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Fogarty MJ. Loss of larger hypoglossal motor neurons in aged Fischer 344 rats. Respir Physiol Neurobiol 2023:104092. [PMID: 37331418 DOI: 10.1016/j.resp.2023.104092] [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: 05/05/2023] [Revised: 06/06/2023] [Accepted: 06/15/2023] [Indexed: 06/20/2023]
Abstract
The intrinsic (longitudinal, transversalis and verticalis) and extrinsic (genioglossus, styloglossus, hyoglossus and geniohyoid) tongue muscles are innervated by hypoglossal motor neurons (MNs). Tongue muscle activations occur during many behaviors: maintaining upper airway patency, chewing, swallowing, vocalization, vomiting, coughing, sneezing and grooming/sexual activities. In the tongues of the elderly, reduced oral motor function and strength contribute to increased risk of obstructive sleep apnoea. Tongue muscle atrophy and weakness is also described in rats, yet hypoglossal MN numbers are unknown. In young (6-months, n=10) and old (24-months, n=8) female and male Fischer 344 (F344) rats, stereological assessment of hypoglossal MN numbers and surface areas were performed on 16µm Nissl-stained brainstem cryosections. We observed a robust loss of ~15% of hypoglossal MNs and a modest ~8% reduction in their surface areas with age. In the larger size tertile of hypoglossal MNs, age-associated loss of hypoglossal MNs approached ~30% These findings uncover a potential neurogenic locus of pathology for age-associated tongue dysfunctions.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN 55905.
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2
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Benedict PA, Kravietz A, Yang J, Achlatis E, Doyle C, Johnson AM, Dion GR, Amin MR. Longitudinal Effects of Base of Tongue Concurrent Chemoradiation Therapy in a Pre-Clinical Model. Laryngoscope 2023; 133:1455-1461. [PMID: 36134872 PMCID: PMC10030382 DOI: 10.1002/lary.30393] [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: 03/22/2022] [Revised: 08/14/2022] [Accepted: 08/18/2022] [Indexed: 11/12/2022]
Abstract
BACKGROUND/OBJECTIVES Base of tongue (BOT) dysfunction is common following oropharyngeal concurrent chemoradiation therapy (CCRT). We present a clinically relevant animal model quantifying the effects of CCRT on tongue strength and elasticity over time. METHODS Fifty-three male and 53 female Sprague-Dawley rats were randomized to control or experimental groups. Experimental animals received cisplatin, 5-fluorouracil, and 5 fractions of 7 Gy directed to the BOT. Controls received no intervention. At 2 weeks, 5 months, or 10 months after CCRT, animals underwent non-survival surgery to measure twitch and tetanic tongue strength, which were analyzed using multivariate linear mixed effects models. Tongue displacement, a surrogate for tongue elasticity, was also determined via stress-strain testing and analyzed via a multivariate linear mixed effects model. RESULTS Reporting the combined results of both sexes, the estimated experimental group mean peak twitch forces became more divergent over time compared to controls, being 8.3% lower than controls at 2 weeks post-CCRT, 15.7% lower at 5 months, and 31.6% lower at 10 months. Estimated experimental group mean peak tetanic forces followed a similar course and were 2.9% lower than controls at 2 weeks post CCRT, 20.7% lower at 5 months, and 27.0% lower at 10 months. Stress-strain testing did not find CCRT to have a significant effect on tongue displacement across experimental timepoints. CONCLUSIONS This study demonstrates an increasing difference in tongue strength over time between controls and animals exposed to CCRT. Tongue elasticity was not significantly affected by CCRT, suggesting that changes in strength may not be caused by fibrosis. LEVEL OF EVIDENCE NA Laryngoscope, 133:1455-1461, 2023.
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Affiliation(s)
- Peter A. Benedict
- Department of Otolaryngology-Head and Neck Surgery, New York University Grossman School of Medicine, New York, NY, USA
| | - Adam Kravietz
- Department of Otolaryngology-Head and Neck Surgery, New York University Grossman School of Medicine, New York, NY, USA
| | - Jackie Yang
- Department of Otolaryngology-Head and Neck Surgery, New York University Grossman School of Medicine, New York, NY, USA
| | - Efstratios Achlatis
- Department of Otolaryngology-Head and Neck Surgery, New York University Grossman School of Medicine, New York, NY, USA
| | - Carina Doyle
- Department of Otolaryngology-Head and Neck Surgery, New York University Grossman School of Medicine, New York, NY, USA
| | - Aaron M. Johnson
- Department of Otolaryngology-Head and Neck Surgery, New York University Grossman School of Medicine, New York, NY, USA
| | - Gregory R. Dion
- Department of Otolaryngology-Head and Neck Surgery, Brooke Army Medical Center, Fort Sam Houston, TX
- Dental and Craniofacial Trauma Research Department, U.S. Army Institute of Surgical Research, JBSA Fort Sam Houston, TX
| | - Milan R. Amin
- Department of Otolaryngology-Head and Neck Surgery, New York University Grossman School of Medicine, New York, NY, USA
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Bioenergetic Evaluation of Muscle Fatigue in Murine Tongue. Dysphagia 2022:10.1007/s00455-022-10537-y. [DOI: 10.1007/s00455-022-10537-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 10/26/2022] [Indexed: 11/21/2022]
Abstract
AbstractMuscle fatigue is the diminution of force required for a particular action over time. Fatigue may be particularly pronounced in aging muscles, including those used for swallowing actions. Because risk for swallowing impairment (dysphagia) increases with aging, the contribution of muscle fatigue to age-related dysphagia is an emerging area of interest. The use of animal models, such as mice and rats (murine models) allows experimental paradigms for studying the relationship between muscle fatigue and swallowing function with a high degree of biological precision that is not possible in human studies. The goal of this article is to review basic experimental approaches to the study of murine tongue muscle fatigue related to dysphagia. Traditionally, murine muscle fatigue has been studied in limb muscles through direct muscle stimulation and behavioral exercise paradigms. As such, physiological and bioenergetic markers of muscle fatigue that have been validated in limb muscles may be applicable in studies of cranial muscle fatigue with appropriate modifications to account for differences in muscle architecture, innervation ratio, and skeletal support. Murine exercise paradigms may be used to elicit acute fatigue in tongue muscles, thereby enabling study of putative muscular adaptations. Using these approaches, hypotheses can be developed and tested in mice and rats to allow for future focused studies in human subjects geared toward developing and optimizing treatments for age-related dysphagia.
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Assays of Tongue Force, Timing, and Dynamics in Rat and Mouse Models. Brain Res Bull 2022; 185:49-55. [PMID: 35469932 PMCID: PMC10187612 DOI: 10.1016/j.brainresbull.2022.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 04/13/2022] [Accepted: 04/20/2022] [Indexed: 12/18/2022]
Abstract
Communication and swallowing are highly complex sensorimotor events that are tightly linked to respiration and vital to health and well-being. The tongue is a complex organ, often described as a muscular hydrostat, that is crucial for maintaining airway patency, preparing and safely transporting food/liquid, and rapidly changing position and shape for speech. As with any complex behavior, tongue function can be compromised with aging, diseases/conditions, trauma, or as a pharmacologic side effect. As such, modeling lingual function and dysfunction for basic and translational research is paramount; understanding how the nervous system controls tongue function for complex behavior is foundational to this work. Non-invasive access to tongue tissues and kinematics during awake behavior has been historically challenging, creating a critical need to measure tongue function in model systems. Germane to this field of study are the instruments and assays of licking/lapping and drinking, including tongue force and timing measures, many of which were designed or modified by Dr. Stephen C. Fowler. The focus of this paper is to review some of the important contributions of measuring tongue behaviors in awake rats and mice and how these have been modified by other researchers to advance translational science.
