Predator odor (TMT) exposure potentiates interoceptive sensitivity to alcohol and increases GABAergic gene expression in the anterior insular cortex and nucleus accumbens in male rats. Alcohol 2022; 104:1-11. [PMID: 36150613 PMCID: PMC9733390 DOI: 10.1016/j.alcohol.2022.07.002] [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: 02/17/2022] [Revised: 06/03/2022] [Accepted: 07/06/2022] [Indexed: 01/26/2023]
Abstract
Post-traumatic stress disorder (PTSD) confers enhanced vulnerability to developing comorbid alcohol use disorder (AUD). Exposure to the scent of a predator, such as the fox odor TMT, has been used to model a traumatic stressor with relevance to PTSD symptomatology. Alcohol produces distinct interoceptive (subjective) effects that may influence vulnerability to problem drinking and AUD. As such, understanding the lasting impact of stressors on sensitivity to the interoceptive effects of alcohol is clinically relevant. The present study used a 2-lever, operant drug discrimination procedure to train male Long-Evans rats to discriminate the interoceptive effects of alcohol (2 g/kg, i.g. [intragastrically]) from water. Upon stable performance, rats underwent a 15-min exposure to TMT. Two weeks later, an alcohol dose-response curve was conducted to evaluate the lasting effects of the TMT stressor on the interoceptive effects of alcohol. The TMT group showed a leftward shift in the effective dose (ED50) of the dose-response curve compared to controls, reflecting potentiated interoceptive sensitivity to alcohol. TMT exposure did not affect response rate. GABAergic signaling in both the anterior insular cortex (aIC) and the nucleus accumbens (Acb) is involved in the interoceptive effects of alcohol and stressor-induced adaptations. As such, follow-up experiments in alcohol-naïve rats examined neuronal activation (as measured by c-Fos immunoreactivity) following TMT and showed that TMT exposure increased c-Fos expression in the aIC and the nucleus accumbens core (AcbC). Two weeks after TMT exposure, Gad-1 gene expression was elevated in the aIC and Gat-1 was increased in the Acb, compared to controls. Lastly, the alcohol discrimination and alcohol-naïve groups displayed dramatic differences in stress reactive behaviors during the TMT exposure, suggesting that alcohol exposure may alter the behavioral response to predator odor. Together, these data suggest that predator odor stressor results in potentiated sensitivity to alcohol, possibly through GABAergic adaptations in the aIC and Acb, which may be relevant to understanding PTSD-AUD comorbidity.
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Stress resilience-associated behaviors following predator scent stress are accompanied by upregulated nucleus accumbens mGlu5 transcription in female Sprague Dawley rats. Behav Brain Res 2022; 436:114090. [DOI: 10.1016/j.bbr.2022.114090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 08/19/2022] [Accepted: 08/29/2022] [Indexed: 12/27/2022]
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Alavi M, Ryabinin AE, Helms ML, Nipper MA, Devaud LL, Finn DA. Sensitivity and Resilience to Predator Stress-Enhanced Ethanol Drinking Is Associated With Sex-Dependent Differences in Stress-Regulating Systems. Front Behav Neurosci 2022; 16:834880. [PMID: 35645747 PMCID: PMC9132579 DOI: 10.3389/fnbeh.2022.834880] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 04/19/2022] [Indexed: 12/02/2022] Open
Abstract
Stress can increase ethanol drinking, and evidence confirms an association between post-traumatic stress disorder (PTSD) and the development of alcohol use disorder (AUD). Exposure to predator odor is considered a traumatic stressor, and predator stress (PS) has been used extensively as an animal model of PTSD. Our prior work determined that repeated exposure to intermittent PS significantly increased anxiety-related behavior, corticosterone levels, and neuronal activation in the hippocampus and prefrontal cortex in naïve male and female C57BL/6J mice. Intermittent PS exposure also increased subsequent ethanol drinking in a subgroup of animals, with heterogeneity of responses as seen with comorbid PTSD and AUD. The present studies built upon this prior work and began to characterize “sensitivity” and “resilience” to PS-enhanced drinking. Ethanol drinking was measured during baseline, intermittent PS exposure, and post-stress; mice were euthanized after 24-h abstinence. Calculation of median and interquartile ranges identified “sensitive” (>20% increase in drinking over baseline) and “resilient” (no change or decrease in drinking from baseline) subgroups. Intermittent PS significantly increased subsequent ethanol intake in 24% of male (↑60%) and in 20% of female (↑71%) C57BL/6J mice in the “sensitive” subgroup. Plasma corticosterone levels were increased significantly after PS in both sexes, but levels were lower in the “sensitive” vs. “resilient” subgroups. In representative mice from “sensitive” and “resilient” subgroups, prefrontal cortex and hippocampus were analyzed by Western Blotting for levels of corticotropin releasing factor (CRF) receptor 1, CRF receptor 2, CRF binding protein, and glucocorticoid receptor, vs. separate naïve age-matched mice. In prefrontal cortex, CRF receptor 1, CRF receptor 2, CRF binding protein, and glucocorticoid receptor levels were significantly higher in “sensitive” vs. naïve and “resilient” mice only in females. In hippocampus, CRF receptor 1, CRF receptor 2 and glucocorticoid receptor levels were significantly lower in “resilient” vs. naïve and “sensitive” mice across both sexes. These results indicate that sex strongly influences the effects of ethanol drinking and stress on proteins regulating stress and anxiety responses. They further suggest that targeting the CRF system and glucocorticoid receptors in AUD needs to consider the comorbidity of PTSD with AUD and sex of treated individuals.
