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Frazure M, Morimoto I, Fielder N, Mellen N, Iceman K, Pitts T. Serotonin therapies for opioid-induced disordered swallow and respiratory depression. J Appl Physiol (1985) 2024; 136:821-843. [PMID: 38385184 DOI: 10.1152/japplphysiol.00509.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 02/13/2024] [Accepted: 02/19/2024] [Indexed: 02/23/2024] Open
Abstract
Opioids are well-known to cause respiratory depression, but despite clinical evidence of dysphagia, the effects of opioids on swallow excitability and motor pattern are unknown. We tested the effects of the clinically relevant opioid buprenorphine on pharyngeal swallow and respiratory drive in male and female rats. We also evaluated the utility of 5-HT1A agonists (8-OH-DPAT and buspirone) to improve swallowing and breathing following buprenorphine administration. Experiments were performed on 44 freely breathing Sprague-Dawley rats anesthetized with sodium pentobarbital. Bipolar fine wire electrodes were inserted into the mylohyoid, thyroarytenoid, posterior cricoarytenoid, thyropharyngeus, and diaphragm muscles to measure electromyographic (EMG) activity of swallowing and breathing. We evaluated the hypotheses that swallowing varies by stimulus, opioids depress swallowing and breathing, and that 5-HT1A agonists improve these depressions. Our results largely confirmed the following hypotheses: 1) swallow-related EMG activity was larger during swallows elicited by esophageal distension plus oral water infusion than by either stimulus alone. 2) Buprenorphine depressed swallow in both sexes, but females were more susceptible to total swallow suppression. 3) Female animals were also more vulnerable to opioid-induced respiratory depression. 4) 8-OH-DPAT rescued breathing following buprenorphine-induced respiratory arrest, and pretreatment with the partial 5-HT1A agonist buspirone prevented buprenorphine-induced respiratory arrest in female animals. 5) 8-OH-DPAT enhanced mylohyoid and thyropharyngeus EMG amplitude during swallow but did not restore excitability of the swallow pattern generator following total suppression by buprenorphine. Our results highlight sex-specific and behavior-specific effects of buprenorphine and provide preclinical evidence of a 5HT1A agonist for the treatment of respiratory depression and dysphagia.NEW & NOTEWORTHY This is the first study, to our knowledge, to evaluate sex-specific effects of opioid administration on pharyngeal swallow. We expand on a small but growing number of studies that report a lower threshold for opioid-induced respiratory depression in females compared with males, and we are the first to produce this effect with the partial μ-opioid-receptor agonist buprenorphine. This is the first demonstration, to our knowledge, that activation of 5-HT1A receptors can improve swallow and breathing outcomes following systemic buprenorphine administration.
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Affiliation(s)
- Michael Frazure
- Department of Physiology, School of Medicine, University of Louisville, Louisville, Kentucky, United States
| | - In Morimoto
- Department of Mechanical and Intelligent Systems Engineering, The University of Electro-Communications, Tokyo, Japan
| | - Nathan Fielder
- School of Medicine, University of Louisville, Louisville, Kentucky, United States
| | - Nicholas Mellen
- Department of Neurology, School of Medicine, University of Louisville, Louisville, Kentucky, United States
| | - Kimberly Iceman
- Department of Speech, Language, and Hearing Sciences and Dalton Cardiovascular Center, University of Missouri, Columbia, Missouri, United States
| | - Teresa Pitts
- Department of Speech, Language, and Hearing Sciences and Dalton Cardiovascular Center, University of Missouri, Columbia, Missouri, United States
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Chamoun K, Chevillard L, Hajj A, Callebert J, Mégarbane B. Mechanisms of Neurorespiratory Toxicity Induced by Fentanyl Analogs—Lessons from Animal Studies. Pharmaceuticals (Basel) 2023; 16:ph16030382. [PMID: 36986482 PMCID: PMC10051837 DOI: 10.3390/ph16030382] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 02/26/2023] [Accepted: 02/27/2023] [Indexed: 03/06/2023] Open
Abstract
In 2020, fentanyl and its analogs contributed to ~65% of drug-attributed fatalities in the USA, with a threatening increasing trend during the last ten years. These synthetic opioids used as potent analgesics in human and veterinary medicine have been diverted to recreational aims, illegally produced and sold. Like all opioids, central nervous system depression resulting from overdose or misuse of fentanyl analogs is characterized clinically by the onset of consciousness impairment, pinpoint miosis and bradypnea. However, contrasting with what observed with most opioids, thoracic rigidity may occur rapidly with fentanyl analogs, contributing to increasing the risk of death in the absence of immediate life support. Various mechanisms have been proposed to explain this particularity associated with fentanyl analogs, including the activation of noradrenergic and glutamatergic coerulospinal neurons and dopaminergic basal ganglia neurons. Due to the high affinities to the mu-opioid receptor, the need for more elevated naloxone doses than usually required in morphine overdose to reverse the neurorespiratory depression induced by fentanyl analogs has been questioned. This review on the neurorespiratory toxicity of fentanyl and analogs highlights the need for specific research focused on these agents to better understand the involved mechanisms of toxicity and develop dedicated strategies to limit the resulting fatalities.
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Affiliation(s)
- Karam Chamoun
- Inserm, UMR-S1144, Paris Cité University, 75006 Paris, France
- Faculty of Pharmacy, Saint-Joseph University, Beirut 1100, Lebanon
- Laboratory of Pharmacology, Clinical Pharmacy, and Medicine Quality Control, Saint-Joseph University, Beirut 1100, Lebanon
| | | | - Aline Hajj
- Faculty of Pharmacy, Saint-Joseph University, Beirut 1100, Lebanon
- Laboratory of Pharmacology, Clinical Pharmacy, and Medicine Quality Control, Saint-Joseph University, Beirut 1100, Lebanon
- Research Center, Quebec University Hospital, Laval University, Québec, QC G1V 0A6, Canada
| | - Jacques Callebert
- Inserm, UMR-S1144, Paris Cité University, 75006 Paris, France
- Laboratory of Biochemistry and Molecular Biology, AP-HP, Lariboisière Hospital, 75010 Paris, France
| | - Bruno Mégarbane
- Inserm, UMR-S1144, Paris Cité University, 75006 Paris, France
- Department of Medical and Toxicological Critical Care, Lariboisière Hospital, Federation of Toxicology APHP, 75010 Paris, France
- Correspondence:
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Getsy PM, Baby SM, May WJ, Bates JN, Ellis CR, Feasel MG, Wilson CG, Lewis THJ, Gaston B, Hsieh YH, Lewis SJ. L-cysteine methyl ester overcomes the deleterious effects of morphine on ventilatory parameters and arterial blood-gas chemistry in unanesthetized rats. Front Pharmacol 2022; 13:968378. [PMID: 36249760 PMCID: PMC9554613 DOI: 10.3389/fphar.2022.968378] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/22/2022] [Indexed: 11/25/2022] Open
Abstract
We are developing a series of thiolesters that produce an immediate and sustained reversal of the deleterious effects of opioids, such as morphine and fentanyl, on ventilation without diminishing the antinociceptive effects of these opioids. We report here the effects of systemic injections of L-cysteine methyl ester (L-CYSme) on morphine-induced changes in ventilatory parameters, arterial-blood gas (ABG) chemistry (pH, pCO2, pO2, sO2), Alveolar-arterial (A-a) gradient (i.e., the index of alveolar gas-exchange within the lungs), and antinociception in unanesthetized Sprague Dawley rats. The administration of morphine (10 mg/kg, IV) produced a series of deleterious effects on ventilatory parameters, including sustained decreases in tidal volume, minute ventilation, inspiratory drive and peak inspiratory flow that were accompanied by a sustained increase in end inspiratory pause. A single injection of L-CYSme (500 μmol/kg, IV) produced a rapid and long-lasting reversal of the deleterious effects of morphine on ventilatory parameters, and a second injection of L-CYSme (500 μmol/kg, IV) elicited pronounced increases in ventilatory parameters, such as minute ventilation, to values well above pre-morphine levels. L-CYSme (250 or 500 μmol/kg, IV) also produced an immediate and sustained reversal of the deleterious effects of morphine (10 mg/kg, IV) on arterial blood pH, pCO2, pO2, sO2 and A-a gradient, whereas L-cysteine (500 μmol/kg, IV) itself was inactive. L-CYSme (500 μmol/kg, IV) did not appear to modulate the sedative effects of morphine as measured by righting reflex times, but did diminish the duration, however, not the magnitude of the antinociceptive actions of morphine (5 or 10 mg/kg, IV) as determined in tail-flick latency and hindpaw-withdrawal latency assays. These findings provide evidence that L-CYSme can powerfully overcome the deleterious effects of morphine on breathing and gas-exchange in Sprague Dawley rats while not affecting the sedative or early stage antinociceptive effects of the opioid. The mechanisms by which L-CYSme interferes with the OR-induced signaling pathways that mediate the deleterious effects of morphine on ventilatory performance, and by which L-CYSme diminishes the late stage antinociceptive action of morphine remain to be determined.