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Fogarty MJ, Sieck GC. Tongue muscle contractile, fatigue, and fiber type properties in rats. J Appl Physiol (1985) 2021; 131:1043-1055. [PMID: 34323593 DOI: 10.1152/japplphysiol.00329.2021] [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: 12/12/2022] Open
Abstract
The intrinsic and extrinsic tongue muscles manipulate the position and shape of the tongue and are activated during many oral and respiratory behaviors. In the present study, in 6-mo-old Fischer 344 rats, we examined mechanical and fatigue properties of tongue muscles in relation to their fiber type composition. In an ex vivo preparation, isometric force and fatigue was assessed by direct muscle stimulation. Tongue muscles were frozen in melting isopentane and transverse sections cut at 10 µm. In hematoxylin-eosin (H&E)-stained muscle sections, the relative fractions of muscle versus extracellular matrix were determined. Muscle fibers were classified as type I, IIa and IIx, and/or IIb based on immunoreactivity to specific myosin heavy chain isoform antibodies. Cross-sectional areas (CSAs) and proportions of different fiber types were used to calculate their relative contribution to total muscle CSAs. We found that the superior and inferior longitudinal intrinsic muscles (4.4 N/cm2) and genioglossus muscle (3.0 N/cm2) generated the greatest maximum isometric force compared with the transversalis muscle (0.9 N/cm2). The longitudinal muscles and the transversalis muscle displayed greater fatigue during repetitive stimulation consistent with the greater relative contribution of type IIx and/or IIb fibers. By contrast, the genioglossus, comprising a higher proportion of type I and IIa fibers, was more fatigue resistant. This study advances our understanding of the force, fatigue, and fiber type-specific properties of individual tongue musculature. The assessments and approach provide a readily accessible muscular readout for scenarios where motor control dysfunction or tongue weakness is evident.NEW & NOTEWORTHY For the individual tongue muscles, relatively little quantification of uniaxial force, fatigue, and fiber type-specific properties has been documented. Here, we assessed uniaxial-specific force generation, fatigability, and muscle fiber type-specific properties in the superior and inferior longitudinal muscles, the transversalis, and the genioglossus in Fischer 344 rats. The longitudinal muscles produced the greatest isometric tetanic-specific forces. The genioglossus was more fatigue resistant and comprised higher proportions of I and IIa fibers.
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Affiliation(s)
- Matthew J Fogarty
- Department of Physiology and Biomedical Engineering, grid.66875.3aMayo Clinic, Rochester, Minnesota
| | - Gary C Sieck
- Department of Physiology and Biomedical Engineering, grid.66875.3aMayo Clinic, Rochester, Minnesota
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Kletzien H, Kelm-Nelson CA, Wang S, Suzuki M, Connor NP. Myogenic marker expression as a function of age and exercise-based therapy in the tongue. Exp Gerontol 2020; 142:111104. [PMID: 33017670 PMCID: PMC7748063 DOI: 10.1016/j.exger.2020.111104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/29/2020] [Accepted: 09/24/2020] [Indexed: 12/30/2022]
Abstract
Degeneration of tongue muscles with aging may contribute to swallowing deficits observed in elderly people. However, the capacity for tongue muscle stem cells (SCs) to regenerate and repair the aged tongue and improve tongue strength following tongue exercise (a current clinical treatment) has never been examined. We found that the expression of regenerative, myogenic markers were impaired with age and may be related to increased expression of senescent marker p16INK4a. Tongue strength increased in young adult and old rats following exercise and was related to the expression of Pax7, MyoD, myogenin, and p16INK4a. Our study also suggests that strengthening of tongue muscles via clinical rehabilitation strategies also increased the expression of SC regenerative markers in the tongue throughout the exercise duration.
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Affiliation(s)
- Heidi Kletzien
- Department of Biomedical Engineering, University of Wisconsin-Madison, United States of America; Department of Surgery, University of Wisconsin School of Medicine and Public Health, United States of America; Department of Stem Cell and Regenerative Biology, Harvard University, United States of America.
| | - Cynthia A Kelm-Nelson
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, United States of America
| | - Sabrina Wang
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, United States of America
| | - Masatoshi Suzuki
- Department of Biomedical Engineering, University of Wisconsin-Madison, United States of America; Department of Comparative Biosciences, University of Wisconsin-Madison, United States of America
| | - Nadine P Connor
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, United States of America; Department of Communication Sciences and Disorders, University of Wisconsin-Madison, United States of America
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Krekeler BN, Weycker JM, Connor NP. Effects of Tongue Exercise Frequency on Tongue Muscle Biology and Swallowing Physiology in a Rat Model. Dysphagia 2020; 35:918-934. [PMID: 32130514 DOI: 10.1007/s00455-020-10105-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 02/25/2020] [Indexed: 11/28/2022]
Abstract
Age-related changes in muscle composition and function are often treated using exercise, including muscles of the tongue to treat swallowing impairments (dysphagia). Although tongue exercise is commonly prescribed, optimal tongue exercise doses have not been determined. The purpose of this study was to evaluate effects of varying tongue exercise frequency on tongue force, genioglossus muscle fiber size, composition and metabolism, and swallowing in a rat model. We randomized 41 old and 40 young adult Fischer 344/Brown Norway rats into one of four tongue exercise groups: 5 days/week; 3 days/week; 1 day/week; or sham. Tongue force was higher following all exercise conditions (vs sham); the 5 day/week group had the greatest change in tongue force (p < 0.001). There were no exercise effects on genioglossus (GG) fiber size or MyHC composition (p > 0.05). Significant main effects for age showed a greater proportion of Type I fibers in (p < 0.0001) and increased fiber size of IIa fibers (p = 0.026) in old. There were no significant effects of citrate synthase activity or PGC-1α expression. Significant differences were found in bolus speed and area (size), but findings were potentially influenced by variability. Our findings suggest that tongue force is influenced by exercise frequency; however, these changes were not reflected in characteristics of the GG muscle assayed in this study. Informed by findings of this study, future work in tongue dose optimization will be required to provide better scientific premise for clinical treatments in humans.
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Affiliation(s)
- Brittany N Krekeler
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, Goodnight Hall, 1300 University Ave, Madison, WI, 53706, USA. .,Department of Surgery-Otolaryngology, Clinical Science Center, University of Wisconsin-Madison, 600 Highland Avenue, Madison, WI, 53792-7375, USA. .,Department of Communication Sciences and Disorders, Northwestern University, Swallowing Cross-Systems Collaborative, 2240 Campus Drive, Evanston, IL, 60208, USA.
| | - Jacqueline M Weycker
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, Goodnight Hall, 1300 University Ave, Madison, WI, 53706, USA.,Department of Surgery-Otolaryngology, Clinical Science Center, University of Wisconsin-Madison, 600 Highland Avenue, Madison, WI, 53792-7375, USA
| | - Nadine P Connor
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, Goodnight Hall, 1300 University Ave, Madison, WI, 53706, USA.,Department of Surgery-Otolaryngology, Clinical Science Center, University of Wisconsin-Madison, 600 Highland Avenue, Madison, WI, 53792-7375, USA
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8
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Cullins MJ, Wenninger JM, Cullen JS, Russell JA, Kleim JA, Connor NP. Tongue Force Training Induces Plasticity of the Lingual Motor Cortex in Young Adult and Aged Rats. Front Neurosci 2019; 13:1355. [PMID: 31920514 PMCID: PMC6931318 DOI: 10.3389/fnins.2019.01355] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 12/02/2019] [Indexed: 11/24/2022] Open
Abstract
Tongue exercise programs are used clinically for dysphagia in aged individuals and have been shown to improve lingual strength. However, the neural mechanisms of age-related decline in swallowing function and its association with lingual strength are not well understood. Using an established rat model of aging and tongue exercise, we hypothesized that the motor cortex of aged rats would have a smaller lingual motor map area than young adult rats and would increase in size as a function of tongue exercise. Over 8 weeks, rats either underwent a progressive resistance tongue exercise program (TE), learned the task but did not exercise (trained controls, TC), or were naïve untrained controls (UC). Cortical motor map areas for tongue and jaw were determined using intracortical microstimulation (ICMS). Rats in the TE and TC groups had a significantly larger motor cortex region for the tongue than the UC group. Lingual cortical motor area was not correlated with protrusive tongue force gains and did not differ significantly with age. These results suggest that learning a novel tongue force skill was sufficient to induce plasticity of the lingual motor cortex yet increasing tongue strength with progressive resistance exercise did not significantly expand the lingual motor area beyond the gains that occurred through the skilled learning component.
