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Junichi Kitagawa - One of the best experts on this subject based on the ideXlab platform.
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Functional involvement of acid-sensing ion channel 3 in the Swallowing Reflex in rats.
Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society, 2019Co-Authors: Mohammad Zakir Hossain, Hiroshi Ando, Shumpei Unno, Tetsuji Nakamoto, Junichi KitagawaAbstract:Background Difficulty Swallowing represents a major health problem. Swallowing function is improved by incorporating weak acids in suspensions/food boluses, implicating acid-sensing ion channels (ASICs) in the Swallowing Reflex. However, the functional involvement of ASICs in the Swallowing Reflex has not been fully elucidated. Methods We localized ASIC3s in Swallowing-related regions innervated by the superior laryngeal nerves (SLNs) and those in the nodose-petrosal-jugular ganglionic complex (NPJc) and examined their functional involvement in evoking the Swallowing Reflex in rats. Key results We localized ASIC3s on epithelial cells and nerve fibers in Swallowing-related regions innervated by the SLNs. In the NPJc, around half of the SLN-afferent neurons expressed ASIC3. Two-thirds of ASIC3s were localized on unmyelinated neurons in the nodose and petrosal ganglia. In the jugular ganglia, they were equally distributed on unmyelinated and myelinated neurons. Topical application of a synthetic non-proton ASIC3 activator, 2-guanidine-4-methylquinazoline (GMQ), and its natural endogenous ligand agmatine (a metabolite of the amino acid arginine) in Swallowing-related regions evoked a considerable number of Swallowing Reflexes. Increasing the concentration of GMQ and agmatine up to a certain concentration increased the number of evoked Reflexes and shortened the interval between the evoked Reflexes. Agmatine was less potent than GMQ in its ability to evoke Swallowing Reflexes. Prior topical application of an ASIC3 antagonist significantly attenuated the number of GMQ- and agmatine-evoked Swallowing Reflexes. Conclusions & inferences Acid-sensing ion channel 3s localized on nerves and epithelial cells in Swallowing-related regions are functional in evoking the Swallowing Reflex and activation of these channels via a pharmacological agonist appears to improve Swallowing behavior.
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Functional involvement of acid-sensing ion channel 3 in the Swallowing Reflex in rats.
Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society, 2019Co-Authors: Mohammad Zakir Hossain, Hiroshi Ando, Shumpei Unno, Tetsuji Nakamoto, Junichi KitagawaAbstract:Difficulty Swallowing represents a major health problem. Swallowing function is improved by incorporating weak acids in suspensions/food boluses, implicating acid-sensing ion channels (ASICs) in the Swallowing Reflex. However, the functional involvement of ASICs in the Swallowing Reflex has not been fully elucidated. We localized ASIC3s in Swallowing-related regions innervated by the superior laryngeal nerves (SLNs) and those in the nodose-petrosal-jugular ganglionic complex (NPJc) and examined their functional involvement in evoking the Swallowing Reflex in rats. We localized ASIC3s on epithelial cells and nerve fibers in Swallowing-related regions innervated by the SLNs. In the NPJc, around half of the SLN-afferent neurons expressed ASIC3. Two-thirds of ASIC3s were localized on unmyelinated neurons in the nodose and petrosal ganglia. In the jugular ganglia, they were equally distributed on unmyelinated and myelinated neurons. Topical application of a synthetic non-proton ASIC3 activator, 2-guanidine-4-methylquinazoline (GMQ), and its natural endogenous ligand agmatine (a metabolite of the amino acid arginine) in Swallowing-related regions evoked a considerable number of Swallowing Reflexes. Increasing the concentration of GMQ and agmatine up to a certain concentration increased the number of evoked Reflexes and shortened the interval between the evoked Reflexes. Agmatine was less potent than GMQ in its ability to evoke Swallowing Reflexes. Prior topical application of an ASIC3 antagonist significantly attenuated the number of GMQ- and agmatine-evoked Swallowing Reflexes. Acid-sensing ion channel 3s localized on nerves and epithelial cells in Swallowing-related regions are functional in evoking the Swallowing Reflex and activation of these channels via a pharmacological agonist appears to improve Swallowing behavior. © 2019 John Wiley & Sons Ltd.
