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Carotid body stimulation as a potential intervention in sudden death in epilepsy. Epilepsy Behav 2022; 136:108918. [PMID: 36202052 PMCID: PMC10187768 DOI: 10.1016/j.yebeh.2022.108918] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 09/09/2022] [Accepted: 09/11/2022] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To investigate carotid body (CB) mechanisms related to sudden death during seizure. Ictal activation of oxygen-conserving reflexes (OCRs) can trigger fatal cardiorespiratory collapse in seizing rats, which presents like human sudden unexpected death in epilepsy (SUDEP). The CB is strongly implicated in OCR pathways; we hypothesize that modulating CB activity will provide insight into these mechanisms of death. METHODS Long-Evans rats were anesthetized with urethane. Recordings included: electrocorticography, electrocardiography, respiration via nasal thermocouple, and blood pressure (BP). The mammalian diving reflex (MDR) was activated by cold water delivered through a nasal cannula. Reflex and stimulation trials were repeated up to 16 times (4 pre-intervention, 12 post-intervention) or until death. In some animals, one or both carotid bodies were denervated. In some animals, the CB was electrically stimulated, both with and without MDR. Seizures were induced with kainic acid (KA). RESULTS Animals without seizure and with no CB modulation survived all reflexes. Non-seizing animals with CB denervation survived 7.1 ± 5.4 reflexes before death, and only 1 of 7 survived past the 12-trial threshold. Electrical CB stimulation without seizure and without reflex caused significant tachypnea and hypotension. Electrical CB stimulation with seizure and without reflex required higher amplitudes to replicate the physiological responses seen outside seizure. Seizing animals without CB intervention survived 3.2 ± 3.6 trials (per-reflex survival rate 42.0% ± 44.4%), and 0 of 7 survived past the 12-trial threshold. Seizing animals with electrical CB stimulation survived 10.5 ± 4.7 ictal trials (per-reflex survival rate 86.3% ± 35.0%), and 6 of 8 survived past the 12-trial threshold. SIGNIFICANCE These results suggest that, during seizure, the ability of the CB to stimulate a restart of respiration is impaired. The CB and its afferents may be relevant to fatal ictal apnea and SUDEP in humans, and CB stimulation may be a relevant intervention technique in these deaths.
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2
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Schifrin BS, Koos BJ, Cohen WR, Soliman M. Approaches to Preventing Intrapartum Fetal Injury. Front Pediatr 2022; 10:915344. [PMID: 36210941 PMCID: PMC9537758 DOI: 10.3389/fped.2022.915344] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 06/21/2022] [Indexed: 12/05/2022] Open
Abstract
Electronic fetal monitoring (EFM) was introduced into obstetric practice in 1970 as a test to identify early deterioration of fetal acid-base balance in the expectation that prompt intervention ("rescue") would reduce neonatal morbidity and mortality. Clinical trials using a variety of visual or computer-based classifications and algorithms for intervention have failed repeatedly to demonstrate improved immediate or long-term outcomes with this technique, which has, however, contributed to an increased rate of operative deliveries (deemed "unnecessary"). In this review, we discuss the limitations of current classifications of FHR patterns and management guidelines based on them. We argue that these clinical and computer-based formulations pay too much attention to the detection of systemic fetal acidosis/hypoxia and too little attention not only to the pathophysiology of FHR patterns but to the provenance of fetal neurological injury and to the relationship of intrapartum injury to the condition of the newborn. Although they do not reliably predict fetal acidosis, FHR patterns, properly interpreted in the context of the clinical circumstances, do reliably identify fetal neurological integrity (behavior) and are a biomarker of fetal neurological injury (separate from asphyxia). They provide insight into the mechanisms and trajectory (evolution) of any hypoxic or ischemic threat to the fetus and have particular promise in signaling preventive measures (1) to enhance the outcome, (2) to reduce the frequency of "abnormal" FHR patterns that require urgent intervention, and (3) to inform the decision to provide neuroprotection to the newborn.