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Affiliation(s)
- Miranda J. Cullins
- Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States
- *Correspondence: Miranda J. Cullins,
| | - Julie M. Wenninger
- Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States
| | - Jared S. Cullen
- Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States
| | - John A. Russell
- Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States
| | - Jeffrey A. Kleim
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States
| | - Nadine P. Connor
- Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States
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9
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Balou M, Herzberg EG, Kamelhar D, Molfenter SM. An intensive swallowing exercise protocol for improving swallowing physiology in older adults with radiographically confirmed dysphagia. Clin Interv Aging 2019; 14:283-288. [PMID: 30804667 PMCID: PMC6375531 DOI: 10.2147/cia.s194723] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Purpose The aim of this study was to investigate improvements in swallowing function and physiology in a series of healthy older adults with radiographically confirmed dysphagia, following completion of an exercise-based swallowing intervention. Patients and methods Nine otherwise healthy older adults (six females, mean age =75.3, SD =5.3) had confirmed impairments in swallowing safety and/or efficiency on a modified barium swallow study. Each participant completed an 8-week swallowing treatment protocol including effortful swallows, Mendelsohn maneuvers, tongue-hold swallows, supraglottic swallows, Shaker exercises and effortful pitch glides. Treatment sessions were conducted once per week with additional daily home practice. Penetration–Aspiration Scale and the Modified Barium Swallowing Impairment Profile (MBSImP) were scored in a blind and randomized fashion to examine changes to swallowing function and physiology from baseline to post-treatment. Results There were significant improvements in swallowing physiology as represented by improved oral and pharyngeal composite scores of the MBSImP. Specific components to demonstrate statistical improvement included initiation of the pharyngeal swallow, laryngeal elevation and pharyngeal residue. There was a nonsignificant reduction in median PAS scores. Conclusion Swallowing physiology can be improved using this standardized high-intensity exercise protocol in healthy adults with evidence of dysphagia. Future research is needed to examine the individual potential of each exercise in isolation and to determine ideal dose and frequency. Studies on various etiological groups are warranted.
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Affiliation(s)
- Matina Balou
- Department of Otolaryngology, New York University School of Medicine, Head & Neck Surgery, New York, NY, USA
| | - Erica G Herzberg
- Department of Speech-Language Pathology, New York University Langone Health, Rusk Rehabilitation, New York, NY, USA
| | - David Kamelhar
- New York University School of Medicine, Department of Pulmonary Medicine, New York, NY, USA
| | - Sonja M Molfenter
- Department of Communicative Sciences and Disorder, Communicative Sciences and Disorders, New York University Steinhardt, New York, NY, USA,
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Kletzien H, Russell JA, Leverson G, Connor NP. Effect of neuromuscular electrical stimulation frequency on muscles of the tongue. Muscle Nerve 2018; 58:441-448. [PMID: 29797723 DOI: 10.1002/mus.26173] [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: 09/11/2017] [Revised: 05/09/2018] [Accepted: 05/11/2018] [Indexed: 11/08/2022]
Abstract
INTRODUCTION Neuromuscular electrical stimulation (NMES) for the treatment of swallowing disorders is delivered at a variety of stimulation frequencies. We examined the effects of stimulation frequency on tongue muscle plasticity in an aging rat model. METHODS Eighty-six young, middle-aged, and old rats were assigned to either bilateral hypoglossal nerve stimulation at 10 or 100 Hz (5 days/week, 8 weeks), sham, or no-implantation conditions. Muscle contractile properties and myosin heavy chain (MyHC) composition were determined for hyoglossus (HG) and styloglossus (SG) muscles. RESULTS Eight weeks of 100-Hz stimulation resulted in the greatest changes in muscle contractile function with significantly longer contraction and half-decay times, the greatest reduction in fatigue, and a transition toward slowly contracting, fatigue-resistant MyHC isoforms. DISCUSSION NMES at 100-Hz induced considerable changes in contractile and phenotypic profiles of HG and SG muscles, suggesting higher frequency NMES may yield a greater therapeutic effect. Muscle Nerve, 2018.
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Affiliation(s)
- Heidi Kletzien
- Department of Biomedical Engineering University of Wisconsin-Madison, 1300 University Avenue, Room 481, Madison, Wisconsin 53706, USA
| | - John A Russell
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Glen Leverson
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Nadine P Connor
- Department of Communication Sciences and Disorders, University of Wisconsin-Madison, Madison, Wisconsin, USA
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11
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Volumetric Changes to the Pharynx in Healthy Aging: Consequence for Pharyngeal Swallow Mechanics and Function. Dysphagia 2018; 34:129-137. [PMID: 30039259 DOI: 10.1007/s00455-018-9924-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 07/11/2018] [Indexed: 10/28/2022]
Abstract
Pharyngeal lumen volume is prone to increase as a consequence of pharyngeal muscle atrophy in aging. Yet, the impact of this on swallowing mechanics and function is poorly understood. We examined the relationship between pharyngeal volume and pharyngeal swallowing mechanics and function in a sample of healthy community-dwelling seniors. Data were collected from 44 healthy seniors (21 male, mean age = 76.9, SD = 7.1). Each participant swallowed 9 boluses of barium (3 × 5 ml thin, 3 × 20 ml thin, 3 × 5 ml nectar). Pharyngeal shortening, pharyngeal constriction, pyriform sinus and vallecular residue were quantified from lateral view videofluorosopic swallowing studies. Pharyngeal lumen volume was captured during an oral breathing task with acoustic pharyngometry. In addition, within-participant measures of strength and anthropometrics were collected. Four linear mixed effects regression models were run to study the relationship between pharyngeal volume and pharyngeal constriction, pharyngeal shortening, pyriform sinus residue, and vallecular residue while controlling for bolus condition, age, sex, and posterior tongue strength. Increasing pharyngeal lumen volume was significantly related to worse constriction and vallecular residue. In general, larger and thicker boluses resulted in worse pharyngeal constriction and residue. Pharyngeal shortening was only significantly related to posterior tongue strength. Our work establishes the utility of acoustic pharyngometry to monitor pharyngeal lumen volume. Increasing pharyngeal lumen volume appears to impact both pharyngeal swallowing mechanics and function in a sample of healthy, functional seniors.