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Activation of TRPV1 and TRPM8 Channels in the Larynx and Associated Laryngopharyngeal Regions Facilitates the Swallowing Reflex
International journal of molecular sciences, 2018Co-Authors: Mohammad Zakir Hossain, Hiroshi Ando, Shumpei Unno, Yuji Masuda, Junichi KitagawaAbstract:The larynx and associated laryngopharyngeal regions are innervated by the superior laryngeal nerve (SLN) and are highly Reflexogenic. Transient receptor potential (TRP) channels have recently been detected in SLN innervated regions; however, their involvement in the Swallowing Reflex has not been fully elucidated. Here, we explore the contribution of two TRP channels, TRPV1 and TRPM8, located in SLN-innervated regions to the Swallowing Reflex. Immunohistochemistry identified TRPV1 and TRPM8 on cell bodies of SLN afferents located in the nodose-petrosal-jugular ganglionic complex. The majority of TRPV1 and TRPM8 immunoreactivity was located on unmyelinated neurons. Topical application of different concentrations of TRPV1 and TRPM8 agonists modulated SLN activity. Application of the agonists evoked a significantly greater number of Swallowing Reflexes compared with the number evoked by distilled water. The interval between the Reflexes evoked by the agonists was shorter than that produced by distilled water. Prior topical application of respective TRPV1 or TRPM8 antagonists significantly reduced the number of agonist-evoked Reflexes. The findings suggest that the activation of TRPV1 and TRPM8 channels present in the Swallowing-related regions can facilitate the evoking of Swallowing Reflex. Targeting the TRP channels could be a potential therapeutic strategy for the management of dysphagia.
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Facilitation of the Swallowing Reflex with bilateral afferent input from the superior laryngeal nerve
Neuroscience letters, 2014Co-Authors: Kojiro Takahashi, Tomio Shingai, Isao Saito, Kensuke Yamamura, Yoshiaki Yamada, Junichi KitagawaAbstract:To determine the cooperative effect of laryngeal afferent signals on the Swallowing Reflex, we examined whether afferent signals originating from the left and right superior laryngeal nerve (SLN) modulates elicitation of the Swallowing Reflex in urethane-anesthetized rats. Mylohyoid electromyographic activity was recorded to quantify the Swallowing Reflex. The onset latency of the Swallowing Reflex and the time intervals between successive swallows were used to quantify and compare the effects of unilateral and bilateral electrical stimulations of the SLN. The mean latency of the first swallow and the mean time interval between swallows evoked with low frequency stimulation were both significantly different between unilateral and bilateral stimulations of the SLN. These findings suggest that facilitatory effect of afferent signals originating from the SLN bilaterally increase the motoneuronal activity in the medullary Swallowing center and enhance the Swallowing Reflex.
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cannabinoids facilitate the Swallowing Reflex elicited by the superior laryngeal nerve stimulation in rats
PLOS ONE, 2012Co-Authors: Rahman Md. Mostafeezur, Kensuke Yamamura, Yoshiaki Yamada, Hanako Takatsuji, Hossain Md. Zakir, Junichi KitagawaAbstract:Cannabinoids have been reported to be involved in affecting various biological functions through binding with cannabinoid receptors type 1 (CB1) and 2 (CB2). The present study was designed to investigate whether Swallowing, an essential component of feeding behavior, is modulated after the administration of cannabinoid. The Swallowing Reflex evoked by the repetitive electrical stimulation of the superior laryngeal nerve in rats was recorded before and after the administration of the cannabinoid receptor agonist, WIN 55-212-2 (WIN), with or without CB1 or CB2 antagonist. The onset latency of the first swallow and the time intervals between swallows were analyzed. The onset latency and the intervals between swallows were shorter after the intravenous administration of WIN, and the strength of effect of WIN was dose-dependent. Although the intravenous administration of CB1 antagonist prior to intravenous administration of WIN blocked the effect of WIN, the administration of CB2 antagonist did not block the effect of WIN. The microinjection of the CB1 receptor antagonist directly into the nucleus tractus solitarius (NTS) prior to intravenous administration of WIN also blocked the effect of WIN. Immunofluorescence histochemistry was conducted to assess the co-localization of CB1 receptor immunoreactivity to glutamic acid decarboxylase 67 (GAD67) or glutamate in the NTS. CB1 receptor was co-localized more with GAD67 than glutamate in the NTS. These findings suggest that cannabinoids facilitate the Swallowing Reflex via CB1 receptors. Cannabinoids may attenuate the tonic inhibitory effect of GABA (gamma-aminobuteric acid) neurons in the central pattern generator for Swallowing.
Makoto Inoue - One of the best experts on this subject based on the ideXlab platform.