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Affiliation(s)
- Paulina M. Getsy
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States
- *Correspondence: Paulina M. Getsy,
| | | | - Walter J. May
- Pediatric Respiratory Medicine, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - James N. Bates
- Department of Anesthesiology, University of Iowa Hospitals and Clinics, Iowa City, IA, United States
| | - Christopher R. Ellis
- United States Army CCDC Chemical Biological Center, Aberdeen Proving Ground, MD, United States
| | - Michael G. Feasel
- United States Army CCDC Chemical Biological Center, Aberdeen Proving Ground, MD, United States
| | - Christopher G. Wilson
- Department of Basic Sciences, Division of Physiology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Tristan H. J. Lewis
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States
| | - Benjamin Gaston
- Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Yee-Hsee Hsieh
- Division of Pulmonary, Critical Care and Sleep Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Stephen J. Lewis
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH, United States
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Zhuang J, Xu F. Systemic 8-OH-DPAT challenge causes hyperventilation largely via activating pre-botzinger complex 5-HT 1A receptors. Respir Physiol Neurobiol 2021; 296:103810. [PMID: 34728431 DOI: 10.1016/j.resp.2021.103810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 09/23/2021] [Accepted: 10/27/2021] [Indexed: 11/24/2022]
Abstract
Systemic 8-OH-DPAT (a 5-HT1A receptor agonist) challenge evokes hyperventilation independent of peripheral 5-HT1A receptors. Though the pre-Botzinger Complex (PBC) is critical in generating respiratory rhythm and activation of local 5-HT1A receptors induces tachypnea via disinhibition of local GABAA neurons, its role in the respiratory response to systemic 8-OH-DPAT challenge is still unclear. In anesthetized rats, 8-OH-DPAT (100 μg/kg, iv) was injected twice to confirm the reproducibility of the evoked responses. The same challenges were performed after bilateral microinjections of (S)-WAY-100135 (a 5-HT1A receptor antagonist) or gabazine (a GABAA receptor antagonist) into the PBC. Our results showed that: 1) 8-OH-DPAT caused reproducible hyperventilation associated with hypotension and bradycardia; 2) microinjections of (S)-WAY-100135 into the PBC attenuated the hyperventilation by ˜60 % without effect on the evoked hypotension and bradycardia; and 3) the same hyperventilatory attenuation was also observed after microinjections of gabazine into the PBC. Our data suggest that PBC 5-HT1A receptors play a key role in the respiratory response to systemic 8-OH-DPAT challenge likely via disinhibiting local GABAergic neurons.
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Affiliation(s)
- Jianguo Zhuang
- Pathophysiology Program, Lovelace Biomedical Research Institute, 2425 Ridgecrest Drive SE, Albuquerque, NM, 87108, United States
| | - Fadi Xu
- Pathophysiology Program, Lovelace Biomedical Research Institute, 2425 Ridgecrest Drive SE, Albuquerque, NM, 87108, United States.
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5
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The lamprey respiratory network: Some evolutionary aspects. Respir Physiol Neurobiol 2021; 294:103766. [PMID: 34329767 DOI: 10.1016/j.resp.2021.103766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/19/2021] [Accepted: 07/25/2021] [Indexed: 01/25/2023]
Abstract
Breathing is a complex behaviour that involves rhythm generating networks. In this review, we examine the main characteristics of respiratory rhythm generation in vertebrates and, in particular, we describe the main results of our studies on the role of neural mechanisms involved in the neuromodulation of the lamprey respiration. The lamprey respiratory rhythm generator is located in the paratrigeminal respiratory group (pTRG) and shows similarities with the mammalian preBötzinger complex. In fact, within the pTRG a major role is played by glutamate, but also GABA and glycine display important contributions. In addition, neuromodulatory influences are exerted by opioids, substance P, acetylcholine and serotonin. Both structures respond to exogenous ATP with a biphasic response and astrocytes there located strongly contribute to the modulation of the respiratory pattern. The results emphasize that some important characteristics of the respiratory rhythm generating network are, to a great extent, maintained throughout evolution.
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6
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Cinelli E, Mutolo D, Pantaleo T, Bongianni F. Neural mechanisms underlying respiratory regulation within the preBötzinger complex of the rabbit. Respir Physiol Neurobiol 2021; 293:103736. [PMID: 34224867 DOI: 10.1016/j.resp.2021.103736] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 07/01/2021] [Accepted: 07/01/2021] [Indexed: 11/29/2022]
Abstract
The preBötzinger complex (preBötC) is a medullary area essential for normal breathing and widely recognized as necessary and sufficient to generate the inspiratory phase of respiration. It has been studied mainly in rodents. Here we report the main results of our studies revealing the characteristics of the rabbit preBötC identified by means of neuronal recordings, D,L-homocysteic acid microinjections and histological controls. A crucial role in the respiratory rhythmogenesis within this neural substrate is played by excitatory amino acids, but also GABA and glycine display important contributions. Increases in respiratory frequency are induced by microinjections of neurokinins, somatostatin as well by serotonin (5-HT) through an action on 5-HT1A and 5-HT3 receptors or the disinhibition of a GABAergic circuit. Respiratory depression is observed in response to microinjections of the μ-opioid receptor agonist DAMGO. Our results show similarities and differences with the rodent preBötC and emphasize the importance of comparative studies on the mechanisms underlying respiratory rhythmogenesis in different animal species.
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Affiliation(s)
- Elenia Cinelli
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università Degli Studi di Firenze, Viale G.B. Morgagni 63, Firenze, 50134, Italy
| | - Donatella Mutolo
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università Degli Studi di Firenze, Viale G.B. Morgagni 63, Firenze, 50134, Italy
| | - Tito Pantaleo
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università Degli Studi di Firenze, Viale G.B. Morgagni 63, Firenze, 50134, Italy
| | - Fulvia Bongianni
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università Degli Studi di Firenze, Viale G.B. Morgagni 63, Firenze, 50134, Italy.
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7
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Dandrea KE, Cotten JF. A Comparison of Breathing Stimulants for Reversal of Synthetic Opioid-Induced Respiratory Depression in Conscious Rats. J Pharmacol Exp Ther 2021; 378:146-156. [PMID: 34021024 DOI: 10.1124/jpet.121.000675] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 05/11/2021] [Indexed: 11/22/2022] Open
Abstract
Potent synthetic opioids are an important cause of death in the United States' opioid epidemic, and a breathing stimulant may have utility in treating opioid overdose. We hypothesized that sufentanil-induced respiratory depression may be reversed by breathing stimulant administration. Using nose-only plethysmography and arterial blood analysis, we compared effects of several breathing stimulants in reversing sufentanil-induced respiratory depression in conscious rats. We studied taltirelin (1 mg/kg i.v.), PKTHPP (5 mg/kg i.v.), CX717 (30 mg/kg i.v.), BIMU8 (1 mg/kg i.v.), A85380 (30 μg/kg i.v.), and 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) (150 μg/kg i.v./i.m.) and used sufentanil (10 μg/kg i.v.). By plethysmography (in % baseline, mean ± S.E.M.), taltirelin restored ventilation in sufentanil-treated rats (from 50 ± 5% to 102 ± 8%) by increased breathing rates (from 80 ± 4% to 160 ± 12%). By arterial blood analysis, however, taltirelin did not correct hypoxia, decreased hypercarbia only after 45 minutes, and worsened metabolic acidosis (base excess from +0 ± 1 to -7 ± 1 mEq/l). Additionally, taltirelin increased exhaled carbon dioxide, an estimate of oxygen consumption, by up to 64%. PKTHPP, CX717, BIMU8, and A85380 failed to significantly change ventilation or arterial blood values in sufentanil-treated rats. 8-OH-DPAT, however, improved ventilation (from 54 ± 8% to 92 ± 10%), reversed hypercarbia (from 64 ± 6 to 47 ± 2 mmHg), and shortened time to righting from 43 ± 4 to 15 ± 1 minutes in sufentanil-treated rats placed supine. Taltirelin has limited therapeutic potential, as its ventilatory effects are offset by metabolic acidosis, possibly from increased oxygen consumption. At the doses studied, PKTHPP, CX717, BIMU8, and A85380 have limited effects in reversing sufentanil-induced respiratory depression; 8-OH-DPAT, however, warrants further study. SIGNIFICANCE STATEMENT: Respiratory depression is an important cause of death after potent synthetic opioid overdose. 8-Hydroxy-2-(di-n-propylamino)tetralin or related compounds may be useful in treating respiratory depression as caused by potent synthetic opioids.