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Affiliation(s)
- Barry S. Schifrin
- Department of Obstetrics and Gynecology, Western University of Health Sciences, Pomona, CA, United States
| | - Brian J. Koos
- Department of Obstetrics and Gynecology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, United States
| | - Wayne R. Cohen
- Department of Obstetrics and Gynecology, University of Arizona College of Medicine, Tucson, AZ, United States
| | - Mohamed Soliman
- Department of Obstetrics and Gynecology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA, United States
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3
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Borioni F, Biino V, Tinagli V, Pesce C. Effects of Baby Swimming on Motor and Cognitive Development: A Pilot Trial. Percept Mot Skills 2022; 129:977-1000. [PMID: 35473471 DOI: 10.1177/00315125221090203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Contact with water, even from birth, may be an important experience for child development. In this work, we aimed to investigate if baby swimming might influence infant development in motor and cognitive domains. We assigned infants to either a 10-week baby swimming intervention (n = 12; M age = 13 months (SD) = 7) or a control group (n = 15; M age = 22 months (SD) = 6). We assessed motor development with the Peabody Developmental Motor Scales (2nd edition, PDMS-2) and cognitive development with core tests of executive functions: delayed response for working memory, object retrieval for inhibition, and A-not-B for response shifting. Non-parametric analyses revealed that infants in the baby-swimming group improved in gross, fine, and total motor skills, and showed marginally better inhibition speed and shifting accuracy, with associated gains of shifting accuracy and fine and total motor skills. Even with in this small-sized convenience sample, this pilot study revealed promising benefits from baby swimming on motor development that warrant further study. This preliminary work paves the way for replication and illustrates what effect sizes may be expected in sufficiently powered well-designed follow-up research targeted to aid the joint development of motor and cognitive skills as early as infancy.
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Affiliation(s)
- Federica Borioni
- Department of Movement, Human and Health Sciences, 56862University of Rome "Foro Italico", Rome, Italy
| | - Valentina Biino
- Department of Neuroscience, Biomedicine and Movement Science, 197867University of Verona, Verona, Italy
| | - Valeria Tinagli
- Department of Movement, Human and Health Sciences, 56862University of Rome "Foro Italico", Rome, Italy
| | - Caterina Pesce
- Department of Movement, Human and Health Sciences, 56862University of Rome "Foro Italico", Rome, Italy
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4
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Kuypers K, Martherus T, Lamberska T, Dekker J, Hooper SB, Te Pas AB. Reflexes that impact spontaneous breathing of preterm infants at birth: a narrative review. Arch Dis Child Fetal Neonatal Ed 2020; 105:675-679. [PMID: 32350064 DOI: 10.1136/archdischild-2020-318915] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 03/17/2020] [Accepted: 03/30/2020] [Indexed: 02/06/2023]
Abstract
Some neural circuits within infants are not fully developed at birth, especially in preterm infants. Therefore, it is unclear whether reflexes that affect breathing may or may not be activated during the neonatal stabilisation at birth. Both sensory reflexes (eg, tactile stimulation) and non-invasive ventilation (NIV) can promote spontaneous breathing at birth, but the application of NIV can also compromise breathing by inducing facial reflexes that inhibit spontaneous breathing. Applying an interface could provoke the trigeminocardiac reflex (TCR) by stimulating the trigeminal nerve resulting in apnoea and a reduction in heart rate. Similarly, airflow within the nasopharynx can elicit the TCR and/or laryngeal chemoreflex (LCR), resulting in glottal closure and ineffective ventilation, whereas providing pressure via inflations could stimulate multiple receptors that affect breathing. Stimulating the fast adapting pulmonary receptors may activate Head's paradoxical reflex to stimulate spontaneous breathing. In contrast, stimulating the slow adapting pulmonary receptors or laryngeal receptors could induce the Hering-Breuer inflation reflex or LCR, respectively, and thereby inhibit spontaneous breathing. As clinicians are most often unaware that starting primary care might affect the breathing they intend to support, this narrative review summarises the currently available evidence on (vagally mediated) reflexes that might promote or inhibit spontaneous breathing at birth.
