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The Food Contaminant Mycotoxin Deoxynivalenol Inhibits the Swallowing Reflex in Anaesthetized Rats.

Abysique A, Tardivel C, Troadec JD, Félix B - PLoS ONE (2015)

Bottom Line: To better understand DON effects on ingestive behaviour, we have studied its effects on rhythmic swallowing in the rat, after intravenous and central administration.Repetitive electrical stimulation of the superior laryngeal nerve or of the tractus solitarius, induces rhythmic swallowing that can be recorded using electromyographic electrodes inserted in sublingual muscles.Our data show that DON modifies swallowing and interferes with central neuronal networks dedicated to food intake regulation.

View Article: PubMed Central - PubMed

Affiliation: EA 4674, Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif, Aix-Marseille University, Marseille, France.

ABSTRACT
Deoxynivalenol (DON), one of the most abundant mycotoxins found on cereals, is known to be implicated in acute and chronic illnesses in both humans and animals. Among the symptoms, anorexia, reduction of weight gain and decreased nutrition efficiency were described, but the mechanisms underlying these effects on feeding behavior are not yet totally understood. Swallowing is a major motor component of ingestive behavior which allows the propulsion of the alimentary bolus from the mouth to the esophagus. To better understand DON effects on ingestive behaviour, we have studied its effects on rhythmic swallowing in the rat, after intravenous and central administration. Repetitive electrical stimulation of the superior laryngeal nerve or of the tractus solitarius, induces rhythmic swallowing that can be recorded using electromyographic electrodes inserted in sublingual muscles. Here we provide the first demonstration that, after intravenous and central administration, DON strongly inhibits the swallowing reflex with a short latency and in a dose dependent manner. Moreover, using c-Fos staining, a strong neuronal activation was observed in the solitary tract nucleus which contains the central pattern generator of swallowing and in the area postrema after DON intravenous injection. Our data show that DON modifies swallowing and interferes with central neuronal networks dedicated to food intake regulation.

No MeSH data available.


Related in: MedlinePlus

A. Schematic representation of the brainstem at the DVC level showing the central pattern generator of swallowing (SwCPG) and the solitary tract (ST). Coronal diagram of the medulla drawn from the atlas of Paxinos and Watson [27] corresponding to the level of glutamate and DON injection sites (between 0.2 and 0.5 mm in front of the caudal edge of the area postrema and 0.5 to 0.7 mm lateral) and to the level of stimulation of the solitary tract (ST). Although microinjections and ST stimulations were made on either side of the medulla, all injection sites have been reported to the left side and dotted in the hatched area corresponding to the region of the interstitial and intermediate solitary tract nucleus (NTS) subnuclei. Histological micrographs illustrating the stimulating ST site show the bipolar electrode tract (see *). Amb, ambiguous nucleus; AP, area postrema; OL, inferior olive; RVL, rostroventral reticular nucleus; SpT5, spinal trigeminal tract; ST, solitary tract; 10, dorsal motor nucleus of the vagus; 12, hypoglossal nucleus; 12n, hypoglossal nerve. B. Parameters recorded in the rat during the experiment. Stim, stimulation of the superior laryngeal nerve (SLN), at 15 pulses/s during 5 s (pulse parameters: 2.5V and 0.06ms); EMG, sublingual muscle electromyogram (note rhythmic swallowing triggered by SLN stimulation); ECG, electrocardiological activity; Resp, respiration (note respiration blockade during SLN stimulation), ∫EMG, electromyogram envelope signal normalized, Sw Number, number of swallows triggered by SLN stimulation; ECG Frequency and Resp Frequency; “o” above the recording are event markers for ECG, Resp and EMG. Note that ST stimulation produced similar responses.
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pone.0133355.g001: A. Schematic representation of the brainstem at the DVC level showing the central pattern generator of swallowing (SwCPG) and the solitary tract (ST). Coronal diagram of the medulla drawn from the atlas of Paxinos and Watson [27] corresponding to the level of glutamate and DON injection sites (between 0.2 and 0.5 mm in front of the caudal edge of the area postrema and 0.5 to 0.7 mm lateral) and to the level of stimulation of the solitary tract (ST). Although microinjections and ST stimulations were made on either side of the medulla, all injection sites have been reported to the left side and dotted in the hatched area corresponding to the region of the interstitial and intermediate solitary tract nucleus (NTS) subnuclei. Histological micrographs illustrating the stimulating ST site show the bipolar electrode tract (see *). Amb, ambiguous nucleus; AP, area postrema; OL, inferior olive; RVL, rostroventral reticular nucleus; SpT5, spinal trigeminal tract; ST, solitary tract; 10, dorsal motor nucleus of the vagus; 12, hypoglossal nucleus; 12n, hypoglossal nerve. B. Parameters recorded in the rat during the experiment. Stim, stimulation of the superior laryngeal nerve (SLN), at 15 pulses/s during 5 s (pulse parameters: 2.5V and 0.06ms); EMG, sublingual muscle electromyogram (note rhythmic swallowing triggered by SLN stimulation); ECG, electrocardiological activity; Resp, respiration (note respiration blockade during SLN stimulation), ∫EMG, electromyogram envelope signal normalized, Sw Number, number of swallows triggered by SLN stimulation; ECG Frequency and Resp Frequency; “o” above the recording are event markers for ECG, Resp and EMG. Note that ST stimulation produced similar responses.

