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Thuo J, Towett P, Kanui T, Abelson K. Effects of dexamethasone and acetylsalicylic acid on inflammation caused by complete Freund’s adjuvant in the naked mole rat (Heterocephalus glaber). Heliyon 2022; 8:e08920. [PMID: 35198780 PMCID: PMC8850730 DOI: 10.1016/j.heliyon.2022.e08920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/05/2021] [Accepted: 02/04/2022] [Indexed: 11/30/2022] Open
Abstract
The naked mole rat (NMR) is a fossorial rodent that has been observed to have a unique nociceptive system in comparison to others. In this study, we explored on characterization of chronic inflammation in the NMR using Complete Freund's adjuvant (CFA) and investigated the effects of dexamethasone and acetylsalicylic acid on the resulting inflammation. The NMRs were injected with 0.1 ml of CFA subcutaneously in the right hind paw, and an equivalent volume of normal saline was injected to the control group. Swelling of the injected right hind limb was observed within 24 h of injection, which involved the tibiotarsal joint, palmar surface and the digits of the injected paw. Swelling persisted for 6 weeks of experimentation and peaked between day 14 and 21. The resulting inflammation affected the mobility, stance and joint rigidity of CFA treated NMRs in comparison to the control group. Treatment of the chronic phase of the inflammation from the 11th day with dexamethasone and acetylsalicylic acid showed no statistical significance in paw circumference compared to the control group, other than on a few, negligible occasions. The present data showed that CFA was able to induce chronic inflammation in the NMR, and the NMR could thus be established as a model for chronic inflammation. There is, however, need for more sensitive parameters to evaluate the effects of anti-inflammatory drugs.
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Affiliation(s)
- J.K.N. Thuo
- Department of Experimental Medicine, University of Copenhagen, Denmark
- Department of Veterinary Anatomy and Physiology, Egerton University, Kenya
- Corresponding author.
| | - P.K. Towett
- Department of Veterinary Anatomy and Physiology, University of Nairobi, Kenya
| | - T.I. Kanui
- Department of Agricultural Sciences, South Eastern Kenya University, Kenya
| | - K.S.P. Abelson
- Department of Experimental Medicine, University of Copenhagen, Denmark
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Mwobobia RM, Kanui TI, Abelson KSP. The effects of clonidine and yohimbine in the tail flick and hot plate tests in the naked mole rat (Heterocephalus glaber). BMC Res Notes 2021; 14:191. [PMID: 34001271 PMCID: PMC8130107 DOI: 10.1186/s13104-021-05607-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/08/2021] [Indexed: 11/10/2022] Open
Abstract
Objective The naked mole rat (NMR) (Heterocephalus glaber) is increasingly considered an important biomedical research model for various conditions like hypoxic brain injury, cancer and nociception. This study was designed to investigate the effects of clonidine and yohimbine, an alpha-2 (α2) adrenoceptor agonist and antagonist respectively in the tail flick and hot plate tests. Results A significant difference in tail flick latency was noted between saline control and 30 µg/kg clonidine, which was reduced after administration of 30 µg/kg yohimbine. A significant difference in hot plate latency was also noted between saline control and 30 µg/kg clodinine during the periods 30, 45, 60, 75 and 90 min after administration, and between saline control and 10 µg/kg clonidine during 30 min after administration. The hot plate latency by 30 µg/kg clonidine was also reduced by 30 µg/kg yohimbine during 30 min after administration. Since the tail-flick and hot plate tests mediate the effects at spinal and supraspinal levels respectively, the present study indicates the presence and involvement of noradrenergic receptors in thermal antinociception at spinal and supraspinal levels of the NMR, similar to what has been found in other mammals.
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Affiliation(s)
- R M Mwobobia
- School of Agriculture and Veterinary Sciences, South Eastern Kenya University, P O Box 170-90200, Kitui, Kenya. .,Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamvej 3B, 2200, Copenhagen, Denmark.
| | - T I Kanui
- School of Agriculture and Veterinary Sciences, South Eastern Kenya University, P O Box 170-90200, Kitui, Kenya
| | - K S P Abelson
- Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamvej 3B, 2200, Copenhagen, Denmark
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The Somatosensory World of the African Naked Mole-Rat. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1319:197-220. [PMID: 34424517 DOI: 10.1007/978-3-030-65943-1_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The naked mole-rat (Heterocephalus glaber) is famous for its longevity and unusual physiology. This eusocial species that lives in highly ordered and hierarchical colonies with a single breeding queen, also discovered secrets enabling somewhat pain-free living around 20 million years ago. Unlike most mammals, naked mole-rats do not feel the burn of chili pepper's active ingredient, capsaicin, nor the sting of acid. Indeed, by accumulating mutations in genes encoding proteins that are only now being exploited as targets for new pain therapies (the nerve growth factor receptor TrkA and voltage-gated sodium channel, NaV1.7), this species mastered the art of analgesia before humans evolved. Recently, we have identified pain-insensitivity as a trait shared by several closely related African mole-rat species. In this chapter we will show how African mole-rats have evolved pain insensitivity as well as discussing what the proximate factors may have been that led to the evolution of pain-free traits.
