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Campos-Ordoñez T, Buriticá J. Assessment of the inbred C57BL/6 and outbred CD1 mouse strains using a progressive ratio schedule during development. Physiol Behav 2024; 277:114485. [PMID: 38336087 DOI: 10.1016/j.physbeh.2024.114485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/26/2024] [Accepted: 02/06/2024] [Indexed: 02/12/2024]
Abstract
Inbred strains have a genetic similarity of at least 98.6% compared to their outbred counterparts. Several studies have shown that inbred C57BL/6 mice and outbred ICR (CD1) mice differ in locomotion, cognitive flexibility, and aggression. However, their performance in operant paradigms is not well understood. A progressive ratio (PR) schedule of reinforcement is a method of quantitative estimation of the incentive state of an animal for a reward by increasing response requirements for reinforcer delivery, which is relevant to assess the breakpoint (amount of response effort an animal is willing to invest for a single unit of reward). This study tested male and female C57BL/6 and CD1 mice with an open field to analyze locomotion. Then, we used conditioning chambers with a PR3 schedule for ten consecutive days (P30-P40). PR performance was measured with the breakpoint, and the mathematical principles of reinforcement (MPR) were used to estimate motivation, impulsivity, and motor skills to manipulate the operandum. We found that CD1 mice showed higher locomotor activity than C57BL/6 independently of sex. CD1 mice had a higher breakpoint. However, male CD1 mice gradually increased breakpoint until the last session. In the MPR model, CD1 mice showed decreased fixed paused parameter (impulsivity) than C57BL/6, independent of sex. Our data suggest that the higher breakpoint in CD1 strain may partially be related to impulsivity. Therefore, the MPR model can help identify factors that affect performances, such as motivation, impulsivity, and motor skills during a PR in adolescent CD1 and C57BL/6 mice. These findings are essential to characterize the differences in the behavioral performance between C57BL/6 and CD1 strains and their potential as animal models.
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Affiliation(s)
- Tania Campos-Ordoñez
- Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias. Universidad de Guadalajara, Jalisco 45200, México.
| | - Jonathan Buriticá
- Laboratorio de Cognición y Aprendizaje Comparado, Centro de Estudios e Investigaciones en Comportamiento, Universidad de Guadalajara, Jalisco 44130, México.
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Renda B, Andrade AK, Wylie IR, Stone AP, Antenos M, Leri F, Murray JE. Adolescent restraint stress enhances adult nicotine reinforcement in male and female rats. Psychoneuroendocrinology 2024; 161:106927. [PMID: 38113767 DOI: 10.1016/j.psyneuen.2023.106927] [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: 07/02/2023] [Revised: 10/16/2023] [Accepted: 12/10/2023] [Indexed: 12/21/2023]
Abstract
Adolescent stress is a risk factor for the initiation of nicotine use, but whether adolescent stress can enhance nicotine reinforcement when it is initiated later in adulthood is unknown, and it is unclear whether males and females are equally impacted. Therefore, this study assessed physiological responses (body weight and blood serum corticosterone - CORT) to restraint stress (RS) during adolescence (P28-55) or during adulthood (P70-96) in male and female Sprague-Dawley rats. When all subjects reached adulthood (P69 or 110; 2 weeks after termination of stress exposure), they were tested on sucrose preference and intravenous single-dose nicotine (0.03 mg/kg/infusion) self-administration. It was found that all rats displayed a significant CORT response to RS. Importantly, stress during adolescence, but not during adulthood, enhanced subsequent acquisition of nicotine intake tested in adulthood. Although this effect was observed in both sexes, only males displayed reduced body weight gain and adult sucrose preference. Moreover, regardless of stress exposure, females were more stimulated by nicotine, consumed more nicotine overall, and displayed enhanced nicotine seeking. These results suggest that adolescence is a period of heightened sensitivity to the enhancing effect of repeated stress on the susceptibility to develop nicotine dependence later in life in both sexes.
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Affiliation(s)
- Briana Renda
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neuroscience Program, University of Guelph, Guelph, ON, Canada
| | - Allyson K Andrade
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neuroscience Program, University of Guelph, Guelph, ON, Canada
| | - Isabella R Wylie
- Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Adiia P Stone
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neuroscience Program, University of Guelph, Guelph, ON, Canada
| | - Monica Antenos
- Department of Biomedical Sciences, University of Guelph, Guelph, ON, Canada
| | - Francesco Leri
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neuroscience Program, University of Guelph, Guelph, ON, Canada
| | - Jennifer E Murray
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neuroscience Program, University of Guelph, Guelph, ON, Canada.