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Affiliation(s)
- Kaye E Dandrea
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Joseph F Cotten
- Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Boston, Massachusetts
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Cummings KJ. Eupnea and gasping in vivo are facilitated by the activation of 5-HT 2A receptors. J Neurophysiol 2021; 125:1543-1551. [PMID: 33760672 DOI: 10.1152/jn.00088.2021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Eupnea and gasping in infancy depend on central nervous system (CNS) serotonin (5-hydroxytryptamine; 5-HT). Although previous in vitro preparations have provided some evidence that 5-HT acts through type 2 A receptors (5-HT2A) to facilitate eupnea and gasping, here the hypothesis addressed is that 5-HT2A receptor activation is necessary for eupnea and the proper generation of gasping in vivo. To test this, we administered 2,5-dimethoxy-4-iodoamphetamine (DOI; 0.25 mg/kg i.p.), a 5-HT2A agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT; 0.25 mg/kg i.p.), a 5-HT1A agonist, or vehicle (saline) to 7-9-day-old tryptophan hydroxylase 2 knockout (TPH2-/-) mice. A second experiment assessed the effect of MDL-11,939 (MDL; 10 mg/kg i.p.), the specific 5-HT2A antagonist, or vehicle (DMSO) on the gasping of wild-type (TPH2+/+) animals. Drugs were given 15 min prior to five episodes of severe hypoxia that elicited gasping. TPH2-/- breathed more slowly but had the same V̇e and V̇e/V̇o2 compared with TPH2+/+. As previously reported, the gasping of TPH2-/- was significantly delayed (P < 0.001) and occurred at a significantly lower frequency compared with TPH2+/+ (P = 0.04). For both genotypes, DOI hastened eupneic frequency but had no effect on V̇e or V̇e/V̇o2. The gasping of TPH2-/-, although unaffected by 8-OH-DPAT, was indistinguishable from the gasping of TPH2+/+ following DOI. In TPH2+/+, application of MDL led to hypoventilation (P = 0.01), a delay in the appearance of gasping (P = 0.005), and reduced gasp frequency (P = 0.05). These data show that, in vivo, 5-HT2A receptors facilitate both eupnea and gasping. As has been shown in vitro, 5-HT2A probably promotes gasping by exciting hypoxia-resistant pacemaker neurons.NEW & NOTEWORTHY Previous in vitro studies suggest that 5-HT2A receptors contribute to eupnea and are necessary for fictive gasping. The current study shows that the impaired gasping displayed by neonatal TPH2-/- mice, deficient in CNS serotonin, is restored by 5-HT2A receptor activation. Following 5-HT2A blockade, wild-type mice hypoventilated and their gasping resembled that of TPH2-/- mice. This study shows that both eupnea and gasping in vivo rely on the activation of 5-HT2A receptors.
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Affiliation(s)
- Kevin J Cummings
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri and Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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Tod N, Stalder G, Rauch H, Boehmdorfer S, Haw A, Gerritsmann H, Painer J, Meyer L. Investigation of cardiorespiratory effects of the selective 5-HT4 agonist BIMU-8 in etorphine-immobilised goats (Capra aegagrus hircus) in a randomized, blinded and controlled trial. Vet Rec 2021; 189:e76. [PMID: 33908044 DOI: 10.1002/vetr.76] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 12/01/2020] [Accepted: 12/24/2020] [Indexed: 11/07/2022]
Abstract
BACKGROUND Opioid-induced respiratory compromise remains a significant challenge in etorphine-immobilised wildlife. Serotonergic agonists offer a potential avenue for preventing or treating opioid-induced respiratory compromise. We therefore aimed to determine whether the selective 5-hydroxytryptamine receptor 4 (5-HT4) agonist, BIMU-8, reverses opioid-induced respiratory compromise in etorphine-immobilised goats. METHODS Seven healthy adult goats were immobilised with etorphine, then treated with BIMU-8 or sterile water 5 minutes later in a randomised, prospective cross-over study. Cardiorespiratory variables were measured at 1-minute intervals from 4 minutes before etorphine to 15 minutes after its administration. Arterial blood gas analyses were also performed before and after etorphine administration and the respective treatments. RESULTS Intravenous injection of BIMU-8 attenuated etorphine-induced respiratory compromise, as indicated by improvements, compared to baseline and between treatments, in respiratory rate (fR ), peripheral arterial blood oxygen saturation (SpO2 ), partial pressure of arterial oxygen (PaO2 ) and the alveolar-arterial oxygen partial pressure gradient (P(A-a)O2 ). BIMU-8 caused an increase in heart rate and a temporary decrease in arterial blood pressure. Mild movements and slight muscle spasm occurred but BIMU-8 did not reverse immobilisation. CONCLUSION Our results indicate that BIMU-8 may be a potential drug candidate for the treatment, or prevention, of etorphine-induced respiratory compromise in immobilised ungulates.
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Affiliation(s)
- Nadine Tod
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Gabrielle Stalder
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Hanna Rauch
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Stefan Boehmdorfer
- Department of Chemistry, Institute of Chemistry of Renewable Resources, BOKU - University of Natural Resources and Life Sciences, Vienna, Austria
| | - Anna Haw
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Hanno Gerritsmann
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Johanna Painer
- Department of Interdisciplinary Life Sciences, Research Institute of Wildlife Ecology, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Leith Meyer
- Centre for Veterinary Wildlife Studies and Department of Paraclinical Sciences, University of Pretoria, Pretoria, South Africa
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Cinelli E, Mutolo D, Iovino L, Pantaleo T, Bongianni F. Key role of 5-HT 1A receptors in the modulation of the neuronal network underlying the respiratory rhythm generation in lampreys. Eur J Neurosci 2020; 52:3903-3917. [PMID: 32378271 DOI: 10.1111/ejn.14769] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 04/06/2020] [Accepted: 04/29/2020] [Indexed: 12/17/2022]
Abstract
In mammals, 5-HTexcitatory respiratory effects imply 5-HT1A receptor-mediated disinhibition of pre-Bötzinger complex neurons. In the lamprey, 5-HT1A receptors are involved in the neural control of locomotion, but their role in the respiratory regulation, particularly at the level of the putative respiratory rhythm generator, the paratrigeminal respiratory group (pTRG), is not known. We here investigate the respiratory function of inhibitory 5-HT1A receptors within the pTRG of the isolated brainstem of the adult lamprey. The 5-HT1A receptor agonists either bath applied or microinjected into the pTRG did not cause significant effects. However, the selective 5-HT1A receptor antagonist (S)-WAY 100135 bath applied or microinjected into the pTRG induced depressing respiratory effects or even apnoea, thus revealing that 5-HT exerts a 5-HT1A receptor-mediated potent tonic influence on respiration and contributes to maintain baseline levels of respiratory activity. Microinjections of strychnine or bicuculline, either alone or in combination, into the pTRG prevented (S)-WAY 100135-induced apnoea. In addition, immunohistochemical studies corroborate the present findings suggesting that 5-HT1A receptors are widely expressed in close apposition to the soma of glycine-immunoreactive cells located within the pTRG region. The results show that in the lamprey respiratory network, 5-HT exerts a tonic influence on respiration by a potent inhibitory control on both GABAergic and glycinergic mechanisms. The observed disinhibitory effects resemble the excitatory respiratory modulation exerted by 5-HT1A receptor-mediated inhibition of glycinergic and/or GABAergic neurons present in mammals, supporting the notion that some features of the neuronal network subserving respiratory rhythm generation are highly conserved throughout phylogeny.
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Affiliation(s)
- Elenia Cinelli
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Firenze, Italy
| | - Donatella Mutolo
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Firenze, Italy
| | - Ludovica Iovino
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Firenze, Italy
| | - Tito Pantaleo
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Firenze, Italy
| | - Fulvia Bongianni
- Dipartimento di Medicina Sperimentale e Clinica, Sezione Scienze Fisiologiche, Università degli Studi di Firenze, Firenze, Italy
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11
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Iovino L, Mutolo D, Cinelli E, Contini M, Pantaleo T, Bongianni F. Breathing stimulation mediated by 5-HT1A and 5-HT3 receptors within the preBötzinger complex of the adult rabbit. Brain Res 2019; 1704:26-39. [DOI: 10.1016/j.brainres.2018.09.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 09/10/2018] [Accepted: 09/18/2018] [Indexed: 02/06/2023]
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Szereda-Przestaszewska M, Kaczyńska K. Pharmacologically evoked apnoeas. Receptors and nervous pathways involved. Life Sci 2018; 217:237-242. [PMID: 30553870 DOI: 10.1016/j.lfs.2018.12.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 12/05/2018] [Accepted: 12/12/2018] [Indexed: 01/07/2023]
Abstract
This review analyses the knowledge about the incidence of transient apnoeic spells, induced by substances which activate vagal chemically sensitive afferents. It considers the specificity and expression of appropriate receptors, and relevant research on pontomedullary circuits contributing to a cessation of respiration. Insight is gained into an excitatory drive of 5-HT1A serotonin receptors in overcoming opioid-induced respiratory inhibition.
