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Stucke AG, Levitt ES, Montandon G. Editorial: Opioid-induced respiratory depression: neural circuits and cellular pathways. Front Physiol 2023; 14:1348910. [PMID: 38179143 PMCID: PMC10766328 DOI: 10.3389/fphys.2023.1348910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 12/06/2023] [Indexed: 01/06/2024] Open
Affiliation(s)
- Astrid G. Stucke
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States
- Children’s Wisconsin, Milwaukee, WI, United States
| | - Erica S. Levitt
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Gaspard Montandon
- Department of Medicine, University of Toronto, Toronto, ON, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
- Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Toronto, ON, Canada
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Tamir-Hostovsky L, Ivanovska J, Parajón E, Patel R, Wang H, Biouss G, Ivanovski N, Belik J, Pierro A, Montandon G, Gauda EB. Maturational effect of leptin on CO 2 chemosensitivity in newborn rats. Pediatr Res 2023; 94:971-978. [PMID: 37185965 DOI: 10.1038/s41390-023-02604-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 03/28/2023] [Accepted: 04/01/2023] [Indexed: 05/17/2023]
Abstract
BACKGROUND Leptin augments central CO2 chemosensitivity and stabilizes breathing in adults. Premature infants have unstable breathing and low leptin levels. Leptin receptors are on CO2 sensitive neurons in the Nucleus Tractus Solitarius (NTS) and locus coeruleus (LC). We hypothesized that exogenous leptin improves hypercapnic respiratory response in newborn rats by improving central CO2 chemosensitivity. METHODS In rats at postnatal day (p)4 and p21, hyperoxic and hypercapnic ventilatory responses, and pSTAT and SOCS3 protein expression in the hypothalamus, NTS and LC were measured before and after treatment with exogenous leptin (6 µg/g). RESULTS Exogenous leptin increased the hypercapnic response in p21 but not in p4 rats (P ≤ 0.001). At p4, leptin increased pSTAT expression only in the LC, and SOCS3 expression in the NTS and LC; while at p21 pSTAT and SOCS3 levels were higher in the hypothalamus, NTS, and LC (P ≤ 0.05). CONCLUSIONS We describe the developmental profile of the effect of exogenous leptin on CO2 chemosensitivity. Exogenous leptin does not augment central CO2 sensitivity during the first week of life in newborn rats. The translational implication of these findings is that low plasma leptin levels in premature infants may not be contributing to respiratory instability. IMPACT Exogenous leptin does not augment CO2 sensitivity during the first week of life in newborn rats, similar to the developmental period when feeding behavior is resistant to leptin. Exogenous leptin increases CO2 chemosensitivity in newborn rats after the 3rd week of life and upregulates the expression of pSTAT and SOC3 in the hypothalamus, NTS and LC. Low plasma leptin levels in premature infants are unlikely contributors to respiratory instability via decreased CO2 sensitivity in premature infants. Thus, it is highly unlikely that exogenous leptin would alter this response.
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Affiliation(s)
- Liran Tamir-Hostovsky
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada.
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Julijana Ivanovska
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Eleana Parajón
- Cellular and Molecular Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Rachana Patel
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Huanhuan Wang
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - George Biouss
- Division of General and Thoracic Surgery, Developmental and Stem Cell Biology Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Nikola Ivanovski
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Jaques Belik
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Agostino Pierro
- Division of General and Thoracic Surgery, Developmental and Stem Cell Biology Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Gaspard Montandon
- Keenan Research Centre for Biomedical Sciences, St. Michael's Hospital, Unity Health Toronto, University of Toronto, Toronto, ON, Canada
| | - Estelle B Gauda
- Division of Neonatology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- Translational Program, Peter Gilgan Center for Research and Learning, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
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Rousseau JP, Furdui A, Silveira Scarpellini CD, Horner RL, Montandon G. Medullary tachykinin precursor 1 neurons promote rhythmic breathing. eLife 2023; 12:e85575. [PMID: 37458576 PMCID: PMC10400077 DOI: 10.7554/elife.85575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 07/15/2023] [Indexed: 08/04/2023] Open
Abstract
Rhythmic breathing is generated by neural circuits located in the brainstem. At its core is the preBötzinger Complex (preBötC), a region of the medulla, necessary for the generation of rhythmic breathing in mammals. The preBötC is comprised of various neuronal populations expressing neurokinin-1 receptors, the cognate G-protein-coupled receptor of the neuropeptide substance P (encoded by the tachykinin precursor 1 or Tac1). Neurokinin-1 receptors are highly expressed in the preBötC and destruction or deletion of neurokinin-1 receptor-expressing preBötC neurons severely impair rhythmic breathing. Although, the application of substance P to the preBötC stimulates breathing in rodents, substance P is also involved in nociception and locomotion in various brain regions, suggesting that Tac1 neurons found in the preBötC may have diverse functional roles. Here, we characterized the role of Tac1-expressing preBötC neurons in the generation of rhythmic breathing in vivo, as well as motor behaviors. Using a cre-lox recombination approach, we injected adeno-associated virus containing the excitatory channelrhodopsin-2 ChETA in the preBötC region of Tac1-cre mice. Employing a combination of histological, optogenetics, respiratory, and behavioral assays, we showed that stimulation of glutamatergic or Tac1 preBötC neurons promoted rhythmic breathing in both anesthetized and freely moving animals, but also triggered locomotion and overcame respiratory depression by opioid drugs. Overall, our study identified a population of excitatory preBötC with major roles in rhythmic breathing and behaviors.