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Goud TJ. Epigenetic and Long-Term Effects of Nicotine on Biology, Behavior, and Health. Pharmacol Res 2023; 192:106741. [PMID: 37149116 DOI: 10.1016/j.phrs.2023.106741] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/15/2023] [Accepted: 03/20/2023] [Indexed: 05/08/2023]
Abstract
Tobacco and nicotine use are associated with disease susceptibility and progression. Health challenges associated with nicotine and smoking include developmental delays, addiction, mental health and behavioral changes, lung disease, cardiovascular disease, endocrine disorders, diabetes, immune system changes, and cancer. Increasing evidence suggests that nicotine-associated epigenetic changes may mediate or moderate the development and progression of a myriad of negative health outcomes. In addition, nicotine exposure may confer increased lifelong susceptibility to disease and mental health challenges through alteration of epigenetic signaling. This review examines the relationship between nicotine exposure (and smoking), epigenetic changes, and maladaptive outcomes that include developmental disorders, addiction, mental health challenges, pulmonary disease, cardiovascular disease, endocrine disorders, diabetes, immune system changes, and cancer. Overall, findings support the contention that nicotine (or smoking) associated altered epigenetic signaling is a contributing factor to disease and health challenges.
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Affiliation(s)
- Thomas J Goud
- Department of Biobehavioral Health, The Pennsylvania State University, Penn State University, University Park, PA, USA.
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Ren M, Lotfipour S, Leslie F. Unique effects of nicotine across the lifespan. Pharmacol Biochem Behav 2022; 214:173343. [PMID: 35122768 PMCID: PMC8904294 DOI: 10.1016/j.pbb.2022.173343] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 01/27/2022] [Accepted: 01/28/2022] [Indexed: 12/23/2022]
Abstract
Smoking remains the leading cause of preventable death in the United States. Although combustible cigarettes are largely being replaced by tobacco-free products, nicotine use continues to increase in vulnerable populations, including youth, adolescents, and pregnant women. Nicotine exerts unique effects on specific brain regions during distinct developmental periods due to the dynamic expression of nicotinic acetylcholine receptors (nAChRs) throughout the lifespan. Nicotine exposure is a health concern not only for adults but also has neurotoxic effects on the fetus, newborn, child, and adolescent. In this review, we aim to highlight the dynamic roles of nAChRs throughout gestation, adolescence, and adulthood. We also provide clinical and preclinical evidence of the neurodevelopmental, cognitive, and behavioral consequences of nicotine exposure at different developmental periods. This comprehensive review highlights unique effects of nicotine throughout the lifespan to help elucidate interventions and public health measures to protect sensitive populations from nicotine exposure.
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Affiliation(s)
- Michelle Ren
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, USA.
| | - Shahrdad Lotfipour
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, USA; Department of Emergency Medicine, School of Medicine, University of California, Irvine, Irvine, CA, USA; Department of Pathology and Laboratory Medicine, School of Medicine, University of California, Irvine, Irvine, CA, USA
| | - Frances Leslie
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, USA
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Chen G, Ghazal M, Rahman S, Lutfy K. The impact of adolescent nicotine exposure on alcohol use during adulthood: The role of neuropeptides. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2021; 161:53-93. [PMID: 34801174 DOI: 10.1016/bs.irn.2021.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Nicotine and alcohol abuse and co-dependence represent major public health crises. Indeed, previous research has shown that the prevalence of alcoholism is higher in smokers than in non-smokers. Adolescence is a susceptible period of life for the initiation of nicotine and alcohol use and the development of nicotine-alcohol codependence. However, there is a limited number of pharmacotherapeutic agents to treat addiction to nicotine or alcohol alone. Notably, there is no effective medication to treat this comorbid disorder. This chapter aims to review the early nicotine use and its impact on subsequent alcohol abuse during adolescence and adulthood as well as the role of neuropeptides in this comorbid disorder. The preclinical and clinical findings discussed in this chapter will advance our understanding of this comorbid disorder's neurobiology and lay a foundation for developing novel pharmacotherapies to treat nicotine and alcohol codependence.
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Affiliation(s)
- G Chen
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA, United States; Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, CA, United States
| | - M Ghazal
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, CA, United States
| | - S Rahman
- Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD, United States
| | - K Lutfy
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, CA, United States.