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Affiliation(s)
- Małgorzata Szereda-Przestaszewska
- Department of Respiration Physiology, Mossakowski Medical Research Centre Polish Academy of Sciences, A. Pawińskiego 5, 02-106 Warsaw, Poland
| | - Katarzyna Kaczyńska
- Department of Respiration Physiology, Mossakowski Medical Research Centre Polish Academy of Sciences, A. Pawińskiego 5, 02-106 Warsaw, Poland.
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13
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Silva TLA, Braz GRF, Silva SCDA, Pedroza AADS, Freitas CDM, Ferreira DJS, da Silva AI, Lagranha CJ. Serotonin transporter inhibition during neonatal period induces sex-dependent effects on mitochondrial bioenergetics in the rat brainstem. Eur J Neurosci 2018; 48:1620-1634. [PMID: 29802653 DOI: 10.1111/ejn.13971] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 04/19/2018] [Accepted: 05/14/2018] [Indexed: 12/29/2022]
Abstract
The serotonin reuptake is mainly regulated by the serotonin transporters (SERTs), which are abundantly found in the raphe nuclei, located in the brainstem. Previous studies have shown that dysfunction in the SERT has been associated with several disorders, including depression and cardiovascular diseases. In this manuscript, we aimed to investigate how gender and the treatment with a serotonin selective reuptake inhibitor (SSRI) could affect mitochondrial bioenergetics and oxidative stress in the brainstem of male and female rats. Fluoxetine, our chosen SSRI, was used during the neonatal period (i.e., from postnatal Day 1 to postnatal Day 21-PND1 to PND21) in both male and female animals. Thereafter, experiments were conducted in adult rats (60 days old). Our results demonstrate that, during lactation, fluoxetine treatment modulates the mitochondrial bioenergetics in a sex-dependent manner, such as improving male mitochondrial function and female antioxidant capacity.
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Affiliation(s)
- Tercya Lucidi Araujo Silva
- Neuropsychiatry and Behavioral Science Graduate Program, Federal University of Pernambuco, Recife, Brazil
| | - Glauber Rudá Feitoza Braz
- Neuropsychiatry and Behavioral Science Graduate Program, Federal University of Pernambuco, Recife, Brazil
| | | | | | | | | | - Aline Isabel da Silva
- Neuropsychiatry and Behavioral Science Graduate Program, Federal University of Pernambuco, Recife, Brazil
| | - Claudia Jacques Lagranha
- Neuropsychiatry and Behavioral Science Graduate Program, Federal University of Pernambuco, Recife, Brazil
- Biochemistry and Physiology Graduate Program, Federal University of Pernambuco, Recife, Brazil
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Imam MZ, Kuo A, Ghassabian S, Smith MT. Progress in understanding mechanisms of opioid-induced gastrointestinal adverse effects and respiratory depression. Neuropharmacology 2017; 131:238-255. [PMID: 29273520 DOI: 10.1016/j.neuropharm.2017.12.032] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 12/18/2017] [Accepted: 12/19/2017] [Indexed: 02/06/2023]
Abstract
Opioids evoke analgesia through activation of opioid receptors (predominantly the μ opioid receptor) in the central nervous system. Opioid receptors are abundant in multiple regions of the central nervous system and the peripheral nervous system including enteric neurons. Opioid-related adverse effects such as constipation, nausea, and vomiting pose challenges for compliance and continuation of the therapy for chronic pain management. In the post-operative setting opioid-induced depression of respiration can be fatal. These critical limitations warrant a better understanding of their underpinning cellular and molecular mechanisms to inform the design of novel opioid analgesic molecules that are devoid of these unwanted side-effects. Research efforts on opioid receptor signalling in the past decade suggest that differential signalling pathways and downstream molecules preferentially mediate distinct pharmacological effects. Additionally, interaction among opioid receptors and, between opioid receptor and non-opioid receptors to form signalling complexes shows that opioid-induced receptor signalling is potentially more complicated than previously thought. This complexity provides an opportunity to identify and probe relationships between selective signalling pathway specificity and in vivo production of opioid-related adverse effects. In this review, we focus on current knowledge of the mechanisms thought to transduce opioid-induced gastrointestinal adverse effects (constipation, nausea, vomiting) and respiratory depression.
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Affiliation(s)
- Mohammad Zafar Imam
- Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia; UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Andy Kuo
- UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Sussan Ghassabian
- UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Maree T Smith
- UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia; School of Pharmacy, Faculty of Health and Behavioural Sciences, The University of Queensland, Brisbane, QLD, Australia.
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15
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Zuperku EJ, Stucke AG, Hopp FA, Stuth EAE. Characteristics of breathing rate control mediated by a subregion within the pontine parabrachial complex. J Neurophysiol 2016; 117:1030-1042. [PMID: 27974449 DOI: 10.1152/jn.00591.2016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 12/12/2016] [Indexed: 11/22/2022] Open
Abstract
The role of the dorsolateral pons in the control of expiratory duration (Te) and breathing frequency is incompletely understood. A subregion of the pontine parabrachial-Kölliker-Fuse (PB-KF) complex of dogs was identified via microinjections, in which localized pharmacologically induced increases in neuronal activity produced increases in breathing rate while decreases in neuronal activity produced decreases in breathing rate. This subregion is also very sensitive to local and systemic opioids. The purpose of this study was to precisely characterize the relationship between the PB-KF subregion pattern of altered neuronal activity and the control of respiratory phase timing as well as the time course of the phrenic nerve activity/neurogram (PNG). Pulse train electrical stimulation patterns synchronized with the onset of the expiratory (E) and/or phrenic inspiratory (I) phase were delivered via a small concentric bipolar electrode while the PNG was recorded in decerebrate, vagotomized dogs. Step frequency patterns during the E phase produced a marked frequency-dependent decrease in Te, while similar step inputs during the I phase increased inspiratory duration (Ti) by 14 ± 3%. Delayed pulse trains were capable of pacing the breathing rate by terminating the E phase and also of triggering a consistent stereotypical inspiratory PNG pattern, even when evoked during apnea. This property suggests that the I-phase pattern generator functions in a monostable circuit mode with a stable E phase and a transient I phase. Thus the I-pattern generator must contain neurons with nonlinear pacemaker-like properties, which allow the network to rapidly obtain a full on-state followed by relatively slow inactivation. The activated network can be further modulated and supplies excitatory drive to the neurons involved with pattern generation.NEW & NOTEWORTHY A circumscribed subregion of the pontine medial parabrachial nucleus plays a key role in the control of breathing frequency primarily via changes in expiratory duration. Excitation of this subregion triggers the onset of the inspiratory phase, resulting in a stereotypical ramplike phrenic activity pattern independent of time within the expiratory phase. The ability to pace the I-burst rate suggests that the in vivo I-pattern generating network must contain functioning pacemaker neurons.
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Affiliation(s)
- Edward J Zuperku
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, Wisconsin; .,Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin; and
| | - Astrid G Stucke
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, Wisconsin.,Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin; and.,Pediatric Anesthesia, Children's Hospital of Wisconsin, Milwaukee, Wisconsin
| | - Francis A Hopp
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, Wisconsin
| | - Eckehard A E Stuth
- Clement J. Zablocki Department of Veterans Affairs Medical Center, Milwaukee, Wisconsin.,Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin; and.,Pediatric Anesthesia, Children's Hospital of Wisconsin, Milwaukee, Wisconsin
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Cerritelli S, Hirschberg S, Hill R, Balthasar N, Pickering AE. Activation of Brainstem Pro-opiomelanocortin Neurons Produces Opioidergic Analgesia, Bradycardia and Bradypnoea. PLoS One 2016; 11:e0153187. [PMID: 27077912 PMCID: PMC4831707 DOI: 10.1371/journal.pone.0153187] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 03/14/2016] [Indexed: 11/19/2022] Open
Abstract
Opioids are widely used medicinally as analgesics and abused for hedonic effects, actions that are each complicated by substantial risks such as cardiorespiratory depression. These drugs mimic peptides such as β-endorphin, which has a key role in endogenous analgesia. The β-endorphin in the central nervous system originates from pro-opiomelanocortin (POMC) neurons in the arcuate nucleus and nucleus of the solitary tract (NTS). Relatively little is known about the NTSPOMC neurons but their position within the sensory nucleus of the vagus led us to test the hypothesis that they play a role in modulation of cardiorespiratory and nociceptive control. The NTSPOMC neurons were targeted using viral vectors in a POMC-Cre mouse line to express either opto-genetic (channelrhodopsin-2) or chemo-genetic (Pharmacologically Selective Actuator Modules). Opto-genetic activation of the NTSPOMC neurons in the working heart brainstem preparation (n = 21) evoked a reliable, titratable and time-locked respiratory inhibition (120% increase in inter-breath interval) with a bradycardia (125±26 beats per minute) and augmented respiratory sinus arrhythmia (58% increase). Chemo-genetic activation of NTSPOMC neurons in vivo was anti-nociceptive in the tail flick assay (latency increased by 126±65%, p<0.001; n = 8). All effects of NTSPOMC activation were blocked by systemic naloxone (opioid antagonist) but not by SHU9119 (melanocortin receptor antagonist). The NTSPOMC neurons were found to project to key brainstem structures involved in cardiorespiratory control (nucleus ambiguus and ventral respiratory group) and endogenous analgesia (periaqueductal gray and midline raphe). Thus the NTSPOMC neurons may be capable of tuning behaviour by an opioidergic modulation of nociceptive, respiratory and cardiac control.