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Affiliation(s)
- Jean-Philippe Rousseau
- Keenan Research Centre for Biomedical Sciences. St. Michael's Hospital, Unity Health Toronto, Toronto, Canada
| | - Andreea Furdui
- Keenan Research Centre for Biomedical Sciences. St. Michael's Hospital, Unity Health Toronto, Toronto, Canada
| | | | - Richard L Horner
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Gaspard Montandon
- Keenan Research Centre for Biomedical Sciences. St. Michael's Hospital, Unity Health Toronto, Toronto, Canada
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Canada
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Furdui A, da Silveira Scarpellini C, Montandon G. Fentanyl-induced respiratory depression and locomotor hyperactivity are mediated by µ-opioid receptors expressed in somatostatin-negative neurons. eNeuro 2023:ENEURO.0035-23.2023. [PMID: 37364996 DOI: 10.1523/eneuro.0035-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 05/03/2023] [Accepted: 05/26/2023] [Indexed: 06/28/2023] Open
Abstract
Opioid drugs are widely used as analgesics but cause respiratory depression, a potentially lethal side-effect with overdose, by acting on µ-opioid receptors (MORs) expressed in brainstem regions involved in the control of breathing. Although many brainstem regions have been shown to regulate opioid-induced respiratory depression, the types of neurons involved have not been identified. Somatostatin is a major neuropeptide found in brainstem circuits regulating breathing, but it is unknown whether somatostatin-expressing circuits regulate respiratory depression by opioids. We examined the co-expression of Sst (gene encoding somatostatin) and Oprm1 (gene encoding MORs) mRNAs in brainstem regions involved in respiratory depression. Interestingly, Oprm1 mRNA expression was found in the majority (> 50%) of Sst-expressing cells in the preBötzinger Complex, the nucleus tractus solitarius, the nucleus ambiguus, and the Kölliker-Fuse nucleus. We then compared respiratory responses to fentanyl between wild-type and Oprm1 full knockout mice and found that the lack of MORs prevented respiratory rate depression from occurring. Next, using transgenic knockout mice lacking functional MORs specifically in Sst-expressing cells, we compared respiratory responses to fentanyl between control and the conditional knockout mice. We found that respiratory rate depression by fentanyl was preserved when MORs were deleted only in Sst-expressing cells. Our results show that despite co-expression of Sst and Oprm1 in respiratory circuits and the importance of somatostatin-expressing cells in the regulation of breathing, these cells do not mediate opioid-induced respiratory rate depression. Instead, MORs found in respiratory cell populations other than Sst-expressing cells likely contribute to the respiratory effects of fentanyl.Significance statementOpioid drugs cause respiratory depression, a potentially lethal side-effect with overdose, by acting on µ-opioid receptors in brainstem regions regulating breathing, therefore limiting their effective use as analgesics. Somatostatin is a major neuropeptide found within these brainstem circuits, but it is unknown whether somatostatin circuits regulate respiratory depression by opioids. We found that somatostatin-expressing neurons co-express µ-opioid receptors in respiratory circuits but that respiratory rate depression by fentanyl was preserved despite genetic deletion of µ-opioid receptors in somatostatin-expressing cells. Our results suggest that somatostatin-expressing cells are resistant to the rate-depressive effects of opioids and that other cells contribute to the effects of fentanyl on breathing. Somatostatin-expressing cells may constitute a cell population that can be targeted to stimulate breathing when it fails with opioids.
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Affiliation(s)
- Andreea Furdui
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto
| | | | - Gaspard Montandon
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
- Institute of Medical Science, Faculty of Medicine, University of Toronto
- Division of Respirology, Department of Medicine, University of Toronto
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Danaf J, da Silveira Scarpellini C, Montandon G. βγ G-proteins, but not regulators of G-protein signaling 4, modulate opioid-induced respiratory rate depression. Front Physiol 2023; 14:1043581. [PMID: 37089428 PMCID: PMC10117644 DOI: 10.3389/fphys.2023.1043581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 03/24/2023] [Indexed: 04/09/2023] Open
Abstract
Opioid medications are the mainstay of pain management but present substantial side-effects such as respiratory depression which can be lethal with overdose. Most opioid drugs, such as fentanyl, act on opioid receptors such as the G-protein-coupled µ-opioid receptors (MOR). G-protein-coupled receptors activate pertussis toxin-sensitive G-proteins to inhibit neuronal activity. Binding of opioid ligands to MOR and subsequent activation G proteins βγ is modulated by regulator of G-protein signaling (RGS). The roles of G-proteins βγ and RGS in MOR-mediated inhibition of the respiratory network are not known. Using rodent models to pharmacologically modulate G-protein signaling, we aim to determine the roles of βγ G-proteins and RGS4. We showed that inhibition of βγ G-proteins using gallein perfused in the brainstem circuits regulating respiratory depression by opioid drugs results in complete reversal of respiratory depression. Blocking of RGS4 using CCG55014 did not change the respiratory depression induced by MOR activation despite co-expression of RGS4 and MORs in the brainstem. Our results suggest that neuronal inhibition by opioid drugs is mediated by G-proteins, but not by RGS4, which supports the concept that βγ G-proteins could be molecular targets to develop opioid overdose antidotes without the risks of re-narcotization often found with highly potent opioid drugs. On the other hand, RGS4 mediates opioid analgesia, but not respiratory depression, and RGS4 may be molecular targets to develop pain therapies without respiratory liability.
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Affiliation(s)
- Jamil Danaf
- St. Michael’s Hospital, Unity Health Toronto, Toronto, ON, Canada
| | | | - Gaspard Montandon
- St. Michael’s Hospital, Unity Health Toronto, Toronto, ON, Canada
- Department of Medicine, University of Toronto, Toronto, ON, Canada
- *Correspondence: Gaspard Montandon,
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Parzei N, Scarpellini C, Montandon G. Chemogenetic activation of glutamatergic preBötzinger Complex neurons increases breathing in mice. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r2372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Natalka Parzei
- Keenan Research Centre for Biomedical ScienceTorontoON
- Institute of Medical ScienceUniversity of TorontoTorontoON
| | | | - Gaspard Montandon
- Institute of Medical ScienceUniversity of TorontoTorontoON
- Department of MedicineUniversity of TorontoTorontoON
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7
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Rousseau J, Scarpellini CS, Montandon G. Tac1‐expressing cells in the pre‐Bötzinger complex are potential targets to prevent opioid‐induced respiratory depression. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r3183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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8
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Zayed Y, Gao V, Ray P, Montandon G. Discovery of Novel Pain Therapies Without Side‐effects by Combining Targeted Mutagenesis and Phenotype‐based Drug Screening in Larval Zebrafish. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r2780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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9
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Schumacker KS, Scarpellini C, Montandon G. Roles of GABAergic and Glutamatergic Prebötzinger Complex Circuits in Opioid‐Induced Respiratory Depression. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r5388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Gaspard Montandon
- MedicineUniversity of TorontoTorontoON
- University of TorontoTorontoON
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10
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Abstract
Opiates, such as morphine, and synthetic opioids, such as fentanyl, constitute a class of drugs acting on opioid receptors which have been used therapeutically and recreationally for centuries. Opioid drugs have strong analgesic properties and are used to treat moderate to severe pain, but also present side effects including opioid dependence, tolerance, addiction, and respiratory depression, which can lead to lethal overdose if not treated. This chapter explores the pathophysiology, the neural circuits, and the cellular mechanisms underlying opioid-induced respiratory depression and provides a translational perspective of the most recent research. The pathophysiology discussed includes the effects of opioid drugs on the respiratory system in patients, as well as the animal models used to identify underlying mechanisms. Using a combination of gene editing and pharmacology, the neural circuits and molecular pathways mediating neuronal inhibition by opioids are examined. By using pharmacology and neuroscience approaches, new therapies to prevent or reverse respiratory depression by opioid drugs have been identified and are currently being developed. Considering the health and economic burden associated with the current opioid epidemic, innovative research is needed to better understand the side effects of opioid drugs and to discover new therapeutic solutions to reduce the incidence of lethal overdoses.
