Asuncion Rocher

Universidad de Valladolid | UVA · Department of Biochemistry and Molecular Biology and Physiology

Obstructive sleep apnea (OSA) is a common sleep disorder that is associated with a wide variety of health conditions, including cardiovascular, cerebrovascular, metabolic, neoplastic, and neurocognitive manifestations. OSA is mainly characterized by repeated upper airway obstructions during sleep that cause episodes of chronic intermittent hypoxia...

Experimental evidence suggests that chronic intermittent hypoxia (CIH), a major hallmark of obstructive sleep apnea (OSA), boosts carotid body (CB) responsiveness, thereby causing in-creased sympathetic activity, arterial and pulmonary hypertension, and cardiovascular disease. An enhanced circulatory chemoreflex, oxidative stress, and NO signaling...

On the thirty-fifth anniversary of the first description of O2-sensitive K+ channels in the carotid body chemoreceptors O2 sensing remains a salient issue in the literature. Whereas much has been learned about this subject, important questions such as the identity of the specific K+ channel subtype(s) responsible for O2 sensing by chemoreceptors an...

On the thirty-fifth anniversary of the first description of O2-sensitive K+ channels in the carotid body chemoreceptors [1], O2 sensing remains a salient issue in the literature. Whereas much has been learned about this subject, important questions such as the identity of the specific K+ channel subtype(s) responsible for O2 sensing by chemorecepto...

Citation: Fernandes, J.L.; Martins, F.O.; Olea, E.; Prieto-Lloret, J.; Braga, P.C.; Sacramento, J.F.; Sequeira, C.O.; Negrinho, A.P.; Pereira, S.A.; Alves, M.G.; et al. Chronic Intermittent Hypoxia-Induced Dysmetabolism Is Abstract: The association between obstructive sleep apnea (OSA) and metabolic disorders is well-established; however, the under...

This work analyses the impact of intermittent hypoxia exposure and high-fat diet feeding, as models of sleep apnoea, on both autonomic activity and histolog-ical structure of the rat jejunum and whether the overlapping of both conditions, as often observed in patients, produces a more deleterious effect on the intestinal barrier. We found alteratio...

Finding novel pathological mechanisms that lead to innovative strategies to treat obesity and its associated illness are critically needed. The carotid bodies (CB) are metabolic sensors whose dysfunction contributes to insulin resistance and glucose intolerance development. Herein, we find that the ablation of CB activity, through resection of caro...

Obstructive sleep apnea (OSA) during pregnancy is characterized by episodes of intermittent hypoxia (IH) during sleep, resulting in adverse health outcomes for mother and offspring. Despite a prevalence of 8–20% in pregnant women, this disorder is often underdiagnosed.We have developed a murine model of gestational OSA to study IH effects on pregna...

This work analyzes the impact of two conditions, intermittent hypoxia exposure and high-fat diet in rats as models of sleep apnea. We studied the autonomic activity and histological structure of the rat jejunum and whether the overlapping of both conditions, as often observed in patients, induces more deleterious effects on the intestinal barrier....

The association between obstructive sleep apnea (OSA) and metabolic disorders is well-established but the underlying mechanisms that elucidate this relationship remain incompletely understood. Since the liver is a major organ in the maintenance of metabolic homeostasis, we hypothesize that liver dysfunction plays a crucial role in the pathogenesis...

Hypoxia may be associated with alterations in bone remodeling, but the published results are contradictory. The aim of this study was to characterize the bone morphometry changes subject to hypoxia for a better understanding of the bone response to hypoxia and its possible clinical consequences on the bone metabolism. This study analyzed the bone m...

Oxygen is such an essential element for life that multiple mechanisms have evolved to maintain oxygen homeostasis, including those which detect decreases in arterial O2 and generate adaptive responses to hypoxia [...]

Chronic sustained hypoxia (CSH), as found in individuals living at a high altitude or in patients suffering respiratory disorders, initiates physiological adaptations such as carotid body stimulation to maintain oxygen levels, but has deleterious effects such as pulmonary hypertension (PH). Obstructive sleep apnea (OSA), a respiratory disorder of i...

Several studies demonstrated a link between obstructive sleep apnea (OSA) and the development of insulin resistance. However, the main event triggering insulin resistance in OSA remains to be clarified. Herein, we investigated the effect of mild and severe chronic intermittent hypoxia (CIH) on whole-body metabolic deregulation and visceral adipose...