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Hauser SR, Rodd ZA, Deehan GA, Liang T, Rahman S, Bell RL. Effects of adolescent substance use disorders on central cholinergic function. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2021; 160:175-221. [PMID: 34696873 DOI: 10.1016/bs.irn.2021.07.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Adolescence is a transitional period between childhood and adulthood, in which the individual undergoes significant cognitive, behavioral, physical, emotional, and social developmental changes. During this period, adolescents engage in experimentation and risky behaviors such as licit and illicit drug use. Adolescents' high vulnerability to abuse drugs and natural reinforcers leads to greater risk for developing substance use disorders (SUDs) during adulthood. Accumulating evidence indicates that the use and abuse of licit and illicit drugs during adolescence and emerging adulthood can disrupt the cholinergic system and its processes. This review will focus on the effects of peri-adolescent nicotine and/or alcohol use, or exposure, on the cholinergic system during adulthood from preclinical and clinical studies. This review further explores potential cholinergic agents and pharmacological manipulations to counteract peri-adolescent nicotine and/or alcohol abuse.
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Affiliation(s)
- S R Hauser
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States.
| | - Z A Rodd
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States
| | - G A Deehan
- Department of Psychology, East Tennessee State University, Johnson City, TN, United States
| | - T Liang
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Shafiqur Rahman
- Department of Pharmaceutical Sciences, South Dakota State University, Brookings, SD, United States
| | - Richard L Bell
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, United States; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, United States.
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Adolescent nicotine treatment causes robust locomotor sensitization during adolescence but impedes the spontaneous acquisition of nicotine intake in adult female Wistar rats. Pharmacol Biochem Behav 2021; 207:173224. [PMID: 34197844 DOI: 10.1016/j.pbb.2021.173224] [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: 01/31/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 11/20/2022]
Abstract
Very few people are able to quit smoking, and therefore it is essential to know which factors contribute to the development of compulsive nicotine use. These studies aimed to investigate if early-adolescent nicotine exposure causes locomotor sensitization and affects anxiety-like behavior and the spontaneous acquisition of intravenous nicotine self-administration. Early-adolescent male and female rats were treated with nicotine from postnatal (P) days 24 to 42, and anxiety-like behavior and locomotor activity were investigated one day after the cessation of nicotine treatment and in adulthood (>P75). The spontaneous acquisition of nicotine self-administration was also investigated in adulthood. The rats self-administered 0.03 mg/kg/infusion of nicotine for six days under a fixed-ratio (FR) 1 schedule and four days under an FR2 schedule (3-h sessions). Repeated nicotine administration increased locomotor activity, rearing, and stereotypies in a small open field in adolescent male and female rats. One day after the last nicotine injection, the percentage of open arm entries in the elevated plus-maze test was decreased in the males and increased in the females. However, locomotor activity in the small open field was unaffected. Adolescent nicotine treatment did not affect anxiety-like behavior and locomotor activity in adulthood. During the 10-day nicotine self-administration period, the females had a higher level of nicotine intake than the males. Adolescent nicotine treatment decreased nicotine intake in the females. In conclusion, these findings indicate that repeated nicotine administration during adolescence causes robust behavioral sensitization and leads to lower nicotine intake in females throughout the acquisition period in adulthood in rats.
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Fisher ML, Pauly JR, Froeliger B, Turner JR. Translational Research in Nicotine Addiction. Cold Spring Harb Perspect Med 2021; 11:cshperspect.a039776. [PMID: 32513669 DOI: 10.1101/cshperspect.a039776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
While commendable strides have been made in reducing smoking initiation and improving smoking cessation rates, current available smoking cessation treatment options are still only mildly efficacious and show substantial interindividual variability in their therapeutic responses. Therefore, the primary goal of preclinical research has been to further the understanding of the neural substrates and genetic influences involved in nicotine's effects and reassess potential drug targets. Pronounced advances have been made by investing in new translational approaches and placing more emphasis on bridging the gap between human and rodent models of dependence. Functional neuroimaging studies have identified key brain structures involved with nicotine-dependence phenotypes such as craving, impulsivity, withdrawal symptoms, and smoking cessation outcomes. Following up with these findings, rodent-modeling techniques have made it possible to dissect the neural circuits involved in these motivated behaviors and ascertain mechanisms underlying nicotine's interactive effects on brain structure and function. Likewise, translational studies investigating single-nucleotide polymorphisms (SNPs) within the cholinergic, dopaminergic, and opioid systems have found high levels of involvement of these neurotransmitter systems in regulating the reinforcing aspects of nicotine in both humans and mouse models. These findings and coordinated efforts between human and rodent studies pave the way for future work determining gene by drug interactions and tailoring treatment options to each individual smoker.