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11
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Rousseau J, Montandon G. Optogenetic activation of preBötzinger Complex cells alleviates respiratory depression by opioids. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.02913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Furdui A, Scarpellini C, Montandon G. The Role of Somatostatin‐Expressing Cells in Opioid‐Induced Respiratory Depression. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.04268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Andreea Furdui
- Institute of Medical ScienceUniversity of TorontoTorontoON
| | - Carolina Scarpellini
- Keenan Research Centre for Biomedical ScienceSt. Michael's Hospital, TorontoTorontoON
| | - Gaspard Montandon
- Division of RespirologyDepartment of MedicineUniversity of TorontoTorontoON
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13
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Biancardi V, Zhang Y, Zoccal D, Alvares T, Scarpellini C, Pagliardini S, Montandon G, Funk G. P2Y
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receptor modulation of Ih in the preBötzinger inspiratory rhythm generator may underlie the ATP‐mediated attenuation of the hypoxic respiratory depression. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.02104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Yong Zhang
- PhysiologyUniversity of AlbertaEdmontonAB
| | - Daniel Zoccal
- PhysiologyNMHIWCHRIUniversity of AlbertaEdmontonAB
- Physiology and PathologyUniversity of AlbertaEdmontonAB
| | | | | | | | - Gaspard Montandon
- Keenan Research Centre for Biomedical ScienceSt. Michael's HospitalTorontoON
| | - Gregory Funk
- PhysiologyNMHIWCHRIUniversity of AlbertaEdmontonAB
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Zaig S, Scarpellini C, Montandon G. Investigating Opioid‐induced Respiratory Depression and Analgesia Using Larval Zebrafish. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.01994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Shenhab Zaig
- Keenan Research Centre for Biomedical ScienceSt. Michael's HospitalTorontoON
- MedicineUniversity of TorontoTorontoON
| | | | - Gaspard Montandon
- Keenan Research Centre for Biomedical ScienceSt. Michael's HospitalTorontoON
- MedicineUniversity of TorontoTorontoON
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Zaig S, da Silveira Scarpellini C, Montandon G. Respiratory depression and analgesia by opioid drugs in freely behaving larval zebrafish. eLife 2021; 10:63407. [PMID: 33720013 PMCID: PMC8060028 DOI: 10.7554/elife.63407] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 03/11/2021] [Indexed: 12/24/2022] Open
Abstract
An opioid epidemic is spreading in North America with millions of opioid overdoses annually. Opioid drugs, like fentanyl, target the mu opioid receptor system and induce potentially lethal respiratory depression. The challenge in opioid research is to find a safe pain therapy with analgesic properties but no respiratory depression. Current discoveries are limited by lack of amenable animal models to screen candidate drugs. Zebrafish (Danio rerio) is an emerging animal model with high reproduction and fast development, which shares remarkable similarity in their physiology and genome to mammals. However, it is unknown whether zebrafish possesses similar opioid system, respiratory and analgesic responses to opioids than mammals. In freely-behaving larval zebrafish, fentanyl depresses the rate of respiratory mandible movements and induces analgesia, effects reversed by μ-opioid receptor antagonists. Zebrafish presents evolutionary conserved mechanisms of action of opioid drugs, also found in mammals, and constitute amenable models for phenotype-based drug discovery. When it comes to treating severe pain, a doctor’s arsenal is somewhat limited: synthetic or natural opioids such as morphine, fentanyl or oxycodone are often one of the only options available to relieve patients. Yet these compounds can make breathing slower and shallower, quickly depriving the body of oxygen and causing death. This lethal side-effect is particularly devastating as opioids misuse has reached dangerously high levels in the United States, creating an ‘opioid epidemic’ which has claimed the lives of over 80,000 Americans in 2020. It is therefore crucial to find safer drugs that do not have this effect on breathing, but this research has been slowed down by the lack of animal models in which to study the effect of new compounds. Zebrafish are small freshwater fish that reproduce and develop fast, yet they are also remarkably genetically similar to mammals and feature a complex nervous system. However, it is not known whether the effect of opioids on zebrafish is comparable to mammals, and therefore whether these animals can be used to test new drugs for pain relief. To investigate this question, Zaig et al. exposed zebrafish larvae to fentanyl, showing that the fish then exhibited slower lower jaw movements – a sign of decreased breathing. The fish also could also tolerate a painful stimulus for longer, suggesting that this opioid does reduce pain in the animals. Together, these results point towards zebrafish and mammals sharing similar opioid responses, demonstrating that the fish could be used to test potential pain medications. The methods Zaig et al. have developed to establish these results could be harnessed to quickly assess large numbers of drug compounds, as well as decipher how pain emerges and can be stopped.