Oxygen is an essential requirement for metabolism in mammals and many other animals. Therefore, pathways that sense a reduction in available oxygen are critical for organism survival. Higher mammals developed specialized organs to detect and respond to changes in O2 content to maintain gas homeostasis by balancing oxygen demand and supply. Here, we...

The sleep apnea-hypopnea syndrome (SAHS) involves periods of intermittent hypoxia, experimentally reproduced by exposing animal models to oscillatory PO2 patterns. In both situations, chronic intermittent hypoxia (CIH) exposure produces carotid body (CB) hyperactivation generating an increased input to the brainstem which originates sympathetic hyp...

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 CB, although this concept remains controversial. In the present study we have used the H2S scavenger...

The molecular mechanisms underlying O2-sensing by carotid body (CB) chemoreceptors remain undetermined. Mitochondria have been implicated, due to the sensitivity of CB response to electron transport chain (ETC) blockers. ETC is one of the major sources of reactive oxygen species, proposed as mediators in oxygen sensing. Fas-activated serine/threoni...

The molecular mechanisms underlying O2-sensing by carotid body (CB) chemoreceptors remain undetermined. Mitochondria have been related, due to the sensitivity of CB response, to electron transport chain (ETC) blockers. ETC is one of the major sources of Reactive Oxygen Species, proposed as mediators in oxygen sensing. Fas-activated serine/threonine...

Clinical and experimental evidence indicates a positive correlation between chronic intermittent hypoxia (CIH), increased carotid body (CB) chemosensitivity, enhanced sympatho-respiratory coupling and arterial hypertension and cardiovascular disease. Several groups have reported that both the afferent and efferent arms of the CB chemo-reflex are en...

Guinea pigs (GP), originally from the Andes, have absence of hypoxia-driven carotid body (CB) reflex. Neonatal mammals have an immature CB chemo reflex and respond to hypoxia with metabolic changes arising from direct effects of hypoxia on adrenal medulla (AM). Our working hypothesis is that adult GP would mimic neonatal mammals. Plasma epinephrine...

Pulmonary arterial hypertension (PAH) is characterized by the progressive elevation of pulmonary arterial pressure (PAP), remodeling of pulmonary arteries (PA), inflammation and thrombosis, leading ultimately to death from right heart failure. In spite of the well documented protective effect of estrogens on the pulmonary vasculature (attenuated va...

Mammals have developed different mechanisms to maintain oxygen supply to cells in response to hypoxia. One of those mechanisms, the carotid body (CB) chemoreceptors, is able to detect physiological hypoxia and generate homeostatic reflex responses, mainly ventilatory and cardiovascular. It has been reported that guinea pigs, originally from the And...

Se sabe que hay un claro predominio en el desarrollo de la hipertensión pulmonar (HP) en la población femenina en relación a la masculina (2:1), aunque con un mayor índice de supervivencia femenina. No existe una explicación para la influencia del sexo en la patogénesis y progresión de la HP. El objetivo del trabajo ha sido desarrollar y caract...

Chronic Intermittent Hypoxia (CIH) is considered one of the main causes of cardiovascular and metabolic alterations observed in the obstructive sleep apnea syndrome. Previous observations show that deleterious effects of CIH seem to be less pronounced in aged animals. Carotid body (CB) hypofunctionality and lower redox effects in old rats have been...

The extracellular calcium-sensing receptor (CaSR) is a unique G protein–coupled receptor (GPCR) activated by extracellular Ca2+ and by other physiological cations including Mg2+, amino acids, and polyamines. CaSR is the most important master controller of the extracellular Ca2+ homeostatic system being expressed at high levels in the parathyroid gl...

The cascade of transduction of hypoxia and hypercapnia, the natural stimuli to chemoreceptor cells, is incompletely understood. A particular gap in that knowledge is the role played by second messengers, or in a most ample term, of modulators. A recently described modulator of chemoreceptor cell responses is the gaseous transmitter hydrogen sulfide...

Adult mammalians possess three cell systems that are activated by acute bodily hypoxia: pulmonary artery smooth muscle cells (PASMC), carotid body chemoreceptor cells (CBCC) and erythropoietin (EPO)-producing cells. In rats, chronic perinatal hyperoxia causes permanent carotid body (CB) atrophy and functional alterations of surviving CBCC. There ar...

