Distribution of Fos-Like Immunoreactivity, Catecholaminergic and Serotoninergic Neurons Activated by the Laryngeal Chemoreflex in the Medulla Oblongata of Rats.

Xiaolu Wang,Ruichen Guo,Wenjing Zhao,William Hj Norton

doi:10.1371/journal.pone.0130822

Xiaolu Wang, Ruichen Guo + Show 2 more

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https://doi.org/10.1371/journal.pone.0130822

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Journal: PloS one	Publication Date: Jun 18, 2015
Citations: 8	License type: CC BY 4.0

Affiliation: Qilu Hospital of Shandong University

Abstract

The laryngeal chemoreflex (LCR) induces apnea, glottis closure, bradycardia and hypertension in young and maturing mammals. We examined the distribution of medullary nuclei that are activated by the LCR and used immunofluorescent detection of Fos protein as a cellular marker for neuronal activation to establish that the medullary catecholaminergic and serotoninergic neurons participate in the modulation of the LCR. The LCR was elicited by the infusion of KCl-HCl solution into the laryngeal lumen of adult rats in the experimental group, whereas the control group received the same surgery but no infusion. In comparison, the number of regions of Fos-like immunoreactivity (FLI) that were activated by the LCR significantly increased in the nucleus of the solitary tract (NTS), the vestibular nuclear complex (VNC), the loose formation of the nucleus ambiguus (AmbL), the rostral ventral respiratory group (RVRG), the ventrolateral reticular complex (VLR), the pre-Bötzinger complex (PrBöt), the Bötzinger complex (Böt), the spinal trigeminal nucleus (SP5), and the raphe obscurus nucleus (ROb) bilaterally from the medulla oblongata. Furthermore, 12.71% of neurons with FLI in the dorsolateral part of the nucleus of the solitary tract (SolDL) showed tyrosine hydroxylase-immunoreactivity (TH-ir, catecholaminergic), and 70.87% of neurons with FLI in the ROb were serotoninergic. Our data demonstrated the distribution of medullary nuclei that were activated by the LCR, and further demonstrated that catecholaminergic neurons of the SolDL and serotoninergic neurons of the ROb were activated by the LCR, indicating the potential central pathway of the LCR.

Highlights

The laryngeal chemoreflex (LCR) is a specific response initiated by chemical stimulation in the laryngeal lumen that results in series of reactions including respiratory inhibition, glottis closure, bradycardia and redistribution of blood flow [1,2]
We present the first description of the distribution of the medullary nuclei activated by the LCR in rats, indicating the potential central pathway of LCR in the medulla
We show for the first time that a number of the catecholaminergic neurons of the SolDL and of the serotoninergic neurons of the raphe obscurus nucleus (ROb) were activated by the LCR

Summary

Introduction

The laryngeal chemoreflex (LCR) is a specific response initiated by chemical stimulation in the laryngeal lumen that results in series of reactions including respiratory inhibition, glottis closure, bradycardia and redistribution of blood flow [1,2]. This protective reflex is a primary function to prevent food and gastric juices from entering the lower respiratory tract [3,4]. It has been reported that Fos-like immunoreactivity (FLI) is expressed in the rat hypothalamus and the amygdala of the forebrain after a chemical solution is infused into the rat laryngopharyngeal area [20] It remains unknown which specific medullary nuclei are involved in the LCR

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