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Harris AC, Muelken P, Liu SX, Smethells JR, LeSage MG, Gewirtz JC. Magnitude and predictors of elasticity of demand for morphine are similar in male and female rats. Front Behav Neurosci 2024; 18:1443364. [PMID: 39267985 PMCID: PMC11390466 DOI: 10.3389/fnbeh.2024.1443364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Accepted: 08/16/2024] [Indexed: 09/15/2024] Open
Abstract
Introduction Sex differences in vulnerability to opioid use disorder (OUD) have been reported in some clinical and preclinical studies, but findings are mixed and further research is needed in this area. The goal of this study was to compare elasticity of demand (reinforcement efficacy) in an i.v. morphine self-administration (SA) model in male and female rats using a translationally relevant behavioral economics approach. Rate of acquisition and predictors of individual differences in demand (e.g., cumulative morphine infusions during acquisition) were also evaluated in both sexes. Materials methods and results Acquisition of morphine SA (0.4 mg/kg/infusion) under a fixed ratio (FR) 1 schedule of reinforcement was slower and infusions earned were lower in females than in males (n = 30-31/sex), but infusions earned did not differ between sexes during the FR 2 and FR 3 phases of acquisition. Increases in the FR response requirement across sessions during demand testing (FR 1-FR 96) resulted in a progressive reduction in morphine infusions in both sexes. Morphine consumption was well-described by an exponential demand function in both sexes and was associated with considerable individual vulnerability. There were no sex differences in elasticity of demand (rate of decline in morphine consumption with increasing price) or intensity of demand (consumption at zero price). A higher number of infusions earned during the FR 2 and FR 3 phases of acquisition and greater maximum response rates during demand testing were associated with lower demand elasticity (i.e., greater reinforcing efficacy) in both males and females, whereas other relationships were sex-specific (e.g., higher intensity of demand was associated with lower elasticity of demand in males but not in females). Conclusion Our findings indicate similar elasticity of demand and predictors of individual differences in demand for morphine in male and female rats, although sex differences were observed in initial rate of acquisition and in some correlations between morphine SA measures. These data are consistent with findings of similar OUD vulnerability in males and females in some human and animal studies.
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Affiliation(s)
- Andrew C Harris
- Hennepin Healthcare Research Institute, Minneapolis, MN, United States
- Department of Medicine, University of Minnesota, Minneapolis, MN, United States
- Department of Psychology, University of Minnesota, Minneapolis, MN, United States
| | - Peter Muelken
- Hennepin Healthcare Research Institute, Minneapolis, MN, United States
| | - Shirelle X Liu
- Hennepin Healthcare Research Institute, Minneapolis, MN, United States
- Department of Psychology, University of Minnesota, Minneapolis, MN, United States
| | - John R Smethells
- Hennepin Healthcare Research Institute, Minneapolis, MN, United States
- Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Mark G LeSage
- Hennepin Healthcare Research Institute, Minneapolis, MN, United States
- Department of Medicine, University of Minnesota, Minneapolis, MN, United States
- Department of Psychology, University of Minnesota, Minneapolis, MN, United States
| | - Jonathan C Gewirtz
- Department of Psychology, University of Minnesota, Minneapolis, MN, United States
- Department of Psychology, Arizona State University, Tempe, AZ, United States
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Santos-Toscano R, Arevalo MA, Garcia-Segura LM, Grassi D, Lagunas N. Interaction of gonadal hormones, dopaminergic system, and epigenetic regulation in the generation of sex differences in substance use disorders: A systematic review. Front Neuroendocrinol 2023; 71:101085. [PMID: 37543184 DOI: 10.1016/j.yfrne.2023.101085] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 07/24/2023] [Accepted: 07/25/2023] [Indexed: 08/07/2023]
Abstract
Substance use disorder (SUD) is a chronic condition characterized by pathological drug-taking and seeking behaviors. Remarkably different between males and females, suggesting that drug addiction is a sexually differentiated disorder. The neurobiological bases of sex differences in SUD include sex-specific reward system activation, influenced by interactions between gonadal hormone level changes, dopaminergic reward circuits, and epigenetic modifications of key reward system genes. This systematic review, adhering to PICOS and PRISMA-P 2015 guidelines, highlights the sex-dependent roles of estrogens, progesterone, and testosterone in SUD. In particular, estradiol elevates and progesterone reduces dopaminergic activity in SUD females, whilst testosterone and progesterone augment SUD behavior in males. Finally, SUD is associated with a sex-specific increase in the rate of opioid and monoaminergic gene methylation. The study reveals the need for detailed research on gonadal hormone levels, dopaminergic or reward system activity, and epigenetic landscapes in both sexes for efficient SUD therapy development.