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Affiliation(s)
- Miranda L Fisher
- Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, Kentucky 40536-0596, USA
| | - James R Pauly
- Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, Kentucky 40536-0596, USA
| | - Brett Froeliger
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | - Jill R Turner
- Department of Pharmaceutical Sciences, University of Kentucky College of Pharmacy, Lexington, Kentucky 40536-0596, USA
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9
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Renda B, Andrade AK, Stone APS, El Azali R, Sharivker M, Khokhar JY, Antenos M, Murray JE. Adolescent nicotine and footshock exposure augments adult nicotine self-administration and drug-seeking without affecting baseline anxiety-like behaviour or stress responsivity in male rats. Psychopharmacology (Berl) 2021; 238:1687-1701. [PMID: 33649967 PMCID: PMC8141046 DOI: 10.1007/s00213-021-05803-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 02/15/2021] [Indexed: 12/30/2022]
Abstract
RATIONALE Over the past decade, adolescent cigarette smoking has been declining. However, adolescent nicotine consumption via electronic cigarettes is rapidly gaining popularity. Earlier onset nicotine use is associated with increased risk of dependence. A bidirectional relationship between nicotine and stress exists; perceived stress is a predictor for nicotine use, and stress reduction is a commonly reported reason for using nicotine. OBJECTIVES We assessed the prolonged impact of adolescent high-dose nicotine and/or footshock exposure on adult nicotine self-administration, anxiety-like behaviour, and hormonal responsivity. METHODS During adolescence (postnatal day [P]28-56) male Sprague-Dawley rats were assigned to one of five groups: saline (SALPRE: 1 ml/kg, SC, every day), nicotine (NICPRE: 1 mg/kg, SC, alternating daily with saline; 14 total nicotine injections), footshock (SHOCKPRE: 8 of 0.5 s, 0.8 mA alternating sessions; saline every day), or combination nicotine and footshock (NIC+SHOCK: concurrent and alternating daily with saline, or NIC-SHOCK: alternating with saline on shock sessions). On P70, one cohort underwent spontaneous intravenous nicotine self-administration (0.03 mg/kg/infusion); another cohort was assessed for open-field behaviour (P71), then corticosterone (CORT) response to nicotine or footshock in adulthood (P72-73). RESULTS Intermittent adolescent nicotine or footshock alone (NICPRE and SHOCKPRE) did not potentiate adult spontaneous nicotine intake compared to SALPRE. However, both combination groups (NIC+SHOCK, NIC-SHOCK) showed increased adult nicotine consumption without associated differences in baseline anxiety-like behaviour or CORT response. CONCLUSIONS Adolescent nicotine and footshock stressors have a synergistic effect on adult nicotine consumption, enhancing nicotine intake. Avenues toward reducing stress in adolescent nicotine users may provide opportunities to reduce vulnerability to adult nicotine consumption.
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Affiliation(s)
- Briana Renda
- Department of Psychology, University of Guelph, Guelph, ON, N1G 2W1, Canada
- Collaborative Neuroscience Program, University of Guelph, Guelph, ON, Canada
| | - Allyson K Andrade
- Department of Psychology, University of Guelph, Guelph, ON, N1G 2W1, Canada
- Collaborative Neuroscience Program, University of Guelph, Guelph, ON, Canada
| | - Adiia P S Stone
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Rita El Azali
- Department of Psychology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Michael Sharivker
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Jibran Y Khokhar
- Collaborative Neuroscience Program, University of Guelph, Guelph, ON, Canada
- Department of Biomedical Sciences, University of Guelph, Guelph, ON, Canada
| | - Monica Antenos
- Department of Biomedical Sciences, University of Guelph, Guelph, ON, Canada
| | - Jennifer E Murray
- Department of Psychology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
- Collaborative Neuroscience Program, University of Guelph, Guelph, ON, Canada.