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Affiliation(s)
- Mehrdad Alavi
- School of Pharmacy, Pacific University, Hillsboro, OR, United States
| | - Andrey E. Ryabinin
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, United States
| | - Melinda L. Helms
- Department of Research, VA Portland Health Care System, Portland, OR, United States
| | - Michelle A. Nipper
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, United States
| | - Leslie L. Devaud
- School of Pharmacy, Pacific University, Hillsboro, OR, United States
| | - Deborah A. Finn
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, United States
- Department of Research, VA Portland Health Care System, Portland, OR, United States
- *Correspondence: Deborah A. Finn,
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Lovelock DF, Nguyen T, Van Voorhies K, Zhang Y, Besheer J. RTICBM-74 Is a Brain-Penetrant Cannabinoid Receptor Subtype 1 Allosteric Modulator that Reduces Alcohol Intake in Rats. J Pharmacol Exp Ther 2022; 380:153-161. [PMID: 34930820 PMCID: PMC11047052 DOI: 10.1124/jpet.121.000919] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 12/17/2021] [Indexed: 11/22/2022] Open
Abstract
The endocannabinoid system is implicated in the neuronal mechanisms of alcohol use disorder (AUD), with the cannabinoid receptor subtype 1 (CB1) representing a promising target for AUD therapeutic interventions. We have previously shown negative allosteric modulators (NAMs) of the CB1 receptor attenuated the reinstatement of other drugs of abuse including cocaine and methamphetamine in rats; however, their effects on alcohol-related behaviors have not been investigated. Here, we tested the pharmacokinetic properties of one such CB1 NAM, RTICBM-74, and its effects on alcohol self-administration in rats. RTICBM-74 showed low aqueous solubility and high protein binding but had excellent half-life and low clearance against rat liver microsomes and hepatocytes, and excellent brain penetrance in rats. RTICBM-74 pretreatment specifically reduced alcohol intake across a range of doses in male or female Wistar or Long-Evans rats that were trained to self-administer alcohol. These effects were similar to the CB1 antagonist/inverse agonist rimonabant, which was tested as a positive control. Importantly, RTICBM-74 was effective at reducing alcohol intake at doses that did not affect locomotion or sucrose self-administration. Our findings suggest that CB1 NAMs such as RTICBM-74 have promising therapeutic potential in treatment of AUD. SIGNIFICANCE STATEMENT: The present work shows that a metabolically stable and brain-penetrant cannabinoid receptor subtype 1 negative allosteric modulator reduces alcohol self-administration in rats without affecting locomotion or sucrose self-administration, suggesting potential therapeutic relevance for the treatment of alcohol use disorder.
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Affiliation(s)
- Dennis F Lovelock
- Bowles Center for Alcohol Studies (D.F.L., K.V.V., J.B.) and Department of Psychiatry (J.B.), University of North Carolina - Chapel Hill, Chapel Hill, North Carolina; and Research Triangle Institute, Research Triangle Park, North Carolina (T.N., Y.Z.)
| | - Thuy Nguyen
- Bowles Center for Alcohol Studies (D.F.L., K.V.V., J.B.) and Department of Psychiatry (J.B.), University of North Carolina - Chapel Hill, Chapel Hill, North Carolina; and Research Triangle Institute, Research Triangle Park, North Carolina (T.N., Y.Z.)
| | - Kalynn Van Voorhies
- Bowles Center for Alcohol Studies (D.F.L., K.V.V., J.B.) and Department of Psychiatry (J.B.), University of North Carolina - Chapel Hill, Chapel Hill, North Carolina; and Research Triangle Institute, Research Triangle Park, North Carolina (T.N., Y.Z.)