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Mwobobia R, Kanui T, Abelson K. Investigation of noradrenergic receptor system in anti-nociception using formalin test in the naked mole rat ( Heterocephalus glaber). Heliyon 2020; 6:e05216. [PMID: 33134574 PMCID: PMC7586093 DOI: 10.1016/j.heliyon.2020.e05216] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/15/2020] [Accepted: 10/07/2020] [Indexed: 02/05/2023] Open
Abstract
The naked mole rat (NMR) is a rodent that has gained importance as a biomedical research model for various conditions like hypoxic brain injury, cancer and nociception. This study was designed to investigate possible involvement of the noadrenergic receptor system in antinoception in the NMR, using the alpha-2 adrenergic receptor specific ligands clonidine (agonist) and yohimbine (antagonist) in the formalin test. Formalin test followed 30 min after intraperitoneal administration of ligands or control. A total of 96 naked mole rats were used. A significant reduction in nociceptive behaviours was demonstrated after administration of clonidine in the doses 1,3,10 and 30 μg/kg (n = 8 per group). Doses of clonidine above 30 μg/kg caused loss of motor and proprietion skills exhibited by prostration and failure to turn over when placed on their backs. The antinociception by 3 μg/kg clonidine was reversed by administration of 30 μg/kg of yohimbine. The present study demonstrates that the noradrenergic receptor system is present and involved in formalin test-related antinociceptive mechanisms in the NMR, similar to other mammals. Given the increasing importance of the NMR as a model for pain and nociception, the species may prove useful as an animal model for noradrenergic mechanisms in pain modulation.
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Affiliation(s)
- R.M. Mwobobia
- School of Agriculture and Veterinary Sciences, South Eastern Kenya University, P O Box 170-90200, Kitui, Kenya
- Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamvej 3B, 2200, Copenhagen, Denmark
| | - T.I. Kanui
- School of Agriculture and Veterinary Sciences, South Eastern Kenya University, P O Box 170-90200, Kitui, Kenya
| | - K.S.P. Abelson
- Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamvej 3B, 2200, Copenhagen, Denmark
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Smith ESJ, Park TJ, Lewin GR. Independent evolution of pain insensitivity in African mole-rats: origins and mechanisms. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:313-325. [PMID: 32206859 PMCID: PMC7192887 DOI: 10.1007/s00359-020-01414-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/10/2020] [Accepted: 02/27/2020] [Indexed: 12/21/2022]
Abstract
The naked mole-rat (Heterocephalus glaber) is famous for its longevity and unusual physiology. This eusocial species that lives in highly ordered and hierarchical colonies with a single breeding queen, also discovered secrets enabling somewhat pain-free living around 20 million years ago. Unlike most mammals, naked mole-rats do not feel the burn of chili pepper's active ingredient, capsaicin, nor the sting of acid. Indeed, by accumulating mutations in genes encoding proteins that are only now being exploited as targets for new pain therapies (the nerve growth factor receptor TrkA and voltage-gated sodium channel, NaV1.7), this species mastered the art of analgesia before humans evolved. Recently, we have identified pain insensitivity as a trait shared by several closely related African mole-rat species. One of these African mole-rats, the Highveld mole-rat (Cryptomys hottentotus pretoriae), is uniquely completely impervious and pain free when confronted with electrophilic compounds that activate the TRPA1 ion channel. The Highveld mole-rat has evolved a biophysical mechanism to shut down the activation of sensory neurons that drive pain. In this review, we will show how mole-rats have evolved pain insensitivity as well as discussing what the proximate factors may have been that led to the evolution of pain-free traits.
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Affiliation(s)
- Ewan St John Smith
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, UK
| | - Thomas J Park
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Gary R Lewin
- Molecular Physiology of Somatic Sensation, Max Delbrück Center for Molecular Medicine, Robert-Rössle Str. 10, D-13125, Berlin, Germany.