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Affiliation(s)
- Serena Cerritelli
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Stefan Hirschberg
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Rob Hill
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Nina Balthasar
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Anthony E. Pickering
- School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, United Kingdom
- Department of Anaesthesia, University Hospitals Bristol, Bristol, BS2 8HW, United Kingdom
- * E-mail:
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Radocaj T, Mustapic S, Prkic I, Stucke AG, Hopp FA, Stuth EAE, Zuperku EJ. Activation of 5-HT1A receptors in the preBötzinger region has little impact on the respiratory pattern. Respir Physiol Neurobiol 2015; 212-214:9-19. [PMID: 25850079 DOI: 10.1016/j.resp.2015.03.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 02/10/2015] [Accepted: 03/19/2015] [Indexed: 11/24/2022]
Abstract
The preBötzinger (preBötC) complex has been suggested as the primary site where systemically administered selective serotonin agonists have been shown to reduce or prevent opioid-induced depression of breathing. However, this hypothesis has not been tested pharmacologically in vivo. This study sought to determine whether 5-HT1A receptors within the preBötC and ventral respiratory column (VRC) mediate the tachypneic response induced by intravenous (IV) (±)-8-Hydroxy-2-diproplyaminotetralin hydrobromide (8-OH-DPAT) in a decerebrated dog model. IV 8-OH-DPAT (19 ± 2 μg/kg) reduced both inspiratory (I) and expiratory (E) durations by ∼ 40%, but had no effect on peak phrenic activity (PPA). Picoejection of 1, 10, and 100 μM 8-OH-DPAT on I and E preBötC neurons produced dose-dependent decreases up to ∼ 40% in peak discharge. Surprisingly, microinjections of 8-OH-DPAT and 5-HT within the VRC from the obex to 9 mm rostral had no effect on timing and PPA. These results suggest that the tachypneic effects of IV 8-OH-DPAT are due to receptors located outside of the areas we studied.
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Affiliation(s)
- Tomislav Radocaj
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Clement J. Zablocki VA Medical Center, Milwaukee, WI 53295, United States
| | - Sanda Mustapic
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Clement J. Zablocki VA Medical Center, Milwaukee, WI 53295, United States
| | - Ivana Prkic
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Clement J. Zablocki VA Medical Center, Milwaukee, WI 53295, United States
| | - Astrid G Stucke
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Children's Hospital of Wisconsin, Pediatric Anesthesia, Milwaukee, WI, United States
| | - Francis A Hopp
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Clement J. Zablocki VA Medical Center, Milwaukee, WI 53295, United States
| | - Eckehard A E Stuth
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Children's Hospital of Wisconsin, Pediatric Anesthesia, Milwaukee, WI, United States
| | - Edward J Zuperku
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States; Clement J. Zablocki VA Medical Center, Milwaukee, WI 53295, United States.
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18
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Bergfeld C, Beyerbach M, Voigt AM, Kästner SBR. [Evaluation of heart rate variability for monitoring the depth of anaesthesia in dogs. Investigations based on total intravenous anaesthesia using propofol alone or in combination with dexmedetomidine or remifentanil]. TIERAERZTLICHE PRAXIS AUSGABE KLEINTIERE HEIMTIERE 2014; 43:1-10. [PMID: 25428443 DOI: 10.15654/tpk-130744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 05/12/2014] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Evaluation of heart-rate variability (HRV) as an indicator for autonomous activity to monitor anaesthesia in dogs during three different total intravenous anaesthetic protocols and three anaesthetic depth levels as well as before and after electrical nociceptive stimulation. MATERIAL AND METHODS Seven beagle dogs (14.3±1.7 kg) were used in a randomised experimental trial with a complete cross-over design. Each dog went through all three anaesthetic protocols, which were propofol alone (group P) and propofol combined with dexmedetomidine (3 µg/kg/h, group PD) or remifentanil (18 µg/kg/h, group PR). Propofol was given using target-controlled infusion. Three anaesthetic depth levels (light, medium, deep) were defined by target concentrations for propofol in the blood and were adapted to the individual animal and treatment (mean of 7, 9 and 11 µg/ml, and in combination with dexmedetomidine or remifentanil, a mean of 3, 5 and 7 µg/ml). During each anaesthetic level, a standardised supramaximal nociceptive electric stimulus (50 Hz, 50 V, 10 ms) was applied medially to the right forearm. The bipolar-derived electrocardiogram (ECG) was recorded continuously. For each anaesthetic depth, the RR-intervals recorded 2 minutes before and after each stimulation were included in the statistical analysis. Using an HRV analytical program (Kubios HRV), the frequency domain HRV-parameters low (LF) and high (HF) frequency and the time-domain HRV-parameters RR-intervals, standard deviation of all RR-intervals (SDNN) and the square root of the mean of the sum of the squares of the differences between consecutive RR-intervals (RMSSD) were determined. RESULTS Neither the RR-intervals nor the currently available HRV-parameters which were derived from the RR-intervals were able to discriminate between the different anaesthetic depths levels. Nociception could only be represented by the RR-intervals. CONCLUSION Overall, the investigated standard HRV parameters offered no additional information for the monitoring of anaesthetic depths at the investigated, clinically used dose rates.
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Affiliation(s)
- C Bergfeld
- Carina Bergfeld, Klinik für Kleintiere, Stiftung Tierärztliche Hochschule Hannover, Bünteweg 9, 30559 Hannover, E-Mail:
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19
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Carnevali L, Sgoifo A. Vagal modulation of resting heart rate in rats: the role of stress, psychosocial factors, and physical exercise. Front Physiol 2014; 5:118. [PMID: 24715877 PMCID: PMC3970013 DOI: 10.3389/fphys.2014.00118] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 03/10/2014] [Indexed: 01/07/2023] Open
Abstract
In humans, there are large individual differences in the levels of vagal modulation of resting heart rate (HR). High levels are a recognized index of cardiac health, whereas low levels are considered an important risk factor for cardiovascular morbidity and mortality. Several factors are thought to contribute significantly to this inter-individual variability. While regular physical exercise seems to induce an increase in resting vagal tone, chronic life stress, and psychosocial factors such as negative moods and personality traits appear associated with vagal withdrawal. Preclinical research has been attempting to clarify such relationships and to provide insights into the neurobiological mechanisms underlying vagal tone impairment/enhancement. This paper focuses on rat studies that have explored the effects of stress, psychosocial factors and physical exercise on vagal modulation of resting HR. Results are discussed with regard to: (i) individual differences in resting vagal tone, cardiac stress reactivity and arrhythmia vulnerability; (ii) elucidation of the neurobiological determinants of resting vagal tone.
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Affiliation(s)
- Luca Carnevali
- Stress Physiology Laboratory, Department of Neuroscience, University of Parma Parma, Italy
| | - Andrea Sgoifo
- Stress Physiology Laboratory, Department of Neuroscience, University of Parma Parma, Italy
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20
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Abstract
Inhibitory 5-HT(1a) receptors are located on serotonin (5-HT) neurons (autoreceptors) as well as neurons of the respiratory network (heteroreceptors). Thus, effects on breathing of 5-HT(1a) agonists, such as (R)-(+)-8-hydroxy-2-(di-N-propylamino) tetralin (8-OH-DPAT), could either be due to decreased firing of 5-HT neurons or direct effects on the respiratory network. Mice in which the transcription factor LMX1B is genetically deleted selectively in Pet1-1-expressing cells (Lmx1b(f/f/p)) essentially have complete absence of central 5-HT neurons, providing a unique opportunity to separate the effect of activation of downstream 5-HT(1a) heteroreceptors from that of autoreceptors. We used rhythmically active medullary slices from wild-type (WT) and Lmx1b(f/f/p) neonatal mice to differentiate autoreceptor versus heteroreceptor effects of 8-OH-DPAT on hypoglossal nerve respiratory output. 8-OH-DPAT transiently increased respiratory burst frequency in Lmx1b(f/f/p) preparations, but not in WT slices. This excitation was abolished when synaptic inhibition was blocked by GABAergic/glycinergic receptor antagonists. Conversely, after 10 min of application, frequency in Lmx1b(f/f/p) slices was not different from baseline, whereas it was significantly depressed in WT slices. In WT mice in vivo, subcutaneous injection of 8-OH-DPAT produced similar biphasic respiratory effects as in Lmx1b(f/f/p) mice. We conclude that 5-HT1a receptor agonists have two competing effects: rapid stimulation of breathing due to excitation of the respiratory network, and delayed inhibition of breathing due to autoreceptor inhibition of 5-HT neurons. The former effect is presumably due to inhibition of inhibitory interneurons embedded in the respiratory network.