| | - Yanan Zhang
- Bowles Center for Alcohol Studies (D.F.L., K.V.V., J.B.) and Department of Psychiatry (J.B.), University of North Carolina - Chapel Hill, Chapel Hill, North Carolina; and Research Triangle Institute, Research Triangle Park, North Carolina (T.N., Y.Z.)
| | - Joyce Besheer
- Bowles Center for Alcohol Studies (D.F.L., K.V.V., J.B.) and Department of Psychiatry (J.B.), University of North Carolina - Chapel Hill, Chapel Hill, North Carolina; and Research Triangle Institute, Research Triangle Park, North Carolina (T.N., Y.Z.)
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Calpe-López C, Martínez-Caballero MA, García-Pardo MP, Aguilar MA. Resilience to the effects of social stress on vulnerability to developing drug addiction. World J Psychiatry 2022; 12:24-58. [PMID: 35111578 PMCID: PMC8783163 DOI: 10.5498/wjp.v12.i1.24] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 08/01/2021] [Accepted: 12/23/2021] [Indexed: 02/06/2023] Open
Abstract
We review the still scarce but growing literature on resilience to the effects of social stress on the rewarding properties of drugs of abuse. We define the concept of resilience and how it is applied to the field of drug addiction research. We also describe the internal and external protective factors associated with resilience, such as individual behavioral traits and social support. We then explain the physiological response to stress and how it is modulated by resilience factors. In the subsequent section, we describe the animal models commonly used in the study of resilience to social stress, and we focus on the effects of chronic social defeat (SD), a kind of stress induced by repeated experience of defeat in an agonistic encounter, on different animal behaviors (depression- and anxiety-like behavior, cognitive impairment and addiction-like symptoms). We then summarize the current knowledge on the neurobiological substrates of resilience derived from studies of resilience to the effects of chronic SD stress on depression- and anxiety-related behaviors in rodents. Finally, we focus on the limited studies carried out to explore resilience to the effects of SD stress on the rewarding properties of drugs of abuse, describing the current state of knowledge and suggesting future research directions.
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Affiliation(s)
| | | | - Maria P García-Pardo
- Faculty of Social and Human Sciences, University of Zaragoza, Teruel 44003, Spain
| | - Maria A Aguilar
- Department of Psychobiology, University of Valencia, Valencia 46010, Spain
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Bowen MT, George O, Muskiewicz DE, Hall FS. FACTORS CONTRIBUTING TO THE ESCALATION OF ALCOHOL CONSUMPTION. Neurosci Biobehav Rev 2022; 132:730-756. [PMID: 34839930 PMCID: PMC8892842 DOI: 10.1016/j.neubiorev.2021.11.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 11/05/2021] [Accepted: 11/12/2021] [Indexed: 01/03/2023]
Abstract
Understanding factors that contribute to the escalation of alcohol consumption is key to understanding how an individual transitions from non/social drinking to AUD and to providing better treatment. In this review, we discuss how the way ethanol is consumed as well as individual and environmental factors contribute to the escalation of ethanol consumption from intermittent low levels to consistently high levels. Moreover, we discuss how these factors are modelled in animals. It is clear a vast array of complex, interacting factors influence changes in alcohol consumption. Some of these factors act early in the acquisition of ethanol consumption and initial escalation, while others contribute to escalation of ethanol consumption at a later stage and are involved in the development of alcohol dependence. There is considerable need for more studies examining escalation associated with the formation of dependence and other hallmark features of AUD, especially studies examining mechanisms, as it is of considerable relevance to understanding and treating AUD.
