Induction of the Swallowing Reflex by Electrical Stimulation of the Posterior Oropharyngeal Region in Awake Humans

AbstractDysphagia is common in neurological disease. However, our understanding of swallowing and its central nervous control is limited. Sensory information plays a vital role in the initiation of the swallowing reflex and is often reduced in stroke patients. We hypothesized that the sensitivity threshold of the anterior faucial pillar could be facilitated by either electrical stimulation (ES) or taste and smell information. The sensitivity threshold was measured by ES in the anterior faucial pillar region. The measurement was repeated 5 min after baseline. Thirty minutes after baseline, the participants underwent a test for taste and smell. Immediately after the test, the ES was repeated. Thirty healthy volunteers with a mean age of 27 ± 5.1 participated in the trial. Mean sensitivity threshold at baseline was 1.9 ± 0.59 mA. The values 5 min after baseline (1.74 ± 0.56 mA, p = 0.027) and 30 min after baseline (1.67 ± 0.58 mA, p = 0.011) were significantly lower compared to the baseline, but there was no difference between the latter (p = 0.321). After 5 min, a potentially facilitating effect was found on oral sensitivity by ES of the faucial pillar area. Thirty minutes later, this effect was still present.Trial registration Clinicaltrials.gov, NCT03240965. Registered 7th August 2017—https://clinicaltrials.gov/ct2/show/NCT03240965.

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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 ◽

10.3390/life10090190 ◽

2020 ◽

Vol 10 (9) ◽

pp. 190

Author(s):

Yoshihide Satoh ◽

Kojun Tsuji

Keyword(s):

Electrical Stimulation ◽

Reticular Formation ◽

Superior Laryngeal Nerve ◽

Amygdaloid Nucleus ◽

Jaw Movements ◽

Morphological Studies ◽

Swallowing Reflex ◽

Central Amygdaloid Nucleus ◽

Repetitive Electrical Stimulation ◽

Stimulation Of

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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Facilitation of Oral Sensitivity by Electrical Stimulation of the Faucial Pillars

10.21203/rs.3.rs-279064/v1 ◽

2021 ◽

Author(s):

Tobias Braun ◽

Samra Hamzic ◽

Johanna Doerr ◽

Laura Peters ◽

Maxime Viard ◽

...

Keyword(s):

Electrical Stimulation ◽

Sensory Information ◽

Vital Role ◽

Sensitivity Threshold ◽

Nervous Control ◽

Swallowing Reflex ◽

Oral Sensitivity ◽

Taste And Smell ◽

Stimulation Of ◽

Faucial Pillar

Abstract BackgroundDysphagia is common in neurological disease. However, our understanding of swallowing and its central nervous control is limited. Sensory information plays a vital role in the initiation of the swallowing reflex and is often reduced in stroke patients. We hypothesized that the sensitivity threshold of the anterior faucial pillar could be facilitated by either electrical stimulation (ES) or taste and smell information.MethodsThe sensitivity threshold was measured by ES in the anterior faucial pillar region. The measurement was repeated 5 minutes after baseline. Thirty minutes after baseline, the participants underwent a test for taste and smell. Immediately after the test, the ES was repeated. ResultsThirty healthy volunteers with a mean age of 27±5.1 participated in the trial. Mean sensitivity threshold at baseline was 1.9mA ± 0.59mA. The values 5 minutes after baseline (1.74mA ± 0.56mA, p=0.027) and 30 minutes after baseline (1.67mA ± 0.58mA, p=0.011) were significantly lower compared to the baseline, but there was no difference between the latter (p=0.321).Conclusion After 5 minutes, a potentially facilitating effect was found on oral sensitivity by ES of the faucial pillar area. Thirty minutes later, this effect was still present.

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Pharyngeal branch of the glossopharyngeal nerve plays a major role in reflex swallowing from the pharynx

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00556.2001 ◽

2002 ◽

Vol 282 (5) ◽

pp. R1342-R1347 ◽

Cited By ~ 69

Author(s):

Jun-Ichi Kitagawa ◽

Tomio Shingai ◽

Yoshihiro Takahashi ◽

Yoshiaki Yamada

Keyword(s):

Electrical Stimulation ◽

Mechanical Stimulation ◽

Stimulus Frequency ◽

Superior Laryngeal Nerve ◽

Posterior Pharyngeal Wall ◽

Glossopharyngeal Nerve ◽

Pharyngeal Wall ◽

Swallowing Reflex ◽

Pharyngeal Branch ◽

Stimulation Of

Mechanical stimulation of the pharyngeal areas readily elicits reflex swallowing. However, it is much more difficult for electrical stimulation of the glossopharyngeal nerve (GPN) to evoke reflex swallowing than it is for stimulation of the superior laryngeal nerve (SLN) to do so. These paradoxical findings remain unexplained; hence, the main purpose of this study was to explain this contradiction by using a urethane-anesthetized rat. Mechanical stimulation easily elicited reflex swallowing from the pharynx. The posterior pillars, posterior pharyngeal wall, and the soft palate of the rat were extremely reflexogenic areas for swallowing. Sectioning the pharyngeal branch of the GPN (GPN-ph), however, eliminated the swallowing reflex from these areas. In contrast, sectioning the lingual branch of the GPN had no effect on the elicitation of swallowing. Electrical stimulation of the GPN-ph and SLN elicited sequentially occurring swallows. The relationship between stimulus frequency and the latency of swallowing for the GPN-ph was approximately the same as that for the SLN. These results indicate that the GPN-ph plays a major role in the initiation of reflex swallowing from the pharynx in rats.

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