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Affiliation(s)
- Raquel Santos-Toscano
- School of Medicine, University of Central Lancashire, 135A Adelphi St, Preston PR1 7BH, United Kingdom
| | - Maria Angeles Arevalo
- Neuroactive Steroids Lab, Cajal Institute, CSIC, Avenida Doctor Arce 37, 28002 Madrid, Spain; Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Luis Miguel Garcia-Segura
- Neuroactive Steroids Lab, Cajal Institute, CSIC, Avenida Doctor Arce 37, 28002 Madrid, Spain; Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Daniela Grassi
- Neuroactive Steroids Lab, Cajal Institute, CSIC, Avenida Doctor Arce 37, 28002 Madrid, Spain; Centro de Investigación Biomédica en Red de Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, 28029 Madrid, Spain; Department of Anatomy, Histology and Neuroscience, Autonoma University of Madrid, Calle Arzobispo Morcillo 4, 28029 Madrid, Spain.
| | - Natalia Lagunas
- Neuroactive Steroids Lab, Cajal Institute, CSIC, Avenida Doctor Arce 37, 28002 Madrid, Spain; Department of Legal Medicine, Psychiatry and Pathology, School of Medicine, Complutense University of Madrid, Ciudad Universitaria, Plaza Ramón y Cajal s/n, 28040 Madrid, Spain
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Marinelli S, Basile G, Manfredini R, Zaami S. Sex- and Gender-Specific Drug Abuse Dynamics: The Need for Tailored Therapeutic Approaches. J Pers Med 2023; 13:965. [PMID: 37373954 DOI: 10.3390/jpm13060965] [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: 04/06/2023] [Revised: 06/06/2023] [Accepted: 06/06/2023] [Indexed: 06/29/2023] Open
Abstract
Sex and gender have been gaining ever greater attention due to their associated risks, dynamics, patterns and protective factors underlying substance abuse and addiction. Such differentiations and the clarification of complexities thereof take on even greater relevance in light of drug abuse scope worldwide. According to the 2022 World Drug Report released by the United Nations Office on Drugs and Crime (UNODC), in 2020 an estimated 284 million people worldwide aged 15-64 had used a drug within the last 12 months. The authors have set out to shed a light on determinants and contributing factors of drug abuse based on sex and gender and outline policy and medicolegal remarks aimed at delineating sex- and gender-based approaches towards drug abuse therapeutic interventions that are both therapeutically and ethically/legally viable and grounded in an evidence-based set of standards. Neurobiological data suggest that estrogen may facilitate drug taking by interacting with reward- and stress-related systems. In animal research, the administration of estrogen increases drug taking and facilitates the acquisition, escalation, and reinstatement of cocaine-seeking behavior. From a medicolegal perspective, it is of utmost importance to take into account the whole picture constituting each patient profile, which certainly includes gender factors and contributors, when outlining a therapeutic approach. Failure to do so could lead to negligence-based malpractice allegations, in light of the scientific findings representing best practices with which clinicians need to comply when caring for SUD patients.