Abstract Obstructive sleep apnea (OSA) consists of sleep-related repetitive obstructions of upper airways which generate episodes of recurrent or intermittent hypoxia (IH). OSA commonly generates cardiovascular and metabolic pathologies defining the obstructive sleep apnea syndrome (OSAS). Literature usually links OSA-associated pathologies to IH e...

When de Castro entered the carotid body (CB) field, the organ was considered to be a small autonomic ganglion, a gland, a glomus or glomerulus, or a paraganglion. In his 1928 paper, de Castro concluded: "In sum, the Glomus caroticum is innervated by centripetal fibers, whose trophic centers are located in the sensory ganglia of the glossopharyngeal...

Carotid body chemoreceptor cells in response to hypoxic and hypercapnic stimulus increase their resting rate of release of neurotransmitters and their action potential frequency in the carotid sinus sensory nerve. When chemoreceptor activity is assessed at the level of the carotid sinus nerve and on ventilation, there exists an interaction between...

Serotonin or 5-HT is a biogenic amine present in the carotid body (CB) of several species as evidenced in many immunocytochemical studies and in a few biochemical measurements. Early literature on 5-HT actions in the CB in all studied species has lead to the conclusion that it does not participate in the setting of conducted action potentials in th...

The views presented in this article are the fruit of reflections and discussion with my colleagues at Valladolid and with the members of the Sleep Apnea Hypopnea Syndrome Group of the CIBERES (Spain). We have assembled the article in three sections. In the first one we provide a mechanistic description of obstructive sleep apnea (OSA) and all of it...

Carotid bodies (CBs) are secondary sensory receptors in which the sensing elements, chemoreceptor cells, are activated by decreases in arterial PO(2) (hypoxic hypoxia). Upon activation, chemoreceptor cells (also known as Type I and glomus cells) increase their rate of release of neurotransmitters that drive the sensory activity in the carotid sinus...

An increase in intracellular Ca²(+) is crucial to O₂ sensing by the carotid body. Polyamines have been reported to modulate both the extracellular Ca²(+)-sensing receptor (CaR) and voltage-gated Ca²(+) channels in a number of cell types. Using RT-PCR and immunohistochemistry, the predominant voltage-gated Ca²(+) channels expressed in the adult rat...

Oxygen-sensing and transduction in purposeful responses in cells and organisms is of great physiological and medical interest. All animals, including humans, encounter in their lifespan many situations in which oxygen availability might be insufficient, whether acutely or chronically, physiologically or pathologically. Therefore to trace at the mol...

Chemoreceptor cells of the carotid bodies (CB) are activated by hypoxia and acidosis, responding with an increase in their rate of neurotransmitter release, which in turn increases the electrical activity in the carotid sinus nerve and evokes a homeostatic hyperventilation. Studies in isolated chemoreceptor cells have shown that moderate hypoxias (...

Carotid body (CB) chemoreceptor cells from adult rats that in the perinatal life have been exposed to 55% O2 have a diminished capacity to respond to hypoxia (Prieto-Lloret et al., J Physiol. 554:126-44, 2004). We have tested the hypothesis that hyperoxia alters the ability of pulmonary artery smooth muscle cells to respond to hypoxia, and thereby...

Polyamines modulate many biological functions. Here we report a novel inhibitory modulation by spermine of catecholamine release by the rat carotid body and have identified the molecular mechanism underpinning it. We used molecular (RT-PCR and confocal microscopy) and functional (i.e., neurotransmitter release, patch clamp recording and calcium ima...

Mechanisms involved in carotid body (CB) chemoreceptor cells O(2)-sensing and responses are not fully understood. So far, it is known that hypoxia depolarizes chemoreceptor cells via O(2)-sensitive K(+)-channel inhibition; calcium influx via voltage-gated channels and neurotransmitter secretion follow. Presence of high voltage activated (HVA) calci...

We have assessed the expression, molecular identification and functional role of Na+ channels (Na(v)) in carotid bodies (CB) obtained from normoxic and chronically hypoxic adult rats. Veratridine evoked release of catecholamines (CA) from an in vitro preparation of intact CBs obtained from normoxic animals, the response being Ca2+ and Na+-dependent...

Superoxide anion is the most important reactive oxygen species (ROS) primarily generated in cells. The main cellular constituents with capabilities to generate superoxide anion are NADPH oxidases and mitochondrial respiratory chain. The emphasis of our article is centered in critically examining hypotheses proposing that ROS generated by NADPH oxid...