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Abstract
Pontine respiratory nuclei provide synaptic input to medullary rhythmogenic circuits to shape and adapt the breathing pattern. An understanding of this statement depends on appreciating breathing as a behavior, rather than a stereotypic rhythm. In this review, we focus on the pontine-mediated inspiratory off-switch (IOS) associated with postinspiratory glottal constriction. Further, IOS is examined in the context of pontine regulation of glottal resistance in response to multimodal sensory inputs and higher commands, which in turn rules timing, duration, and patterning of respiratory airflow. In addition, network plasticity in respiratory control emerges during the development of the pons. Synaptic plasticity is required for dynamic and efficient modulation of the expiratory breathing pattern to cope with rapid changes from eupneic to adaptive breathing linked to exploratory (foraging and sniffing) and expulsive (vocalizing, coughing, sneezing, and retching) behaviors, as well as conveyance of basic emotions. The speed and complexity of changes in the breathing pattern of behaving animals implies that "learning to breathe" is necessary to adjust to changing internal and external states to maintain homeostasis and survival.
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Affiliation(s)
- Mathias Dutschmann
- Florey Neurosciences Institutes, University of Melbourne, Victoria, Australia.
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22
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Levitt ES, Hunnicutt BJ, Knopp SJ, Williams JT, Bissonnette JM. A selective 5-HT1a receptor agonist improves respiration in a mouse model of Rett syndrome. J Appl Physiol (1985) 2013; 115:1626-33. [PMID: 24092697 DOI: 10.1152/japplphysiol.00889.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Rett syndrome is a neurological disorder caused by loss of function mutations in the gene that encodes the DNA binding protein methyl-CpG-binding protein 2 (Mecp2). A prominent feature of the syndrome is disturbances in respiration characterized by frequent apnea and an irregular interbreath cycle. 8-Hydroxy-2-dipropylaminotetralin has been shown to positively modulate these disturbances (Abdala AP, Dutschmann M, Bissonnette JM, Paton JF, Proc Natl Acad Sci U S A 107: 18208-18213, 2010), but the mode of action is not understood. Here we show that the selective 5-HT1a biased agonist 3-chloro-4-fluorophenyl-(4-fluoro-4-{[(5-methylpyrimidin-2-ylmethyl)-amino]-methyl}-piperidin-1-yl)-methanone (F15599) decreases apnea and corrects irregularity in both heterozygous Mecp2-deficient female and in Mecp2 null male mice. In whole cell voltage-clamp recordings from dorsal raphe neurons, F15599 potently induced an outward current, which was blocked by barium, reversed at the potassium equilibrium potential, and was antagonized by the 5-HT1a antagonist WAY100135. This is consistent with somatodendritic 5-HT1a receptor-mediated activation of G protein-coupled inwardly rectifying potassium channels (GIRK). In contrast, F15599 did not activate 5-HT1b/d receptors that mediate inhibition of glutamate release from terminals in the nucleus accumbens by a presynaptic mechanism. Thus F15599 activated somatodendritic 5-HT1a autoreceptors, but not axonal 5-HT1b/d receptors. In unanesthetized Mecp2-deficient heterozygous female mice, F15599 reduced apnea in a dose-dependent manner with maximal effect of 74.5 ± 6.9% at 0.1 mg/kg and improved breath irrregularity. Similarly, in Mecp2 null male mice, apnea was reduced by 62 ± 6.6% at 0.25 mg/kg, and breathing became regular. The results indicate respiration is improved with a 5-HT1a agonist that activates GIRK channels without affecting neurotransmitter release.
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Affiliation(s)
- Erica S Levitt
- Vollum Institute, Oregon Health and Science University, Portland, Oregon
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23
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Miller JR, Neumueller S, Muere C, Olesiak S, Pan L, Hodges MR, Forster HV. Changes in neurochemicals within the ventrolateral medullary respiratory column in awake goats after carotid body denervation. J Appl Physiol (1985) 2013; 115:1088-98. [PMID: 23869058 DOI: 10.1152/japplphysiol.00293.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A current and major unanswered question is why the highly sensitive central CO2/H(+) chemoreceptors do not prevent hypoventilation-induced hypercapnia following carotid body denervation (CBD). Because perturbations involving the carotid bodies affect central neuromodulator and/or neurotransmitter levels within the respiratory network, we tested the hypothesis that after CBD there is an increase in inhibitory and/or a decrease in excitatory neurochemicals within the ventrolateral medullary column (VMC) in awake goats. Microtubules for chronic use were implanted bilaterally in the VMC within or near the pre-Bötzinger Complex (preBötC) through which mock cerebrospinal fluid (mCSF) was dialyzed. Effluent mCSF was collected and analyzed for neurochemical content. The goats hypoventilated (peak +22.3 ± 3.4 mmHg PaCO2) and exhibited a reduced CO2 chemoreflex (nadir, 34.8 ± 7.4% of control ΔVE/ΔPaCO2) after CBD with significant but limited recovery over 30 days post-CBD. After CBD, GABA and glycine were above pre-CBD levels (266 ± 29% and 189 ± 25% of pre-CBD; P < 0.05), and glutamine and dopamine were significantly below pre-CBD levels (P < 0.05). Serotonin, substance P, and epinephrine were variable but not significantly (P > 0.05) different from control after CBD. Analyses of brainstem tissues collected 30 days after CBD exhibited 1) a midline raphe-specific reduction (P < 0.05) in the percentage of tryptophan hydroxylase-expressing neurons, and 2) a reduction (P < 0.05) in serotonin transporter density in five medullary respiratory nuclei. We conclude that after CBD, an increase in inhibitory neurotransmitters and a decrease in excitatory neuromodulation within the VMC/preBötC likely contribute to the hypoventilation and attenuated ventilatory CO2 chemoreflex.
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24
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Burke PGR, Sousa LO, Tallapragada VJ, Goodchild AK. Inhibition of protein kinase A activity depresses phrenic drive and glycinergic signalling, but not rhythmogenesis in anaesthetized rat. Eur J Neurosci 2013; 38:2260-70. [PMID: 23627348 DOI: 10.1111/ejn.12230] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 03/20/2013] [Accepted: 03/25/2013] [Indexed: 11/28/2022]
Abstract
The cAMP-protein kinase A (PKA) pathway plays a critical role in regulating neuronal activity. Yet, how PKA signalling shapes the population activity of neurons that regulate respiratory rhythm and motor patterns in vivo is poorly defined. We determined the respiratory effects of focally inhibiting endogenous PKA activity in defined classes of respiratory neurons in the ventrolateral medulla and spinal cord by microinjection of the membrane-permeable PKA inhibitor Rp-adenosine 3',5'-cyclic monophosphothioate (Rp-cAMPS) in urethane-anaesthetized adult Sprague Dawley rats. Phrenic nerve activity, end-tidal CO2 and arterial pressure were recorded. Rp-cAMPS in the preBötzinger complex (preBötC) caused powerful, dose-dependent depression of phrenic burst amplitude and inspiratory period. Rp-cAMPS powerfully depressed burst amplitude in the phrenic premotor nucleus, but had no effect at the phrenic motor nucleus, suggesting a lack of persistent PKA activity here. Surprisingly, inhibition of PKA activity in the preBötC increased phrenic burst frequency, whereas in the Bötzinger complex phrenic frequency decreased. Pretreating the preBötC with strychnine, but not bicuculline, blocked the Rp-cAMPS-evoked increase in frequency, but not the depression of phrenic burst amplitude. We conclude that endogenous PKA activity in excitatory inspiratory preBötzinger neurons and phrenic premotor neurons, but not motor neurons, regulates network inspiratory drive currents that underpin the intensity of phrenic nerve discharge. We show that inhibition of PKA activity reduces tonic glycinergic transmission that normally restrains the frequency of rhythmic respiratory activity. Finally, we suggest that the maintenance of the respiratory rhythm in vivo is not dependent on endogenous cAMP-PKA signalling.
