DSpace Angular :: Browsing by Author "Del Rio, Rodrigo"

Browsing by Author "Del Rio, Rodrigo"

Now showing 1 - 16 of 16

Activation of Intra-nodose Ganglion P2X7 Receptors Elicit Increases in Neuronal Activity
(2023) Alcayaga, Julio; Vera, Jorge; Reyna-Jeldes, Mauricio; Covarrubias, Alejandra A. A.; Coddou, Claudio; Diaz-Jara, Esteban; Del Rio, Rodrigo; Retamal, Mauricio A. A.
Vagus nerve innervates several organs including the heart, stomach, and pancreas among others. Somas of sensory neurons that project through the vagal nerve are located in the nodose ganglion. The presence of purinergic receptors has been reported in neurons and satellite glial cells in several sensory ganglia. In the nodose ganglion, calcium depletion-induced increases in neuron activity can be partly reversed by P2X7 blockers applied directly into the ganglion. The later suggest a possible role of P2X7 receptors in the modulation of neuronal activity within this sensory ganglion. We aimed to characterize the response to P2X7 activation in nodose ganglion neurons under physiological conditions. Using an ex vivo preparation for electrophysiological recordings of the neural discharges of nodose ganglion neurons, we found that treatments with ATP induce transient neuronal activity increases. Also, we found a concentration-dependent increase in neural activity in response to Bz-ATP (ED50 = 0.62 mM, a selective P2X7 receptor agonist), with a clear desensitization pattern when applied every similar to 30 s. Electrophysiological recordings from isolated nodose ganglion neurons reveal no differences in the responses to Bz-ATP and ATP. Finally, we showed that the P2X7 receptor was expressed in the rat nodose ganglion, both in neurons and satellite glial cells. Additionally, a P2X7 receptor negative allosteric modulator decreased the duration of Bz-ATP-induced maximal responses without affecting their amplitude. Our results show the presence of functional P2X7 receptors under physiological conditions within the nodose ganglion of the rat, and suggest that ATP modulation of nodose ganglion activity may be in part mediated by the activation of P2X7 receptors.
Acute Effects of Systemic Erythropoietin Injections on Carotid Body Chemosensory Activity Following Hypoxic and Hypercapnic Stimulation
(2018) Andrade Andrade, David Cristóbal; Iturriaga Agüera, Rodrigo; Jeton, Florine; Alcayaga Urbina, Julio Andrés; Voituron, Nicolas; Del Rio, Rodrigo
Carbamylated form of human erythropoietin normalizes cardiorespiratory disorders triggered by intermittent hypoxia mimicking sleep apnea syndrome
(LIPPINCOTT WILLIAMS & WILKINS, 2021) Andrade, David C.; Toledo, Camilo; Diaz, Hugo S.; Pereyra, Katherin, V; Schwarz, Karla G.; Diaz Jara, Esteban; Melipillan, Claudia; Rios Gallardo, Angelica P.; Uribe Ojeda, Atenea; Alcayaga, Julio; Quintanilla, Rodrigo A.; Iturriaga, Rodrigo; Richalet, Jean Paul; Voituron, Nicolas; Del Rio, Rodrigo
Background and objective: Chronic intermittent hypoxia (CIH), one of the main features of obstructive sleep apnea (OSA), enhances carotid body-mediated chemoreflex and induces hypertension and breathing disorders. The carbamylated form of erythropoietin (cEpo) may have beneficial effects as it retains its antioxidant/anti-inflammatory and neuroprotective profile without increasing red blood cells number. However, no studies have evaluated the potential therapeutic effect of cEpo on CIH-related cardiorespiratory disorders. We aimed to determine whether cEpo normalized the CIH-enhanced carotid body ventilatory chemoreflex, the hypertension and ventilatory disorders in rats. Methods: Male Sprague-Dawley rats (250 g) were exposed to CIH (5% O-2, 12/h, 8 h/day) for 28 days. cEPO (20 mu g/kg, i.p) was administrated from day 21 every other day for one more week. Cardiovascular and respiratory function were assessed in freely moving animals. Results: Twenty-one days of CIH increased carotid body-mediated chemoreflex responses as evidenced by a significant increase in the hypoxic ventilatory response (FiO2 10%) and triggered irregular eupneic breathing, active expiration, and produced hypertension. cEpo treatment significantly reduced the carotid body--chemoreflex responses, normalizes breathing patterns and the hypertension in CIH. In addition, cEpo treatment effectively normalized carotid body chemosensory responses evoked by acute hypoxic stimulation in CIH rats. Conclusion: Present results strongly support beneficial cardiorespiratory therapeutic effects of cEpo during CIH exposure.
Cardiovascular and autonomic dysfunction in long-COVID syndrome and the potential role of non-invasive therapeutic strategies on cardiovascular outcomes
(2023) Allendes, Francisca J.; Diaz, Hugo S.; Ortiz, Fernando C.; Marcus, Noah J.; Quintanilla, Rodrigo; Inestrosa, Nibaldo C.; Del Rio, Rodrigo
