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Rieger NS, Worley NB, Ng AJ, Christianson JP. Insular cortex modulates social avoidance of sick rats. Behav Brain Res 2022; 416:113541. [PMID: 34425184 PMCID: PMC8492531 DOI: 10.1016/j.bbr.2021.113541] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/29/2021] [Accepted: 08/18/2021] [Indexed: 02/07/2023]
Abstract
Avoidance of sick individuals is vital to the preservation of one's health and preventing transmission of communicable diseases. To do this successfully, one must identify social cues for sickness, which include sickness behaviors and chemosignals, and use this information to orchestrate social interactions. While many social species are highly capable with this process, the neural mechanisms that provide for social responses to sick individuals are only partially understood. To this end, we used a task in which experimental rats were allowed to investigate two conspecifics, one healthy and one sick. To imitate sickness, one conspecific received the viral mimic Polyinosinic:polycytidylic acid (Poly I:C) and the other saline. In a 5-minute social preference test, experimental male and female adult rats avoided Poly I:C treated adult conspecifics but did not adjust social interaction in response to Poly I:C treated juvenile conspecifics. Seeking a neural locus of this behavior, we inhibited the insular cortex, a region necessary for social behaviors directed toward conspecifics in distress. Insular cortex inactivation via administration of the GABAA agonist muscimol to experimental rats prior to social preference tests eliminated the preference to avoid sick adult conspecifics. These results suggest that some aspect of conspecific illness may be encoded in the insular cortex which is anatomically positioned to coordinate a situationally appropriate social response.
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Affiliation(s)
- Nathaniel S Rieger
- Department of Psychology and Neuroscience, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA, 02467 USA
| | - Nicholas B Worley
- Department of Psychology and Neuroscience, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA, 02467 USA
| | - Alexandra J Ng
- Department of Psychology and Neuroscience, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA, 02467 USA
| | - John P Christianson
- Department of Psychology and Neuroscience, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA, 02467 USA.
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Worley NB, Varela JA, Gaillardetz GP, Hill MN, Christianson JP. Monoacylglycerol lipase alpha inhibition alters prefrontal cortex excitability and blunts the consequences of traumatic stress in rat. Neuropharmacology 2020; 166:107964. [PMID: 31954713 DOI: 10.1016/j.neuropharm.2020.107964] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 01/03/2020] [Accepted: 01/11/2020] [Indexed: 02/01/2023]
Abstract
Neural activity within the ventromedial prefrontal cortex (vmPFC) is a critical determinant of stressor-induced anxiety. Pharmacological activation of the vmPFC during stress protects against stress-induced social anxiety suggesting that altering the excitatory/inhibitory (E/I) tone in the vmPFC may promote stress resilience. E/I balance is maintained, in part, by endogenous cannabinoid (eCB) signaling with the calcium dependent retrograde release of 2-arachidonoylglycerol (2-AG) suppressing presynaptic neurotransmitter release. We hypothesized that raising 2-AG levels, via inhibition of its degradation enzyme monoacylglycerol lipase (MAGL) with KML29, would shift vmPFC E/I balance and promote resilience. In acute slice experiments, bath application of KML29 (100 nM) augmented evoked excitatory neurotransmission as evidenced by a left-shift in fEPSP I/O curve, and decreased sIPSC amplitude. In whole-cell recordings, KML29 increased resting membrane potential but reduced the after depolarization, bursting rate, membrane time constant and slow after hyperpolarization. Intra-vmPFC administration of KML29 (200ng/0.5μL/hemisphere) prior to inescapable stress (IS) exposure (25, 5s tail shocks) prevented stress induced anxiety as measured by juvenile social exploration 24 h after stressor exposure. Conversely, systemic administration of KML29 (40 mg/kg, i.p.) 2 h before IS exacerbated stress induced anxiety. MAGL inhibition in the vmPFC may promote resilience by augmenting the output of neurons that project to brainstem and limbic structures that mediate stress responses.
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Affiliation(s)
- N B Worley
- Department of Psychology, Boston College, Chestnut Hill, MA, 02467, USA.