Mentions: We studied how DON affects the rhythmic swallowing elicited by repetitive stimulations of the SLN (or the ST). Previous studies have shown that a microinjection of glutamate within the intermediate NTS, containing the SwCPG, can initiate swallowing [18, 23, 26]. Thus, glutamate microinjection (1 fmol) was used as a control to check that the microelectrode was positioned within the SwCPG. When such a glutamate microinjection elicited swallowing, the stereotaxic coordinates were conserved for DON injections. The precise coordinates extended [23] between 0.2–0.7 mm rostral to the caudal edge of the AP (taken as the 0) 0.5–0.7 mm laterally and 0.4–0.8 mm in depth, roughly corresponding to those previously used. Fig 1A represents the precise area of drug injections (from Paxinos and Watson [27]).


The Food Contaminant Mycotoxin Deoxynivalenol Inhibits the Swallowing Reflex in Anaesthetized Rats.

Abysique A, Tardivel C, Troadec JD, Félix B - PLoS ONE (2015)

A. Schematic representation of the brainstem at the DVC level showing the central pattern generator of swallowing (SwCPG) and the solitary tract (ST). Coronal diagram of the medulla drawn from the atlas of Paxinos and Watson [27] corresponding to the level of glutamate and DON injection sites (between 0.2 and 0.5 mm in front of the caudal edge of the area postrema and 0.5 to 0.7 mm lateral) and to the level of stimulation of the solitary tract (ST). Although microinjections and ST stimulations were made on either side of the medulla, all injection sites have been reported to the left side and dotted in the hatched area corresponding to the region of the interstitial and intermediate solitary tract nucleus (NTS) subnuclei. Histological micrographs illustrating the stimulating ST site show the bipolar electrode tract (see *). Amb, ambiguous nucleus; AP, area postrema; OL, inferior olive; RVL, rostroventral reticular nucleus; SpT5, spinal trigeminal tract; ST, solitary tract; 10, dorsal motor nucleus of the vagus; 12, hypoglossal nucleus; 12n, hypoglossal nerve. B. Parameters recorded in the rat during the experiment. Stim, stimulation of the superior laryngeal nerve (SLN), at 15 pulses/s during 5 s (pulse parameters: 2.5V and 0.06ms); EMG, sublingual muscle electromyogram (note rhythmic swallowing triggered by SLN stimulation); ECG, electrocardiological activity; Resp, respiration (note respiration blockade during SLN stimulation), ∫EMG, electromyogram envelope signal normalized, Sw Number, number of swallows triggered by SLN stimulation; ECG Frequency and Resp Frequency; “o” above the recording are event markers for ECG, Resp and EMG. Note that ST stimulation produced similar responses.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4507856&req=5