Caffeine, an unspecific antagonist of adenosine receptors, is commonly used to treat the apnea of prematurity. We have defined the effects of caffeine on the carotid body (CB) chemoreceptors, the main peripheral controllers of breathing, and identified the adenosine receptors involved. Caffeine inhibited basal (IC50, 210 microm) and low intensity (...

Carotid body (CB) chemoreceptors sense arterial PO2and PCO2/pH becoming activated in hypoxic hypoxia and in all types of acidosis. The sensing structures in the CB are chemoreceptor cells (CBCC), which are connected synaptically with the sensory nerve endings of the carotid sinus nerve (CSN). In situations of hypoxia and acidosis, CBCC are activate...

We have defined Ca2+ channel subtypes expressed in rabbit carotid body (CB) chemoreceptor cells and their participation in the stimulus-evoked catecholamine (CA) release. Ca2+ currents (I(Ca)) activated at -30 mV, peaked at +10 mV and were fully blocked by 200 microm Cd2+. L-type channels (sensitive to 2 microm nisoldipine) activated at -30 mV and...

We show a first practical experience in the Process of Teaching Adaptation to European Convergence in High Education. This project is created with the main purpose of making an adaptation of different subjects included in the Spanish Studies of Speech Therapy Degree, trying to get them closer to the European Credit of Transfer System. To make it po...

Se presenta una primera experiencia práctica en el marco del proceso de Convergencia Europea de la enseñanza. El proyecto nace con el objetivo de adaptar asignaturas seleccionadas del actual plan de estudios de la Titulación (Diplomatura) de Logopedia al reciente �Sistema de Transferencia de Créditos Europeos� (créditos ECTS o European Credit Trans...

The significance of voltage-gated tetrodotoxin (TTX) -sensitive Na+ channels in O2-sensing in rat carotid body (CB) chemoreceptors cells is controversial, with some studies denying the presence of Na+ channels in the cells. A confounding variable might be an age-dependence variation in the expression of the channels, as studies have been carried ou...

Hypoxia increases the release of neurotransmitters from chemoreceptor cells of the carotid body (CB) and the activity in the carotid sinus nerve (CSN) sensory fibers, elevating ventilatory drive. According to previous reports, perinatal hyperoxia causes CSN hypotrophy and varied diminishment of CB function and the hypoxic ventilatory response. The...

The carotid body is a sensory chemoreceptor organ located in the vicinity of the carotid bifurcation. Structurally it is composed of cell clusters formed by chemoreceptor and supporting cells. The sensory nerve endings of the carotid sinus nerve penetrate the clusters to synapse with chemoreceptor cells. The carotid body plays an important role in...

Dinitrophenol (2,4 dinitrophenol; DNP) was early identified as a potent stimulant of the carotid body (CB; Shen and Hauss, 1939). DNP acts directly upon chemoreceptor cells promoting an increase in the intracellular calcium concentration and the release of catecholamine (CA); both responses are strongly dependent on the presence of Ca2+and Na+in th...

The arterial carotid body (CB) chemoreceptors are highly vascularized sensory organs located in the proximity of the carotid artery bifurcation and formed by clusters of parenchymal cells. The cell clusters are penetrated by sensory fibers of the carotid sinus nerve (CSN) which form synapses with the parenchymal chemoreceptor cells. Functionally, t...

Reactive oxygen species (ROS) include a large number of oxygen-containing molecules having in common a greater reactivity than molecular O2. Free radicals are a subgroup of ROS that, in addition to the great reactivity, have one or more unpaired electrons. In the context of this chapter the most important ROS are H2O2 (hydrogen peroxide), (superoxi...

The carotid body is a sensory chemoreceptor organ located in the vicinity of the carotid bifurcation. Structurally it is composed of cell clusters formed by chemoreceptor and supporting cells. The sensory nerve endings of the carotid sinus nerve penetrate the clusters to synapse with chemoreceptor cells. The carotid body plays an important role in...

Reactive oxygen species (ROS) are oxygen-containing molecular entities which are more potent and effective oxidizing agents than is molecular oxygen itself. With the exception of phagocytic cells, where ROS play an important physiological role in defense reactions, ROS have classically been considered undesirable byproducts of cell metabolism, exis...