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Affiliation(s)
- Kristel Kuypers
- Neonatology, Leiden University Medical Center, Leiden, The Netherlands
| | - Tessa Martherus
- Neonatology, Leiden University Medical Center, Leiden, The Netherlands
| | - Tereza Lamberska
- Neonatology, General University Hospital in Prague, Prague, Czech Republic
| | - Janneke Dekker
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Arjan B Te Pas
- Neonatology, Leiden University Medical Center, Leiden, The Netherlands
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5
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Blix AS. A possible cause of Sudden Infant Death Syndrome. Med Hypotheses 2019; 136:109520. [PMID: 31855683 DOI: 10.1016/j.mehy.2019.109520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 11/29/2019] [Accepted: 12/07/2019] [Indexed: 11/16/2022]
Abstract
It is suggested that an orienting response to loud sound causes apnea, which, in already asphyxic infants, triggers a maximal secondary chemoreceptor response, with massive vagal stimulation of the heart, which causes heart arrest.
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Affiliation(s)
- Arnoldus Schytte Blix
- Department of Arctic and Marine Biology, UiT - The Arctic University of Norway, Tromsø, Norway; St. Catharine's College, Cambridge CB2 1RL, UK.
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6
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Kuypers KL, Lamberska T, Martherus T, Dekker J, Böhringer S, Hooper SB, Plavka R, te Pas AB. The effect of a face mask for respiratory support on breathing in preterm infants at birth. Resuscitation 2019; 144:178-184. [DOI: 10.1016/j.resuscitation.2019.08.043] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/23/2019] [Accepted: 08/26/2019] [Indexed: 11/24/2022]
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7
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Meuwly C, Chowdhury T, Sandu N, Golanov E, Erne P, Rosemann T, Schaller B. Definition and Diagnosis of the Trigeminocardiac Reflex: A Grounded Theory Approach for an Update. Front Neurol 2017; 8:533. [PMID: 29085328 PMCID: PMC5649131 DOI: 10.3389/fneur.2017.00533] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 09/25/2017] [Indexed: 12/11/2022] Open
Abstract
Background The trigeminocardiac reflex (TCR) is defined as sudden onset of parasympathetic dysrhythmias including hemodynamic irregularities, apnea, and gastric hypermotility during stimulation of sensory branches of the trigeminal nerve. Since the first description of the TCR in 1999, there is an ongoing discussion about a more emergent clinical definition. In this work, the author worked out an approach to such an improved definition. Methods In this study, a grounded theory approach was used. Literature about TCR was systematically identified through PubMed (MEDLINE), EMBASE (Ovid SP), and ISI Web of Sciences databases from 1/2005 until 8/2015. TCR was defined as a drop of heart rate (HR) below 60 bpm or 20% to the baseline. A grounded theory approach was used to analyze and interpret the data through a synthesis by the researcher’s perspectives, values, and positions. Results Out of the included studies, the authors formed available data to an update of the understanding of changes in hemodynamic parameters (HR and blood pressure) in a TCR. According to this update, an HR deceleration should be a constant observation to identify a TCR episode while a drop in blood pressure should probably not being fixed to a certain percentage of decrease. Conclusion The here presented working definition improves our understanding of the TCR. It leads the way to a new understanding of the TCR for a proper clinical definition.