pone.0133355.g001: A. Schematic representation of the brainstem at the DVC level showing the central pattern generator of swallowing (SwCPG) and the solitary tract (ST). Coronal diagram of the medulla drawn from the atlas of Paxinos and Watson [27] corresponding to the level of glutamate and DON injection sites (between 0.2 and 0.5 mm in front of the caudal edge of the area postrema and 0.5 to 0.7 mm lateral) and to the level of stimulation of the solitary tract (ST). Although microinjections and ST stimulations were made on either side of the medulla, all injection sites have been reported to the left side and dotted in the hatched area corresponding to the region of the interstitial and intermediate solitary tract nucleus (NTS) subnuclei. Histological micrographs illustrating the stimulating ST site show the bipolar electrode tract (see *). Amb, ambiguous nucleus; AP, area postrema; OL, inferior olive; RVL, rostroventral reticular nucleus; SpT5, spinal trigeminal tract; ST, solitary tract; 10, dorsal motor nucleus of the vagus; 12, hypoglossal nucleus; 12n, hypoglossal nerve. B. Parameters recorded in the rat during the experiment. Stim, stimulation of the superior laryngeal nerve (SLN), at 15 pulses/s during 5 s (pulse parameters: 2.5V and 0.06ms); EMG, sublingual muscle electromyogram (note rhythmic swallowing triggered by SLN stimulation); ECG, electrocardiological activity; Resp, respiration (note respiration blockade during SLN stimulation), ∫EMG, electromyogram envelope signal normalized, Sw Number, number of swallows triggered by SLN stimulation; ECG Frequency and Resp Frequency; “o” above the recording are event markers for ECG, Resp and EMG. Note that ST stimulation produced similar responses.
Mentions: We studied how DON affects the rhythmic swallowing elicited by repetitive stimulations of the SLN (or the ST). Previous studies have shown that a microinjection of glutamate within the intermediate NTS, containing the SwCPG, can initiate swallowing [18, 23, 26]. Thus, glutamate microinjection (1 fmol) was used as a control to check that the microelectrode was positioned within the SwCPG. When such a glutamate microinjection elicited swallowing, the stereotaxic coordinates were conserved for DON injections. The precise coordinates extended [23] between 0.2–0.7 mm rostral to the caudal edge of the AP (taken as the 0) 0.5–0.7 mm laterally and 0.4–0.8 mm in depth, roughly corresponding to those previously used. Fig 1A represents the precise area of drug injections (from Paxinos and Watson [27]).

Bottom Line: To better understand DON effects on ingestive behaviour, we have studied its effects on rhythmic swallowing in the rat, after intravenous and central administration.Repetitive electrical stimulation of the superior laryngeal nerve or of the tractus solitarius, induces rhythmic swallowing that can be recorded using electromyographic electrodes inserted in sublingual muscles.Our data show that DON modifies swallowing and interferes with central neuronal networks dedicated to food intake regulation.

View Article: PubMed Central - PubMed

Affiliation: EA 4674, Laboratoire de Physiologie et Physiopathologie du Système Nerveux Somato-Moteur et Neurovégétatif, Aix-Marseille University, Marseille, France.

ABSTRACT
Deoxynivalenol (DON), one of the most abundant mycotoxins found on cereals, is known to be implicated in acute and chronic illnesses in both humans and animals. Among the symptoms, anorexia, reduction of weight gain and decreased nutrition efficiency were described, but the mechanisms underlying these effects on feeding behavior are not yet totally understood. Swallowing is a major motor component of ingestive behavior which allows the propulsion of the alimentary bolus from the mouth to the esophagus. To better understand DON effects on ingestive behaviour, we have studied its effects on rhythmic swallowing in the rat, after intravenous and central administration. Repetitive electrical stimulation of the superior laryngeal nerve or of the tractus solitarius, induces rhythmic swallowing that can be recorded using electromyographic electrodes inserted in sublingual muscles. Here we provide the first demonstration that, after intravenous and central administration, DON strongly inhibits the swallowing reflex with a short latency and in a dose dependent manner. Moreover, using c-Fos staining, a strong neuronal activation was observed in the solitary tract nucleus which contains the central pattern generator of swallowing and in the area postrema after DON intravenous injection. Our data show that DON modifies swallowing and interferes with central neuronal networks dedicated to food intake regulation.

No MeSH data available.


Related in: MedlinePlus