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Affiliation(s)
- Shenhab Zaig
- Keenan Research Centre for Biomedical Sciences. St. Michael's Hospital Unity Health Toronto, Toronto, Canada
| | | | - Gaspard Montandon
- Keenan Research Centre for Biomedical Sciences. St. Michael's Hospital Unity Health Toronto, Toronto, Canada
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Ahmad A, Ahmad R, Meteb M, Ryan CM, Leung RS, Montandon G, Luks V, Kendzerska T. The relationship between opioid use and obstructive sleep apnea: A systematic review and meta-analysis. Sleep Med Rev 2021; 58:101441. [PMID: 33567395 DOI: 10.1016/j.smrv.2021.101441] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 08/11/2020] [Accepted: 10/27/2020] [Indexed: 12/26/2022]
Abstract
We conducted a systematic review to address limited evidence suggesting that opioids may induce or aggravate obstructive sleep apnea (OSA). All clinical trials or observational studies on adults from 1946 to 2018 found through MEDLINE, EMBASE, CINAHL, PsycINFO, Cochrane Databases were eligible. We assessed the quality of the studies using published guidelines. Fifteen studies (six clinical trials and nine observational) with only two of good quality were included. Fourteen studies investigated the impact of opioids on the presence or severity of OSA, four addressed the effects of treatment for OSA in opioid users, and none explored the consequences of opioid use in individuals with OSA. Eight of 14 studies found no significant relationship between opioid use or dose and apnea-hypopnea index (AHI) or degree of nocturnal desaturation. A random-effects meta-analysis (n = 10) determined the pooled mean change in AHI associated with opioid use of 1.47/h (-2.63-5.57; I2 = 65%). Three of the four studies found that continuous positive airway pressure (CPAP) therapy reduced AHI by 17-30/h in opioid users with OSA. Bilevel therapy with a back-up rate and adaptive servo-ventilation (ASV) without mandatory pressure support successfully normalized AHI (≤5) in opioid users. Limited by a paucity of good-quality studies, our review did not show a significant relationship between opioid use and the severity of OSA. There was some evidence that CPAP, Bilevel therapy, and ASV alleviate OSA for opioid users, with higher failure rates observed in patients on CPAP in opioid users.
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Affiliation(s)
- Aseel Ahmad
- The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; University of Ottawa, Ontario, Canada
| | - Randa Ahmad
- The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; University of Ottawa, Ontario, Canada
| | - Moussa Meteb
- The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Clodagh M Ryan
- University of Toronto, Toronto, Ontario, Canada; Toronto Rehabilitation Institute, University Health Network, Ontario, Canada
| | - Richard S Leung
- University of Toronto, Toronto, Ontario, Canada; St. Michael's Hospital, Toronto, Ontario, Canada
| | - Gaspard Montandon
- University of Toronto, Toronto, Ontario, Canada; Keenan Research Centre for Biomedical Sciences, St. Michael's Hospital, Unity Health Toronto, Ontario, Canada
| | - Vanessa Luks
- The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; University of Ottawa, Ontario, Canada
| | - Tetyana Kendzerska
- The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada; University of Ottawa, Ontario, Canada.
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Rousseau JP, Montandon G. Optogenetic activation of preBötzinger Complex cells alleviates respiratory depression by opioids. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.05523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18
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Zaig S, Scarpellini C, Montandon G. Investigating Opioid‐induced Respiratory Depression and Analgesia Using Larval Zebrafish. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.03042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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19
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Montandon G, Horner RL. Electrocortical changes associating sedation and respiratory depression by the opioid analgesic fentanyl. Sci Rep 2019; 9:14122. [PMID: 31575947 PMCID: PMC6773755 DOI: 10.1038/s41598-019-50613-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 09/12/2019] [Indexed: 01/05/2023] Open
Abstract
Opioid drugs are the mainstay of pain management but present the side-effect of respiratory depression that can be lethal with overdose. In addition to their respiratory effect, opioids also induce a profound sedative state and produce electrocortical features characteristic of a state of reduced brain arousal, similar to anaesthesia or sleep. In such states, respiratory activity depends more on the integrity of the brainstem respiratory network than it does during wakefulness. Accordingly, we propose that sedation by fentanyl induces specific electrocortical changes consistent with reduced brain arousal, and that the magnitude of respiratory depression is associated with distinct electrocortical changes. To these aims, we determined the effects of systemic injections of fentanyl (dosage 100 µg ·kg) versus control on electrocortical and respiratory activities of freely-behaving rats. We found that fentanyl induced electrocortical changes that differed from those observed in sleep or wakefulness. Fentanyl increased δ (1-3 Hz) frequency power (P < 0.001), but reduced α (7.5-13.5 Hz) and β2 (20-30 Hz) powers (P = 0.012 and P < 0.001, respectively), when compared to wakefulness. Interestingly, respiratory rate depression by fentanyl was significantly correlated with increased θ power (R = 0.61, P < 0.001), therefore showing a clear association between electrocortical activity and the magnitude of respiratory rate depression. Overall, we provide new evidence linking specific electrocortical changes to the severity of respiratory depression by opioids, which highlights the importance of considering the cortical and subcortical effects of opioids in addition to their impacts on breathing when evaluating opioid-induced respiratory depression.
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Affiliation(s)
- Gaspard Montandon
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Canada.
- Keenan Research Centre for Biomedical Sciences, Unity Health Toronto - St. Michael's Hospital, Toronto, Canada.
