Glomus Cells (glomu + cell)

Distribution by Scientific Domains


Selected Abstracts


Expression of histamine receptors and effect of histamine in the rat carotid body chemoafferent pathway

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2006
Nikolai Lazarov
Abstract Chemosensory information from peripheral arterial oxygen sensors in the carotid body is relayed by petrosal ganglion neurons to the respiratory networks in the medulla oblongata. Biogenic amines, including histamine, released from glomus (type I) cells of the carotid body are considered to be primary transmitters in hypoxic chemosensitivity. Immunocytochemistry at light-and electron-microscopical levels, and RT-PCR, revealed the expression of histamine receptors 1 and 3 as well as histidine decarboxylase in the rat carotid body glomus cells and petrosal ganglion neurons. Histamine receptors 1 and 3, but not histidine decarboxylase, were also observed in the ventrolateral, intermediate and commissural subnuclei of the nucleus tractus solitarii in the medulla oblongata. In order to examine the possible role of histamine in the afferent branch of the respiratory system, we applied histamine receptor 1 and 3 agonists to the carotid body, which caused a mildly increased phrenic nerve activity in a working heart,brainstem preparation. Moreover, microinjection of antagonists of histamine receptors 1 and 3 into the nucleus tractus solitarii caused significant changes in the inspiratory timing and the chemoreceptor response. Our data show that histamine acting via histamine receptors 1 and 3 plays an important neuromodulatory role in the afferent control of chemosensitivity. [source]


Glomus Coccygeum: Report of a Case

JOURNAL OF CUTANEOUS PATHOLOGY, Issue 1 2005
A. Rahemtullah
The glomus coccygeum is a vestigial structure related to the canals of Sucquet-Hoyer, an arteriovenous anastomosis surrounded by glomus cells derived from modified smooth muscle and involved in thermoregulation. It is an incidental finding in specimens from the sacral area and may represent a diagnostic challenge to the unaware observer. We present a case of a glomus coccygeum, presenting as a 1.5 mm structure adjacent to a typical pilonidal cyst excised from a 7-month-old boy, that was the subject of a second opinion consultation. The lesion showed small to medium sized clusters of predominantly epithelioid cells with moderate amounts of clear to eosinophilic cytoplasm, intercellular borders and plump, round nuclei with fine chromatin. These cells were closely associated with small vascular channels and nerves. Immunohistochemistry revealed that the epithelioid cells expressed vimentin, muscle-specific actin, neuron-specific enolase, and S-100 protein, were weakly positive for smooth muscle actin, and negative for desmin, synaptophysin and chromogranin. The endothelial cells of the vascular channels were antibody CD31 positive. Recognition of the histological features of glomus coccygeum is important to avoid confusion with glomus tumor and neural or smooth muscle neoplasms in the sacral area. [source]


Melatonin enhances the hypoxic response of rat carotid body chemoreceptor

JOURNAL OF PINEAL RESEARCH, Issue 3 2005
Yueping Chen
Abstract:, Melatonin attenuates carotid chemoreceptor response to hypercapnic acidosis and may contribute to the effect of circadian rhythms on the chemoreflex. The purpose of this study was to test the hypothesis that melatonin modulates rat carotid chemoreceptor response to hypoxia. To examine the effect of melatonin on the hypoxic response of the chemosensitive cells, cytosolic calcium ([Ca2+]i) was measured by spectrofluorometry in fura-2-loaded type-I (glomus) cells dissociated from rat carotid bodies. Melatonin (0.01,10 nm) did not change the resting [Ca2+]i level of the glomus cells but it concentration-dependently increased peak [Ca2+]i response to cyanide or deoxygenated buffer. An agonist of melatonin receptors, iodomelatonin also enhanced the [Ca2+]i response to hypoxia. The melatonin-induced enhancement of the [Ca2+]i response was abolished by pretreatment with nonselective mt1/MT2 antagonist, luzindole, and by MT2 antagonists, 4-phenyl-2-propionamidotetraline or DH97. These findings suggest that melatonin receptors in the glomus cells mediate the effect of melatonin on the chemoreceptor response to hypoxia. In addition, melatonin increased the carotid afferent response to hypoxia in unitary activities recorded from the sinus nerve in isolated carotid bodies superfused with bicarbonate-buffer saline. Furthermore, plethysmographic measurement of ventilatory activities in unanesthetized rats revealed that melatonin (1 mg/kg, i.p.) increased the ventilatory response to hypoxia. Hence, the circadian rhythm of melatonin in arterial blood can modulate the carotid chemoreceptor response to hypoxia. This modulation may be a physiological mechanism involved in the day-light differences in ventilatory activities. [source]


Gene expression in peripheral arterial chemoreceptors

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2002
Estelle B. Gauda
Abstract The peripheral arterial chemoreceptors of the carotid body participate in the ventilatory responses to hypoxia and hypercapnia, the arousal responses to asphyxial apnea, and the acclimatization to high altitude. In response to an excitatory stimuli, glomus cells in the carotid body depolarize, their intracellular calcium levels rise, and neurotransmitters are released from them. Neurotransmitters then bind to autoreceptors on glomus cells and postsynaptic receptors on chemoafferents of the carotid sinus nerve. Binding to inhibitory or excitatory receptors on chemoafferents control the electrical activity of the carotid sinus nerve, which provides the input to respiratory-related brainstem nuclei. We and others have used gene expression in the carotid body as a tool to determine what neurotransmitters mediate the response of peripheral arterial chemoreceptors to excitatory stimuli, specifically hypoxia. Data from physiological studies support the involvement of numerous putative neurotransmitters in hypoxic chemosensitivity. This article reviews how in situ hybridization histochemistry and other cellular localization techniques confirm, refute, or expand what is known about the role of dopamine, norepinephrine, substance P, acetylcholine, adenosine, and ATP in chemotransmission. In spite of some species differences, review of the available data support that 1) dopamine and norepinephrine are synthesized and released from glomus cells in all species and play an inhibitory role in hypoxic chemosensitivity; 2) substance P and acetylcholine are not synthesized in glomus cells of most species but may be made and released from nerve fibers innervating the carotid body in essentially all species; 3) adenosine and ATP are ubiquitous molecules that most likely play an excitatory role in hypoxic chemosensitivity. Microsc. Res. Tech. 59:153,167, 2002. © 2002 Wiley-Liss, Inc. [source]


Multiple hereditary glomangiomas: Successful treatment with sclerotherapy

AUSTRALASIAN JOURNAL OF DERMATOLOGY, Issue 1 2002
Kurosh Parsi
SUMMARY Glomangiomas are characterized by cavernous vascular channels surrounded by glomus cells. Multiple glomangiomas, although usually painless, can be a few centimetres in size and appear as blue phlebectatic lesions. Surgical excision of multiple glomangiomas can lead to scarring and recurrences. Laser treatment using vascular lasers and CO2 lasers has been useful in small, superficial lesions. We present the successful sclerotherapy treatment of multiple glomangiomas using sodium tetradecyl sulphate in a 59-year-old man who presented with postoperative recurrence of multiple lesions. [source]