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12
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Benedict PA, Ruiz R, Verma A, Dion GR, Oh P, Wang B, Ahmed OH, Hiwatashi N, Bing R, Victor K, Hu KS, Johnson A, Branski RC, Amin MR. The effects of concurrent chemoradiation therapy to the base of tongue in a preclinical model. Laryngoscope 2017; 128:1783-1790. [PMID: 29280493 DOI: 10.1002/lary.27033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 10/16/2017] [Accepted: 11/06/2017] [Indexed: 11/10/2022]
Abstract
OBJECTIVES/HYPOTHESIS To develop a clinically relevant model of oropharyngeal concurrent chemoradiation therapy (CCRT) in order to quantify the effects of CCRT on tongue function and structure. CCRT for advanced oropharyngeal cancer commonly leads to tongue base dysfunction and dysphagia. However, no preclinical models currently exist to study the pathophysiology of CCRT-related morbidity, thereby inhibiting the development of targeted therapeutics. STUDY DESIGN Animal model. METHODS Twenty-one male Sprague-Dawley rats were randomized into three groups: 2 week (2W), 5 month (5M), and control (C). The 2W and 5M animals received cisplatin, 5-fluorouracil, and five fractions of 7 Gy to the tongue base; the C animals received no intervention. In vivo tongue strength and displacement, as well as hyoglossus muscle collagen content, were assessed. Analyses were conducted 2 weeks or 5 months following completion of CCRT in the 2W and 5M groups, respectively. RESULTS Peak tetanic and twitch tongue forces were significantly reduced in both 2W and 5M animals compared to controls (tetanic: P = .0041, P = .0089, respectively; twitch: P = .0201, P = .0020, respectively). Twitch half-decay time was prolonged in 2W animals compared to controls (P = .0247). Tongue displacement was significantly reduced across all testing parameters in 5M animals compared to both the C and 2W groups. No differences in collagen content were observed between experimental groups. CONCLUSIONS The current study is the first to describe a preclinical model of CCRT to the head and neck with an emphasis on clinical relevance. Tongue strength decreased at 2 weeks and 5 months post-CCRT. Tongue displacement increased only at 5 months post-CCRT. Fibrosis was not detected, implicating alternative causative factors for these findings. LEVEL OF EVIDENCE NA Laryngoscope, 1783-1790, 2018.
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Affiliation(s)
- Peter A Benedict
- Department of Otolaryngology-Head and Neck Surgery, New York University Voice Center, New York University School of Medicine, New York, New York
| | - Ryan Ruiz
- Department of Otolaryngology-Head and Neck Surgery, New York University Voice Center, New York University School of Medicine, New York, New York
| | - Avanti Verma
- Department of Otolaryngology-Head and Neck Surgery, New York University Voice Center, New York University School of Medicine, New York, New York
| | - Gregory R Dion
- Department of Otolaryngology-Head and Neck Surgery, New York University Voice Center, New York University School of Medicine, New York, New York.,Department of Otolaryngology-Head and Neck Surgery, Brooke Army Medical Center, Fort Sam Houston, Texas, U.S.A
| | - Philmo Oh
- Department of Radiation Oncology, New York University School of Medicine, New York, New York
| | - Binhuan Wang
- Department of Population Heath, Division of Biostatistics, New York University School of Medicine, New York, New York
| | - Omar H Ahmed
- Department of Otolaryngology-Head and Neck Surgery, New York University Voice Center, New York University School of Medicine, New York, New York
| | - Nao Hiwatashi
- Department of Otolaryngology-Head and Neck Surgery, New York University Voice Center, New York University School of Medicine, New York, New York
| | - Renjie Bing
- Department of Otolaryngology-Head and Neck Surgery, New York University Voice Center, New York University School of Medicine, New York, New York
| | - Kristen Victor
- Department of Otolaryngology-Head and Neck Surgery, New York University Voice Center, New York University School of Medicine, New York, New York
| | - Kenneth S Hu
- Department of Radiation Oncology, New York University School of Medicine, New York, New York
| | - Aaron Johnson
- Department of Otolaryngology-Head and Neck Surgery, New York University Voice Center, New York University School of Medicine, New York, New York
| | - Ryan C Branski
- Department of Otolaryngology-Head and Neck Surgery, New York University Voice Center, New York University School of Medicine, New York, New York
| | - Milan R Amin
- Department of Otolaryngology-Head and Neck Surgery, New York University Voice Center, New York University School of Medicine, New York, New York
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13
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Cullins MJ, Connor NP. Alterations of intrinsic tongue muscle properties with aging. Muscle Nerve 2017; 56:E119-E125. [PMID: 28181263 DOI: 10.1002/mus.25605] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/27/2017] [Accepted: 02/03/2017] [Indexed: 11/09/2022]
Abstract
INTRODUCTION Age-related decline in the intrinsic lingual musculature could contribute to swallowing disorders, yet the effects of age on these muscles is unknown. We hypothesized there is reduced muscle fiber size and shifts to slower myosin heavy chain (MyHC) fiber types with age. METHODS Intrinsic lingual muscles were sampled from 8 young adult (9 months) and 8 old (32 months) Fischer 344/Brown Norway rats. Fiber size and MyHC were determined by fluorescent immunohistochemistry. RESULTS Age was associated with a reduced number of rapidly contracting muscle fibers, and more slowly contracting fibers. Decreased fiber size was found only in the transverse and verticalis muscles. DISCUSSION Shifts in muscle composition from faster to slower MyHC fiber types may contribute to age-related changes in swallowing duration. Decreasing muscle fiber size in the protrusive transverse and verticalis muscles may contribute to reductions in maximum isometric tongue pressure found with age. Differences among regions and muscles may be associated with different functional demands. Muscle Nerve 56: E119-E125, 2017.
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Affiliation(s)
- Miranda J Cullins
- Department of Surgery, University of Wisconsin-Madison, 1300 University Avenue, Madison, Wisconsin, 53706, USA
| | - Nadine P Connor
- Department of Surgery, University of Wisconsin-Madison, 1300 University Avenue, Madison, Wisconsin, 53706, USA
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Tadros MA, Fuglevand AJ, Brichta AM, Callister RJ. Intrinsic excitability differs between murine hypoglossal and spinal motoneurons. J Neurophysiol 2016; 115:2672-80. [PMID: 26936988 DOI: 10.1152/jn.01114.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 02/29/2016] [Indexed: 12/12/2022] Open
Abstract
Motoneurons differ in the behaviors they control and their vulnerability to disease and aging. For example, brain stem motoneurons such as hypoglossal motoneurons (HMs) are involved in licking, suckling, swallowing, respiration, and vocalization. In contrast, spinal motoneurons (SMs) innervating the limbs are involved in postural and locomotor tasks requiring higher loads and lower movement velocities. Surprisingly, the properties of these two motoneuron pools have not been directly compared, even though studies on HMs predominate in the literature compared with SMs, especially for adult animals. Here we used whole cell patch-clamp recording to compare the electrophysiological properties of HMs and SMs in age-matched neonatal mice (P7-P10). Passive membrane properties were remarkably similar in HMs and SMs, and afterhyperpolarization properties did not differ markedly between the two populations. HMs had narrower action potentials (APs) and a faster upstroke on their APs compared with SMs. Furthermore, HMs discharged APs at higher frequencies in response to both step and ramp current injection than SMs. Therefore, while HMs and SMs have similar passive properties, they differ in their response to similar levels of depolarizing current. This suggests that each population possesses differing suites of ion channels that allow them to discharge at rates matched to the different mechanical properties of the muscle fibers that drive their distinct motor functions.
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Affiliation(s)
- M A Tadros
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Hunter Medical Research Institute, The University of Newcastle, Callaghan, New South Wales, Australia; and
| | - A J Fuglevand
- Department of Physiology, College of Medicine, University of Arizona, Tucson, Arizona
| | - A M Brichta
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Hunter Medical Research Institute, The University of Newcastle, Callaghan, New South Wales, Australia; and
| | - R J Callister
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Hunter Medical Research Institute, The University of Newcastle, Callaghan, New South Wales, Australia; and
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Schaser AJ, Ciucci MR, Connor NP. Cross-activation and detraining effects of tongue exercise in aged rats. Behav Brain Res 2015; 297:285-96. [PMID: 26477376 DOI: 10.1016/j.bbr.2015.10.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 10/09/2015] [Accepted: 10/11/2015] [Indexed: 02/05/2023]
Abstract
Voice and swallowing deficits can occur with aging. Tongue exercise paired with a swallow may be used to treat swallowing disorders, but may also benefit vocal function due to cross-system activation effects. It is unknown how exercise-based neuroplasticity contributes to behavior and maintenance following treatment. Eighty rats were used to examine behavioral parameters and changes in neurotrophins after tongue exercise paired with a swallow. Tongue forces and ultrasonic vocalizations were recorded before and after training/detraining in young and old rats. Tissue was analyzed for neurotrophin content. Results showed tongue exercise paired with a swallow was associated with increased tongue forces at all ages. Gains diminished after detraining in old rats. Age-related changes in vocalizations, neurotrophin 4 (NT4), and brain derived neurotrophic factor (BDNF) were found. Minimal cross-system activation effects were observed. Neuroplastic benefits were demonstrated with exercise in old rats through behavioral improvements and up-regulation of BDNF in the hypoglossal nucleus. Tongue exercise paired with a swallow should be developed, studied, and optimized in human clinical research to treat swallowing and voice disorders in elderly people.