| | - Richard L Horner
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada
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Zaig S, Da Silveira Scarpellini C, Wen X, Montandon G. Zebrafish Models to Understand Respiratory Depression and Analgesia by Opioids and to Identify Safe Opioid Pain Therapies. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.663.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Satkunendrarajah K, Karadimas SK, Laliberte AM, Montandon G, Fehlings MG. Cervical excitatory neurons sustain breathing after spinal cord injury. Nature 2018; 562:419-422. [DOI: 10.1038/s41586-018-0595-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 08/14/2018] [Indexed: 11/09/2022]
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Nagappa M, Weingarten TN, Montandon G, Sprung J, Chung F. Opioids, respiratory depression, and sleep-disordered breathing. Best Pract Res Clin Anaesthesiol 2017; 31:469-485. [DOI: 10.1016/j.bpa.2017.05.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 05/10/2017] [Accepted: 05/12/2017] [Indexed: 10/19/2022]
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Salam MT, Montandon G, Genov R, Devinsky O, Del Campo M, Carlen PL. Mortality with brainstem seizures from focal 4-aminopyridine-induced recurrent hippocampal seizures. Epilepsia 2017; 58:1637-1644. [PMID: 28691204 DOI: 10.1111/epi.13846] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2017] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Sudden unexplained death in epilepsy is the leading cause of death in young adult epilepsy patients, typically occurring during the early postictal period, presumably resulting from brainstem and cardiorespiratory dysfunction. We hypothesized that ictal discharges in the brainstem disrupt the cardiorespiratory network, causing mortality. To study this hypothesis, we chose an animal model comprising focal unilateral hippocampal injection of 4-aminopyridine (4-AP), which produced focal recurrent hippocampal seizures with secondary generalization in awake, behaving rats. METHODS We studied ictal and interictal intracranial electrographic activity (iEEG) in 23 rats implanted with a custom electrode array into the hippocampus, the contralateral cortex, and brainstem. The hippocampal electrodes contained a cannula to administer the potassium channel blocker and convulsant (4-AP). iEEG was recorded continuously before, during, and after seizures induced by 4-AP infusion into the hippocampus. RESULTS The control group (n = 5) was monitored for 2-3 months, and the weekly baseline iEEG recordings showed long-term stability. The low-dose group (1 μL 4-AP, 40 mm, n = 5) exhibited local electrographic seizures without spread to the contralateral cerebral cortex or brainstem. The high-dose group (5 μL 4-AP, 40 mm, n = 3) had several hippocampal electrographic seizures, which spread contralaterally and triggered brainstem discharges within 40 min, and were associated with violent motor seizures followed by dyspnea and respiratory arrest, with cortical and hippocampal iEEG flattening. The group that received high-dose 4-AP without brainstem implantation (n = 5) had similar seizure-related respiratory difficulties. Finally, five rats that received high-dose 4-AP without EEG recording also developed violent motor seizures with postictal respiratory arrest. Following visualized respiratory arrest in groups III, IV, and V, manual respiratory resuscitation was successful in five of 13 animals. SIGNIFICANCE These studies show that hippocampal seizure activity can spread or trigger brainstem epileptiform discharges that may cause mortality, possibly mediated by respiratory network dysfunction.
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Affiliation(s)
- Muhammad Tariqus Salam
- Krembil Research Institute, University of Toronto, Toronto, Ontario, Canada.,Departments of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada.,Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Gaspard Montandon
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Roman Genov
- Departments of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Orrin Devinsky
- Department of Neurology, New York University Medical Center, New York, New York, U.S.A
| | - Martin Del Campo
- Krembil Research Institute, University of Toronto, Toronto, Ontario, Canada
| | - Peter L Carlen
- Krembil Research Institute, University of Toronto, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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Poublanc J, Crawley AP, Sobczyk O, Montandon G, Sam K, Mandell DM, Dufort P, Venkatraghavan L, Duffin J, Mikulis DJ, Fisher JA. Measuring cerebrovascular reactivity: the dynamic response to a step hypercapnic stimulus. J Cereb Blood Flow Metab 2015; 35:1746-56. [PMID: 26126862 PMCID: PMC4635229 DOI: 10.1038/jcbfm.2015.114] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 04/13/2015] [Accepted: 04/14/2015] [Indexed: 11/09/2022]
Abstract
We define cerebral vascular reactivity (CVR) as the ratio of the change in blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) signal (S) to an increase in blood partial pressure of CO2 (PCO2): % Δ S/Δ PCO2 mm Hg. Our aim was to further characterize CVR into dynamic and static components and then study 46 healthy subjects collated into a reference atlas and 20 patients with unilateral carotid artery stenosis. We applied an abrupt boxcar change in PCO2 and monitored S. We convolved the PCO2 with a set of first-order exponential functions whose time constant τ was increased in 2-second intervals between 2 and 100 seconds. The τ corresponding to the best fit between S and the convolved PCO2 was used to score the speed of response. Additionally, the slope of the regression between S and the convolved PCO2 represents the steady-state CVR (ssCVR). We found that both prolongations of τ and reductions in ssCVR (compared with the reference atlas) were associated with the reductions in CVR on the side of the lesion. τ and ssCVR are respectively the dynamic and static components of measured CVR.
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Affiliation(s)
- Julien Poublanc
- Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | - Adrian P Crawley
- Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | - Olivia Sobczyk
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Gaspard Montandon
- Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | - Kevin Sam
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Daniel M Mandell
- Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | - Paul Dufort
- Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada
| | | | - James Duffin
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.,Department of Anaesthesia and Pain Management, University Health Network, Toronto, Ontario, Canada
| | - David J Mikulis
- Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Joseph A Fisher
- Joint Department of Medical Imaging, University Health Network, Toronto, Ontario, Canada.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada.,Department of Anaesthesia and Pain Management, University Health Network, Toronto, Ontario, Canada
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Montandon G, Horner R. CrossTalk proposal: The preBotzinger complex is essential for the respiratory depression following systemic administration of opioid analgesics. J Physiol 2015; 592:1159-62. [PMID: 24634011 DOI: 10.1113/jphysiol.2013.261974] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Kinkead R, Montandon G, Bairam A, Lajeunesse Y, Horner R. Neonatal maternal separation disrupts regulation of sleep and breathing in adult male rats. Sleep 2010; 32:1611-20. [PMID: 20041597 DOI: 10.1093/sleep/32.12.1611] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
STUDY OBJECTIVES Neonatal maternal separation (NMS) disrupts development of cardiorespiratory regulation. Adult male rats previously subjected to NMS are hypertensive and show a hypoxic ventilatory response greater than that of controls. These results have been obtained in awake or anesthetised animals, and the consequences of NMS on respiratory control during normal sleep are unknown. This study tested the following. HYPOTHESES NMS augments respiratory variability across sleep-wake states, and NMS-related enhancement of the hypoxic ventilatory response occurs during sleep. METHODS Two groups of adult rats were used: controls (no treatment) and rats subjected to NMS. Ventilatory activity, coefficient of variation, and hypoxic ventilatory response were compared between groups and across sleep-wake states. SUBJECTS Male Sprague Dawley rats-NMS: n=11; controls: n=10. Pups subjected to NMS were isolated from their mother for 3 hours per day from postnatal days 3 to 12. Controls were undisturbed. MEASUREMENTS AND RESULTS At adulthood, sleep-wake states were monitored by telemetry, and ventilatory activity was measured using whole-body plethysmography. Sleep and breathing were measured for 2.5 hours (in the morning) while the rats were breathing room air. Data were analysed in 20-second epochs. Rats were then exposed to a brief (90-sec) hypoxic episode (nadir = 12% O2) to measure the hypoxic ventilatory response. The coefficient of variability for tidal volume and breathing frequency decreased during sleep but remained more elevated in NMS rats than in controls. During non-rapid eye movement sleep, the breathing-frequency response to hypoxia of NMS rats was significantly greater than that of controls. CONCLUSION Neonatal maternal separation results in persistent disruption of respiratory control during sleep.
