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Altitude, temperature, circadian rhythms and exercise
Published in Adam P. Sharples, James P. Morton, Henning Wackerhage, Molecular Exercise Physiology, 2022
Henning Wackerhage, Kenneth A. Dyar, Martin Schönfelder
How is the oxygen concentration sensed? The ventilation-regulating signals of O2, CO2 and pH are sensed by peripheral chemoreceptors such as the carotid and aortic bodies and by central chemoreceptors in the brain. The ≈20 mm3 large carotid body, located at the bifurcation of the carotid artery that supplies the head and brain with oxygen, is a sensitive oxygen sensor that monitors the arterial O2 tension (PaO2) and stimulates ventilation when the PaO2 drops below ≈60 mmHg. The carotid body contains three main cell types (5, 6): Oxygen-sensing glomus cells (type 1),Subtentacular cells (type 2),Afferent nerve fibres whose axons convey the hypoxia message to the ventilation-regulating parts of the brain.
Complications of extracranial carotid aneurysm repair and resection of carotid body tumor
Published in Sachinder Singh Hans, Mark F. Conrad, Vascular and Endovascular Complications, 2021
Sachinder Singh Hans, Mary Lee
In a series of over 500 contemporary cases, stroke rate following carotid body tumor resection is reported to be about 4%.4 A mortality rate as high as 8.8% has been reported in complex cases requiring arterial resection.3,4 Cranial nerve injury is the most common complication, and incidence of cranial nerve dysfunction can be as high as 40%. Permanent cranial nerve injury occurs in about 20% of patients (8–39%).3,4 Pseudoaneurysm is an extremely uncommon complication of resection of carotid body tumor.4 Complete resection of carotid body tumor can be performed in most patients, and the survival of the patients following complete resection is similar to general population. Recurrence can occasionally occur. Patients with malignant carotid body tumor (exceedingly rare) require post-radiation therapy and late metastatic disease has been reported.5
Surgery
Published in Seema Khan, Get Through, 2020
Carotid body tumours are located in the anterior triangle of the neck and present as a painless slow-growing lump in the neck. They are rare and usually benign lesions found at the bifurcation of the carotid artery. Surgical removal is advocated to prevent compression of neurovascular structures.
Novel approaches: targeting sympathetic outflow in the carotid sinus
Published in Blood Pressure, 2023
Dagmara Hering, Krzysztof Narkiewicz
In addition to the role of the carotid body in the control of ventilation, findings in animal models suggest that the carotid body is a peripheral insulin sensor involved in the control of energy homeostasis [20]. Animals exposed to hypercaloric diets exhibit carotid body activity contributing to insulin resistance and hypertension through augmented sympathetic activation [18]. In support of this concept, further experimental studies have shown that selective bilateral resection of the carotid sinus nerve (CBD) completely prevents diet-induced insulin resistance, hyperglycaemia, dyslipidaemia, hypertension and sympathetic adrenal hyperactivity [18]. These findings indicate that neuromodulation of carotid body activity is another potential therapeutic intervention for metabolic diseases, but human studies on disorders of glucose metabolism are lacking.
Obstructive sleep apnea: personalizing CPAP alternative therapies to individual physiology
Published in Expert Review of Respiratory Medicine, 2022
Brandon Nokes, Jessica Cooper, Michelle Cao
It is worth mentioning here that there are two chemoreceptive sensors with converging data on the respiratory pattern generator; the pre-Botzinger complex (preBotC) [54]. The carotid body is the principle O2 sensor in humans (the aortic body appears to be less relevant) [55]. This organ is unique in that it has the most blood flow per gram of tissue in the human body, allowing for rapid detection of subtle polymodal chemical cues by highly specialized glomus cells [56]. This arrangement facilitates changes in neural output in response to subtle changes in O2 partial pressure, pH, glucose, etc. Of note, there appear to be two distinct populations of glomus cells: 1) chemosensory – dopamine beta hydroxylase positive, express nicotinic receptors, elaborate norepinephrine in response to hypoxia, and are inhibited by dopamine, and 2) sympatho-excitatory – tyrosine hydroxylase positive, express purinergic receptors (P2X3), elaborate adenosine triphosphate (ATP) in response to hypoxia, and can be stimulated with angiotensin II [56,57]. These two glomus cell populations drive the ventilatory and sympathetic responses to hypoxia, respectively. These subtleties are worth considering, because medications such as anti-dopaminergic agents and anti-purinergic agents (such as Ticagrelor) can exert effects on ventilatory control stability through their actions on the carotid body [58,59].
Strong stimulation triggers full fusion exocytosis and very slow endocytosis of the small dense core granules in carotid glomus cells
Published in Journal of Neurogenetics, 2018
Amy Tse, Andy K. Lee, Noriko Takahashi, Alex Gong, Haruo Kasai, Frederick W. Tse
Male Sprague-Dawley rats (200–250 g) were euthanized in accordance to the standards of the Canadian Council on Animal Care. The carotid bodies were removed and dissociated enzymatically as described in our previous studies (Xu, Tse, & Tse, 2007; Yan, Lee, Tse, & Tse, 2012). Single carotid cells or cell clusters were plated onto glass coverslips and kept in a medium containing F-12/Dulbecco’s modified Eagle’s medium (1:1), supplemented with 5% fetal calf serum, 50 U/ml of penicillin G and 50 µg/ml of streptomycin. All culture materials were from Gibco (Grand Island, NY, USA). Recordings were performed on cells maintained in culture for 24–40 h. The carotid body contains glomus (type I) and the glial-like sustentacular (type II) cells. We identified glomus cells based on their ovoid shape and/or the presence of voltage-gated Ca2+ channels as described previously (Xu, Xu, Tse, & Tse, 2005).