Search results for "Carotid body"
showing 10 items of 17 documents
An O2-sensitive glomus cell-stem cell synapse induces carotid body growth in chronic hypoxia.
2013
Summary Neural stem cells (NSCs) exist in germinal centers of the adult brain and in the carotid body (CB), an oxygen-sensing organ that grows under chronic hypoxemia. How stem cell lineage differentiation into mature glomus cells is coupled with changes in physiological demand is poorly understood. Here, we show that hypoxia does not affect CB NSC proliferation directly. Rather, mature glomus cells expressing endothelin-1, the O 2 -sensing elements in the CB that secrete neurotransmitters in response to hypoxia, establish abundant synaptic-like contacts with stem cells, which express endothelin receptors, and instruct their growth. Inhibition of glomus cell transmitter release or their sel…
Calcium/calmodulin-dependent protein kinases in the carotid body: an immunohistochemical study
2012
We determined the presence of Ca(2+)/calmodulin-dependent protein kinases (CaMKs), a family of multifunctional proteins engaged in Ca(2+)-linked signaling, in carotid body chemoreceptor cells which are critical for the hypoxia-sensing. Carotid bodies were dissected from anesthetized normoxic adult Wistar rats and were double stained for individual CaMKs and for tyrosine hydroxylase (TH), a marker of chemoreceptor cells. Immunofluorescence was examined by confocal laser scanning microscopy. We found that CaMKI and CaMKII were expressed in chemoreceptor cells, but their distribution and intensity varied. CaMKI immunoreactivity was distributed throughout the cytoplasm, whereas that of CaMKII w…
Connexin36 (Cx36) expression and protein detection in the mouse carotid body and myenteric plexus
2013
AbstractAlthough connexin36 (Cx36) has been studied in several tissues, it is notable that no data are available on Cx36 expression in the carotid body and the intestine. The present study was undertaken to evaluate using immunohistochemistry, PCR and Western blotting procedures, whether Cx36 was expressed in the mouse carotid body and in the intestine at ileum and colon level. In the carotid body, Cx36 was detected as diffuse punctate immunostaining and as protein by Western blotting and mRNA by RT-PCR. Cx36 punctate immunostaining was also evident in the intestine with localization restricted to the myenteric plexus of both the ileum and the colon, and this detection was also confirmed by…
Expression of p11 and TASK1 Channels in Rat Carotid Body Glomus Cells Subjected to Chronic Intermittent Hypoxia
2022
Chronic intermittent hypoxia (CIH) has been used as a model to mimic nocturnal apnea, which is associated with hypertension. One of the mechanisms for hypertension in patients with nocturnal apnea is an enhancement of the plasma membrane response to acute hypoxia in carotid body glomus cells. Hypoxia is known to induce depolarization via inhibiting TWIK-related acid-sensitive K+ (TASK) channels, one type of leak K+ channels, in glomus cells. The present experiment was undertaken to immunocytochemically investigate the effects of CIH on the expression and intracellular localization of TASK1 channels and p11 that critically affect the trafficking of TASK1 to the cell surface. The expression l…
Role of IP3 Receptors in Shaping the Carotid Chemoreceptor Response to Hypoxia but not to Hypercapnia in the Rat Carotid Body: An Evidence Review
2021
This article addresses the disparity in the transduction pathways for hypoxic and hypercapnic stimuli in carotid body glomus cells. We investigated and reviewed the experimental evidence showing that the response to hypoxia, but not to hypercapnia, is mediated by 1,4,5-inositol triphosphate receptors (IP3R/s) regulating the intracellular calcium content [Ca2+]c in glomus cells. The rationale was based on the past observations that inhibition of oxidative phosphorylation leads to the explicit inhibition of the hypoxic chemoreflex. [Ca2+]c changes were measured using cellular Ca2+-sensitive fluorescent probes, and carotid sinus nerve (CSN) sensory discharge was recorded with bipolar electrode…
Paragangliomi cervicali: diagnosi e trattamento
2006
Inhibition of Peripheral Dopamine Metabolism and the Ventilatory Response to Hypoxia in the Rat
2014
Dopamine (DA) is a putative neurotransmitter in the carotid body engaged in the generation of the hypoxic ventilatory response (HVR). However, the action of endogenous DA is unsettled. This study seeks to determine the ventilatory effects of increased availability of endogenous DA caused by inhibition of DA enzymatic breakdown. The peripheral inhibitor of MAO – debrisoquine, or COMT – entacapone, or both combined were injected to conscious rats. Ventilation and its responses to acute 8 % O2 in N2 were investigated in a whole body plethysmograph. We found that inhibition of MAO augmented the hyperventilatory response to hypoxia. Inhibition of COMT failed to influence the hypoxic response. Ho…
Development and Aging Are Oxygen-Dependent and Correlate with VEGF and NOS along Life Span
2012
During development and aging, vascular remodeling represents a critical adaptive response to modifications in oxygen supply to tissues. Hypoxia inducible factor (HIF) has a crucial role and is modulated by oxygen levels, with an age-dependent response in neonates, adult, and aged people. ROS are generated under hypoxic conditions and the accumulation of free radicals during life reduces the ability of tissues to their removal. In this immunohistochemical study we investigated the presence and localization of VEGF and iNOS in human carotid bodies (CB) sampled at autopsy from three children (mean age – 2 years), four adult young subjects (mean age – 44.3 years), and four old subjects (mean ag…
Selective expression of galanin in neuronal-like cells of the human carotid body
2015
The carotid body is a neural-crest-derived organ devoted to respiratory homeostasis through sensing changes in blood oxygen levels. The sensory units are the glomeruli composed of clusters of neuronal-like (type I) cells surrounded by glial-like (type II) cells. During chronic hypoxia, the carotid body shows growth, with increasing neuronal-like cell numbers. We are interested in the signals involved in the mechanisms that underlie such response, because they are not well understood and described. Considering that, in literature, galanin is involved in neurotrophic or neuroprotective role in cell proliferation and is expressed in animal carotid body, we investigated its expression in human.…
Role of IP3 Receptors in Shaping the Carotid Chemoreceptor Response to Hypoxia But Not to Hypercapnia in the Rat Carotid Body: An Evidence Review
2020
This article addresses the disparity in the transduction pathways for hypoxic and hypercapnic stimuli in carotid body glomus cells. We investigated and reviewed the experimental evidence showing that the response to hypoxia, but not to hypercapnia, is mediated by 1,4,5-inositol triphosphate receptors (IP3R/s) regulating the intracellular calcium content [Ca2+]c in glomus cells. The rationale was based on the past observations that inhibition of oxidative phosphorylation leads to the explicit inhibition of the hypoxic chemoreflex. [Ca2+]c changes were measured using cellular Ca2+-sensitive fluorescent probes, and carotid sinus nerve (CSN) sensory discharge was recorded with bipolar electrode…