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Mercieri M, Palmisani S, De Blasi RA, D'Andrilli A, Naccarato A, Silvestri B, Tigano S, Massullo D, Rocco M, Arcioni R. Low-dose buprenorphine infusion to prevent postoperative hyperalgesia in patients undergoing major lung surgery and remifentanil infusion: a double-blind, randomized, active-controlled trial. Br J Anaesth 2017; 119:792-802. [DOI: 10.1093/bja/aex174] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/16/2017] [Indexed: 02/03/2023] Open
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Jørgensen KB, Krogh-Jensen K, Pickering DS, Kanui TI, Abelson KSP. Investigation of the presence and antinociceptive function of muscarinic acetylcholine receptors in the African naked mole-rat (Heterocephalus glaber). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2015; 202:7-15. [PMID: 26520141 PMCID: PMC4698283 DOI: 10.1007/s00359-015-1048-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 10/18/2015] [Accepted: 10/22/2015] [Indexed: 11/30/2022]
Abstract
The present study investigated the cholinergic system in the African naked mole-rat (Heterocephalus glaber) with focus on the muscarinic acetylcholine receptor subtypes M1 and M4. The protein sequences for the subtypes m1–5 of the naked mole-rat were compared to that of the house mouse (Mus musculus) using basic local alignment search tool (BLAST). The presence and function of M1 and M4 was investigated in vivo, using the formalin test with the muscarinic receptor agonists xanomeline and VU0152100. Spinal cord tissue from the naked mole-rat was used for receptor saturation binding studies with [3H]-N-methylscopolamine. The BLAST test revealed 95 % protein sequence homology showing the naked mole-rat to have the genetic potential to express all five muscarinic acetylcholine receptor subtypes. A significant reduction in pain behavior was demonstrated after administration of 8.4 mg/kg in the formalin test. Administration of 50 mg/kg VU0152100 resulted in a non-significant tendency towards antinociception. The antinociceptive effects were reversed by the muscarinic acetylcholine receptor antagonist atropine. Binding studies indicated presence of muscarinic acetylcholine receptors with a radioligand affinity comparable to that reported in mice. In conclusion, muscarinic acetylcholine receptor subtypes are present in the naked mole-rat and contribute to antinociception in the naked mole-rat.
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Affiliation(s)
- Kristine B Jørgensen
- Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamvej 3B, 2200, Copenhagen, Denmark
| | - Karen Krogh-Jensen
- Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamvej 3B, 2200, Copenhagen, Denmark
| | - Darryl S Pickering
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100, Copenhagen, Denmark
| | - Titus I Kanui
- School of Agricultural and Veterinary Sciences, South Eastern Kenya University, P.O. BOX 170-90200, Kitui, Kenya
| | - Klas S P Abelson
- Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamvej 3B, 2200, Copenhagen, Denmark.
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Cheong MC, Artyukhin AB, You YJ, Avery L. An opioid-like system regulating feeding behavior in C. elegans. eLife 2015; 4. [PMID: 25898004 PMCID: PMC4427864 DOI: 10.7554/elife.06683] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/21/2015] [Indexed: 01/29/2023] Open
Abstract
Neuropeptides are essential for the regulation of appetite. Here we show that neuropeptides could regulate feeding in mutants that lack neurotransmission from the motor neurons that stimulate feeding muscles. We identified nlp-24 by an RNAi screen of 115 neuropeptide genes, testing whether they affected growth. NLP-24 peptides have a conserved YGGXX sequence, similar to mammalian opioid neuropeptides. In addition, morphine and naloxone respectively stimulated and inhibited feeding in starved worms, but not in worms lacking NPR-17, which encodes a protein with sequence similarity to opioid receptors. Opioid agonists activated heterologously expressed NPR-17, as did at least one NLP-24 peptide. Worms lacking the ASI neurons, which express npr-17, did not response to naloxone. Thus, we suggest that Caenorhabditis elegans has an endogenous opioid system that acts through NPR-17, and that opioids regulate feeding via ASI neurons. Together, these results suggest C. elegans may be the first genetically tractable invertebrate opioid model. DOI:http://dx.doi.org/10.7554/eLife.06683.001 When and how much an animal eats is controlled by a complex web of signals that are produced by the animal's body and brain. Molecules called opioid neuropeptides are among these signals, and act to control eating in mammals by binding to receptors in the brain and body. These receptors can also bind to similar molecules called opiates (such as morphine); opiates are amongst the oldest drugs used by humans and have diverse effects ranging from pain relief to addiction. While the activities of opiates and opioid neuropeptides have been studied in mammals, relatively little is known about opioid signaling in simpler animals. The mechanisms behind many biological processes have been investigated using a worm called C. elegans as a model system because it has a simple body plan and its genes can be altered easily. The feeding behavior of C. elegans is no exception. This worm feeds by contracting and relaxing its pharyngeal muscle to move food into its gut. When the worms sense that food is available, this ‘pharyngeal pumping’ is regulated by one type of nerve cell. Slow pharyngeal pumping also continues in starved worms when food is not available, possibly to encourage them to eat new potential sources of food. However, this slow pumping does not require the