Norepinephrine-containing glomus cells in the rabbit carotid body. I. Autoradiographic and morphometric study after tritiated norepinephrine uptake

1992 ◽  
Vol 21 (5) ◽  
pp. 341-352 ◽  
Author(s):  
A. Schamel ◽  
A. Verna
Keyword(s):  
Carotid Body ◽  
Morphometric Study ◽  
Glomus Cells ◽  
Norepinephrine Uptake

Fine Structure of Carotid Body: Normal and Anoxic Cats

1967 ◽  
Vol 25 ◽  
pp. 150-151
Author(s):  
Fadhil Al-Lami ◽  
R.G. Murray
Keyword(s):  
Fine Structure ◽  
Adrenal Medulla ◽  
Carotid Body ◽  
Uranyl Acetate ◽  
Lead Citrate ◽  
Glomus Cells ◽  
Sustentacular Cells ◽  
Carotid Bodies

Although the fine structure of the carotid body has been described in several recent reports, uncertainties remain, and the morphological effects of anoxia on the carotid body cells of the cat have never been reported. We have, therefore, studied the fine structure of the carotid body both in normal and severely anoxic cats, and to test the specificity of the effects, have compared them with the effects on adrenal medulla, kidney, and liver of the same animals. Carotid bodies of 50 normal and 15 severely anoxic cats (9% oxygen in nitrogen) were studied. Glutaraldehyde followed by OsO4 fixations, Epon 812 embedding, and uranyl acetate and lead citrate staining, were the technics employed.We have called the two types of glomus cells enclosed and enclosing cells. They correspond to those previously designated as chemoreceptor and sustentacular cells respectively (1). The enclosed cells forming the vast majority, are irregular in shape with many processes and occasional peripheral densities (Fig. 1).

Acute O2 sensing through HIF2α-dependent expression of atypical cytochrome oxidase subunits in arterial chemoreceptors

2019 ◽  
Vol 13 (615) ◽  
pp. eaay9452 ◽  
Author(s):  
Alejandro Moreno-Domínguez ◽  
Patricia Ortega-Sáenz ◽  
Lin Gao ◽  
Olalla Colinas ◽  
Paula García-Flores ◽  
...  
Keyword(s):  
Ion Channels ◽  
Carotid Body ◽  
Acute Hypoxia ◽  
Mechanistic Explanation ◽  
Nerve Fibers ◽  
Adaptive Responses ◽  
Glomus Cells ◽  
Adult Mice ◽  
Genes Encoding ◽  
Regulation Of Breathing

Acute cardiorespiratory responses to O2 deficiency are essential for physiological homeostasis. The prototypical acute O2-sensing organ is the carotid body, which contains glomus cells expressing K+ channels whose inhibition by hypoxia leads to transmitter release and activation of nerve fibers terminating in the brainstem respiratory center. The mechanism by which changes in O2 tension modulate ion channels has remained elusive. Glomus cells express genes encoding HIF2α (Epas1) and atypical mitochondrial subunits at high levels, and mitochondrial NADH and reactive oxygen species (ROS) accumulation during hypoxia provides the signal that regulates ion channels. We report that inactivation of Epas1 in adult mice resulted in selective abolition of glomus cell responsiveness to acute hypoxia and the hypoxic ventilatory response. Epas1 deficiency led to the decreased expression of atypical mitochondrial subunits in the carotid body, and genetic deletion of Cox4i2 mimicked the defective hypoxic responses of Epas1-null mice. These findings provide a mechanistic explanation for the acute O2 regulation of breathing, reveal an unanticipated role of HIF2α, and link acute and chronic adaptive responses to hypoxia.

scholarly journals Evolution of the hypoxia-sensitive cells involved in amniote respiratory reflexes

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Dorit Hockman ◽  
Alan J Burns ◽  
Gerhard Schlosser ◽  
Keith P Gates ◽  
Benjamin Jevans ◽  
...  
Keyword(s):  
Neural Crest ◽  
Blood Vessels ◽  
Carotid Body ◽  
Lineage Tracing ◽  
Neuroendocrine Cells ◽  
Genetic Lineage ◽  
Glomus Cells ◽  
Evolutionary Origins ◽  
Embryonic Origin ◽  
Respiratory Reflexes

The evolutionary origins of the hypoxia-sensitive cells that trigger amniote respiratory reflexes – carotid body glomus cells, and ‘pulmonary neuroendocrine cells’ (PNECs) - are obscure. Homology has been proposed between glomus cells, which are neural crest-derived, and the hypoxia-sensitive ‘neuroepithelial cells’ (NECs) of fish gills, whose embryonic origin is unknown. NECs have also been likened to PNECs, which differentiate in situ within lung airway epithelia. Using genetic lineage-tracing and neural crest-deficient mutants in zebrafish, and physical fate-mapping in frog and lamprey, we find that NECs are not neural crest-derived, but endoderm-derived, like PNECs, whose endodermal origin we confirm. We discover neural crest-derived catecholaminergic cells associated with zebrafish pharyngeal arch blood vessels, and propose a new model for amniote hypoxia-sensitive cell evolution: endoderm-derived NECs were retained as PNECs, while the carotid body evolved via the aggregation of neural crest-derived catecholaminergic (chromaffin) cells already associated with blood vessels in anamniote pharyngeal arches.

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