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Affiliation(s)
- Richard Kinkead
- Centre de Recherche du CHUQ, Hôpital St-François d'Assise, Université Laval, Québec, Canada.
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Montandon G, Horner RL, Kinkead R, Bairam A. Caffeine in the neonatal period induces long-lasting changes in sleep and breathing in adult rats. J Physiol 2009; 587:5493-507. [PMID: 19770189 DOI: 10.1113/jphysiol.2009.171918] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Caffeine is commonly used clinically to treat apnoeas and unstable breathing associated with premature birth. Caffeine antagonizes adenosine receptors and acts as an efficient respiratory stimulant in neonates. Owing to its persistent effects on adenosine receptor expression in the brain, neonatal caffeine administration also has significant effects on maturation of the respiratory control system. However, since adenosine receptors are critically involved in sleep regulation, and sleep also modulates breathing, we tested the hypothesis that neonatal caffeine treatment disrupts regulation of sleep and breathing in the adult rat. Neonatal caffeine treatment (15 mg kg(-1) day(-1)) was administered from postnatal days 3-12. At adulthood (8-10 weeks old), sleep and breathing were measured with a telemetry system and whole-body plethysmography respectively. In adult rats treated with caffeine during the neonatal period, sleep time was reduced, sleep onset latency was increased, and non-rapid eye movement (non-REM) sleep was fragmented compared to controls. Ventilation at rest was higher in caffeine-treated adult rats compared to controls across sleep/wake states. Hypercapnic ventilatory responses were significantly reduced in caffeine-treated rats compared to control rats across sleep/wake states. Additional experiments in adult anaesthetized rats showed that at similar levels of arterial blood gases, phrenic nerve activity was enhanced in caffeine-treated rats. This study demonstrates that administration of caffeine in the neonatal period alters respiratory control system activity in awake and sleeping rats, as well as in the anaesthetized rats, and also has persistent disrupting effects on sleep that are apparent in adult rats.
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Affiliation(s)
- Gaspard Montandon
- Departments of Medicine and Physiology, Faculty of Medicine, University of Toronto, Ontario, Canada.
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Affiliation(s)
- Gaspard Montandon
- Depts of Physiology and MedicineUniversity of TorontoTorontoONCanada
| | - Richard L Horner
- Depts of Physiology and MedicineUniversity of TorontoTorontoONCanada
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Montandon G, Bairam A, Kinkead R. Neonatal caffeine induces sex-specific developmental plasticity of the hypoxic respiratory chemoreflex in adult rats. Am J Physiol Regul Integr Comp Physiol 2008; 295:R922-34. [PMID: 18596110 DOI: 10.1152/ajpregu.00059.2008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Caffeine is widely used to treat apneas of prematurity during the neonatal period; however, the potential consequences of administering a neonatal caffeine treatment (NCT) during a critical period for respiratory control development are unknown. The present study therefore determined whether NCT in rats alters the hypoxic respiratory chemoreflex measured at adulthood. Newborn rats received either caffeine (15 mg/kg) or water (control) each day from postnatal day 3 to 12. The ventilatory response to a hypoxic challenge (inspired O(2) fraction = 0.12) was first evaluated in awake adult female and male rats using whole body plethysmography. Results showed that NCT increased the initial phase of the breathing frequency response to hypoxia in males only. This result was confirmed in anesthetized and artificially ventilated adult male rats where NCT also increased the phrenic burst frequency response to hypoxia. RT-PCR assessment of mRNA encoding for adenosine A(1A) and A(2A) receptors, dopamine D(2) receptors, and tyrosine hydroxylase in the rat carotid bodies showed that NCT enhanced mRNA expression levels of adenosine A(2A), dopamine D(2) receptors, and tyrosine hydroxylase of males but not females. Subsequent experiments on awake male rats showed that injection of the adenosine A(2A) receptor antagonist ZM2413855 (1 mg/kg ip) before ventilatory measurements abolished, in NCT rats, the enhanced respiratory frequency response observed during the early phase of hypoxia. We propose that NCT elicits a sex-specific increase in the hypoxic respiratory chemoreflex, which is related, at least partially, to an enhancement in adenosine A(2A) receptors in the rat carotid body.
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Affiliation(s)
- Gaspard Montandon
- Dept. of Physiology, Univ. of Toronto, Medical Sciences Bldg., Rm. 7308, 1, King's College Circle, Toronto, ON, Canada M5S 1A8.
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Bairam A, kinkead R, Lajeunesse Y, Fournier S, Montandon G, Joseph V. Interactions between gonadal steroids and neonatal caffeine exposure on HVR in adult male rats. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.955.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kinkead R, Montandon G, Lajeunesse Y, Bairam A, Horner R. Enhancement of the hypoxic ventilatory reponse in adult rats subjected to neonatal maternal separation is not affected by sleep‐wake states. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.1172.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | - Richard Horner
- Physiology and MedicineUniversity of TorontoTorontoCanada
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Montandon G, Kinkead R, Bairam A. Disruption of adenosinergic modulation of ventilation at rest and during hypercapnia by neonatal caffeine in young rats: role of adenosine A1 and A2A receptors. Am J Physiol Regul Integr Comp Physiol 2007; 292:R1621-31. [PMID: 17138726 DOI: 10.1152/ajpregu.00514.2006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Caffeine is commonly used to treat respiratory instabilities related to prematurity. However, the role of adenosinergic modulation and the potential long-term effects of neonatal caffeine treatment (NCT) on respiratory control are poorly understood. To address these shortcomings, we tested the following hypotheses: 1) adenosine A1- and A2A-receptor antagonists modulate respiratory activity at rest and during hypercapnia; 2) NCT has long-term consequences on adenosinergic modulation of respiratory control. Rat pups received by gavage either caffeine (15 mg/kg) or water (control) once a day from postnatal days 3 to 12. At day 20, rats received intraperitoneal injection with vehicle, DPCPX (A1 antagonist, 4 mg/kg), or ZM-241385 (A2A antagonist, 1 mg/kg) before plethysmographic measurements of resting ventilation, hypercapnic ventilatory response (5% CO2), and occurrence of apneas in freely behaving rats. In controls, data show that A2A, but not A1, antagonist decreased resting ventilation by 31% ( P = 0.003). A1 antagonist increased the hypercapnic response by 60% ( P < 0.001), whereas A2A antagonist increased the hypercapnic response by 42% ( P = 0.033). In NCT rats, A1 antagonist increased resting ventilation by 27% ( P = 0.02), but the increase of the hypercapnic response was blunted compared with controls. A1 antagonist enhanced the occurrence of spontaneous apneas in NCT rats only ( P = 0.005). Finally, A2A antagonist injected in NCT rats had no effect on ventilation. These data show that hypercapnia activates adenosinergic pathways, which attenuate responsiveness (and/or sensitivity) to CO2 via A1 receptors. NCT elicits developmental plasticity of adenosinergic modulation, since neonatal caffeine persistently decreases ventilatory sensitivity to adenosine blockers.