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Affiliation(s)
- Susanna Marinelli
- School of Law, Università Politecnica delle Marche, 60121 Ancona, Italy
| | | | - Roberto Manfredini
- University Center for Studies on Gender Medicine, Department of Medical Sciences, University of Ferrara, Via Luigi Borsari 46, 44121 Ferrara, Italy
| | - Simona Zaami
- Department of Anatomical, Histological, Forensic and Orthopedic Sciences, "Sapienza" University of Rome, 00161 Rome, Italy
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Bender BN, Torregrossa MM. Intermittent cocaine self-administration has sex-specific effects on addiction-like behaviors in rats. Neuropharmacology 2023; 230:109490. [PMID: 36889433 PMCID: PMC10040443 DOI: 10.1016/j.neuropharm.2023.109490] [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: 12/19/2022] [Revised: 02/21/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023]
Abstract
Intermittent access (IntA) models of cocaine self-administration were developed to better model in rodents how cocaine is used by human drug users. Compared to traditional continuous access (ContA) models, IntA has been shown to enhance several pharmacological and behavioral effects of cocaine, but few studies have examined sex differences in IntA. Moreover, no one has examined the efficacy of cue extinction to reduce cocaine seeking in the IntA model, which has previously shown to be ineffective in other models that promote habit-like cocaine seeking. Therefore, rats were implanted with jugular vein catheters and dorsolateral striatum (DLS) cannulae and trained to self-administer cocaine paired with an audiovisual cue with ContA or IntA. In subsets of rats, we evaluated: the ability of Pavlovian cue extinction to reduce cue-induced drug seeking; motivation for cocaine using a progressive ratio procedure; punishment-resistant cocaine taking by pairing cocaine infusions with footshocks; and dependence of drug-seeking on DLS dopamine (a measure of habit-like behavior) with the dopamine antagonist cis-flupenthixol. Overall, cue extinction reduced cue-induced drug seeking after ContA or IntA. Compared to ContA, IntA resulted in increased motivation for cocaine exclusively in females, but IntA facilitated punished cocaine self-administration exclusively in males. After 10 days of IntA training, but not fewer, drug-seeking was dependent on DLS dopamine most notably in males. Our results suggest that IntA may be valuable for identifying sex differences in the early stages of drug use and provide a foundation for the investigation of the mechanisms involved.
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Affiliation(s)
- Brooke N Bender
- Department of Psychiatry, University of Pittsburgh, 450 Technology Drive, Pittsburgh, PA, 15219, USA; Center for Neuroscience, University of Pittsburgh, 4200 Fifth Ave, Pittsburgh, PA, 15213, USA
| | - Mary M Torregrossa
- Department of Psychiatry, University of Pittsburgh, 450 Technology Drive, Pittsburgh, PA, 15219, USA; Center for Neuroscience, University of Pittsburgh, 4200 Fifth Ave, Pittsburgh, PA, 15213, USA.
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Tronson NC, Schuh KM. Hormonal contraceptives, stress, and the brain: The critical need for animal models. Front Neuroendocrinol 2022; 67:101035. [PMID: 36075276 DOI: 10.1016/j.yfrne.2022.101035] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 07/26/2022] [Accepted: 09/01/2022] [Indexed: 01/10/2023]
Abstract
Hormonal contraceptives are among the most important health and economic developments in the 20thCentury, providing unprecedented reproductive control and a range of health benefits including decreased premenstrual symptoms and protections against various cancers. Hormonal contraceptives modulate neural function and stress responsivity. These changes are usually innocuous or even beneficial, including their effects onmood. However, in approximately 4-10% of users, or up to 30 million people at any given time, hormonal contraceptives trigger depression or anxiety symptoms. How hormonal contraceptives contribute to these responses and who is at risk for adverse outcomes remain unknown. In this paper, we discussstudies of hormonal contraceptive use in humans and describe the ways in which laboratory animal models of contraceptive hormone exposure will be an essential tool for expanding findings to understand the precise mechanisms by which hormonal contraceptives influence the brain, stress responses, and depression risk.
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Affiliation(s)
- Natalie C Tronson
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA.
| | - Kristen M Schuh
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
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