1
|
Edmonds CE, Robbins KN, Dvorak EG, Howe SP, Sheldon SA, Mayerl CJ, Owairu BA, Young BM, German RZ. The effects of simulated gastroesophageal reflux on infant pig oropharyngeal feeding physiology. Am J Physiol Gastrointest Liver Physiol 2024; 327:G105-G116. [PMID: 38772905 PMCID: PMC11376974 DOI: 10.1152/ajpgi.00027.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 05/13/2024] [Accepted: 05/16/2024] [Indexed: 05/23/2024]
Abstract
The neural connectivity among the oral cavity, pharynx, and esophagus is a critical component of infant feeding physiology. Central integration of oral and pharyngeal afferents alters motor outputs to structures that power swallowing, but the potential effects of esophageal afferents on preesophageal feeding physiology are unclear. These effects may explain the prevalence of oropharyngeal dysphagia in infants suffering from gastroesophageal reflux (GER), though the mechanism underlying this relationship remains unknown. Here we use the validated infant pig model to assess the impacts of simulated GER on preesophageal feeding parameters. We used high-speed videofluoroscopy and electromyography to record bottle-feeding before and following the infusion of a capsaicin-containing solution into the lower esophagus. Sucking parameters were minimally affected by capsaicin exposure, such that genioglossus activity was unchanged and tongue kinematics were largely unaffected. Aspects of the pharyngeal swallow were altered with simulated GER, including increased thyrohyoid muscle activity, increased excursions of the hyoid and thyroid per swallow, decreased swallow frequency, and increased bolus sizes. These results suggest that esophageal afferents can elicit changes in pharyngeal swallowing. In addition, decreased swallowing frequency may be the mechanism by which esophageal pathologies induce oropharyngeal dysphagia. Although recent work indicates that oral or pharyngeal capsaicin may improve dysphagia symptoms, the decreased performance following esophageal capsaicin exposure highlights the importance of designing sensory interventions based upon neurophysiology and the mechanisms underlying disordered feeding. This mechanistic approach requires comprehensive data collection across the entirety of the feeding process, which can be achieved using models such as the infant pig.NEW & NOTEWORTHY Simulated gastroesophageal reflux (GER) in an infant pig model resulted in significant changes in pharyngeal swallowing, which suggests that esophageal afferents are centrally integrated to alter motor outputs to the pharynx. In addition, decreased swallow frequency and increased bolus sizes may be underlying mechanisms by which esophageal pathologies induce oropharyngeal dysphagia. The infant pig model used here allows for a mechanistic approach, which can facilitate the design of intervention strategies based on neurophysiology.
Collapse
Affiliation(s)
- Chloe E Edmonds
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States
- School of Biomedical Sciences, Kent State University, Kent, Ohio, United States
| | - Kaitlyn N Robbins
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States
- School of Speech-Language Pathology and Audiology, The University of Akron, Akron, Ohio, United States
| | - Elizabeth G Dvorak
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States
- Department of Biology, The University of Akron, Akron, Ohio, United States
| | - Stephen P Howe
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States
| | - Sarah A Sheldon
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States
| | - Christopher J Mayerl
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, United States
| | - Brianna A Owairu
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States
| | - Brady M Young
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States
| | - Rebecca Z German
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, Ohio, United States
- School of Biomedical Sciences, Kent State University, Kent, Ohio, United States
| |
Collapse
|
2
|
Bolser DC, Shen TY, Musselwhite MN, Rose MJ, Hayes JA, Pitts T. Evidence for peripheral and central actions of codeine to dysregulate swallowing in the anesthetized cat. Front Neurol 2024; 15:1356603. [PMID: 38938779 PMCID: PMC11210455 DOI: 10.3389/fneur.2024.1356603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 05/06/2024] [Indexed: 06/29/2024] Open
Abstract
Systemic administration of opioids has been associated with aspiration and swallow dysfunction in humans. We speculated that systemic administration of codeine would induce dysfunctional swallowing and that this effect would have a peripheral component. Experiments were conducted in spontaneously breathing, anesthetized cats. The animals were tracheotomized and electromyogram (EMG) electrodes were placed in upper airway and chest wall respiratory muscles for recording swallow related motor activity. The animals were allocated into three groups: vagal intact (VI), cervical vagotomy (CVx), and supra-nodose ganglion vagotomy (SNGx). A dose response to intravenous codeine was performed in each animal. Swallowing was elicited by injection of 3 mL of water into the oropharynx. The number of swallows after vehicle was significantly higher in the VI group than in SNGx. Codeine had no significant effect on the number of swallows induced by water in any of the groups. However, the magnitudes of water swallow-related EMGs of the thyropharyngeus muscle were significantly increased in the VI and CVx groups by 2-4 fold in a dose-related manner. In the CVx group, the geniohyoid muscle EMG during water swallows was significantly increased. There was a significant dose-related increase in spontaneous swallowing in each group from codeine. The spontaneous swallow number at the 10 mg/kg dose of codeine was significantly larger in the CVx group than that in the SNGx group. During water-evoked swallows, intravenous codeine increased upper airway motor drive in a dose-related manner, consistent with dysregulation. The data support the existence of both central and peripheral actions of codeine on spontaneous swallowing. At the highest dose of codeine, the reduced spontaneous swallow number in the SNGx group relative to CVx is consistent with a peripheral excitatory action of codeine either on pharyngeal/laryngeal receptors or in the nodose ganglion itself. The higher number of swallows in the CVx group than the VI group supports disinhibition of this behavior by elimination of inhibitory vagal sensory afferents.