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Affiliation(s)
- Allison J Schaser
- Department of Communication Sciences and Disorders, Department of Surgery Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin-Madison, 53706, United States.
| | - Michelle R Ciucci
- Department of Communication Sciences and Disorders, Department of Surgery Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin-Madison, 53706, United States
| | - Nadine P Connor
- Department of Communication Sciences and Disorders, Department of Surgery Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin-Madison, 53706, United States
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Uchima Koecklin KH, Kato C, Funaki Y, Hiranuma M, Ishida T, Fujita K, Yabushita T, Kokai S, Ono T. Effect of unilateral nasal obstruction on tongue protrusion forces in growing rats. J Appl Physiol (1985) 2015; 118:1128-35. [DOI: 10.1152/japplphysiol.01152.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 03/10/2015] [Indexed: 01/23/2023] Open
Abstract
Mouth breathing caused by nasal obstruction affects the normal growth and development of craniofacial structures, including changes in the orofacial muscles. Tongue muscles play an important role in patency of the pharyngeal airway, and changes in the breathing pattern may influence tongue function. The purpose of this study was to evaluate the effect of unilateral nasal obstruction during growth on contractile properties of the tongue-protruding muscles. Sixty 6-day-old male Wistar albino rats were divided randomly into control ( n = 30) and experimental ( n = 30) groups. Rats in the experimental group underwent a unilateral nasal obstruction after cauterization of the external nostril at the age of 8 days, and muscle contractile characteristics were measured at 5, 7, and 9 wk of age. The specific parameters measured were twitch force, contraction time, half-decay time, tetanic force, and fatigue index. Repeated-measures multivariate analysis of variance was used for intergroup and intragroup statistical comparisons. Twitch contraction force and half-decay time were significantly increased in the experimental group at all ages. Tetanic forces at 60 and 80 Hz were significantly higher in the experimental group at all ages. The fatigue index was decreased significantly in the experimental group at the age of 5 wk. These results suggest that early unilateral nasal obstruction may increase the contraction force of the tongue-protruding muscles and prolong the duration of muscle contraction, which may influence the shape and development of the craniofacial complex.
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Affiliation(s)
- Karin Harumi Uchima Koecklin
- Orthodontic Science, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Chiho Kato
- Orthodontic Science, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yukiha Funaki
- Orthodontic Science, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Maya Hiranuma
- Orthodontic Science, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takayoshi Ishida
- Orthodontic Science, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Koichi Fujita
- Orthodontic Science, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tadachika Yabushita
- Orthodontic Science, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Satoshi Kokai
- Orthodontic Science, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takashi Ono
- Orthodontic Science, Department of Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
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Molfenter SM, Amin MR, Branski RC, Brumm JD, Hagiwara M, Roof SA, Lazarus CL. Age-Related Changes in Pharyngeal Lumen Size: A Retrospective MRI Analysis. Dysphagia 2015; 30:321-7. [PMID: 25750039 DOI: 10.1007/s00455-015-9602-9] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 02/16/2015] [Indexed: 11/29/2022]
Abstract
Age-related loss of muscle bulk and strength (sarcopenia) is often cited as a potential mechanism underlying age-related changes in swallowing. Our goal was to explore this phenomenon in the pharynx, specifically, by measuring pharyngeal wall thickness and pharyngeal lumen area in a sample of young versus older women. MRI scans of the neck were retrospectively reviewed from 60 women equally stratified into three age groups (20s, 60s, 70+). Four de-identified slices were extracted per scan for randomized, blinded analysis: one mid-sagittal and three axial slices were selected at the anterior inferior border of C2 and C3, and at the pit of the vallecula. Pixel-based measures of pharyngeal wall thickness and pharyngeal lumen area were completed using ImageJ and then converted to metric units. Measures of pharyngeal wall thickness and pharyngeal lumen area were compared between age groups with one-way ANOVAs using Sidak adjustments for post-hoc pairwise comparisons. A significant main effect for age was observed across all variables whereby pharyngeal wall thickness decreased and pharyngeal lumen area increased with advancing age. Pairwise comparisons revealed significant differences between 20s versus 70+ for all variables and 20s versus 60s for all variables except those measured at C2. Effect sizes ranged from 0.54 to 1.34. Consistent with existing sacropenia literature, the pharyngeal muscles appear to atrophy with age and consequently, the size of the pharyngeal lumen increases.
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Affiliation(s)
- Sonja M Molfenter
- Communicative Sciences & Disorders, Steinhardt, New York University, 665 Broadway, Room 934, New York, NY, 10012, USA,
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Becker BJ, Russell JA, Connor NP. Effects of aging on evoked retrusive tongue actions. Arch Oral Biol 2015; 60:966-71. [PMID: 25847069 DOI: 10.1016/j.archoralbio.2015.02.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 02/24/2015] [Accepted: 02/25/2015] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Tongue strength, timing, and coordination deficits may underlie age-related swallowing function. Retrusive tongue actions are likely important in retrograde bolus transport. However, age-related changes in retrusive tongue muscle contractile properties have not been identified in animal studies. Because previous studies employed whole hypoglossal nerve stimulation that activated both protrusive and retrusive tongue muscles, co-contraction may have masked retrusive muscle force decrements. The hypotheses of this study were: (1) retrusive tongue muscle contraction forces would be diminished and temporal characteristics prolonged in old rats when lateral nerves were selectively activated, and (2) greater muscle contractile forces with selective lateral branch stimulation would be found relative to whole hypoglossal nerve stimulation. DESIGN Nineteen Fischer 344/Brown Norway rats (9 old, 10 young adult) underwent tongue muscle contractile property recording elicited by: (1) bilateral whole hypoglossal nerve stimulation, and (2) selective lateral branch stimulation. Twitch contraction time (CT), half-decay time, maximal twitch and tetanic forces, and a fatigue index were measured. RESULTS For whole nerve stimulation, CT was significantly longer in the old group. No significant age group differences were found with selective lateral nerve stimulation. Significantly reduced twitch forces (old group only), increased tetanic forces and significantly less fatigue were found with selective lateral nerve stimulation than with whole hypoglossal stimulation. CONCLUSIONS Retrusive tongue forces are not impaired in old rats. Deficits observed in swallowing with aging may be due to other factors such as inadequate bolus propulsive forces, mediated by protrusive tongue muscles, or timing/coordination of muscle actions.
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Affiliation(s)
- Benjamin J Becker
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin, Madison, WI, United States
| | - John A Russell
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin, Madison, WI, United States
| | - Nadine P Connor
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin, Madison, WI, United States; Department of Communication Sciences and Disorders, University of Wisconsin, Madison, WI, United States.