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Suppression of the Swallowing Reflex by stimulation of the red nucleus
Brain Research Bulletin, 2015Co-Authors: Yoshihide Satoh, Kojun Tsuji, Takanori Tsujimura, Ken'ichi Ishizuka, Makoto InoueAbstract:We study whether the red nucleus is involved in control of Swallowing. The Swallowing Reflex was induced in anesthetized rats by repetitive electrical stimulation of the superior laryngeal nerve. The electromyographic activities of the mylohyoid and thyrohyoid muscles were recorded in order to identify the Swallowing Reflex. Repetitive electrical stimulation applied to the red nucleus reduced the number of swallows. The onset latency of the first swallow was increased during repetitive electrical stimulation applied to the magnocellular part of the red nucleus. Microinjection of monosodium glutamate into the red nucleus also reduced the number of swallows. The onset latency of the first swallow was increased after microinjection of monosodium glutamate into the magnocellular part of the red nucleus. These results imply that the red nucleus is involved in the control of Swallowing.
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Changes in the frequency of Swallowing during electrical stimulation of superior laryngeal nerve in rats
Brain research bulletin, 2014Co-Authors: Kojun Tsuji, Takanori Tsujimura, Jin Magara, Shogo Sakai, Yuki Nakamura, Makoto InoueAbstract:The aim of the present study was to investigate the adaptation of the Swallowing Reflex in terms of reduced Swallowing Reflex initiation following continuous superior laryngeal nerve stimulation. Forty-four male Sprague Dawley rats were anesthetized with urethane. To identify Swallowing, electromyographic activity of the left mylohyoid and thyrohyoid muscles was recorded. To evoke the Swallowing response, the superior laryngeal nerve (SLN), recurrent laryngeal nerve, or cortical Swallowing area was electrically stimulated. Repetitive Swallowing evoked by continuous SLN stimulation was gradually reduced, and this reduction was dependent on the resting time duration between stimulations. Prior SLN stimulation also suppressed subsequent Swallowing initiation. The reduction in evoked swallows induced by recurrent laryngeal nerve or cortical Swallowing area stimulation was less than that following superior laryngeal nerve stimulation. Decerebration had no effect on the reduction in evoked swallows. Prior subthreshold stimulation reduced subsequent initiation of Swallowing, suggesting that there was no relationship between Swallowing movement evoked by prior stimulation and the subsequent reduction in Swallowing initiation. Overall, these data suggest that reduced sensory afferent nerve firing and/or trans-synaptic responses, as well as part of the brainstem central pattern generator, are involved in adaptation of the Swallowing Reflex following continuous stimulation of swallow-inducing peripheral nerves and cortical areas.
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Differential involvement of two cortical masticatory areas in modulation of the Swallowing Reflex in rats.
Neuroscience letters, 2012Co-Authors: Takanori Tsujimura, Kojun Tsuji, Yuki Nakamura, Koichi Iwata, Sajjiv Ariyasinghe, Takako Fukuhara, Aki Yamada, Hirokazu Hayashi, Makoto InoueAbstract:To clarify the functional role of cortical descending inputs involved in the Swallowing Reflex, the effect of electrical stimulation of two cortical masticatory areas (CMAs: A- and P-area) on rhythmic jaw movements (RJMs) and superior laryngeal nerve (SLN)-evoked swallows were studied. RJMs and Swallowing Reflex were elicited by repetitive electrical stimulation of CMAs and the SLN, respectively. The electromyographic activities of jaw-closer (masseter), jaw-opener (digastric), and laryngeal-elevator (thyrohyoid) muscles were recorded to identify the RJMs and Swallowing Reflex. The number of evoked swallows was significantly lower, and Swallowing interval was significantly longer during A-area stimulation compared with those without stimulation. Conversely, these parameters were not significantly altered during P-area stimulation. The inhibition of swallows by A-area stimulation was not affected by an increase in sensory input by wooden stick application between upper and lower teeth, or A-area stimulation preceding SLN stimulation. The present findings suggest that the Swallowing Reflex is inhibited by activation of the A-area, but not the P-area. Since no changes in swallows were seen after the increase in intraoral sensory input and prior activation of masticatory central pattern generator (CPG), Swallowing inhibition may be mediated by direct inputs from the A-area or inputs via the masticatory CPG into the Swallowing CPG.