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Affiliation(s)
| | - Tumul Chowdhury
- Department of Anaesthesiology and Perioperative Medicine, University of Manitoba, Winnipeg, MB, Canada
| | - Nora Sandu
- Department of Pathology, University of Buenos Aires, Buenos Aires, Argentina
| | - Eugene Golanov
- Department of Neurosurgery, Houston Methodist Hospital, Houston, TX, United States
| | - Paul Erne
- University Hospital Basel, Basel, Switzerland
| | - Thomas Rosemann
- Department of Primary Care, University of Zurich, Zürich, Switzerland
| | - Bernhard Schaller
- Department of Primary Care, University of Zurich, Zürich, Switzerland
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8
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Bierens JJLM, Lunetta P, Tipton M, Warner DS. Physiology Of Drowning: A Review. Physiology (Bethesda) 2017; 31:147-66. [PMID: 26889019 DOI: 10.1152/physiol.00002.2015] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Drowning physiology relates to two different events: immersion (upper airway above water) and submersion (upper airway under water). Immersion involves integrated cardiorespiratory responses to skin and deep body temperature, including cold shock, physical incapacitation, and hypovolemia, as precursors of collapse and submersion. The physiology of submersion includes fear of drowning, diving response, autonomic conflict, upper airway reflexes, water aspiration and swallowing, emesis, and electrolyte disorders. Submersion outcome is determined by cardiac, pulmonary, and neurological injury. Knowledge of drowning physiology is scarce. Better understanding may identify methods to improve survival, particularly related to hot-water immersion, cold shock, cold-induced physical incapacitation, and fear of drowning.
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Affiliation(s)
| | - Philippe Lunetta
- Department of Pathology and Forensic Medicine, University of Turku, Turku, Finland
| | - Mike Tipton
- Department of Sport and Exercise Science, Extreme Environments Laboratory, University of Portsmouth, Portsmouth, United Kingdom; and
| | - David S Warner
- Departments of Anesthesiology, Neurobiology and Surgery, Duke University Medical Center, Durham, North Carolina
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Squier W, Mack J, Jansen AC. Infants dying suddenly and unexpectedly share demographic features with infants who die with retinal and dural bleeding: a review of neural mechanisms. Dev Med Child Neurol 2016; 58:1223-1234. [PMID: 27435495 DOI: 10.1111/dmcn.13202] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/31/2016] [Indexed: 01/01/2023]
Abstract
The cause of death in infants who die suddenly and unexpectedly (sudden unexpected death in infancy [SUDI]) remains a diagnostic challenge. Some infants have identified diseases (explained SUDI); those without explanation are called sudden infant death syndrome (SIDS). Demographic data indicate subgroups among SUDI and SIDS cases, such as unsafe sleeping and apparent life-threatening events. Infants dying suddenly with retinal and dural bleeding are often classified as abused, but in many there is no evidence of trauma. Demographic features suggest that they may represent a further subgroup of SUDI. This review examines the neuropathological hypotheses to explain SIDS and highlights the interaction of infant oxygen-conserving reflexes with the brainstem networks considered responsible for SIDS. We consider sex- and age-specific vulnerabilities related to dural bleeding and how sensitization of the dural innervation by bleeding may influence these reflexes, potentially leading to collapse or even death after otherwise trivial insults.
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Affiliation(s)
- Waney Squier
- Formerly Department of Neuropathology, Oxford University John Radcliffe Hospital, Oxford, UK
| | - Julie Mack
- Department of Radiology, Penn State Hershey Medical Center, Hershey, PA, USA
| | - Anna C Jansen
- Paediatric Neurology Unit, Department of Paediatrics, UZ Brussel, Brussels, Belgium.,Neurogenetics Research Unit, Vrije Universiteit Brussel, Brussels, Belgium
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10
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Taylor H, Kleine I, Bewley S, Loucaides E, Sutcliffe A. Neonatal outcomes of waterbirth: a systematic review and meta-analysis. Arch Dis Child Fetal Neonatal Ed 2016; 101:F357-65. [PMID: 27127204 DOI: 10.1136/archdischild-2015-309600] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 04/04/2016] [Indexed: 11/04/2022]
Abstract
INTRODUCTION In 2015, 9% of babies born in the UK were delivered underwater. Waterbirth is increasing in popularity, despite uncertainty regarding its safety for neonates. This systematic review and meta-analysis appraises the existing evidence for neonatal outcomes following waterbirth. METHODS A structured electronic database search was performed with no language restrictions. All comparative studies which reported neonatal outcomes following waterbirth, and that were published since 1995, were included. Quality appraisal was performed using a modified Critical Appraisal Skills Programme scoring system. The primary outcome was neonatal mortality. Data for each neonatal outcome were tabulated and analysed. Meta-analysis was performed for comparable studies which reported sufficient data. RESULTS The majority of the 29 included studies were small, with limited follow-up and methodological flaws. They were mostly conducted in Europe and high-income countries. Reporting of data was heterogeneous. No significant difference in neonatal mortality, neonatal intensive care unit/special care baby unit admission rate, Apgar scores, umbilical cord gases or infection rates was found between babies delivered into water and on land. CONCLUSIONS This systematic review and meta-analysis did not identify definitive evidence that waterbirth causes harm to neonates compared with land birth. However, there is currently insufficient evidence to conclude that there are no additional risks or benefits for neonates when comparing waterbirth and conventional delivery on land.