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Affiliation(s)
- P G R Burke
- Australian School of Advanced Medicine, Level 1, 2 Technology Drive, Macquarie University, Sydney, NSW, Australia
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Gestational stress promotes pathological apneas and sex-specific disruption of respiratory control development in newborn rat. J Neurosci 2013; 33:563-73. [PMID: 23303936 DOI: 10.1523/jneurosci.1214-12.2013] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Recurrent apneas are important causes of hospitalization and morbidity in newborns. Gestational stress (GS) compromises fetal brain development. Maternal stress and anxiety during gestation are linked to respiratory disorders in newborns; however, the mechanisms remain unknown. Here, we tested the hypothesis that repeated activation of the neuroendocrine response to stress during gestation is sufficient to disrupt the development of respiratory control and augment the occurrence of apneas in newborn rats. Pregnant dams were displaced and exposed to predator odor from days 9 to 19 of gestation. Control dams were undisturbed. Experiments were performed on male and female rats aged between 0 and 4 d old. Apnea frequency decreased with age but was consistently higher in stressed pups than controls. At day 4, GS augmented the proportion of apneas with O(2) desaturations by 12%. During acute hypoxia (12% O(2)), the reflexive increase in breathing augmented with age; however, this response was lower in stressed pups. Instability of respiratory rhythm recorded from medullary preparations decreased with age but was higher in stressed pups than controls. GS reduced medullary serotonin (5-HT) levels in newborn pups by 32%. Bath application of 5-HT and injection of 8-OH-DPAT [(±)-8-hydroxy-2-di-(n-propylamino) tetralin hydrobromide; 5-HT(1A) agonist; in vivo] reduced respiratory instability and apneas; these effects were greater in stressed pups than controls. Sex-specific effects were observed. We conclude that activation of the stress response during gestation is sufficient to disrupt respiratory control development and promote pathological apneas in newborn rats. A deficit in medullary 5-HT contributes to these effects.
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Effects of cholinesterase inhibitors and serotonin-1A receptor agonists on morphine-induced ventilatory depression and antinociception in rats. Eur J Pharmacol 2013; 703:33-41. [PMID: 23438874 DOI: 10.1016/j.ejphar.2013.02.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 02/01/2013] [Accepted: 02/07/2013] [Indexed: 11/24/2022]
Abstract
Ventilatory depression is a serious side-effect of opioid analgesics. Naloxone, an antagonist of opioid receptors, eliminates not only ventilatory depression but also analgesic effect of opioids. Pharmacological dissociation of adverse reactions from the main action is important clinically and basically. Cholinergic and serotonergic mechanisms are suggested to counteract the opioid-induced ventilatory disturbances, but their influence on analgesia is still controversial. The present study evaluated the effects of cholinesterase inhibitors and serotonin-1A (5-HT1A) receptor agonists on morphine (1.0mg/kg, i.v.)-induced ventilatory depression and analgesia in rats. In anesthetized animals, spontaneous ventilation and hind leg withdrawal reflexes against nociceptive thermal stimuli were measured simultaneously. Physostigmine (0.1 and 0.2mg/kg, i.v.) and donepezil (0.5 and 1.0mg/kg, i.v.) relieved the morphine-induced ventilatory depression and enhanced its antinociception. On the other hand, (±)-8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT, 0.03 and 0.1mg/kg, i.v.) and buspirone (0.1 and 0.3mg/kg, i.v.) did not influence antinociception of morphine while they restored the decreased ventilation. In unanesthetized animals, hypercapnic ventilatory response was measured by using whole-body plethysmography. Physostigmine (0.3mg/kg, i.p.), donepezil (1.0mg/kg, i.p.), 8-OH-DPAT (0.3mg/kg, i.p.) and buspirone (3.0mg/kg, i.p.) all recovered the morphine (10mg/kg, i.p.)-induced depression of hypercapnic ventilatory response. The present study suggests that activation of cholinergic or serotonergic (5-HT1A) mechanisms may be a useful therapeutic approach for morphine-induced ventilatory depression without loss of its analgesic action.
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Subramanian HH. Descending control of the respiratory neuronal network by the midbrain periaqueductal grey in the rat in vivo. J Physiol 2012; 591:109-22. [PMID: 23129795 DOI: 10.1113/jphysiol.2012.245217] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Emotional reactions such as vocalization take place during expiration, and thus expression of emotional behaviour requires a switch from inspiration to expiration. I investigated how the midbrain periaqueductal grey (PAG), a known behavioural modulator of breathing, influences the inspiratory-to-expiratory phase transition. Contemporary models propose that late inspiratory (late-I) and post-inspiratory (post-I) neurones found in the medulla, which are active during the inspiratory-to-expiratory phase transition are involved in converting inspiration to expiration. I examined the effect of excitatory amino acid (d,l-homocysteic acid; DLH) stimulation of the PAG on the discharge function of late-I and post-I neurones. The data show a topographical organization of DLH-induced late-I and post-I neuronal modulation within the PAG. Dorsal PAG stimulation induced tachypnoea and caused excitation of both the late-I and post-I neurones. Lateral PAG induced inspiratory prolongation and caused an excitation of late-I neurones but inhibition of post-I neurones. Ventrolateral PAG induced expiratory prolongation and caused a persistent activation of post-I neurones. As well, PAG stimulation modulated both the late-I and post-I cells for least two-three breaths even prior to the change in respiratory motor pattern. This indicates that the PAG influences the late-I and post-I cells independent of pulmonary or other sensory afferent feedback. I conclude that the PAG modulates the activity of the medullary late-I and post-I neurones, and this modulation contributes to the conversion of eupnoea into a behavioural breathing pattern.
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Affiliation(s)
- Hari H Subramanian
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3010, Australia.
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Kron M, Zimmermann JL, Dutschmann M, Funke F, Müller M. Altered responses of MeCP2-deficient mouse brain stem to severe hypoxia. J Neurophysiol 2011; 105:3067-79. [DOI: 10.1152/jn.00822.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Rett syndrome (RTT) patients suffer from respiratory arrhythmias with frequent apneas causing intermittent hypoxia. In a RTT mouse model (methyl-CpG-binding protein 2-deficient mice; Mecp2−/ y) we recently discovered an enhanced hippocampal susceptibility to hypoxia and hypoxia-induced spreading depression (HSD). In the present study we investigated whether this also applies to infant Mecp2−/ y brain stem, which could become life-threatening due to failure of cardiorespiratory control. HSD most reliably occurred in the nucleus of the solitary tract (NTS) and the spinal trigeminal nucleus (Sp5). HSD susceptibility of the Mecp2−/ y NTS and Sp5 was increased on 8 mM K+-mediated conditioning. 5-HT1A receptor stimulation with 8-hydroxy-2-(di-propylamino)tetralin (8-OH-DPAT) postponed HSD by up to 40%, mediating genotype-independent protection. The deleterious impact of HSD on in vitro respiration became obvious in rhythmically active slices, where HSD propagation into the pre-Bötzinger complex (pre-BötC) immediately arrested the respiratory rhythm. Compared with wild-type, the Mecp2−/ y pre-BötC was invaded less frequently by HSD, but if so, HSD occurred earlier. On reoxygenation, in vitro rhythms reappeared with increased frequency, which was less pronounced in Mecp2−/ y slices. 8-OH-DPAT increased respiratory frequency but failed to postpone HSD in the pre-BötC. Repetitive hypoxia facilitated posthypoxic recovery only if HSD occurred. In 57% of Mecp2−/ y slices, however, HSD spared the pre-BötC. Although this occasionally promoted residual hypoxic respiratory activity (“gasping”), it also prolonged the posthypoxic recovery, and thus the absence of central inspiratory drive, which in vivo would lengthen respiratory arrest. In view of the breathing disorders in RTTs, the increased hypoxia susceptibility of MeCP2-deficient brain stem potentially contributes to life-threatening disturbances of cardiorespiratory control.