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The Digastric Muscle is Less Involved in Pharyngeal Swallowing in Rabbits
Dysphagia, 2011Co-Authors: Takanori Tsujimura, Yuki Nakamura, Kensuke Yamamura, Takako Fukuhara, Aki Yamada, Makoto InoueAbstract:The Swallowing Reflex is centrally programmed by the lower brain stem, the so-called Swallowing central pattern generator (CPG), and once the Reflex is initiated, many muscles in the oral, pharyngeal, laryngeal, and esophageal regions are systematically activated. The mylohyoid (MH) muscle has been considered to be a “leading muscle” according to previous studies, but the functional role of the digastric (DIG) muscle in the Swallowing Reflex remains unclear. In the present study, therefore, the activities of single units of MH and DIG neurons were recorded extracellularly, and the functional involvement of these neurons in the Swallowing Reflex was investigated. The experiments were carried out on eight adult male Japanese white rabbits anesthetized with urethane. To identify DIG and MH neurons, the peripheral nerve (either DIG or MH) was stimulated to evoke action potentials of single motoneurons. Motoneurons were identified as such if they either (1) responded to antidromic nerve stimulation of DIG or MH in an all-or-none manner at threshold intensities and (2) followed stimulation frequencies of up to 0.5 kHz. As a result, all 11 MH neurons recorded were synchronously activated during the Swallowing Reflex, while there was no activity in any of the 7 DIG neurons recorded during the Swallowing Reflex. All neurons were anatomically localized ventromedially at the level of the caudal portion of the trigeminal motor nucleus, and there were no differences between the MH and DIG neuron sites. The present results strongly suggest that at least in the rabbit, DIG motoneurons are not tightly controlled by the Swallowing CPG and, hence, the DIG muscle is less involved in the Swallowing Reflex.
Kojun Tsuji - One of the best experts on this subject based on the ideXlab platform.
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Suppression of the Swallowing Reflex during Rhythmic Jaw Movements Induced by Repetitive Electrical Stimulation of the Dorsomedial Part of the Central Amygdaloid Nucleus in Rats
Life (Basel Switzerland), 2020Co-Authors: Yoshihide Satoh, Kojun TsujiAbstract:A previous study indicated that the Swallowing Reflex is inhibited during rhythmic jaw movements induced by electrical stimulation of the anterior cortical masticatory area. Rhythmic jaw movements were induced by electrical stimulation of the central amygdaloid nucleus (CeA). The Swallowing central pattern generator is the nucleus of the solitary tract (NTS) and the lateral reticular formation in the medulla. Morphological studies have reported that the CeA projects to the NTS and the lateral reticular formation. It is therefore likely that the CeA is related to the control of the Swallowing Reflex. The purpose of this study was to determine if rhythmic jaw movements driven by CeA had inhibitory roles in the Swallowing Reflex induced by electrical stimulation of the superior laryngeal nerve (SLN). Rats were anesthetised with urethane. The SLN was solely stimulated for 10 s, and the Swallowing Reflex was recorded (SLN stimulation before SLN + CeA stimulation). Next, the SLN and the CeA were electrically stimulated at the same time for 10 s, and the Swallowing Reflex was recorded during rhythmic jaw movements (SLN + CeA stimulation). Finally, the SLN was solely stimulated (SLN stimulation following SLN + CeA stimulation). The number of swallows was reduced during rhythmic jaw movements. The onset latency of the first swallow was significantly longer in the SLN + CeA stimulation than in the SLN stimulation before SLN + CeA stimulation and SLN stimulation following SLN + CeA stimulation. These results support the idea that the coordination of Swallowing Reflex with rhythmic jaw movements could be regulated by the CeA.
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Suppressive effect of the Swallowing Reflex by stimulation of the pedunculopontine tegmental nucleus.
Neuroscience research, 2020Co-Authors: Yoshihide Satoh, Kojun TsujiAbstract:This study investigates whether the Swallowing Reflex is modulated by stimulation of the pedunculopontine tegmental nucleus (PTg). Sprague-Dawley rats under urethane anesthesia were used. The Swallowing Reflex was induced by electrical stimulation of the superior laryngeal nerve and was identified by the electromyographic activities from the mylohyoid muscle. The number of swallows was reduced by electrical stimulation of the PTg. The latency of the onset of the first swallow was increased during stimulation of the PTg. The duration of electromyogram bursts of the mylohyoid muscle was significantly shorter during the PTg stimulation than with no stimulation. The number of swallows was reduced, latency of onset of the first swallow increased, the duration of electromyogram bursts of the mylohyoid muscle was significantly shorter and the peak-to-peak amplitude of electromyogram bursts of the mylohyoid muscle was significantly suppressed after microinjection of glutamate into the PTg. These results suggest that the PTg is involved in the control of Swallowing.
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Suppression of the Swallowing Reflex by stimulation of the red nucleus
Brain Research Bulletin, 2015Co-Authors: Yoshihide Satoh, Kojun Tsuji, Takanori Tsujimura, Ken'ichi Ishizuka, Makoto InoueAbstract:We study whether the red nucleus is involved in control of Swallowing. The Swallowing Reflex was induced in anesthetized rats by repetitive electrical stimulation of the superior laryngeal nerve. The electromyographic activities of the mylohyoid and thyrohyoid muscles were recorded in order to identify the Swallowing Reflex. Repetitive electrical stimulation applied to the red nucleus reduced the number of swallows. The onset latency of the first swallow was increased during repetitive electrical stimulation applied to the magnocellular part of the red nucleus. Microinjection of monosodium glutamate into the red nucleus also reduced the number of swallows. The onset latency of the first swallow was increased after microinjection of monosodium glutamate into the magnocellular part of the red nucleus. These results imply that the red nucleus is involved in the control of Swallowing.