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Affiliation(s)
- Gaspard Montandon
- Department of Pediatric, Laval University, Centre de Recherche Hôpital St-François d'Assise (D0-711 10 rue de l'Espinay, Québec, QC, Canada G1L 3L5.
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Montandon G, Bairam A, Horner R, Kinkead R. Neonatal caffeine persistently increases breathing across sleep‐wake states in freely‐behaving adult rats. FASEB J 2007. [DOI: 10.1096/fasebj.21.6.a1443-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gaspard Montandon
- Department of PediatricsLaval UniversityCentre de recherche (D0‐711), Hopital St‐Francois d’Assise, 10, rue de l’EspinayQuebecG1L 3L5Canada
| | - Aida Bairam
- Department of PediatricsLaval UniversityCentre de recherche (D0‐711), Hopital St‐Francois d’Assise, 10, rue de l’EspinayQuebecG1L 3L5Canada
| | - Richard Horner
- Departments of Medicine and PhysiologyUniversity of TorontoMedical Sciences Building, 1, Kings College CircleTorontoM5S 1A8Canada
| | - Richard Kinkead
- Department of PediatricsLaval UniversityCentre de recherche (D0‐711), Hopital St‐Francois d’Assise, 10, rue de l’EspinayQuebecG1L 3L5Canada
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Montandon G, Bairam A, Horner R, Kinkead R. Long term impact of neonatal caffeine on sleep architecture in freely‐behaving adult rats. FASEB J 2007. [DOI: 10.1096/fasebj.21.6.a1443-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gaspard Montandon
- Department of PediatricsLaval UniversityCentre de recherche (D0‐711), Hopital St‐Francois d’Assise, 10, rue de l’EspinayQuebecG1L 3L5Canada
| | - Aida Bairam
- Department of PediatricsLaval UniversityCentre de recherche (D0‐711), Hopital St‐Francois d’Assise, 10, rue de l’EspinayQuebecG1L 3L5Canada
| | - Richard Horner
- Departments of Medicine and PhysiologyUniversity of TorontoMedical Sciences Building, 1, Kings College CircleTorontoM5S 1A8Canada
| | - Richard Kinkead
- Department of PediatricsLaval UniversityCentre de recherche (D0‐711), Hopital St‐Francois d’Assise, 10, rue de l’EspinayQuebecG1L 3L5Canada
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Montandon G, Bairam A, Kinkead R. P357 Impact of neonatal caffeine on the hypercapnic ventilatory response and occurrence of apneas in juvenile rats: Role of adenosinergic neurotransmission. Sleep Med 2006. [DOI: 10.1016/j.sleep.2006.07.166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Abstract
Caffeine is an adenosine receptor antagonist commonly used as a respiratory stimulant to treat neonatal apneas of premature newborn. Neonatal caffeine treatment (NCT) has long-term effects on adenosine receptor expression and distribution; however, the potential effects of NCT on respiratory control development are unknown. To address this issue, rat pups received orally each day from postnatal d 3-12, 15 mg/kg of caffeine (NCT), water (vehicle), or were undisturbed during early life (control). Measurements of resting ventilation, apnea index, and ventilatory response to moderate hypercapnia (FiCO2 = 0.05) were made using whole-body plethysmography at postnatal d 20 (juvenile) and adulthood. At d 20, resting respiratory variables were not affected by the treatments. Juvenile NCT male rats showed a 22% higher minute ventilation response to hypercapnia than vehicle rats. However, oral gavage alone increased the frequency component of the response by 11%. In adult males, caffeine increased the resting respiratory frequency by 15%. In these animals, the tidal volume response to hypercapnia was increased by 15%, whereas the frequency response was decreased by 20%. In juvenile and adult females, no differences were observed between treatments. In juvenile rats of both sexes, gavage increased the apnea index by at least 200%. These results show that NCT and gavage influence respiratory control during early life and that these effects persist until adulthood. The underlying mechanisms are unclear, but may be related to persistent changes in adenosinergic neurotransmission because neonatal caffeine administration increases A1 adenosine receptor density in adult rats.
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Affiliation(s)
- Gaspard Montandon
- Départment de Pédiatrie, Université Laval, Centre de recherche Hôpital St-François d' Assise, Québec, Canada.