same type of nerve cell. Cheong et al. hypothesized that the slow pumping in starved worms might depend on neuropeptide signaling instead, and have now tested this idea using engineered worms that made lower levels of a number of these molecules. The experiments uncovered a molecule called NLP-24 that promotes the slow pharyngeal pumping. This molecule is similar to opioid neuropeptides found in mammals. Worms that made less NLP-24 than normal grew more slowly; this suggests that they had problems feeding. Moreover, the levels of NLP-24 were found to increase in normal worms soon after they were deprived of food. Further experiments revealed the identity of the receptor for this molecule, which is also similar to mammalian opioid receptors. The discovery that opioid signaling is involved in C. elegans' feeding behavior may well, in future, also help to identify new molecular players involved in opioid signaling. Further studies might also help the search for ways to reduce the problematic side-effects that limit the usefulness of opiate drugs as medicines. DOI:http://dx.doi.org/10.7554/eLife.06683.002
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Affiliation(s)
- Mi Cheong Cheong
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, United States
| | - Alexander B Artyukhin
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, United States
| | - Young-Jai You
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, United States
| | - Leon Avery
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, United States
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Functional characteristics of the naked mole rat μ-opioid receptor. PLoS One 2013; 8:e79121. [PMID: 24312175 PMCID: PMC3842265 DOI: 10.1371/journal.pone.0079121] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 09/26/2013] [Indexed: 12/05/2022] Open
Abstract
While humans and most animals respond to µ-opioid receptor (MOR) agonists with analgesia and decreased aggression, in the naked mole rat (NMR) opioids induce hyperalgesia and severe aggression. Single nucleotide polymorphisms in the human mu-opioid receptor gene (OPRM1) can underlie altered behavioral responses to opioids. Therefore, we hypothesized that the primary structure of the NMR MOR may differ from other species. Sequencing of the NMR oprm1 revealed strong homology to other mammals, but exposed three unique amino acids that might affect receptor-ligand interactions. The NMR and rat oprm1 sequences were cloned into mammalian expression vectors and transfected into HEK293 cells. Radioligand binding and 3'-5'-cyclic adenosine monophosphate (cAMP) enzyme immunoassays were used to compare opioid binding and opioid-mediated cAMP inhibition. At normalized opioid receptor protein levels we detected significantly lower [3H]DAMGO binding to NMR compared to rat MOR, but no significant difference in DAMGO-induced cAMP inhibition. Strong DAMGO-induced MOR internalization was detectable using radioligand binding and confocal imaging in HEK293 cells expressing rat or NMR receptor, while morphine showed weak or no effects. In summary, we found minor functional differences between rat and NMR MOR suggesting that other differences e.g. in anatomical distribution of MOR underlie the NMR's extreme reaction to opioids.
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Towett PK, Kanui TI, Maloiy GMO, Juma F, Olongida Ole Miaron J. Activation of micro, delta or kappa opioid receptors by DAMGO, DPDPE, U-50488 or U-69593 respectively causes antinociception in the formalin test in the naked mole-rat (Heterocephalus glaber). Pharmacol Biochem Behav 2008; 91:566-72. [PMID: 18929596 DOI: 10.1016/j.pbb.2008.09.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Revised: 09/18/2008] [Accepted: 09/23/2008] [Indexed: 10/21/2022]
Abstract
Data available on the role of the opioid systems of the naked mole-rat in nociception is scanty and unique compared to that of other rodents. In the current study, the effect of DAMGO, DPDPE and U-50488 and U-69593 on formalin-induced (20 microl, 10%) nociception were investigated. Nociceptive-like behaviors were quantified by scoring in blocks of 5 min the total amount of time (s) the animal spent scratching/biting the injected paw in the early (0-5 min) and in the late (25-60 min) phase of the test. In both the early and late phases, administration of 1 or 5 mg/kg of DAMGO or DPDPE caused a naloxone-attenuated decrease in the mean scratching/biting time. U-50488 and U-69593 at all the doses tested did not significantly change the mean scratching/biting time in the early phase. However, in the late phase U-50488 or U-69593 at the highest doses tested (1 or 5 mg/kg or 0.025 or 0.05 mg/kg, respectively) caused a statistically significant and naloxone-attenuated decrease in the mean scratching/biting time. The data showed that mu, delta or kappa-selective opioids causes antinociception in the formalin test in this rodent, adding novel information on the role of opioid systems of the animal on pain regulation.
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Affiliation(s)
- Philemon Kipkemoi Towett
- Neurophysiology and Neuropharmacology Research Laboratory, Department of Veterinary Anatomy, University of Nairobi, P.O. Box 00100-30197, Nairobi, Kenya.
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Abstract
This paper is the 29th consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning 30 years of research. It summarizes papers published during 2006 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 (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurological disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, CUNY, 65-30 Kissena Blvd., Flushing, NY 11367, United States.
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