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Peart DR, Claridge EV, Karlovcec JM, El Azali R, LaDouceur KE, Sikic A, Thomas A, Stone AP, Murray JE. Generalization of a positive-feature interoceptive morphine occasion setter across the rat estrous cycle. Horm Behav 2024; 162:105541. [PMID: 38583235 DOI: 10.1016/j.yhbeh.2024.105541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 03/17/2024] [Accepted: 03/29/2024] [Indexed: 04/09/2024]
Abstract
INTRODUCTION Interoceptive stimuli elicited by drug administration acquire conditioned modulatory properties of the induction of conditioned appetitive behaviours by exteroceptive cues. This effect may be modeled using a drug discrimination task in which the drug stimulus is trained as a positive-feature (FP) occasion setter (OS) that disambiguates the relation between an exteroceptive light conditioned stimulus (CS) and a sucrose unconditioned stimulus (US). We previously reported that females are less sensitive to generalization of a FP morphine OS than males, so we investigated the role of endogenous ovarian hormones in this difference. METHODS Male and female rats received intermixed injections of 3.2 mg/kg morphine or saline before each daily training session. Training consisted of 8 presentations of the CS, each followed by access to sucrose on morphine, but not saline sessions. Following acquisiton, rats were tested for generalization of the morphine stimulus to 0, 1.0, 3.2, and 5.4 mg/kg morphine. Female rats were monitored for estrous cyclicity using vaginal cytology throughout the study. RESULTS Both sexes acquired stable drug discrimination. A gradient of generalization was measured across morphine doses and this behaviour did not differ by sex, nor did it differ across the estrous cycle in females. CONCLUSIONS Morphine generalization is independent of fluctuations in levels of sex and endogenous gonadal hormones in females under these experimental conditions.
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Affiliation(s)
- Davin R Peart
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Ella V Claridge
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Jessica M Karlovcec
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Rita El Azali
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Kathleen E LaDouceur
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Anita Sikic
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Abina Thomas
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Adiia P Stone
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Jennifer E Murray
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada.
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Zhang YX, Zhu YM, Yang XX, Gao FF, Chen J, Yu DY, Gao JQ, Chen ZN, Yang JS, Yan CX, Huo FQ. Phosphorylation of Neurofilament Light Chain in the VLO Is Correlated with Morphine-Induced Behavioral Sensitization in Rats. Int J Mol Sci 2023; 24:ijms24097709. [PMID: 37175416 PMCID: PMC10177919 DOI: 10.3390/ijms24097709] [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: 03/17/2023] [Revised: 04/07/2023] [Accepted: 04/15/2023] [Indexed: 05/15/2023] Open
Abstract
Neurofilament light chain (NF-L) plays critical roles in synapses that are relevant to neuropsychiatric diseases. Despite postmortem evidence that NF-L is decreased in opiate abusers, its role and underlying mechanisms remain largely unknown. We found that the microinjection of the histone deacetylase (HDAC) inhibitor Trichostatin A (TSA) into the ventrolateral orbital cortex (VLO) attenuated chronic morphine-induced behavioral sensitization. The microinjection of TSA blocked the chronic morphine-induced decrease of NF-L. However, our chromatin immunoprecipitation (ChIP)-qPCR results indicated that this effect was not due to the acetylation of histone H3-Lysine 9 and 14 binding to the NF-L promotor. In line with the behavioral phenotype, the microinjection of TSA also blocked the chronic morphine-induced increase of p-ERK/p-CREB/p-NF-L. Finally, we compared chronic and acute morphine-induced behavioral sensitization. We found that although both chronic and acute morphine-induced behavioral sensitization were accompanied by an increase of p-CREB/p-NF-L, TSA exhibited opposing effects on behavioral phenotype and molecular changes at different addiction contexts. Thus, our findings revealed a novel role of NF-L in morphine-induced behavioral sensitization, and therefore provided some correlational evidence of the involvement of NF-L in opiate addiction.
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Affiliation(s)
- Yu-Xiang Zhang
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
- NHC Key Laboratory of Drug Addiction Medicine, Kunming Medical University, Kunming 650032, China
| | - Yuan-Mei Zhu
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Xi-Xi Yang
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Fei-Fei Gao
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Jie Chen
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Dong-Yu Yu
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Jing-Qi Gao
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Zhen-Nan Chen
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Jing-Si Yang
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
| | - Chun-Xia Yan
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
- The Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an Jiaotong University, Xi'an 710061, China
| | - Fu-Quan Huo
- The Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an Jiaotong University, Xi'an 710061, China
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China
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Baumbach JL, McCormick CM. Nicotine sensitization (Part 2): Time spent in the centre of an open field sensitizes to repeated nicotine into the drug-free state in female rats. Psychopharmacology (Berl) 2021; 238:371-382. [PMID: 33123818 DOI: 10.1007/s00213-020-05686-7] [Citation(s) in RCA: 3] [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: 06/29/2020] [Accepted: 10/19/2020] [Indexed: 01/08/2023]
Abstract
RATIONALE Nicotine is initially anxiogenic and becomes anxiolytic after prolonged exposure. The mechanisms that facilitate the shift in anxiety-like behaviour produced by nicotine are unclear. OBJECTIVE We investigated the change in time spent in the centre of an open field (as a measure anxiety-like behaviour) produced by three intermittent injections of nicotine as part of experiments of locomotor sensitization to nicotine. METHODS Rats were injected with nicotine (0.4 mg/kg) or saline and immediately placed in the open field arena for 1 h on two consecutive days and again 9 days later. RESULTS When given saline, time spent in the centre of the arena did not change, whereas repeated nicotine injections increased in time spent in the centre beyond the increase produced by an acute injection of nicotine. Repeated nicotine (and not acute nicotine) also increased time in the centre in a drug-free state when tested 24 h after the last injection. CONCLUSION Repeated nicotine sensitized the time spent in the centre of an open field with the long-lasting sensitization of this measure of anxiety-like behaviour evident in a drug-free state, in contrast to locomotor sensitization which does not persist in the drug-free state. The results suggest independence of the mechanisms of sensitization that underlie locomotor and anxiolytic effects.
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Affiliation(s)
| | - Cheryl M McCormick
- Department of Psychology, Department of Biological Sciences, Centre for Neuroscience, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario, L2S 3A1, Canada.
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