1
|
Michalscheck RML, Leidl DM, Westbrook RF, Holmes NM. The Opioid Receptor Antagonist Naloxone Enhances First-Order Fear Conditioning, Second-Order Fear Conditioning and Sensory Preconditioning in Rats. Front Behav Neurosci 2021; 15:771767. [PMID: 34938166 PMCID: PMC8685270 DOI: 10.3389/fnbeh.2021.771767] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/14/2021] [Indexed: 11/13/2022] Open
Abstract
The opioid receptor antagonist naloxone enhances Pavlovian fear conditioning when rats are exposed to pairings of an initially neutral stimulus, such as a tone, and a painful foot shock unconditioned stimulus (US; so-called first-order fear conditioning; Pavlov, 1927). The present series of experiments examined whether naloxone has the same effect when conditioning occurs in the absence of US exposure. In Experiments 1a and 1b, rats were exposed to tone-shock pairings in stage 1 (one trial per day for 4 days) and then to pairings of an initially neutral light with the already conditioned tone in stage 2 (one trial per day for 4 days). Experiment 1a confirmed that this training results in second-order fear of the light; and Experiment 1b showed that naloxone enhances this conditioning: rats injected with naloxone in stage 2 froze more than vehicle-injected controls when tested with the light alone (drug-free). In Experiments 2a and 2b, rats were exposed to light-tone pairings in stage 1 (one trial per day for 4 days) and then to tone-shock pairings in stage 2 (one trial per day for 2 days). Experiment 2a confirmed that this training results in sensory preconditioned fear of the light; and Experiment 2b showed that naloxone enhances sensory preconditioning when injected prior to each of the light-tone pairings: rats injected with naloxone in stage 1 froze more than vehicle-injected controls when tested with the light alone (drug-free). These results were taken to mean that naloxone enhances fear conditioning independently of its effect on US processing; and more generally, that opioids regulate the error-correction mechanisms that underlie associative formation.
Collapse
Affiliation(s)
| | | | | | - Nathan M. Holmes
- School of Psychology, University of New South Wales, Sydney, NSW, Australia
| |
Collapse
|
2
|
Fathi M, Nezamzadeh R, Abdollahpour-Alitappeh M, Yazdi MH, Khoramabadi N, Mahdavi M. Formulation of a recombinant HIV-1 polytope candidate vaccine with naloxone/alum mixture: induction of multi-cytokine responses with a higher regulatory mechanism. APMIS 2021; 129:480-488. [PMID: 33539574 DOI: 10.1111/apm.13122] [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: 07/12/2020] [Accepted: 01/31/2021] [Indexed: 11/26/2022]
Abstract
The potency of a vaccine highly depends upon the nature of the adjuvant used. There are a variety of ineffective vaccines, such as HIV-1 vaccine candidates, that need to be optimized with new adjuvant formulations to improve vaccine potency and efficacy. Studies show the potency of naloxone (NLX)/alum mixture in the induction of Th1/Th2 response for vaccine. However, other immunologic patterns inducing by this adjuvant and its immunoregulatory effect is unclear. In this regard, the aim of the present study was to investigate the effect of the NLX/alum mixture, as an adjuvant, on cytokine networks and immunoregulatory activity for an HIV-1 polytope vaccine. BALB/c mice were divided into six groups (n = 6) and immunized subcutaneously with 10 μg of the vaccine formulated with NLX/alum, NLX, alum, and Freund's adjuvants. At the same time, the mice in the control groups received an equal volume of PBS or NLX. The lymphocyte proliferation assay was carried out using the BrdU method. ELISA was used to measure the levels of IFN-γ, IL-2, IL-4, IL-10, IL-12, and IL-17 cytokines, total IgG, as well as IgG1 and IgG2a subtypes in serum samples. Our findings showed that mice receiving the NLX/alum-adjuvanted vaccine exhibited increased antibody levels compared with other groups. In addition, there was a considerable difference in the levels of IgG1, IgG2a, IFN-γ, IL-2, IL-10, IL-12, and IL-17 in mice receiving the NLX/alum-adjuvanted vaccine as compared with other groups. The NLX/alum mixture, as an adjuvant, may have a positive effect on the induction of multi-cytokine responses, as well as the increased level of IL-10, showing its higher immunogenicity with a higher immunoregulatory mechanism.