En algunos sistemas sensoriales como retina, la ausencia de estimulación en periodos perinatales origina que no se desarrollen adecuadamente los mecanismos responsables de la recepción sensorial frente a dichos estímulos. Respecto a la quimiorrecepción hipóxica se ha demostrado que la hiperoxia perinatal (30-60% de O ) produce una pérdida de la res...

The notion that intracellular Ca(2+) (Ca(i)(2+)) stores play a significant role in the chemoreception process in chemoreceptor cells of the carotid body (CB) appears in the literature in a recurrent manner. However, the structural identity of the Ca(2+) stores and their real significance in the function of chemoreceptor cells are unknown. To assess...

Hypoxic transduction in the carotid body (CB) is regulated by several systems of second messengers, but the role of the phospholipase C system has not been studied. The aim of the present study was to characterize the turnover rate of inositol phosphates (InsPs) and phosphoinositides (PIs) and their modifications by hypoxia in the rabbit CB in vitr...

In an in vitro preparation of the intact carotid body (CB) of the rabbit, adenosine (100 microM) inhibited hypoxia-induced catecholamine release by 25%. The specific A1 antagonist, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; 1 microM) prevented the inhibition and increased the response to hypoxia further. In isolated chemoreceptor cells from the sam...

The effect of chronic alcohol intake on the intestinal absorption of seven compounds belonging to a homologous series (ciprofloxacin derivatives) was evaluated using an in situ rat gut technique that measures the intrinsic absorption rates of the compounds both in control and chronic alcohol-fed rats. For chronic alcohol treatment, the animals were...

The effect of chronic alcohol intake on the intestinal absorption of seven compounds belonging to a homologous series (ciprofloxacin derivatives) was evaluated using an in situ rat gut technique that measures the intrinsic absorption rates of the compounds both in control and chronic alcohol-fed rats. For chronic alcohol treatment, the animals were...

It is known that hypoxia (PO2 approximately equal to 66-18 mm Hg), acting via unknown receptors, increases carotid body cAMP levels in Ca(2+)-free solutions, indicating that low PO2 activates adenylate cyclases independently of the action of the released neurotransmitters. The aim of the present work was to investigate the involvement of G proteins...

A new sulfur-rich basic polypeptide, so called omega-hordothionin, has been isolated from barley endosperm by extractions with NaCl and ammonium bicarbonate followed by reverse-phase high performance liquid chromatography. Purified omega-hordothionin was found to be homogeneous by SDS/polyacrylamide gel electrophoresis, N-terminal amino-acid sequen...

Six distinct gamma- and omega-type secalins, together with two new low molecular mass glycoproteins, have been identified as the major coeliac immunoreactive proteins from a chloroform/methanol soluble extract from rye endosperm. These components were characterized by a combination of reverse-phase high-performance liquid chromatography, immunoblot...

The pivotal role of intracellular free [Ca2+] fluctuations in the control of cellular functions such as contraction and secretion, including the release of neurotransmitters, was recognized many decades ago (see Rubin, 1982). More recently, the list of cellular functions triggered or modulated by the levels of Ca2+i has grown enormously. Additional...

The carotid bodies (CB) are arterial chemoreceptors that by sensing changes of arterial PO2, PCO2 and pH can initiate and modify ventilatory and cardiovascular reflexes in order to maintain PO2, PCO2 and pH within physiological levels. It is now generally accepted that the glomus or type I cells of the CB are the transducers of hypoxic stimuli, and...

A new thionin from barley, omega-hordothionin, has been shown to exist in aqueous solution as a mixture of two different isoforms in a 3:2 ratio, as revealed by a complete analysis of its two-dimensional 1H-nmr spectra. The conformational heterogeneity arises from cis-trans isomerism about the Phe 12-Pro 13 peptide bond, where the major form corres...

The regulation of the chemoreceptor cell function by G proteins has been studied by measuring the release of 3H-labeled catecholamines ([3H]CA) in carotid bodies (CBs) treated with fluoride, cholera toxin (CTX), and pertussis toxin (PTX). Fluoride augmented the basal release of [3H]CA in a dose- (5-20 mM) and Ca(2+)-dependent manner. Nisoldipine (1...

Distinct alpha- and gamma-type gliadins, as well as a few low molecular weight components have been identified as coeliac immunoreactive proteins from a chloroform/methanol extract from wheat endosperm. Characterization of these components involved the combination of reverse-phase high-performance liquid chromatography, immunoblotting following SDS...