| | - J A Varela
- Department of Psychology, Boston College, Chestnut Hill, MA, 02467, USA
| | - G P Gaillardetz
- Department of Psychology, Boston College, Chestnut Hill, MA, 02467, USA
| | - M N Hill
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N4N1, Canada
| | - J P Christianson
- Department of Psychology, Boston College, Chestnut Hill, MA, 02467, USA
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Worley NB, Dumais KM, Yuan JC, Newman LE, Alonso AG, Gillespie TC, Hobbs NJ, Breedlove SM, Jordan CL, Bredewold R, Veenema AH. Oestrogen and androgen receptor activation contribute to the masculinisation of oxytocin receptors in the bed nucleus of the stria terminalis of rats. J Neuroendocrinol 2019; 31:e12760. [PMID: 31233647 DOI: 10.1111/jne.12760] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 06/13/2019] [Accepted: 06/18/2019] [Indexed: 12/29/2022]
Abstract
Oxytocin (OT) often regulates social behaviours in sex-specific ways, and this may be a result of sex differences in the brain OT system. Adult male rats show higher OT receptor (OTR) binding in the posterior bed nucleus of the stria terminalis (pBNST) than adult female rats. In the present study, we investigated the mechanisms that lead to this sex difference. First, we found that male rats have higher OTR mRNA expression in the pBNST than females at postnatal day (P) 35 and P60, which demonstrates the presence of the sex difference in OTR binding density at message level. Second, the sex difference in OTR binding density in the pBNST was absent at P0 and P3, but was present by P5. Third, systemic administration of the oestrogen receptor (ER) antagonist fulvestrant at P0 and P1 dose-dependently reduced OTR binding density in the pBNST of 5-week-old male rats, but did not eliminate the sex difference in OTR binding density. Fourth, pBNST-OTR binding density was lower in androgen receptor (AR) deficient genetic male rats compared to wild-type males, but higher compared to wild-type females. Finally, systemic administration of the histone deacetylase inhibitor valproic acid at P0 and P1 did not alter pBNST-OTR binding density in 5-week-old male and female rats. Interestingly, neonatal ER antagonism, AR deficiency, and neonatal valproic acid treatment each eliminated the sex difference in pBNST size. Overall, we demonstrate a role for neonatal ER and AR activation in setting up the sex difference in OTR binding density in the pBNST, which may underlie sexual differentiation of the pBNST and social behaviour.
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Affiliation(s)
- Nicholas B Worley
- Neurobiology of Social Behavior Laboratory, Department of Psychology, Boston College, Chestnut Hill, MA, USA
| | - Kelly M Dumais
- Neurobiology of Social Behavior Laboratory, Department of Psychology, Boston College, Chestnut Hill, MA, USA
| | - Jingting C Yuan
- Neurobiology of Social Behavior Laboratory, Department of Psychology, Boston College, Chestnut Hill, MA, USA
| | - Laura E Newman
- Neurobiology of Social Behavior Laboratory, Department of Psychology, Boston College, Chestnut Hill, MA, USA
| | - Andrea G Alonso
- Neurobiology of Social Behavior Laboratory, Department of Psychology, Boston College, Chestnut Hill, MA, USA
| | - Tessa C Gillespie
- Neurobiology of Social Behavior Laboratory, Department of Psychology, Boston College, Chestnut Hill, MA, USA
| | - Nicholas J Hobbs
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | - S Marc Breedlove
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | - Cynthia L Jordan
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | - Remco Bredewold
- Neurobiology of Social Behavior Laboratory, Department of Psychology, Boston College, Chestnut Hill, MA, USA
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
- Neurobiology of Social Behavior Laboratory, Department of Psychology, Michigan State University, East Lansing, MI, USA
| | - Alexa H Veenema
- Neurobiology of Social Behavior Laboratory, Department of Psychology, Boston College, Chestnut Hill, MA, USA
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
- Neurobiology of Social Behavior Laboratory, Department of Psychology, Michigan State University, East Lansing, MI, USA
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Worley NB, Hill MN, Christianson JP. Prefrontal endocannabinoids, stress controllability and resilience: A hypothesis. Prog Neuropsychopharmacol Biol Psychiatry 2018; 85:180-188. [PMID: 28392485 PMCID: PMC6746235 DOI: 10.1016/j.pnpbp.2017.04.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 03/09/2017] [Accepted: 04/05/2017] [Indexed: 01/29/2023]
Abstract
Stressor exposure is a predisposing risk factor for many psychiatric conditions such as PTSD and depression. However, stressors do not influence all individuals equally and in response to an identical stressor some individuals may be vulnerable while others are resilient. While various biological and behavioral factors contribute to vulnerability versus resilience, an individual's degree of control over the stressor is among the most potent. Even with only one experience with control over stress, behavioral control has been shown to have acute and long-lasting stress-mitigating effects. This suggests that control both blunts the response to acute stress and prepares the subject to be resilient to future stressors. In this review, we first summarize the evidence which suggests the ventromedial prefrontal cortex (vmPFC) is a critical component of stressor controllability circuits and a locus of neuroplasticity supporting the acute and long-lasting consequences of control. We next review the central endocannabinoid (eCB) system as a possible mediator of short and long-term synaptic transmission in the vmPFC, and offer a hypothesis whereby eCBs regulate vmPFC circuits engaged when a subject has control over stress and may contribute to the encoding of acute stress coping into long lasting stressor resilience.
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Affiliation(s)
- Nicholas B. Worley
- Department of Psychology, Boston College, Chestnut Hill, MA USA,Corresponding Author: Nicholas Worley, Boston College, Department of Psychology, McGuinn Hall Rm. 300, Chestnut Hill, MA 02467 USA,
| | - Matthew N. Hill
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, CAN
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