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Montandon G, Kinkead R, Lajeunesse Y, Bairam A. Neonatal caffeine augments the acute breathing frequency response to hypoxia and the adenosine and the dopamine receptor mRNA expression in the carotid body of adult rats. FASEB J 2006. [DOI: 10.1096/fasebj.20.5.a1215] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gaspard Montandon
- Department of PediatricsLaval UniversitySt‐Francois d'Assise Hospital (CHUQ)10, rue de l'Espinay, QuebecQuebecG1L 3L5Canada
| | - Richard Kinkead
- Department of PediatricsLaval UniversitySt‐Francois d'Assise Hospital (CHUQ)10, rue de l'Espinay, QuebecQuebecG1L 3L5Canada
| | - Yves Lajeunesse
- Department of PediatricsLaval UniversitySt‐Francois d'Assise Hospital (CHUQ)10, rue de l'Espinay, QuebecQuebecG1L 3L5Canada
| | - Aida Bairam
- Department of PediatricsLaval UniversitySt‐Francois d'Assise Hospital (CHUQ)10, rue de l'Espinay, QuebecQuebecG1L 3L5Canada
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Montandon G, Bairam A, Kinkead R. Adenosine A
1
and A
2A
receptors contribute to enhancement of the hypercapnic ventilatory response following neonatal caffeine treatment in rats. FASEB J 2006. [DOI: 10.1096/fasebj.20.5.a1215-a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gaspard Montandon
- Department of PediatricsLaval UniversitySt‐Francois d'Assise Hospital (CHUQ)10, rue de l'Espinay, QuebecQuebecG1L 3L5Canada
| | - Aida Bairam
- Department of PediatricsLaval UniversitySt‐Francois d'Assise Hospital (CHUQ)10, rue de l'Espinay, QuebecQuebecG1L 3L5Canada
| | - Richard Kinkead
- Department of PediatricsLaval UniversitySt‐Francois d'Assise Hospital (CHUQ)10, rue de l'Espinay, QuebecQuebecG1L 3L5Canada
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Montandon G, Kinkead R, Lomenech AM, Bairam A, Guénard H. Heterogeneity of brainstem blood flow response to hypoxia in the anesthetized rat. Respir Physiol Neurobiol 2006; 150:301-6. [PMID: 16557663 DOI: 10.1016/j.resp.2005.05.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Cerebral blood flow is strictly regulated during hypoxic stress. Because of the preponderant role of the brainstem in cardiorespiratory controls, blood flow response to hypoxia is stronger in this region than in the cortex. However, the brainstem is made up of various regions, which differ in their responsiveness to chemical stimuli. The objective of this study was to evaluate the distribution of blood flow during hypoxia using microsphere deposition methods in three brainstem regions containing key structures in cardiorespiratory controls: the nucleus tractus solitarus (NTS), the ventral respiratory groups (VRG) and the pontine respiratory groups (PRG). Microsphere injections were made during normoxia (FIO2 = 0.21) and after 15 min of hypoxia (FIO2 = 0.10). Based on this index, blood flow increase during hypoxia was higher in the VRG than in the dorsal part of the brainstem, containing the NTS and the PRG (P = 0.002, n = 10). These results suggest that blood flow response to hypoxia favours O2 delivery in brainstem regions involved in respiratory rhythm generation.
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Affiliation(s)
- Gaspard Montandon
- Unité de Périnatalogie, Hôpital St-François d' Assie, Université Laval, Québec, Que., Canada G1L 3L5.
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de Bisschop C, Montandon G, Guénard H. Expiratory muscles modulate negative expiratory pressure-induced flow during muscular exercise. Respir Physiol Neurobiol 2006; 154:453-66. [PMID: 16446126 DOI: 10.1016/j.resp.2005.12.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2005] [Revised: 12/22/2005] [Accepted: 12/23/2005] [Indexed: 10/25/2022]
Abstract
The recruitment of expiratory muscles during exercise might be altered by the application of negative expiratory pressure (NEP) inducing a feature of expiratory flow limitation (EFL) called muscle EFL. To check this hypothesis EFL and expiratory muscle EMG (ExpEMG) were measured at rest and during exercise in eight healthy subjects. Six subjects performed isocapnic hyperventilation. At 5hPa NEP, 5/8 subjects had EFL during exercise. This limitation disappeared when NEP value was increased and did not appear during isocapnic hyperventilation. During exercise, in limited subjects, ExpEMG was significantly reduced during expiration with NEP as compared to control. Gastric pressure measured in a limited subject increased during expiration but less with NEP than without it, while this pressure measured in another, non-limited, subject decreased. An inhibitory reflex due to negative pressure could be responsible for muscle EFL by reducing expiratory muscle activity. The response to NEP during exercise should be interpreted with caution.
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Affiliation(s)
- Claire de Bisschop
- Laboratoire des Adaptations Physiologiques aux Activités Physiques, Faculté des Sciences du Sport, UPRES EA 3813, 4 Allée Jean Monnet, 86000 POITIERS, France.
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Montandon G, Kinkead R, Lomenech AM, Bairam A, Guénard H. Heterogeneity of brainstem blood flow response to hypoxia in the anesthetized rat. Respir Physiol Neurobiol 2005; 147:117-22. [PMID: 15848129 DOI: 10.1016/j.resp.2004.12.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2004] [Revised: 12/17/2004] [Accepted: 12/30/2004] [Indexed: 11/16/2022]
Abstract
Cerebral blood flow is strictly regulated during hypoxic stress. Because of the preponderant role of the brainstem in cardiorespiratory controls, blood flow response to hypoxia is stronger in this region than in the cortex. However, the brainstem is made up of various regions which differ in their responsiveness to chemical stimuli. The objective of this study was to evaluate the distribution of blood flow during hypoxia using microsphere deposition methods in three brainstem regions containing key structures in cardiorespiratory controls: the nucleus tractus solitarus (NTS), the ventral respiratory groups (VRG) and the pontine respiratory groups (PRG). Microsphere injections were made during normoxia (FIO2=0.21) and after 15 min of hypoxia (FIO2=0.21). Based on this index, blood flow increase during hypoxia was higher in the VRG than in the dorsal part of the brainstem, containing the NTS and the PRG (P=0.002, n=10). These results suggest that blood flow response to hypoxia favours O(2) delivery in brainstem regions involved in respiratory rhythm generation.
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Affiliation(s)
- Gaspard Montandon
- Unité de Périnatalogie, Hôpital St-François d'Assie, Université Laval, Québec, Que., Canada G1L 3L5.
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Abstract
By presenting, before a "chord" of three pure tones with remote frequencies, a tone relatively close in frequency to one component (T1) of the chord, one can direct the listener's attention onto T1 within the chord. In the first part of the present study, it was found that this increases the accuracy with which the pitch of T1 is perceived. The attentional cue improved the discrimination between the frequency of T1 and that of another tone (T2) presented immediately after the chord or very shortly (300 msec) after it. No improvement was found when T1 was presented alone instead of within a chord. A subsequent experiment, in which the chord and T2 were separated by either 300 msec or 4 sec, indicated that the attentional cue improved not only the perception, but also the memorization of the pitch of T1 (especially when T1 was the intermediate component of the chord). It is argued that the positive effect of attention on memory took place when the pitch percept was encoded into memory, rather than after the formation of the pitch memory trace.
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Affiliation(s)
- Laurent Demany
- Laboratoire de Neurophysiologie, CNRS and Université Victor Segalen, Bordeaux, France.
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