Distinct α- and γ-type gliadins, as well as a few low molecular weight components have been identified as coeliac immunoreactive proteins from a chloroform/methanol extract from wheat endosperm. Characterization of these components involved the combination of reverse-phase high-performance liquid chromatography, immunoblotting following SDS-PAGE us...

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...

Carotid body (CB) chemoreceptors are sensory receptors which are activated by decreases in PaO2 and pH (or increases in PaCO2) and thereby they initiate reflexes directed to maintain adequate O2 levels and contribute to pH homeostasis. Type I cells of the CB are the primary chemoreceptor elements which release neurotransmitters (e.g. catecholamine;...

The involvement of GTP-binding proteins (G proteins) in the regulation of stimulussecretion coupling is extensively documented in a great number of preparations (Gomperts, 1990), and an important regulatory role for G proteins has been described in the transduction process of gustatory and olfactory chemoreceptors (Lancet, 1986; Bruch, 1990). Howev...

We have studied the distribution of the protein synthesis inhibitory activity in the tissues of Saponaria officinalis L. (Caryophyllaceae). Seven major saporins, ribosome-inactivating proteins, were purified to apparent homogeneity from leaves, roots and seeds using a new procedure of RIPs isolation including ion-exchange and hydrophobic chromatogr...

The carotid body (CB) was defined as a sensory organ by De Castro in 1928. Two years later, Heymanns and coworkers demostrated that the organ was sensitive to alterations in blood gases and pH, in such a way that a decrease in blood PO2 or pH or an increase in blood PCO2 produced activation of the CB and, reflexely, hyperventilation. De Castro post...

Six chloroform/methanol-soluble proteins from oat endosperm (Avena sativa) have been isolated and characterized by a purification procedure based on extraction with volatile solvents, followed by reversed-phase high performance liquid chromatography. Three of these proteins, with an assessed molecular weight of 25,000, 27,000 and 32,000 Da, respect...

The connector of bacteriophage phi 29 is required for prohead assembly, binds DNA, and drives DNA packaging into viral proheads. Limited proteolysis of the connector protein with endoproteinase Glu-C from Staphylococcus aureus V8 and chymotrypsin showed that a domain of the NH2-terminal region is involved in DNA binding and in the subsequent packag...

Petrocoptis glaucifolia, a paleoendemic member of the Caryophyllaceae from the North of Spain, was found to contain at least five proteins that inhibit protein synthesis in a rabbit reticulocyte lysate. One of them, for which the name petroglaucin is proposed, was purified to apparent electrophoretic homogeneity by chromatography through S-Sepharos...

The present study utilized an in vitro preparation of the rabbit carotid body, with tissue catecholamine stores labeled by incubation with 3H-tyrosine. The goal was to characterize pharmacologically the voltage-dependent Ca2+ channels present in the type I (glomus) cells of this arterial chemoreceptor organ, and to elucidate their role as pathways...

A new technique for separation and determination of ATP, ADP, AMP, NAD+, NADP+, NADH and NADPH in Lacwbacillus plantarum has been developped. It involves acid and basic extraction of nucleotide pool, analysis by reverse-phase high performance liquid chromatography on a 5 m Spherisorb ODS-1 column and UV detection. The method offers advantages in ac...

1. The release of [3H]dopamine (DA) in response to inhibition of the Na+ pump or to intracellular acid load was studied in rabbit carotid bodies (CB) previously incubated with the precursor [3H]tyrosine. The ionic requirements of the release response and the involvement of specific ion transport systems were investigated. 2. Inhibition of the Na+ p...

Two homologous sulfur-rich basic polypeptides form wheat endosperm, so-called gamma 1-purothionin and gamma 2-purothionin, are described. Purification involves extraction with volatile solvents and ammonium bicarbonate fractionation followed by reversed-phase high-performance liquid chromatography. The complete primary structure of these two polype...

The receptor complex in the carotid body (CB) is formed by clusters of type I cells that are connected synaptically to the endings of the chemosensory fibers of the carotid sinus nerve (CSN), partially covered by type II cells, and surrounded by a dense net of fenestrated capillaries (1).

It is generally accepted that the primary chemoreceptor elements in the mammalian carotid body are the type-I cells, which respond to low pO2, high pCO2, or low pH by secreting neurotransmitters which activate the sensory nerve endings synaptically connected with them1. One of the putative neurotransmitters synthesized and secreted by type-I cells...