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Changes in the frequency of Swallowing during electrical stimulation of superior laryngeal nerve in rats
Brain research bulletin, 2014Co-Authors: Kojun Tsuji, Takanori Tsujimura, Jin Magara, Shogo Sakai, Yuki Nakamura, Makoto InoueAbstract:The aim of the present study was to investigate the adaptation of the Swallowing Reflex in terms of reduced Swallowing Reflex initiation following continuous superior laryngeal nerve stimulation. Forty-four male Sprague Dawley rats were anesthetized with urethane. To identify Swallowing, electromyographic activity of the left mylohyoid and thyrohyoid muscles was recorded. To evoke the Swallowing response, the superior laryngeal nerve (SLN), recurrent laryngeal nerve, or cortical Swallowing area was electrically stimulated. Repetitive Swallowing evoked by continuous SLN stimulation was gradually reduced, and this reduction was dependent on the resting time duration between stimulations. Prior SLN stimulation also suppressed subsequent Swallowing initiation. The reduction in evoked swallows induced by recurrent laryngeal nerve or cortical Swallowing area stimulation was less than that following superior laryngeal nerve stimulation. Decerebration had no effect on the reduction in evoked swallows. Prior subthreshold stimulation reduced subsequent initiation of Swallowing, suggesting that there was no relationship between Swallowing movement evoked by prior stimulation and the subsequent reduction in Swallowing initiation. Overall, these data suggest that reduced sensory afferent nerve firing and/or trans-synaptic responses, as well as part of the brainstem central pattern generator, are involved in adaptation of the Swallowing Reflex following continuous stimulation of swallow-inducing peripheral nerves and cortical areas.
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Differential involvement of two cortical masticatory areas in modulation of the Swallowing Reflex in rats.
Neuroscience letters, 2012Co-Authors: Takanori Tsujimura, Kojun Tsuji, Yuki Nakamura, Koichi Iwata, Sajjiv Ariyasinghe, Takako Fukuhara, Aki Yamada, Hirokazu Hayashi, Makoto InoueAbstract:To clarify the functional role of cortical descending inputs involved in the Swallowing Reflex, the effect of electrical stimulation of two cortical masticatory areas (CMAs: A- and P-area) on rhythmic jaw movements (RJMs) and superior laryngeal nerve (SLN)-evoked swallows were studied. RJMs and Swallowing Reflex were elicited by repetitive electrical stimulation of CMAs and the SLN, respectively. The electromyographic activities of jaw-closer (masseter), jaw-opener (digastric), and laryngeal-elevator (thyrohyoid) muscles were recorded to identify the RJMs and Swallowing Reflex. The number of evoked swallows was significantly lower, and Swallowing interval was significantly longer during A-area stimulation compared with those without stimulation. Conversely, these parameters were not significantly altered during P-area stimulation. The inhibition of swallows by A-area stimulation was not affected by an increase in sensory input by wooden stick application between upper and lower teeth, or A-area stimulation preceding SLN stimulation. The present findings suggest that the Swallowing Reflex is inhibited by activation of the A-area, but not the P-area. Since no changes in swallows were seen after the increase in intraoral sensory input and prior activation of masticatory central pattern generator (CPG), Swallowing inhibition may be mediated by direct inputs from the A-area or inputs via the masticatory CPG into the Swallowing CPG.
Gilles Dhonneur - One of the best experts on this subject based on the ideXlab platform.
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Influence of the cuff pressure on the Swallowing Reflex in tracheostomized intensive care unit patients
British journal of anaesthesia, 2012Co-Authors: Roland Amathieu, D. Luis, V. Slavov, S Sauvat, P Reynaud, A Dinca, Loic Tual, S Bloc, Gilles DhonneurAbstract:Because recovery of an efficient Swallowing Reflex is a determining factor for the recovery of airway protective Reflexes, we have studied the influence of the tracheostomy tube cuff pressure (CP) on the Swallowing Reflex in tracheotomized patients. Twelve conscious adult intensive care unit (ICU) patients who had been weaned from mechanical ventilation were studied. Simultaneous EMG of the submental muscles with measurement of peak activity (EMGp) and amplitude of laryngeal acceleration (ALA) were performed during Reflex swallows elicited by pharyngeal injection of distilled water boluses during end expiration. After cuff deflation, characteristics of the Swallowing Reflex (latency time: LaT, EMGp, and ALA) were measured at CPs of 5, 10, 15, 20, 25, 30, 40, 50, and 60 cm H(2)O. LaT and CP were linearly related (P<0.01). CP was inversely correlated (P<0.01) to both ALA and EMGp. We demonstrated that LaT, EMGp, and ALA of the Swallowing Reflex were influenced by tracheostomy tube CP. The Swallowing Reflex was progressively more difficult to elicit with increasing CP and when activated, the resulting motor Swallowing activity and efficiency at elevating the larynx were depressed.