Collapse
Affiliation(s)
- Donald C. Bolser
- Department of Physiological Sciences, University of Florida, Gainesville, FL, United States
| | - Tabitha Y. Shen
- Department of Physiological Sciences, University of Florida, Gainesville, FL, United States
| | | | - Melanie J. Rose
- Department of Physiological Sciences, University of Florida, Gainesville, FL, United States
| | - John A. Hayes
- Department of Physiological Sciences, University of Florida, Gainesville, FL, United States
| | - Teresa Pitts
- Department of Speech, Language, and Hearing Sciences, Department of Biomedical Sciences, Dalton Cardiovascular Center, University of Missouri, Columbia, MO, United States
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Lowenstein ED, Ruffault PL, Misios A, Osman KL, Li H, Greenberg RS, Thompson R, Song K, Dietrich S, Li X, Vladimirov N, Woehler A, Brunet JF, Zampieri N, Kühn R, Liberles SD, Jia S, Lewin GR, Rajewsky N, Lever TE, Birchmeier C. Prox2 and Runx3 vagal sensory neurons regulate esophageal motility. Neuron 2023; 111:2184-2200.e7. [PMID: 37192624 DOI: 10.1016/j.neuron.2023.04.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 10/31/2022] [Accepted: 04/24/2023] [Indexed: 05/18/2023]
Abstract
Vagal sensory neurons monitor mechanical and chemical stimuli in the gastrointestinal tract. Major efforts are underway to assign physiological functions to the many distinct subtypes of vagal sensory neurons. Here, we use genetically guided anatomical tracing, optogenetics, and electrophysiology to identify and characterize vagal sensory neuron subtypes expressing Prox2 and Runx3 in mice. We show that three of these neuronal subtypes innervate the esophagus and stomach in regionalized patterns, where they form intraganglionic laminar endings. Electrophysiological analysis revealed that they are low-threshold mechanoreceptors but possess different adaptation properties. Lastly, genetic ablation of Prox2 and Runx3 neurons demonstrated their essential roles for esophageal peristalsis in freely behaving mice. Our work defines the identity and function of the vagal neurons that provide mechanosensory feedback from the esophagus to the brain and could lead to better understanding and treatment of esophageal motility disorders.
Collapse
Affiliation(s)
- Elijah D Lowenstein
- Developmental Biology/Signal Transduction, Max Delbrück Center for Molecular Medicine, Berlin, Germany; NeuroCure Cluster of Excellence, CharitéUniversitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Pierre-Louis Ruffault
- Developmental Biology/Signal Transduction, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Aristotelis Misios
- Developmental Biology/Signal Transduction, Max Delbrück Center for Molecular Medicine, Berlin, Germany; NeuroCure Cluster of Excellence, CharitéUniversitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Kate L Osman
- Department of Otolaryngology - Head & Neck Surgery, University of Missouri School of Medicine, Columbia, MO, USA
| | - Huimin Li
- The First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Rachel S Greenberg
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Rebecca Thompson
- Department of Otolaryngology - Head & Neck Surgery, University of Missouri School of Medicine, Columbia, MO, USA
| | - Kun Song
- Developmental Biology/Signal Transduction, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Stephan Dietrich
- Development and Function of Neural Circuits, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Xun Li
- Immune Regulation and Cancer, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Nikita Vladimirov
- Systems Biology Imaging, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Andrew Woehler
- Systems Biology Imaging, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Jean-François Brunet
- Institut de Biologie de l'ENS (IBENS), Inserm, CNRS, École normale supérieure, PSL Research University, Paris, France
| | - Niccolò Zampieri
- Development and Function of Neural Circuits, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Ralf Kühn
- Genome Engineering & Disease Models, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Stephen D Liberles
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Shiqi Jia
- The First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Gary R Lewin
- Molecular Physiology of Somatic Sensation, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Nikolaus Rajewsky
- Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Teresa E Lever
- Department of Otolaryngology - Head & Neck Surgery, University of Missouri School of Medicine, Columbia, MO, USA
| | - Carmen Birchmeier
- Developmental Biology/Signal Transduction, Max Delbrück Center for Molecular Medicine, Berlin, Germany; NeuroCure Cluster of Excellence, CharitéUniversitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
| |
Collapse
|
5
|
Pitts T, Iceman KE. Deglutition and the Regulation of the Swallow Motor Pattern. Physiology (Bethesda) 2023; 38:0. [PMID: 35998250 PMCID: PMC9707372 DOI: 10.1152/physiol.00005.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 08/19/2022] [Accepted: 08/19/2022] [Indexed: 11/22/2022] Open
Abstract
Despite centuries of investigation, questions and controversies remain regarding the fundamental genesis and motor pattern of swallow. Two significant topics include inspiratory muscle activity during swallow (Schluckatmung, i.e., "swallow-breath") and anatomical boundaries of the swallow pattern generator. We discuss the long history of reports regarding the presence or absence of Schluckatmung and the possible advantages of and neural basis for such activity, leading to current theories and novel experimental directions.
Collapse
Affiliation(s)
- Teresa Pitts
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky
| | - Kimberly E Iceman
- Department of Neurological Surgery, Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, Kentucky
| |
Collapse
|