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Affiliation(s)
- Michael T. Bowen
- The University of Sydney, Brain and Mind Centre, Sydney, NSW, 2050, Australia,The University of Sydney, Faculty of Science, School of Psychology, Sydney, NSW, 2006, Australia,Corresponding Author: Michael T. Bowen, Brain and Mind Centre, The University of Sydney, 94 Mallett Street, Camperdown, Sydney, NSW, 2050, Australia,
| | - Olivier George
- Department of Psychology, University of California, San Diego, School of Medicine, La Jolla, CA, 92093, USA
| | - Dawn E. Muskiewicz
- Department of Pharmacology & Experimental Therapeutics, College of Pharmacology and Pharmacological Science, University of Toledo, OH, USA
| | - F. Scott Hall
- Department of Pharmacology & Experimental Therapeutics, College of Pharmacology and Pharmacological Science, University of Toledo, OH, USA
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Bertagna NB, Favoretto CA, Rodolpho BT, Palombo P, Yokoyama TS, Righi T, Loss CM, Leão RM, Miguel TT, Cruz FC. Maternal Separation Stress Affects Voluntary Ethanol Intake in a Sex Dependent Manner. Front Physiol 2021; 12:775404. [PMID: 34950053 PMCID: PMC8691459 DOI: 10.3389/fphys.2021.775404] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 10/26/2021] [Indexed: 01/20/2023] Open
Abstract
Maternal separation (MS) stress is a predictive animal model for evaluating the effects of early stress exposure on alcohol use disorders (AUD). The extended amygdala (AMY) is a complex circuit involved in both stress- and ethanol-related responses. We hypothesized that MS stress may increase ethanol consumption in adulthood, as well as augment neuronal activity in extended AMY, in a sex-dependent manner. We aimed to investigate the influence of MS stress on the ethanol consumption of male and female mice, and the involvement of extended amygdala sub-nuclei in this process. The C57BL/6J pups were subjected to 180min of MS, from postnatal day (PND) 1 to 14. The control group was left undisturbed. On PND 45, mice (n=28) in cages were exposed to a bottle containing 20% ethanol (w/v) for 4h during the dark period of the light-dark cycle, for 3weeks. Afterward, mice underwent ethanol self-administration training in operant chambers under fixed ratio (FR) schedule. Then, subjects were tested under 2h sessions of a progressive-ratio (PR) schedule of reinforcement (the last ratio achieved was considered the breaking point), and at the end, a 4h session of FR schedule (binge-intake). An immunohistochemistry assay for Fos protein was performed in Nucleus Accumbens (NAcc), Bed Nucleus of Stria Terminalis (BNST), and AMY. Our results showed that in the third week of training, the female MS group consumed more ethanol than the respective control group. The MS group presented increased breakpoint parameters. Female control group and male MS group were more resistant to bitter quinine taste. Increased Fos-immunoreactive neurons (Fos-IR) were observed in the central nucleus of AMY, but not in NAcc nor BNST in male maternal-separated mice. Maternal separation stress may influence ethanol intake in adulthood, and it is dependent on the sex and reinforcement protocol.
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Affiliation(s)
- Natalia Bonetti Bertagna
- Molecular and Behavioral Neuroscience Laboratory, Department of Pharmacology, Federal University of São Paulo, São Paulo, Brazil
| | - Cristiane Aparecida Favoretto
- Molecular and Behavioral Neuroscience Laboratory, Department of Pharmacology, Federal University of São Paulo, São Paulo, Brazil
| | - Ben Tagami Rodolpho
- Molecular and Behavioral Neuroscience Laboratory, Department of Pharmacology, Federal University of São Paulo, São Paulo, Brazil
| | - Paola Palombo
- Molecular and Behavioral Neuroscience Laboratory, Department of Pharmacology, Federal University of São Paulo, São Paulo, Brazil
| | - Thais Suemi Yokoyama
- Molecular and Behavioral Neuroscience Laboratory, Department of Pharmacology, Federal University of São Paulo, São Paulo, Brazil
| | - Thamires Righi
- Molecular and Behavioral Neuroscience Laboratory, Department of Pharmacology, Federal University of São Paulo, São Paulo, Brazil
| | - Cássio Morais Loss
- Molecular and Behavioral Neuroscience Laboratory, Department of Pharmacology, Federal University of São Paulo, São Paulo, Brazil.,National Institute for Translational Medicine (INCT-TM), National Council for Scientific and Technological Development (CNPq/CAPES/FAPESP), Ribeirão Preto, Brazil
| | - Rodrigo Molini Leão
- Pharmacology Laboratory, Department of Pharmacology, Biomedical Sciences Institute, Federal University of Uberlândia, Uberlândia, Brazil
| | - Tarciso Tadeu Miguel
- Pharmacology Laboratory, Department of Pharmacology, Biomedical Sciences Institute, Federal University of Uberlândia, Uberlândia, Brazil
| | - Fábio Cardoso Cruz
- Molecular and Behavioral Neuroscience Laboratory, Department of Pharmacology, Federal University of São Paulo, São Paulo, Brazil
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Denny RR, Connelly KL, Ghilotti MG, Meissler JJ, Yu D, Eisenstein TK, Unterwald EM. Artificial Intelligence Identified Resilient and Vulnerable Female Rats After Traumatic Stress and Ethanol Exposure: Investigation of Neuropeptide Y Pathway Regulation. Front Neurosci 2021; 15:772946. [PMID: 34975380 PMCID: PMC8716605 DOI: 10.3389/fnins.2021.772946] [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: 09/09/2021] [Accepted: 11/18/2021] [Indexed: 11/13/2022] Open
Abstract