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Influence of the cuff pressure on the Swallowing Reflex in tracheostomized ICU patients
Critical Care, 2010Co-Authors: Roland Amathieu, D. Luis, W. Kamoun, V. Slavov, Gilles DhonneurAbstract:Because recovery of an efficient Swallowing Reflex is determining factor for patient's spontaneous rehabilitation of airway protective Reflexes, we have studied the influence of cuff pressure of the tracheostomy tube on the Swallowing Reflex elicited in tracheostomized ICU patients.
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midazolam propofol but not propofol alone reversibly depress the Swallowing Reflex
Acta Anaesthesiologica Scandinavica, 1994Co-Authors: Gilles Dhonneur, J. M. Rimaniol, Y. Lambert, El A Sayed, Philippe DuvaldestinAbstract:General anaesthetics depress Swallowing and this is a reason to delay oral intake after general anaesthesia. The Swallowing Reflex was studied 2 h after general anaesthesia for patients undergoing colonoscopy. Forty-one patients were anaesthetized with midazolam 75 micrograms.kg-1 followed by a continuous infusion of propofol and 39 patients with propofol 1.5 mg.kg-1 bolus followed by an infusion. Swallowing Reflex was measured by electromyography 2 h after induction of anaesthesia, before and 5 min after the administration of flumazenil (0.2 mg) or placebo. Two h after anaesthesia, the state of consciousness was almost normal in all patients and did not change after flumazenil. At two hours, the latency times for the Swallowing Reflex in patients treated with propofol alone were of 1.4 +/- 0.4 s and were significantly shorter (P < 0.05) than the value of 1.9 +/- 0.8 s observed in patients who received midazolam with propofol. In the latter group the latency time of the Swallowing Reflex was significantly reduced following the administration of flumazenil but not placebo. In patients who received propofol without midazolam, the administration of flumazenil or placebo was not associated with significant changes in the latency times. There were also no significant differences in the latency times in the subgroup that received midazolam followed by flumazenil and the propofol alone groups that did or did not receive flumazenil. These results suggest that midazolam still exerts a depressive effect on the Swallowing Reflex 2 h after its administration despite the recovery of normal consciousness.
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Recovery of the Swallowing Reflex after propofol anesthesia.
Anesthesia and analgesia, 1994Co-Authors: J. M. Rimaniol, Gilles Dhonneur, Philippe DuvaldestinAbstract:The Swallowing Reflex is depressed by anesthetics. During recovery from anesthesia the rapid return of laryngeal and upper airway Reflexes is important to protect the lower airway from aspiration. This study measures the recovery of the Swallowing Reflex after propofol anesthesia. Fifteen patients undergoing a colonoscopy under general anesthesia were studied. No premedication was given. Anesthesia was induced with propofol 2 mg/kg followed by an infusion of 10 mg.kg-1.h-1. The Swallowing Reflex was measured every 3 min after the end of propofol infusion for 30 min. To initiate Swallowing, 0.3 mL of distilled water was injected into the pharynx at two different speeds: a slow injection over 3 s, and a bolus injection. The Swallowing Reflex was determined by measuring the latency period (i.e., time from water injection to start of electromyographic (EMG) activity measured in the glossal muscles). Swallowing activity was determined by integration of the EMG (EMGi) of the glossal muscles during Swallowing. The latency periods after slow and bolus injections were significantly increased for the first 12 min after the end of the propofol infusion and returned to control (preanesthetic values) at 24 min. The EMGi was significantly decreased over the first 12 min and returned to control at 21 min. Propofol depresses the Swallowing Reflex, but complete recovery is rapid. This study suggests that the oral intake could be allowed early after recovery from anesthesia when propofol is used as the sole anesthetic.
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Midazolam/propofol but not propofol alone reversibly depress the Swallowing Reflex.