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Russell JA, Connor NP. Effects of age and radiation treatment on function of extrinsic tongue muscles. Radiat Oncol 2014; 9:254. [PMID: 25472556 PMCID: PMC4269095 DOI: 10.1186/s13014-014-0254-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 11/05/2014] [Indexed: 11/10/2022] Open
Abstract
Background Radiation treatment for head and neck cancer often results in difficulty swallowing. Muscle weakness and fibrosis have been identified clinically as possible etiologies for swallowing problems following radiation. Aging may compound the effects of radiation on swallowing because radiation-induced damage to muscles and other tissues critical for the oropharyngeal swallow is overlaid on a declining sensorimotor system. However, there have been no investigations of the manner in which aging and radiation treatment effects combine to impact tongue muscles, which are critical effectors of the oropharyngeal swallow. Methods Thirty-seven male Fisher 344/Brown Norway rats were divided into four groups; young adults (9 month old), old (32 months old), young radiation (9 months), and old radiation (32 months old). Two fractions of 11 Gy on consecutive days was delivered by external beam radiation to the ventral side of the rat’s body over the anterior portion (20 X 30 mm area) of the anterior digastric muscle. Two-way analysis of variance (ANOVA) was used to examine the effects of age and radiation and their interaction on muscle contractile properties. Post-hoc testing was completed using Fisher’s least significant differences (LSD). Results Radiation was associated with a significant decrease in tongue force production and reduced speed of tongue muscle contraction. However, radiation treatment did not lead to muscle atrophy and fibrosis formation in the GG muscle. Radiation treatment did not exacerbate atrophic changes observed with aging, or lead to additional fibrosis formation in the GG muscle from that observed in the other groups. Conclusions The purpose of this research was to determine the effect of radiation on muscles of the tongue and to determine whether aging altered the extent of radiation injury to tongue muscles. Radiation was associated with a significant decrease in tongue force production and reduced speed of tongue muscle contraction, and the reduction in the speed of tongue muscle contraction was exacerbated in the aged-rat tongue. This work provides a foundation for future investigations of treatments for concurrent effects of aging and radiation on muscles of the tongue and swallowing.
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Affiliation(s)
- John A Russell
- University of Wisconsin School of Medicine and Public Health, Otolaryngology Head and Neck Surgery, Madison, WI, 53706, USA.
| | - Nadine P Connor
- University of Wisconsin School of Medicine and Public Health, Otolaryngology Head and Neck Surgery, Madison, WI, 53706, USA. .,Department of Communication Sciences and Disorders, University of Wisconsin-Madison, Madison, WI, 53706, USA.
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Differential effects of amphetamine and GBR-12909 on orolingual motor function in young vs aged F344/BN rats. Psychopharmacology (Berl) 2014; 231:4695-701. [PMID: 24923981 PMCID: PMC4301607 DOI: 10.1007/s00213-014-3620-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 05/13/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Orolingual motor deficits, such as dysarthria and dysphagia, contribute to increased morbidity and mortality in the elderly. In preclinical studies, we and others have reported age-related decreases in tongue motility in both F344 and F344/BN rats. The fact that these deficits are associated with nigrostriatal dopamine (DA), tissue measures suggest that increasing dopamine function might normalize tongue motility. OBJECTIVE The purpose of the current study was to determine whether two indirect dopamine agonists with locomotor-enhancing effects, d-amphetamine (amphetamine; 1 and 2 mg/kg) and GBR-12909 (5, 10, and 20 mg/kg), can improve tongue motility in aged F344/BN rats. METHODS Young (6 months) and aged (30 months) F344/BN rats licked water from an isometric force disc so that tongue motility (licks/second) and tongue force could be measured as a function of age and drug dose. RESULTS Consistent with our previous studies, tongue force was greater and tongue motility was lower in the aged group. Tongue motility was increased by amphetamine but not by GBR-12909. Amphetamine decreased peak tongue force, primarily in the young group. GBR-12909 did not affect tongue force. GBR-12909 increased the number of licks/session in the young group but not in the aged group, while amphetamine increased this measure in both groups. CONCLUSION These results demonstrate differential effects of these drugs on orolingual motor function and suggest that blocking DA uptake is insufficient to increase tongue motility in aging.
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Kubo LS, Nascimento WVD, Dantas RO. Efeito da idade, do sexo, da altura e do índice de massa corporal no tempo de sucção oral de líquido. REVISTA BRASILEIRA DE GERIATRIA E GERONTOLOGIA 2013. [DOI: 10.1590/s1809-98232013000100002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJETIVO: Avaliar o efeito da idade, do sexo, da altura e do índice de massa corporal (IMC) no tempo de sucção oral de água em pessoas normais. MÉTODO: O método constou de, em duplicata, cronometrar o tempo de sucção contínua de 40 ml de água à temperatura ambiente, utilizando um canudo com 6 mm de diâmetro e outro com 3 mm de diâmetro. Cada voluntário foi avaliado sentado, com a cabeça formando um ângulo de 90º entre a mandíbula e o pescoço. Foi permitida a deglutição. Em um grupo de 15 indivíduos, foi avaliada a reprodutibilidade do teste em quatro dias diferentes. O trabalho incluiu 180 indivíduos, o grupo jovem (20 a 30 anos, 45 homens e 45 mulheres) e o grupo idoso (65 a 89 anos, 45 homens e 45 mulheres). RESULTADOS: Observou-se diferença significativa no tempo de sucção entre jovens e idosos, sendo maior para os idosos do que para os jovens. Com o canudo de menor diâmetro, as mulheres idosas tiveram maior tempo de sucção do que os homens idosos. Em mulheres jovens, foi encontrada correlação positiva entre o IMC e o tempo de sucção. Não se observou influência da altura. A repetição do estudo em quatro dias mostrou o mesmo resultado. CONCLUSÃO: Concluímos que o envelhecimento compromete a sucção de líquido, e que este comprometimento é maior nas mulheres do que nos homens. Em mulheres jovens, maior IMC está associado ao maior tempo de sucção.
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Connor NP, Russell JA, Jackson MA, Kletzien H, Wang H, Schaser AJ, Leverson GE, Zealear DL. Tongue muscle plasticity following hypoglossal nerve stimulation in aged rats. Muscle Nerve 2012; 47:230-40. [PMID: 23169566 DOI: 10.1002/mus.23499] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2012] [Indexed: 11/10/2022]
Abstract
INTRODUCTION Age-related decreases in tongue muscle mass and strength have been reported. It may be possible to prevent age-related tongue muscle changes using neuromuscular electrical stimulation (NMES). Our hypothesis was that alterations in muscle contractile properties and myosin heavy chain composition would be found after NMES. METHODS Fifty-four young, middle-aged, and old 344/Brown Norway rats were included in this study. Twenty-four rats underwent bilateral electrical stimulation of the hypoglossal nerves for 8 weeks and were compared with control or sham rats. Muscle contractile properties and myosin heavy chain (MHC) in the genioglossus (GG), styloglossus (SG), and hyoglossus (HG) muscles were examined. RESULTS Compared with unstimulated control rats, we found reduced muscle fatigue, increased contraction and half-decay times, and increased twitch and tetanic tension. Increased type I MHC was found, except for in GG in old and middle-aged rats. CONCLUSION Transitions in tongue muscle contractile properties and phenotype were found after NMES.
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Affiliation(s)
- Nadine P Connor
- Department of Surgery, Otolaryngology-Head and Neck Surgery, 600 Highland Avenue, Room K4/711, University of Wisconsin, Madison, Wisconsin 53792, USA.
