Coexpression of Galanin and Nestin in the Chemoreceptor Cells of the Human Carotid Body

The evolutionary and ontogenetic development of the carotid body is still understudied. Research aimed at studying the comparative morphology of the organ at different periods in the individual development of various animal species should play a crucial role in understanding the physiology of the carotid body. However, despite more than two centuries of study, the human carotid body remains poorly understood. There are many knowledge gaps in particular related to the antenatal development of this structure. The aim of our work is to study the morphological and immunohistochemical characteristics of the human carotid body in the antenatal and postnatal periods of development. We investigated the human carotid bodies from 1 embryo, 20 fetuses and 13 adults of different ages using samples obtained at autopsy. Immunohistochemistry revealed expression of βIII-tubulin and tyrosine hydroxylase in the type I cells and nerve fibers at all periods of ontogenesis; synaptophysin and PGP9.5 in the type I cells in some of the antenatal cases and all of the postnatal cases; 200 kDa neurofilaments in nerve fibers in some of the antenatal cases and all of the postnatal cases; and GFAP and S100 in the type II cells and Schwann cells in some of the antenatal cases and all of the postnatal cases. A high level of tyrosine hydroxylase in the type I cells was a distinctive feature of the antenatal carotid bodies. On the contrary, in the type I cells of adults, the expression of tyrosine hydroxylase was significantly lower. Our data suggest that the human carotid body may perform an endocrine function in the antenatal period, while in the postnatal period of development, it loses this function and becomes a chemosensory organ.

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Participation of Na+ channels in the response of carotid body chemoreceptor cells to hypoxia

AJP Cell Physiology ◽

10.1152/ajpcell.1994.267.3.c738 ◽

1994 ◽

Vol 267 (3) ◽

pp. C738-C744 ◽

Cited By ~ 19

Author(s):

A. Rocher ◽

A. Obeso ◽

M. T. Cachero ◽

B. Herreros ◽

C. Gonzalez

Keyword(s):

Carotid Body ◽

Neurotransmitter Release ◽

Marked Reduction ◽

Adult Rabbit ◽

Na Channels ◽

Na Current ◽

Chemoreceptor Cells ◽

Cell Depolarization ◽

First Time ◽

Mild Hypoxia

The role played by Na+ channels of carotid body (CB) chemoreceptor cells was investigated by studying the effects of tetrodotoxin (TTX) on the release of 3H-labeled catecholamines ([3H]CA) by adult rabbit CBs previously incubated with the precursor [3H]tyrosine. TTX inhibited partially the release of [3H]CA elicited by mild hypoxia (10 or 7% O2) or by depolarizing incubation medium containing 20 or 30 mM KCl, but the response to more intense hypoxia (5 or 2% O2) or to higher KCl concentration (40 or 50 mM) was not significantly affected. The release of [3H]CA elicited by acidic stimuli, either 20% CO2 (pH 6.6) or the protonophore dinitrophenol (100 microM), although comparable in magnitude to that elicited by mild hypoxia, was not modified by TTX. These results provide evidence for the first time that Na+ channels of chemoreceptor cells participate in the transduction of hypoxic stimuli into the neurotransmitter release response of these cells and suggest that Na+ current operates as an amplifying device that enhances the initial cell depolarization mediated by the closure of the O2-sensitive K+ channels. Sympathetic denervation of CBs was followed by a marked reduction in the release of [3H]CA elicited by veratridine or by 20 mM KCl, suggesting that the number of Na+ channels in chemoreceptor cells decreases after denervation.

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The Effects of Chronic Hypoxaemia Upon the Structure of the Human Carotid Body

Advances in Experimental Medicine and Biology - Neurobiology and Cell Physiology of Chemoreception ◽

10.1007/978-1-4615-2966-8_6 ◽

1993 ◽

pp. 37-41

Author(s):

J.-O. Habeck ◽

D. J. Pallot ◽

A. Abramovici

Keyword(s):

Carotid Body ◽

Human Carotid

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Hydroxycobalamin Reveals the Involvement of Hydrogen Sulfide in the Hypoxic Responses of Rat Carotid Body Chemoreceptor Cells

Antioxidants ◽

10.3390/antiox8030062 ◽

2019 ◽

Vol 8 (3) ◽

pp. 62

Author(s):

Teresa Gallego-Martin ◽

Jesus Prieto-Lloret ◽

Philip Aaronson ◽

Asuncion Rocher ◽

Ana Obeso

Keyword(s):

Hydrogen Sulfide ◽

Carotid Body ◽

Oxygen Sensor ◽

Catecholamine Release ◽

Glomus Cells ◽

Arterial Blood ◽

Carotid Bodies ◽

High K ◽

Chemoreceptor Cells ◽

Ca2 Channels

Carotid body (CB) chemoreceptor cells sense arterial blood PO2, generating a neurosecretory response proportional to the intensity of hypoxia. Hydrogen sulfide (H2S) is a physiological gaseous messenger that is proposed to act as an oxygen sensor in CBs, although this concept remains controversial. In the present study we have used the H2S scavenger and vitamin B12 analog hydroxycobalamin (Cbl) as a new tool to investigate the involvement of endogenous H2S in CB oxygen sensing. We observed that the slow-release sulfide donor GYY4137 elicited catecholamine release from isolated whole carotid bodies, and that Cbl prevented this response. Cbl also abolished the rise in [Ca2+]i evoked by 50 µM NaHS in enzymatically dispersed CB glomus cells. Moreover, Cbl markedly inhibited the catecholamine release and [Ca2+]i rise caused by hypoxia in isolated CBs and dispersed glomus cells, respectively, whereas it did not alter these responses when they were evoked by high [K+]e. The L-type Ca2+ channel blocker nifedipine slightly inhibited the rise in CB chemoreceptor cells [Ca2+]i elicited by sulfide, whilst causing a somewhat larger attenuation of the hypoxia-induced Ca2+ signal. We conclude that Cbl is a useful and specific tool for studying the function of H2S in cells. Based on its effects on the CB chemoreceptor cells we propose that endogenous H2S is an amplifier of the hypoxic transduction cascade which acts mainly by stimulating non-L-type Ca2+ channels.

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