Acta anaesthesiologica Scandinavica, 1994Co-Authors: Gilles Dhonneur, J. M. Rimaniol, A. El Sayed, Y. Lambert, Philippe DuvaldestinAbstract:General anaesthetics depress Swallowing and this is a reason to delay oral intake after general anaesthesia. The Swallowing Reflex was studied 2 h after general anaesthesia for patients undergoing colonoscopy. Forty-one patients were anaesthetized with midazolam 75 micrograms.kg-1 followed by a continuous infusion of propofol and 39 patients with propofol 1.5 mg.kg-1 bolus followed by an infusion. Swallowing Reflex was measured by electromyography 2 h after induction of anaesthesia, before and 5 min after the administration of flumazenil (0.2 mg) or placebo. Two h after anaesthesia, the state of consciousness was almost normal in all patients and did not change after flumazenil. At two hours, the latency times for the Swallowing Reflex in patients treated with propofol alone were of 1.4 +/- 0.4 s and were significantly shorter (P < 0.05) than the value of 1.9 +/- 0.8 s observed in patients who received midazolam with propofol. In the latter group the latency time of the Swallowing Reflex was significantly reduced following the administration of flumazenil but not placebo. In patients who received propofol without midazolam, the administration of flumazenil or placebo was not associated with significant changes in the latency times. There were also no significant differences in the latency times in the subgroup that received midazolam followed by flumazenil and the propofol alone groups that did or did not receive flumazenil. These results suggest that midazolam still exerts a depressive effect on the Swallowing Reflex 2 h after its administration despite the recovery of normal consciousness.
Takanori Tsujimura - One of the best experts on this subject based on the ideXlab platform.
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Suppression of the Swallowing Reflex by stimulation of the red nucleus
Brain Research Bulletin, 2015Co-Authors: Yoshihide Satoh, Kojun Tsuji, Takanori Tsujimura, Ken'ichi Ishizuka, Makoto InoueAbstract:We study whether the red nucleus is involved in control of Swallowing. The Swallowing Reflex was induced in anesthetized rats by repetitive electrical stimulation of the superior laryngeal nerve. The electromyographic activities of the mylohyoid and thyrohyoid muscles were recorded in order to identify the Swallowing Reflex. Repetitive electrical stimulation applied to the red nucleus reduced the number of swallows. The onset latency of the first swallow was increased during repetitive electrical stimulation applied to the magnocellular part of the red nucleus. Microinjection of monosodium glutamate into the red nucleus also reduced the number of swallows. The onset latency of the first swallow was increased after microinjection of monosodium glutamate into the magnocellular part of the red nucleus. These results imply that the red nucleus is involved in the control of Swallowing.
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Changes in the frequency of Swallowing during electrical stimulation of superior laryngeal nerve in rats
Brain research bulletin, 2014Co-Authors: Kojun Tsuji, Takanori Tsujimura, Jin Magara, Shogo Sakai, Yuki Nakamura, Makoto InoueAbstract:The aim of the present study was to investigate the adaptation of the Swallowing Reflex in terms of reduced Swallowing Reflex initiation following continuous superior laryngeal nerve stimulation. Forty-four male Sprague Dawley rats were anesthetized with urethane. To identify Swallowing, electromyographic activity of the left mylohyoid and thyrohyoid muscles was recorded. To evoke the Swallowing response, the superior laryngeal nerve (SLN), recurrent laryngeal nerve, or cortical Swallowing area was electrically stimulated. Repetitive Swallowing evoked by continuous SLN stimulation was gradually reduced, and this reduction was dependent on the resting time duration between stimulations. Prior SLN stimulation also suppressed subsequent Swallowing initiation. The reduction in evoked swallows induced by recurrent laryngeal nerve or cortical Swallowing area stimulation was less than that following superior laryngeal nerve stimulation. Decerebration had no effect on the reduction in evoked swallows. Prior subthreshold stimulation reduced subsequent initiation of Swallowing, suggesting that there was no relationship between Swallowing movement evoked by prior stimulation and the subsequent reduction in Swallowing initiation. Overall, these data suggest that reduced sensory afferent nerve firing and/or trans-synaptic responses, as well as part of the brainstem central pattern generator, are involved in adaptation of the Swallowing Reflex following continuous stimulation of swallow-inducing peripheral nerves and cortical areas.
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Differential involvement of two cortical masticatory areas in modulation of the Swallowing Reflex in rats.
Neuroscience letters, 2012Co-Authors: Takanori Tsujimura, Kojun Tsuji, Yuki Nakamura, Koichi Iwata, Sajjiv Ariyasinghe, Takako Fukuhara, Aki Yamada, Hirokazu Hayashi, Makoto InoueAbstract:To clarify the functional role of cortical descending inputs involved in the Swallowing Reflex, the effect of electrical stimulation of two cortical masticatory areas (CMAs: A- and P-area) on rhythmic jaw movements (RJMs) and superior laryngeal nerve (SLN)-evoked swallows were studied. RJMs and Swallowing Reflex were elicited by repetitive electrical stimulation of CMAs and the SLN, respectively. The electromyographic activities of jaw-closer (masseter), jaw-opener (digastric), and laryngeal-elevator (thyrohyoid) muscles were recorded to identify the RJMs and Swallowing Reflex. The number of evoked swallows was significantly lower, and Swallowing interval was significantly longer during A-area stimulation compared with those without stimulation. Conversely, these parameters were not significantly altered during P-area stimulation. The inhibition of swallows by A-area stimulation was not affected by an increase in sensory input by wooden stick application between upper and lower teeth, or A-area stimulation preceding SLN stimulation. The present findings suggest that the Swallowing Reflex is inhibited by activation of the A-area, but not the P-area. Since no changes in swallows were seen after the increase in intraoral sensory input and prior activation of masticatory central pattern generator (CPG), Swallowing inhibition may be mediated by direct inputs from the A-area or inputs via the masticatory CPG into the Swallowing CPG.