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Nuckolls AL, Worley C, Leto C, Zhang H, Morris JK, Stanford JA. Tongue force and tongue motility are differently affected by unilateral vs bilateral nigrostriatal dopamine depletion in rats. Behav Brain Res 2012; 234:343-8. [PMID: 22796604 DOI: 10.1016/j.bbr.2012.07.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 07/03/2012] [Accepted: 07/05/2012] [Indexed: 01/05/2023]
Abstract
In addition to its cardinal symptoms of bradykinesia, muscle rigidity, resting tremor and postural disturbances, Parkinson's disease (PD) also affects orolingual motor function. Orolingual motor deficits can contribute to dysphagia, which increases morbidity and mortality in this population. Previous preclinical studies describing orolingual motor deficits in animal models of PD have focused on unilateral nigrostriatal dopamine (DA) depletion. In this study we compared the effects of unilateral vs bilateral 6-hydroxydopamine (6-OHDA)-induced DA depletion in rats trained to lick water from an isometric force-sensing disc. Rats received either unilateral or bilateral 6-OHDA into the medial forebrain bundle and were tested for four weeks post-lesion. Dependent variables included task engagement (the number of licks per session), tongue force (mean and maximum), and tongue motility (the number of licks per second). While both lesion groups exhibited decreased tongue force output, tongue motility deficits were present in only the group that received unilateral nigrostriatal DA depletion. Task engagement was not significantly diminished by 6-OHDA. Analysis of striatal DA tissue content revealed that DA depletion was ∼97% in the unilateral group and ∼90% in the bilateral group. These results suggest that while nigrostriatal DA depletion affects tongue force output, deficits in tongue motility may instead result from a functional imbalance in neural pathways affecting this midline structure.
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Affiliation(s)
- Andrea L Nuckolls
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, United States
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Tamura F, Kikutani T, Tohara T, Yoshida M, Yaegaki K. Tongue thickness relates to nutritional status in the elderly. Dysphagia 2012; 27:556-61. [PMID: 22538556 PMCID: PMC3528964 DOI: 10.1007/s00455-012-9407-z] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 04/05/2012] [Indexed: 12/18/2022]
Abstract
Many elderly people under long-term care suffer from malnutrition caused by dysphagia, frequently leading to sarcopenia. Our hypothesis is that sarcopenia may compromise oral function, resulting in dysphagia. The objectives of this study were to evaluate sarcopenia of the lingual muscles by measuring the tongue thickness, and elucidate its relationship with nutritional status. We examined 104 elderly subjects (mean age = 80.3 ± 7.9 years). Anthropometric data, such as triceps skinfold thickness and midarm muscle area (AMA), were obtained. The tongue thickness of the central part was determined using ultrasonography. Measurement was performed twice and the mean value was obtained. The relationship between tongue thickness and nutritional status was analyzed by Pearson’s correlation coefficient and Spearman’s rank correlation coefficient. AMA and age were identified by multiple-regression analysis as factors influencing tongue thickness. The results of this study suggest that malnutrition may induce sarcopenia not only in the skeletal muscles but also in the tongue.
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Affiliation(s)
- Fumiyo Tamura
- Rehabilitation Clinic for Speech and Swallowing Disorders, The Nippon Dental University School of Life Dentistry at Tokyo, Dental Hospital, Fujimi Chiyoda-ku, Tokyo, Japan.
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Temelli A, Geyikoğlu F. A Comparative Study on the Structural Features of Muscle Fibers in Intrinsic Lingual Muscles of 21 Day Old and 9 Month Old Mice Using Light and Electron Microscopy. JOURNAL OF APPLIED ANIMAL RESEARCH 2011. [DOI: 10.1080/09712119.2006.9706823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Aysel Temelli
- a Department of Biology, Kâzim Karabekir Education Faculty
| | - Fatime Geyikoğlu
- b Department of Biology Faculty of Arts and Science , Atatürk University , Erzurum , Turkey
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Johnson AM, Connor NP. Effects of electrical stimulation on neuromuscular junction morphology in the aging rat tongue. Muscle Nerve 2011; 43:203-11. [PMID: 21254085 DOI: 10.1002/mus.21819] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Alterations in neuromuscular junction (NMJ) structure in cranial muscles may contribute to age-related deficits in critical sensorimotor actions such as swallowing. Neuromuscular electrical stimulation (NMES) is used in swallowing therapy, but it is unclear how NMJ structure is affected or if NMJ morphology is best measured in two or three dimensions. Two- and three-dimensional measurements of NMJ morphology in the genioglossus muscle were compared in rats that had undergone 8 weeks of hypoglossal nerve stimulation vs. untreated controls. The relationship between motor endplate volume and nerve terminal volume had a mean positive slope in 90% of the young adult controls, but it was positive in only 50% of the old controls; 89% of NMES old rats had a positive slope. NMJ measurements were more accurate when measured in three dimensions. In the NMJ, aging and NMES are associated with changes in the pre- and post-synaptic relationship.
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Affiliation(s)
- Aaron M Johnson
- Department of Surgery, University of Wisconsin-Madison, Madison, WI 53792, USA
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Abstract
PURPOSE OF REVIEW With the graying of the world's population, there is an increased interest in the physiological effects of aging. This review examines the physiological changes of the gut with aging and their clinical significance. RECENT FINDINGS Changes with aging in the gastrointestinal tract are variable, but in some cases they are responsible for a variety of symptoms. Thus, alterations in taste and smell, gastric motility, intestinal overgrowth and changes in gastrointestinal hormone release are the basis of the physiological anorexia of aging. Alterations in swallowing lead to silent aspiration. Changes in gastric emptying play a role in postprandial hypotension. Changes in gastrointestinal function can lead to constipation and fecal incontinence. Weakening of the colonic muscular wall produces diverticula. Achlorhydria is associated with malabsorption of some forms of iron and calcium. Vitamin D malabsorption aggravates the hypovitaminosis D that is so common in older persons. Changes in probiotics can lead to diarrhea and altered immune system. In the liver, aging is associated with delayed drug metabolism. SUMMARY Changes in the physiology of the gut play a role in the anorexia of aging, aspiration pneumonia, postprandial hypotension, constipation and fecal incontinence.
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Affiliation(s)
- Asif Bhutto
- Division of Geriatric Medicine, Saint Louis University, USA bGRECC, VA Medical Center, St. Louis, Missouri, USA
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Ray AD, Ogasa T, Magalang UJ, Krasney JA, Farkas GA. Aging increases upper airway collapsibility in Fischer 344 rats. J Appl Physiol (1985) 2008; 105:1471-6. [PMID: 18756010 DOI: 10.1152/japplphysiol.00166.2008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The upper airway muscles play an important role in maintaining upper airway collapsibility, and the incidence of sleep-disordered breathing increases with age. We hypothesize that the increase in airway collapsibility with increasing age can be linked to changes in upper airway muscle mechanics and structure. Eight young (Y: 6 mo) and eight old (O: 30 mo) Fischer 344 rats were anesthetized and mechanically ventilated, and the pharyngeal pressure associated with flow limitation (Pcrit) was measured 1) with the hypoglossal (cnXII) nerve intact, 2) following bilateral cnXII denervation, and 3) during cnXII stimulation. With the cnXII intact, the upper airways of older rats were more collapsible compared with their younger counterparts [Pcrit = -7.1 +/- 0.6 (SE) vs. -9.5 +/- 0.7 cmH2O, respectively; P = 0.033]. CnXII denervation resulted in an increase in Pcrit such that Pcrit became similar in both groups (O: -4.2 +/- 0.5 cmH2O; Y: -5.4 +/- 0.5 cmH2O). In all rats, cnXII stimulation decreased Pcrit (less collapsible) in both groups (O: -11.3 +/- 1.0 cmH2O; Y: -10.2 +/- 1.0 cmH2O). The myosin heavy chain composition of the genioglossus muscle demonstrated a decrease in the percentage of the IIb isoform (38.3 +/- 2.5 vs. 21.7 +/- 1.7%; P < 0.001); in contrast, the sternohyoid muscle demonstrated an increase in the percentage of the IIb isoform (72.2 +/- 2.5 vs. 58.4 +/- 2.3%; P = 0.001) with age. We conclude that the upper airway becomes more collapsible with age and that the increase in upper airway collapsibility with age is likely related to altered neural control rather than to primary alterations in upper airway muscle structure and function.
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Affiliation(s)
- Andrew D Ray
- Center for Research and Education in Special Environments, State University of New York at Buffalo, 515 Kimball Tower, 3435 Main St., Buffalo, NY 14214, USA.