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New designer phenethylamines 2C-C and 2C-P have abuse potential and induce neurotoxicity in rodents. Arch Toxicol 2021; 95:1413-1429. [PMID: 33515270 DOI: 10.1007/s00204-021-02980-x] [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] [Received: 08/18/2020] [Accepted: 01/04/2021] [Indexed: 12/22/2022]
Abstract
2C (2C-x) is the general name for the family of phenethylamines containing two methoxy groups at the 2 and 5 positions of the benzene ring. The abuse of 2C family drugs has grown rapidly, although the abuse potential and neurotoxic properties of 2C drugs have not yet been fully investigated. In this study, we investigated the abuse potential and neurotoxicity of 4-chloro-2,5-dimethoxyphenethylamine (2C-C) and 2,5-dimethoxy-4-propylphenethylamine (2C-P). We found that 2C-C and 2C-P produced conditioned place preference in a dose-dependent manner in mice, and increased self-administration in rats, suggesting that 2C-C and 2C-P have abuse potential. To investigate the neurotoxicity of 2C-C and 2C-P, we examined motor performance and memory impairment after high doses of 2C-C and 2C-P. High doses of 2C-C and 2C-P decreased locomotor activity, rota-rod performance, and lower Y-maze test, novel objective recognition test, and passive avoidance test scores. We also observed that 2C-C and 2C-P affected expression levels of the D1 dopamine receptor, D2 dopamine receptor, dopamine transporter, and phospho-dopamine transporter in the nucleus accumbens and the medial prefrontal cortex, and increased c-Fos immuno-positive cells in the nucleus accumbens. Moreover, high doses of 2C-C and 2C-P induced microglial activation, which is involved in the inflammatory reaction in the striatum. These results suggest that 2C-C and 2C-P have abuse potential by affecting dopaminergic signaling and induce neurotoxicity via initiating neuroinflammation at high doses.
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Renda B, Andrade AK, Frie JA, Sgarbossa CL, Murray JE, Khokhar JY. High-dose adolescent nicotine exposure permits spontaneous nicotine self-administration in adult male rats. Drug Alcohol Depend 2020; 215:108215. [PMID: 32781311 PMCID: PMC7502504 DOI: 10.1016/j.drugalcdep.2020.108215] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 07/13/2020] [Accepted: 07/23/2020] [Indexed: 12/26/2022]
Abstract
INTRODUCTION While cigarette smoking rates have been steadily decreasing over the past decade, there has been a dramatic increase in nicotine use via e-cigarettes, especially during adolescence. Adolescent e-cigarette use is associated with a greater risk of future cigarette smoking, and increased rates of cigarette smoking in individuals who may have otherwise never tried cigarettes. In humans and rodents, early initiation of nicotine use has been associated with greater consumption, dependence, and persistent nicotine use. The present study sought to investigate the long-lasting effect of daily high-dose nicotine exposure during adolescence on nicotine consumption in adulthood. METHOD Male Sprague-Dawley rats were exposed daily to nicotine (1.0 mg/kg, subcutaneous), or vehicle (1 mL/kg saline, subcutaneous) during adolescence (post-natal day [P] 28-41). Adult nicotine self-administration (0.02 mg/kg/infusion, intravenous) was assessed beginning on P75 on fixed-ratio 1 (FR1), fixed-interval 1 min (FI1), and progressive ratio (PR) schedules of reinforcement. RESULTS Adolescent nicotine pre-exposure did not affect adult nicotine self-administration on the simple FR1 schedule, however increased intake and responding for nicotine was observed when a short delay was implemented on an FI1 schedule of reinforcement. CONCLUSIONS Adolescence is a critical period when the brain is especially vulnerable to the effects of nicotine. Nicotine exposure in adolescence enhances susceptibility to increased nicotine intake in adulthood on a reinforcement schedule more reflective of human nicotine intake patterns, and this effect can extend into adulthood even after termination of nicotine exposure during adolescence.
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Affiliation(s)
- Briana Renda
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Allyson K Andrade
- Department of Psychology, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
| | - Jude A Frie
- Department of Biomedical Sciences, 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.
| | - Jibran Y Khokhar
- Department of Biomedical Sciences, University of Guelph, Guelph, ON, Canada; Collaborative Neurosciences Graduate Program, University of Guelph, Guelph, ON, Canada
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25C-NBF, a new psychoactive substance, has addictive and neurotoxic potential in rodents. Arch Toxicol 2020; 94:2505-2516. [DOI: 10.1007/s00204-020-02740-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/06/2020] [Indexed: 12/19/2022]
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