Collapse
Affiliation(s)
- Meimanat Fathi
- Recombinant Vaccine Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.,Department of Genetic, Islamic Azad University, Damghan Branch, Damghan, Iran.,Department of Cell techniques and Applied Stem Cell Biology, Center for Biotechnology and Biomedicine (BBZ), Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Reza Nezamzadeh
- Department of Genetic, Islamic Azad University, Damghan Branch, Damghan, Iran
| | | | - Mohammad Hossein Yazdi
- Biotechnology Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.,Pharmaceutical Sciences Research Center (PSRC), The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran
| | - Nima Khoramabadi
- Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mehdi Mahdavi
- Recombinant Vaccine Research Center, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.,Pharmaceutical Sciences Research Center (PSRC), The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences, Tehran, Iran.,Department of Immunology, Pasteur Institute of Iran, Tehran, Iran
| |
Collapse
|
3
|
Abstract
The failure of traditional antidepressant medications to adequately target cognitive impairment is associated with poor treatment response, increased risk of relapse, and greater lifetime disability. Opioid receptor antagonists are currently under development as novel therapeutics for major depressive disorder (MDD) and other stress-related illnesses. Although it is known that dysregulation of the endogenous opioid system is observed in patients diagnosed with MDD, the impact of opioidergic neurotransmission on cognitive impairment has not been systematically evaluated. Here we review the literature indicating that opioid manipulations can alter cognitive functions in humans. Furthermore, we detail the preclinical studies that demonstrate the ability of mu-opioid receptor and kappa-opioid receptor ligands to modulate several cognitive processes. Specifically, this review focuses on domains within higher order cognitive processing, including attention and executive functioning, which can differentiate cognitive processes influenced by motivational state.
Collapse
|
4
|
Luo W, Deng ZH, Li R, Cheng G, Kotian RN, Li YS, Li WP. Study of analgesic effect of earthworm extract. Biosci Rep 2018; 38:BSR20171554. [PMID: 29273677 PMCID: PMC5784179 DOI: 10.1042/bsr20171554] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 12/03/2017] [Accepted: 12/21/2017] [Indexed: 01/24/2023] Open
Abstract
Pain represents a major clinical problem and one which has exercised generations of healthcare professionals. Earthworms are used as a traditional Chinese medicine, and have been applied pharmacologically and clinically since a long time in China. However, the analgesic effects of earthworm extract (EE) are seldom studied. Hence, we evaluated the analgesic effects of EE in mice. The obtained data showed that EE increased pain threshold and exhibited peripheral but not central analgesic effects in mice; evidenced by increased inhibition ratio in acetic acid writhing test and formalin test, whereas only slight increase in inhibition ratio in hot plate test and tail immersion test. In addition, EE decreased serum norepinephrine (NE), 5-hydroxytryptamine (5-HT), and nitric oxide (NO) synthase (NOS) concentration, similar to other analgesic drugs like morphine and aspirin. In a nutshell, the obtained data have demonstrated that EE has peripheral analgesic properties and could be used as a promising analgesic drug.
Collapse
Affiliation(s)
- Wei Luo
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, P.R. China
| | - Zhen-Han Deng
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, P.R. China
| | - Rui Li
- Department of Animal Science, College of Animal Science and Technology, Hunan Agricultural University, Changsha, Hunan, P.R. China
| | - Guo Cheng
- Department of Animal Science, College of Animal Science and Technology, Hunan Agricultural University, Changsha, Hunan, P.R. China
| | - Ronak Naveenchandra Kotian
- Department of Orthopaedic Surgery, Victoria Hospital, Bangalore Medical College and Research Institute, Bangalore, India
| | - Yu-Sheng Li
- Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha, Hunan, P.R. China
| | - Wen-Ping Li
- Department of Animal Science, College of Animal Science and Technology, Hunan Agricultural University, Changsha, Hunan, P.R. China
| |
Collapse
|
5
|
Abstract
This paper is the thirty-sixth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2013 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia; stress and social status; tolerance and dependence; learning and memory; eating and drinking; alcohol and drugs of abuse; sexual activity and hormones, pregnancy, development and endocrinology; mental illness and mood; seizures and neurologic disorders; electrical-related activity and neurophysiology; general activity and locomotion; gastrointestinal, renal and hepatic functions; cardiovascular responses; respiration and thermoregulation; and immunological responses.
Collapse
Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, Flushing, NY 11367, United States.
| |
Collapse
|