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The Digastric Muscle is Less Involved in Pharyngeal Swallowing in Rabbits
Dysphagia, 2011Co-Authors: Takanori Tsujimura, Yuki Nakamura, Kensuke Yamamura, Takako Fukuhara, Aki Yamada, Makoto InoueAbstract:The Swallowing Reflex is centrally programmed by the lower brain stem, the so-called Swallowing central pattern generator (CPG), and once the Reflex is initiated, many muscles in the oral, pharyngeal, laryngeal, and esophageal regions are systematically activated. The mylohyoid (MH) muscle has been considered to be a “leading muscle” according to previous studies, but the functional role of the digastric (DIG) muscle in the Swallowing Reflex remains unclear. In the present study, therefore, the activities of single units of MH and DIG neurons were recorded extracellularly, and the functional involvement of these neurons in the Swallowing Reflex was investigated. The experiments were carried out on eight adult male Japanese white rabbits anesthetized with urethane. To identify DIG and MH neurons, the peripheral nerve (either DIG or MH) was stimulated to evoke action potentials of single motoneurons. Motoneurons were identified as such if they either (1) responded to antidromic nerve stimulation of DIG or MH in an all-or-none manner at threshold intensities and (2) followed stimulation frequencies of up to 0.5 kHz. As a result, all 11 MH neurons recorded were synchronously activated during the Swallowing Reflex, while there was no activity in any of the 7 DIG neurons recorded during the Swallowing Reflex. All neurons were anatomically localized ventromedially at the level of the caudal portion of the trigeminal motor nucleus, and there were no differences between the MH and DIG neuron sites. The present results strongly suggest that at least in the rabbit, DIG motoneurons are not tightly controlled by the Swallowing CPG and, hence, the DIG muscle is less involved in the Swallowing Reflex.
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Involvement of ERK phosphorylation in brainstem neurons in modulation of Swallowing Reflex in rats.
The Journal of physiology, 2009Co-Authors: Takanori Tsujimura, Junichi Kitagawa, Masahiro Kondo, Yoshiyuki Tsuboi, Kimiko Saito, Haruka Tohara, Koichiro Ueda, Barry J Sessle, Koichi IwataAbstract:In order to evaluate the neuronal mechanisms underlying functional abnormalities of Swallowing in orofacial pain patients, this study investigated the effects of noxious orofacial stimulation on the Swallowing Reflex, phosphorylated extracellular signal-regulated kinase (pERK) and gamma-aminobutyric acid (GABA) immunohistochemical features in brainstem neurons, and also analysed the effects of brainstem lesioning and of microinjection of GABA receptor agonist or antagonist into the nucleus tractus solitarii (NTS) on the Swallowing Reflex in anaesthetized rats. The Swallowing Reflex elicited by topical administration of distilled water to the pharyngolaryngeal region was inhibited after capsaicin injection into the facial (whisker pad) skin or lingual muscle. The capsaicin-induced inhibitory effect on the Swallowing Reflex was itself depressed after the intrathecal administration of MAPK kinase (MEK) inhibitor. No change in the capsaicin-induced inhibitory effect was observed after trigeminal spinal subnucleus caudalis lesioning, but the inhibitory effect was diminished by paratrigeminal nucleus (Pa5) lesioning. Many pERK-like immunoreactive neurons in the NTS showed GABA immunoreactivity. The local microinjection of the GABA(A) receptor agonist muscimol into the NTS produced a significant reduction in Swallowing Reflex, and the capsaicin-induced depression of the Swallowing Reflex was abolished by microinjection of the GABA(A) receptor antagonist bicuculline into the NTS. The present findings suggest that facial skin-NTS, lingual muscle-NTS and lingual muscle-Pa5-NTS pathways are involved in the modulation of Swallowing Reflex by facial and lingual pain, respectively, and that the activation of GABAergic NTS neurons is involved in the inhibition of the Swallowing Reflex following noxious stimulation of facial and intraoral structures.