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Affiliation(s)
- Henry Taylor
- Population, Policy, and Practice, Institute of Child Health, University College Hospital, London, UK
| | - Ira Kleine
- Obstetrics and Gynaecology, Luton and Dunstable University Hospital Trust, Luton, UK
| | - Susan Bewley
- Women's Health Academic Centre, King's College London, London, UK
| | - Eva Loucaides
- Population, Policy, and Practice, Institute of Child Health, University College Hospital, London, UK
| | - Alastair Sutcliffe
- Population, Policy, and Practice, Institute of Child Health, University College Hospital, London, UK
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11
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Meuwly C, Golanov E, Chowdhury T, Erne P, Schaller B. Trigeminal cardiac reflex: new thinking model about the definition based on a literature review. Medicine (Baltimore) 2015; 94:e484. [PMID: 25654391 PMCID: PMC4602726 DOI: 10.1097/md.0000000000000484] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Trigeminocardiac reflex (TCR) is a brainstem reflex that manifests as sudden onset of hemodynamic perturbation in blood pressure (MABP) and heart rate (HR), as apnea and as gastric hypermotility during stimulation of any branches of the trigeminal nerve. The molecular and clinical knowledge about the TCR is in a constant growth since 1999, what implies a current need of a review about its definition in this changing context. Relevant literature was identified through searching in PubMed (MEDLINE) and Google scholar database for the terms TCR, oculocardiac reflex, diving reflex, vasovagale response. The definition of the TCR varies in clinical as well as in research studies. The main difference applies the required change of MABP and sometimes also HR, which most varies between 10% and 20%. Due to this definition problem, we defined, related to actual literature, 2 major (plausibility, reversibility) and 2 minor criteria (repetition, prevention) for a more proper identification of the TCR in a clinical or research setting. Latest research implies that there is a need for a more extended classification with 2 additional subgroups, considering also the diving reflex and the brainstem reflex. In this review, we highlighted criteria for proper definition and classification of the TCR in the light of increased knowledge and present a thinking model to overcome this complexity. Further we separately discussed the role of HR and MABP and their variation in this context. As another subtopic we gave attention to is the chronic TCR; a variant that is rarely seen in clinical medicine.
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Affiliation(s)
- C Meuwly
- From the University of Basel, Switzerland (CM); The Houston Methodist Research Institute, Houston, Texas, USA (EG); Department of Anesthesia and Perioperative Medicine. University of Manitoba, Winnipeg, Canada (TC); Cardiology, St Anna Clinic, Luzern, Switzerland and University of Basel, Switzerland (PE); Department of Research, University of Southampton, United Kingdom (BS); and Academic Editor, Medicine (BS)
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12
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Nutter E, Shaw-Battista J, Marowitz A. Waterbirth Fundamentals for Clinicians. J Midwifery Womens Health 2014; 59:350-4. [DOI: 10.1111/jmwh.12193] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Panneton WM, Anch AM, Panneton WM, Gan Q. Parasympathetic preganglionic cardiac motoneurons labeled after voluntary diving. Front Physiol 2014; 5:8. [PMID: 24478721 PMCID: PMC3904087 DOI: 10.3389/fphys.2014.00008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 01/06/2014] [Indexed: 12/24/2022] Open
Abstract