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Affiliation(s)
- Miriam Kron
- Deutsche Forschungsgemeinschaft Research Center for Molecular Physiology of the Brain, Zentrum für Physiologie und Pathophysiologie, Abteilung Neuro- und Sinnesphysiologie, and
- Bernstein Center for Computational Neuroscience, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Jasper L. Zimmermann
- Deutsche Forschungsgemeinschaft Research Center for Molecular Physiology of the Brain, Zentrum für Physiologie und Pathophysiologie, Abteilung Neuro- und Sinnesphysiologie, and
| | - Mathias Dutschmann
- Deutsche Forschungsgemeinschaft Research Center for Molecular Physiology of the Brain, Zentrum für Physiologie und Pathophysiologie, Abteilung Neuro- und Sinnesphysiologie, and
- Bernstein Center for Computational Neuroscience, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Frank Funke
- Deutsche Forschungsgemeinschaft Research Center for Molecular Physiology of the Brain, Zentrum für Physiologie und Pathophysiologie, Abteilung Neuro- und Sinnesphysiologie, and
| | - Michael Müller
- Deutsche Forschungsgemeinschaft Research Center for Molecular Physiology of the Brain, Zentrum für Physiologie und Pathophysiologie, Abteilung Neuro- und Sinnesphysiologie, and
- Bernstein Center for Computational Neuroscience, Georg-August-Universität Göttingen, Göttingen, Germany
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Brandes IF, Stettner GM, Mörschel M, Kubin L, Dutschmann M. REM sleep-like episodes of motoneuronal depression and respiratory rate increase are triggered by pontine carbachol microinjections in in situ perfused rat brainstem preparation. Exp Physiol 2011; 96:548-55. [PMID: 21335420 DOI: 10.1113/expphysiol.2010.056242] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Hypoglossal nerve activity (HNA) controls the position and movements of the tongue. In persons with compromised upper airway anatomy, sleep-related hypotonia of the tongue and other pharyngeal muscles causes increased upper airway resistance, or total upper airway obstructions, thus disrupting both sleep and breathing. Hypoglossal nerve activity reaches its nadir, and obstructive episodes are longest and most severe, during rapid eye movement stage of sleep (REMS). Microinjections of a cholinergic agonist, carbachol, into the pons have been used in vivo to investigate the mechanisms of respiratory control during REMS. Here, we recorded inspiratory-modulated phrenic nerve activity and HNA and microinjected carbachol (25-50 nl, 10 mm) into the pons in an in situ perfused working heart-brainstem rat preparation (WHBP), an ex vivo model previously validated for studies of the chemical and reflex control of breathing. Carbachol microinjections were made into 40 sites in 33 juvenile rat preparations and, at 24 sites, they triggered depression of HNA with increased respiratory rate and little change of phrenic nerve activity, a pattern akin to that during natural REMS in vivo. The REMS-like episodes started 151 ± 73 s (SD) following microinjections, lasted 20.3 ± 4.5 min, were elicited most effectively from the dorsal part of the rostral nucleus pontis oralis, and were prevented by perfusion of the preparation with atropine. The WHBP offers a novel model with which to investigate cellular and neurochemical mechanisms of REMS-related upper airway hypotonia in situ without anaesthesia and with full control over the cellular environment.
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Affiliation(s)
- Ivo F Brandes
- Department of Anaesthesiology, Emergency and Intensive Care Medicine, University Medicine Gottingen, Georg August University, Gottingen, Germany
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Pavlinac I, Pecotic R, Dogas Z, Valic M. Role of 5-HT1A receptors in induction and preservation of phrenic long-term facilitation in rats. Respir Physiol Neurobiol 2011; 175:146-52. [DOI: 10.1016/j.resp.2010.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 10/21/2010] [Accepted: 10/21/2010] [Indexed: 10/18/2022]
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Abstract
This paper is the 32nd consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2009 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 neurologic 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, 65-30 Kissena Blvd., Flushing, NY 11367, USA.
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Hilaire G, Voituron N, Menuet C, Ichiyama RM, Subramanian HH, Dutschmann M. The role of serotonin in respiratory function and dysfunction. Respir Physiol Neurobiol 2010; 174:76-88. [PMID: 20801236 PMCID: PMC2993113 DOI: 10.1016/j.resp.2010.08.017] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 08/18/2010] [Accepted: 08/20/2010] [Indexed: 01/11/2023]
Abstract
Serotonin (5-HT) is a neuromodulator-transmitter influencing global brain function. Past and present findings illustrate a prominent role for 5-HT in the modulation of ponto-medullary autonomic circuits. 5-HT is also involved in the control of neurotrophic processes during pre- and postnatal development of neural circuits. The functional implications of 5-HT are particularly illustrated in the alterations to the serotonergic system, as seen in a wide range of neurological disorders. This article reviews the role of 5-HT in the development and control of respiratory networks in the ponto-medullary brainstem. The review further examines the role of 5-HT in breathing disorders occurring at different stages of life, in particular, the neonatal neurodevelopmental diseases such as Rett, sudden infant death and Prader-Willi syndromes, adult diseases such as sleep apnoea and mental illness linked to neurodegeneration.
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Affiliation(s)
- Gérard Hilaire
- Mp3-respiration team, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille (CRN2M), Unité Mixte de Recherche 6231, CNRS - Université Aix-Marseille II & III, Faculté Saint Jérôme 13397 Marseille Cedex 20, France
| | - Nicolas Voituron
- Mp3-respiration team, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille (CRN2M), Unité Mixte de Recherche 6231, CNRS - Université Aix-Marseille II & III, Faculté Saint Jérôme 13397 Marseille Cedex 20, France
| | - Clément Menuet
- Mp3-respiration team, Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille (CRN2M), Unité Mixte de Recherche 6231, CNRS - Université Aix-Marseille II & III, Faculté Saint Jérôme 13397 Marseille Cedex 20, France
| | - Ronaldo M. Ichiyama
- Institute of Membrane and Systems Biology, Garstang Building, University of Leeds, Leeds LS2 9JT
| | - Hari H. Subramanian
- Institute of Membrane and Systems Biology, Garstang Building, University of Leeds, Leeds LS2 9JT
| | - Mathias Dutschmann
- Institute of Membrane and Systems Biology, Garstang Building, University of Leeds, Leeds LS2 9JT
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Correction of respiratory disorders in a mouse model of Rett syndrome. Proc Natl Acad Sci U S A 2010; 107:18208-13. [PMID: 20921395 DOI: 10.1073/pnas.1012104107] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Rett syndrome (RTT) is an autism spectrum disorder caused by mutations in the X-linked gene that encodes the transcription factor methyl-CpG-binding protein 2 (MeCP2). A major debilitating phenotype in affected females is frequent apneas, and heterozygous Mecp2-deficient female mice mimic the human respiratory disorder. GABA defects have been demonstrated in the brainstem of Mecp2-deficient mice. Here, using an intact respiratory network, we show that apnea in RTT mice is characterized by excessive excitatory activity in expiratory cranial and spinal nerves. Augmenting GABA markedly improves the respiratory phenotype. In addition, a serotonin 1a receptor agonist that depresses expiratory neuron activity also reduces apnea, corrects the irregular breathing pattern, and prolongs survival in MeCP2 null males. Combining a GABA reuptake blocker with a serotonin 1a agonist in heterozygous females completely corrects their respiratory defects. The results indicate that GABA and serotonin 1a receptor activity are candidates for treatment of the respiratory disorders in Rett syndrome.
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Guenther U, Wrigge H, Theuerkauf N, Boettcher MF, Wensing G, Zinserling J, Putensen C, Hoeft A. Repinotan, a selective 5-HT1A-R-agonist, antagonizes morphine-induced ventilatory depression in anesthetized rats. Anesth Analg 2010; 111:901-7. [PMID: 20802053 DOI: 10.1213/ane.0b013e3181eac011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Spontaneous breathing during mechanical ventilation improves arterial oxygenation and cardiovascular function, but is depressed by opioids during critical care. Opioid-induced ventilatory depression was shown to be counteracted in anesthetized rats by serotonin(1A)-receptor (5-HT(1A)-R)-agonist 8-OH-DPAT, which cannot be applied to humans. Repinotan hydrochloride is a selective 5-HT(1A)-R-agonist already investigated in humans, but the effects on ventilation and nociception are unknown. In this study, we sought to establish (a) the effects of repinotan on spontaneous breathing and nociception, and (b) the interaction with the standard opiate morphine. METHODS The dose-dependent effects of repinotan, given alone or in combination with morphine, on spontaneous minute ventilation (MV) and nociceptive tail-flick reflex latencies (TFLs) were measured simultaneously in spontaneously breathing anesthetized rats. An additional series with NaCl 0.9% and the 5-HT(1A)-R-antagonist WAY 100 135 served as controls. RESULTS (a) Repinotan dose-dependently activated spontaneous breathing (MV, mean [95% confidence interval]; 53% [29%-77%]) of pretreatment level) and suppressed nociception (TLF, 91% maximum possible effect [68%-114%]) with higher doses of repinotan (2-200 μg/kg). On the contrary, nociception was enhanced with a small dose of repinotan (0.2 μg/kg; TFL, -47% maximum possible effect [-95% to 2%]). Effects were prevented by 5-HT(1A)-antagonist WAY 100 135. (B) Morphine-induced depression of ventilation (MV, -72% [-100% to -44%]) was reversed by repinotan (20 μg/kg), which returned spontaneous ventilation to pretreatment levels (MV, 18% [-40% to 77%]). The morphine-induced complete depression of nociception was sustained throughout repinotan and NaCl 0.9% administration. Despite a mild decrease in mean arterial blood pressure, there were no serious cardiovascular side effects from repinotan. CONCLUSIONS The 5-HT(1A)-R-agonist repinotan activates spontaneous breathing in anesthetized rats even in morphine-induced ventilatory depression. The potency of 5-HT(1A)-R-agonists to stimulate spontaneous breathing and their antinociceptive effects should be researched further.
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Affiliation(s)
- U Guenther
- University Hospital of Bonn, Clinic of Anaesthesiology and Intensive Care Medicine, Bonn, Germany.
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Nicholls JG, Paton JFR. Brainstem: neural networks vital for life. Philos Trans R Soc Lond B Biol Sci 2009; 364:2447-51. [PMID: 19651646 DOI: 10.1098/rstb.2009.0064] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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