Post-traumatic stress disorder (PTSD) is initiated by traumatic-stress exposure and manifests into a collection of symptoms including increased anxiety, sleep disturbances, enhanced response to triggers, and increased sympathetic nervous system arousal. PTSD is highly co-occurring with alcohol use disorder. Only some individuals experiencing traumatic stress develop PTSD and a subset of individuals with PTSD develop co-occurring alcohol use disorder. To investigate the basis of these individual responses to traumatic stress, single prolonged stress (SPS) a rodent model of traumatic stress was applied to young adult female rats. Individual responses to SPS were characterized by measuring anxiety-like behaviors with open field and elevated plus maze tests. Rats were then allowed to drink ethanol under an intermittent two bottle choice procedure for 8 weeks, and ethanol consumption was measured. An artificial intelligence algorithm was built to predict resilient and vulnerable individuals based on data from anxiety testing and ethanol consumption. This model was implemented in a second cohort of rats that underwent SPS without ethanol drinking to identify resilient and vulnerable individuals for further study. Analysis of neuropeptide Y (NPY) levels and expression of its receptors Y1R and Y2R mRNA in the central nucleus of the amygdala (CeA), basolateral amygdala (BLA), and bed nucleus stria terminalis (BNST) were performed. Results demonstrate that resilient rats had higher expression of Y2R mRNA in the CeA compared with vulnerable and control rats and had higher levels of NPY protein in the BNST compared to controls. The results of the study show that an artificial intelligence algorithm can identify individual differences in response to traumatic stress which can be used to predict subsequent ethanol drinking, and the NPY pathway is differentially altered following traumatic stress exposure in resilient and vulnerable populations. Understanding neurochemical alterations following traumatic-stress exposure is critical in developing prevention strategies for the vulnerable phenotype and will help further development of novel therapeutic approaches for individuals suffering from PTSD and at risk for alcohol use disorder.
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Affiliation(s)
- Ray R. Denny
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Krista L. Connelly
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Marco G. Ghilotti
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Joseph J. Meissler
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Daohai Yu
- Center for Biostatistics and Epidemiology, Department of Biomedical Education and Data Science, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Toby K. Eisenstein
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States,Department of Neural Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Ellen M. Unterwald
- Center for Substance Abuse Research, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States,Department of Neural Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States,*Correspondence: Ellen M. Unterwald,
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Ornelas LC, Van Voorhies K, Besheer J. The role of the nucleus reuniens in regulating contextual conditioning with the predator odor TMT in female rats. Psychopharmacology (Berl) 2021; 238:3411-3421. [PMID: 34390359 PMCID: PMC8629918 DOI: 10.1007/s00213-021-05957-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/03/2021] [Indexed: 02/06/2023]
Abstract
RATIONALE Experiencing intrusive distressing memories of a traumatic event(s) is a prominent symptom profile for post-traumatic stress disorder (PTSD). Understanding the neurobiological mechanisms associated with this symptom profile can be invaluable for effective treatment for PTSD. OBJECTIVES Here, we investigated the functional role of the nucleus reuniens (RE), a midline thalamic in modulating stressor-related memory. METHODS Female Long Evans rats were implanted with a cannula aimed at the RE. The RE was pharmacologically inactivated via muscimol (0.5 mM) prior to exposure to the predator odor stressor trimethylthiazoline (TMT; synthetically derived fox feces component) or water (controls) in a distinct context with bedding material (experiment 1) or no bedding (experiment 2). To measure context reactivity, the index of the contextual memory, 2 weeks following exposure to TMT, rats were re-exposed to the TMT-paired context (in the absence of TMT). RESULTS In experiment 1, during context re-exposure (with bedding), inactivation of the RE had no effect on context reactivity. In experiment 2, during context re-exposure (no bedding), rats previously exposed to TMT showed decreased immobility compared to controls, indicating reactivity to the context and likely related to theincreased exploration of the environment. Rats in the TMT group that received RE inactivation showed increased immobility relative to rats that received aCSF, suggesting that muscimol pre-treatment blunted context reactivity. CONCLUSION In conclusion, recruitment of the RE in stressor-related contextual memory appears to be dependent on the contextual environment and whether the animal is able to engage in different stress coping strategies.
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Affiliation(s)
- Laura C. Ornelas
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Kalynn Van Voorhies
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Joyce Besheer
- Bowles Center for Alcohol Studies, Chapel Hill, NC, USA. .,Department of Psychiatry, University of North Carolina At Chapel Hill, Chapel Hill, NC, 27599-7171, USA.
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