A dramatic bradycardia is induced by underwater submersion in vertebrates. The location of parasympathetic preganglionic cardiac motor neurons driving this aspect of the diving response was investigated using cFos immunohistochemistry combined with retrograde transport of cholera toxin subunit B (CTB) to double-label neurons. After pericardial injections of CTB, trained rats voluntarily dove underwater, and their heart rates (HR) dropped immediately to 95 ± 2 bpm, an 80% reduction. After immunohistochemical processing, the vast majority of CTB labeled neurons were located in the reticular formation from the rostral cervical spinal cord to the facial motor nucleus, confirming previous studies. Labeled neurons caudal to the rostral ventrolateral medulla were usually spindle-shaped aligned along an oblique line running from the dorsal vagal nucleus to the ventrolateral reticular formation, while those more rostrally were multipolar with extended dendrites. Nine percent of retrogradely-labeled neurons were positive for both cFos and CTB after diving and 74% of these were found rostral to the obex. CTB also was transported transganglionically in primary afferent fibers, resulting in large granular deposits in dorsolateral, ventrolateral, and commissural subnuclei of the nucleus tractus solitarii (NTS) and finer deposits in lamina I and IV-V of the trigeminocervical complex. The overlap of parasympathetic preganglionic cardiac motor neurons activated by diving with those activated by baro- and chemoreceptors in the rostral ventrolateral medulla is discussed. Thus, the profound bradycardia seen with underwater submersion reinforces the notion that the mammalian diving response is the most powerful autonomic reflex known.
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Affiliation(s)
- W Michael Panneton
- Department of Pharmacological and Physiological Science, St. Louis University St. Louis, MO, USA
| | - A Michael Anch
- Department of Psychology, St. Louis University St. Louis, MO, USA
| | - Whitney M Panneton
- Department of Pharmacological and Physiological Science, St. Louis University St. Louis, MO, USA
| | - Qi Gan
- Department of Pharmacological and Physiological Science, St. Louis University St. Louis, MO, USA
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14
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Panneton WM. The mammalian diving response: an enigmatic reflex to preserve life? Physiology (Bethesda) 2014; 28:284-97. [PMID: 23997188 DOI: 10.1152/physiol.00020.2013] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mammalian diving response is a remarkable behavior that overrides basic homeostatic reflexes. It is most studied in large aquatic mammals but is seen in all vertebrates. Pelagic mammals have developed several physiological adaptations to conserve intrinsic oxygen stores, but the apnea, bradycardia, and vasoconstriction is shared with those terrestrial and is neurally mediated. The adaptations of aquatic mammals are reviewed here as well as the neural control of cardiorespiratory physiology during diving in rodents.
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Affiliation(s)
- W Michael Panneton
- Department of Pharmacological and Physiological Science, St. Louis University School of Medicine, St. Louis, MO, USA.
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15
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Xia L, Leiter JC, Bartlett D. Laryngeal reflex apnea in neonates: effects of CO2 and the complex influence of hypoxia. Respir Physiol Neurobiol 2013; 186:109-13. [PMID: 23348024 DOI: 10.1016/j.resp.2013.01.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 01/08/2013] [Accepted: 01/09/2013] [Indexed: 12/22/2022]
Abstract
We have examined influence of hypocapnia, mild hypercapnia and hypoxia on the durations of fictive apnea and respiratory disruption elicited by injection of 0.1ml of water into the laryngeal lumen-the laryngeal chemoreflex (LCR)-in 20 unanesthetized, decerebrate, vagotomized piglets aged 4-10 days that were paralyzed and ventilated with a constant frequency and tidal volume. The LCR was enhanced by hypocapnia and attenuated by hypercapnia as reported by others. The responses to laryngeal stimulation during hypoxia were varied and complex: some animals showed abbreviated responses during the tachypnea of early hypoxia, followed after 10-15min by more prolonged apnea and respiratory disruption accompanying the reduction in ventilatory activity that commonly occurs during sustained hypoxia in neonates. We speculate that this later hypoxic enhancement of the LCR may be due to accumulation of adenosine in the brain stem.
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Affiliation(s)
- L Xia
- Department of Physiology & Neurobiology, The Geisel School of Medicine at Dartmouth, USA
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