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Schwarz EC, Thompson JM, Connor NP, Behan M. The effects of aging on hypoglossal motoneurons in rats. Dysphagia 2008; 24:40-8. [PMID: 18716837 DOI: 10.1007/s00455-008-9169-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Accepted: 04/24/2008] [Indexed: 11/28/2022]
Abstract
Aging can result in a loss of neuronal cell bodies and a decrease in neuronal size in some regions of the brain and spinal cord. Motoneuron loss in the spinal cord is thought to contribute to the progressive decline in muscle mass and strength that occurs with age (sarcopenia). Swallowing disorders represent a large clinical problem in elderly persons; however, age-related alterations in cranial motoneurons that innervate muscles involved in swallowing have been understudied. We aimed to determine if age-related alterations occurred in the hypoglossal nucleus in the brainstem. If present, these changes might help explain alterations at the neuromuscular junction and changes in the contractile properties of tongue muscle that have been reported in older rats. We hypothesized that with increasing age there would be a loss of motoneurons and a reduction in neuronal size and the number of primary dendrites associated with each hypoglossal motoneuron. Neurons in the hypoglossal nucleus were visualized with the neuronal marker NeuN in young (9-10 months), middle-aged (24-25 months), and old (32-33 months) male F344/BN rats. Hypoglossal motoneurons were retrograde-labeled with injections of Cholera Toxin beta into the genioglossus muscle of the tongue and visualized using immunocytochemistry. Results indicated that the number of primary dendrites of hypoglossal motoneurons decreased significantly with age, while no age-associated changes were found in the number or size of hypoglossal motoneurons. Loss of primary dendrites could reduce the number of synaptic inputs and thereby impair function.
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Affiliation(s)
- Emilie C Schwarz
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706, USA
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Connor NP, Ota F, Nagai H, Russell JA, Leverson G. Differences in age-related alterations in muscle contraction properties in rat tongue and hindlimb. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2008; 51:818-827. [PMID: 18658053 PMCID: PMC2892886 DOI: 10.1044/1092-4388(2008/059)] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
PURPOSE Because of differences in muscle architecture and biomechanics, the purpose of this study was to determine whether muscle contractile properties of rat hindlimb and tongue were differentially affected by aging. METHOD Deep peroneal and hypoglossal nerves were stimulated in 6 young and 7 old Fischer 344-Brown Norway rats to allow recording of muscle contractile properties of tongue and extensor digitorum longus (EDL) muscle in the hindlimb. In the same animals, the following measurements were made: (a) twitch contraction time (CT; in milliseconds), (b) half decay time (HDT; in milliseconds), (c) maximum twitch force (in grams), (d) tetanic force, and (e) fatigue index determined from repetitive stimulation of the muscles. RESULTS No significant differences were observed in young versus old groups in retrusive tongue forces, whereas a significant (p < .05) decrement in EDL tetanic forces was found in old rats. Slower CT in old rats was observed only in the tongue. Old and young groups were not significantly different in fatigue index or HDT for tongue or EDL. CONCLUSIONS Old animals generated equivalent maximum tongue forces with stimulation, but they were slower in achieving these forces than young animals. Limb and cranial muscles were not affected equally by aging. As such, information derived from limb muscle studies may not easily generalize to the cranial motor system.
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Affiliation(s)
- Nadine P Connor
- University of Wisconsin Clinical Science Center, Madison, WI 53792-7375, USA.
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Acute and rebound effects of lorazepam on orolingual motor function in young versus aged Fischer 344/Brown Norway rats. Behav Pharmacol 2008; 19:161-5. [PMID: 18332681 DOI: 10.1097/fbp.0b013e3282f62c53] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The purpose of this study was to measure the acute effects of lorazepam [a short-acting benzodiazepine (BZ) with no active metabolites] on orolingual motor function in young (6 months) versus aged (24 months) Fischer 344/Brown Norway hybrid (F344/BN) rats. Rats licked water from an isometric force-sensing operandum so that the number of licks per session, licking rhythm (licks/second), and lick force could be measured during daily sessions. Acute doses (1.0 and 2.0 mg/kg) of lorazepam were administered 30 min before the testing sessions, 4 days apart. Whereas aged rats produced more licks per session, lorazepam increased this measure primarily in the young group. On the days after each lorazepam dose, rats licked less than they did before receiving the drug. This effect was shown by both groups. Aged rats showed significantly slower licking rhythm than young rats. Lorazepam slowed this measure in both groups. Peak tongue forces were significantly increased by lorazepam. These findings suggest that BZs such as lorazepam can affect tongue force output and exacerbate age-related tongue motility deficits. They also suggest that although BZs can directly influence motivation to engage in water-reinforced tasks, opposite 'rebound' effects may occur, even after acute dosing.
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Zhang H, Bethel CS, Smittkamp SE, Stanford JA. Age-related changes in orolingual motor function in F344 vs F344/BN rats. Physiol Behav 2007; 93:461-6. [PMID: 17980393 DOI: 10.1016/j.physbeh.2007.10.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Revised: 08/30/2007] [Accepted: 10/05/2007] [Indexed: 10/22/2022]
Abstract
Normal aging is associated with both locomotor and orolingual motor deficits. Preclinical studies of motor function in normal aging, however, have focused primarily on locomotor activity. The purpose of this study was to measure age-related changes in orolingual motor function and compare these changes between two rat strains commonly used in aging studies: Fischer 344 (F344) and Fischer 344/Brown Norway hybrid (F344/BN) rats. Rats (6-, 12-, 18- and 24-months of age) were trained to lick water from an isometric force-sensing operandum so that the number of licks per session, licking rhythm (licks/second) and lick force could be measured. In both strains, the number of licks per session was greatest in the oldest group, while this measure was greater for F344/BN rats at all ages. Peak tongue force increased with age in F344/BN rats, did not change with age in the F344 rats, and was greater for the F344/BN rats at all ages. Both strains exhibited an age-related slowing of licking rhythm beginning with the 18-month-old group. These findings suggest that despite lifespan differences between these two rat strains, diminished tongue motility emerges at the same age.
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Affiliation(s)
- Hongyu Zhang
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Nagai H, Russell JA, Jackson MA, Connor NP. Effect of aging on tongue protrusion forces in rats. Dysphagia 2007; 23:116-21. [PMID: 17694408 PMCID: PMC2892880 DOI: 10.1007/s00455-007-9103-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Accepted: 05/08/2007] [Indexed: 12/01/2022]
Abstract
The purpose of this study was to ascertain the effect of aging on muscle contractile properties associated with tongue protrusion in a rat model. Fischer 344/Brown Norway hybrid rats, ten young (9 months old) and ten old (32 months old), were used to measure protrusive contractile properties. Results showed a significant reduction in tetanic forces in the old animals. The following measures of muscle contraction were not different between age groups: mean twitch contraction force, twitch contraction time, twitch contraction half-decay time, and a calculated measure of fatigability. In conclusion, aging influenced protrusive tongue muscle contractions in a rat model such that tetanic forces were reduced. The reduction of tetanus force may parallel findings in human subjects relative to isometric tongue force generation and may be associated with age-related disorders of swallowing.
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Affiliation(s)
- Hiromi Nagai
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin, Madison Wisconsin 53792, USA. Department of Otolaryngology-Head and Neck Surgery, Kitasato University School of Medicine, Kanagawa, Japan
| | - John A. Russell
- William S, Middleton Memorial Veterans Hospital, Madison, Wisconsin 53792, USA
| | - Michelle A. Jackson
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin, Madison Wisconsin 53792, USA
| | - Nadine P. Connor
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin, Madison Wisconsin 53792, USA. Department of Communicative Disorders, University of Wisconsin-Madison, Madison, Wisconsin 53792, USA. Otolaryngology Head-Neck Surgery & Communicative Disorders, 600 Highland Avenue, Room K4/711, Madison, Wisconsin 53792, USA
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