A significant percentage of COVID-19 survivors develop long-lasting cardiovascular sequelae linked to autonomic nervous system dysfunction, including fatigue, arrhythmias, and hypertension. This post-COVID-19 cardiovascular syndrome is one facet of "long-COVID," generally defined as long-term health problems persisting/appearing after the typical recovery period of COVID-19. Despite the fact that this syndrome is not fully understood, it is urgent to develop strategies for diagnosing/managing long-COVID due to the immense potential for future disease burden. New diagnostic/therapeutic tools should provide health personnel with the ability to manage the consequences of long-COVID and preserve/improve patient quality of life. It has been shown that cardiovascular rehabilitation programs (CRPs) stimulate the parasympathetic nervous system, improve cardiorespiratory fitness (CRF), and reduce cardiovascular risk factors, hospitalization rates, and cognitive impairment in patients suffering from cardiovascular diseases. Given their efficacy in improving patient outcomes, CRPs may have salutary potential for the treatment of cardiovascular sequelae of long-COVID. Indeed, there are several public and private initiatives testing the potential of CRPs in treating fatigue and dysautonomia in long-COVID subjects. The application of these established rehabilitation techniques to COVID-19 cardiovascular syndrome represents a promising approach to improving functional capacity and quality of life. In this brief review, we will focus on the long-lasting cardiovascular and autonomic sequelae occurring after COVID-19 infection, as well as exploring the potential of classic and novel CRPs for managing COVID-19 cardiovascular syndrome. Finally, we expect this review will encourage health care professionals and private/public health organizations to evaluate/implement non-invasive techniques for the management of COVID-19 cardiovascular sequalae.
Chronic intermittent hypoxia-induced vascular enlargement and VEGF upregulation in the rat carotid body is not prevented by antioxidant treatment
(2011) Del Rio, Rodrigo; Munoz, Cristian; Arias, Paulina; Court, Felipe A.; Moya, Esteban A.; Iturriaga, Rodrigo
Del Rio R, Munoz C, Arias P, Court FA, Moya EA, Iturriaga R. Chronic intermittent hypoxia-induced vascular enlargement and VEGF upregulation in the rat carotid body is not prevented by antioxidant treatment. Am J Physiol Lung Cell Mol Physiol 301: L702-L711, 2011. First published August 5, 2011; doi:10.1152/ajplung.00128.2011.-Chronic intermittent hypoxia (CIH), a characteristic of sleep obstructive apnea, enhances carotid body (CB) chemosensory responses to hypoxia, but its consequences on CB vascular area and VEGF expression are unknown. Accordingly, we studied the effect of CIH on CB volume, glomus cell numbers, blood vessel diameter and number, and VEGF immunoreactivity (VEGF-ir) in male Sprague-Dawley rats exposed to 5% O-2, 12 times/h for 8 h or sham condition for 21 days. We found that CIH did not modify the CB volume or the number of glomus cells but increased VEGF-ir and enlarged the vascular area by increasing the size of the blood vessels, whereas the number of the vessels was unchanged. Because oxidative stress plays an essential role in the CIH-induced carotid chemosensory potentiation, we tested whether antioxidant treatment with ascorbic acid may impede the vascular enlargement and the VEGF upregulation. Ascorbic acid, which prevents the CB chemosensory potentiation, failed to impede the vascular enlargement and the increased VEGF-ir. Thus present results suggest that the CB vascular enlargement induced by CIH is a direct effect of intermittent hypoxia and not secondary to the oxidative stress. Accordingly, the subsequent capillary changes may be secondary to the mechanisms involved in the neural chemosensory plasticity induced by intermittent hypoxia.
Chronic phenytoin treatment reduces rat carotid body chemosensory responses to acute hypoxia
(2016) Alcayaga Urbina, Julio Andrés; Oyarce, María Paz; Del Rio, Rodrigo
Dendrochronological Analysis of Pinus pinea in Central Chile and South Spain for Sustainable Forest Management
(2024) Loewe-Munoz, Veronica; Cachinero-Vivar, Antonio M.; Camarero, Jesus Julio; Del Rio, Rodrigo; Delard, Claudia; Navarro-Cerrillo, Rafael M.
Pinus pinea is an important Mediterranean species due to its adaptability and tolerance to aridity and its high-quality pine nuts. Different forest types located in Mediterranean native and non-native environments provide the opportunity to perform comparative studies on the species' response to climate change. The aims of this study were to elucidate growth patterns of the species growing in native and exotic habitats and to analyze its response to climatic fluctuations, particularly drought, in both geographical contexts. Understanding stone pine (Pinus pinea) growth responses to climate variability in native and exotic habitats by comparing natural stands and plantations may provide useful information to plan adequate management under climate change. By doing so, we enhance the understanding of P. pinea's adaptability and provide practical approaches to its sustainable management. In this study, we reconstructed and compared the stem radial growth of seven stone pine stands, two in southern Spain and five in central-southern Chile, growing under different climatic conditions. We quantified the relationships between growth variability and climate variables (total rainfall, mean temperature, and SPEI drought index). Growth was positively correlated with autumn rainfall in plantations and with autumn-winter rainfall in natural stands. Growth was also enhanced by high autumn-to-spring rainfall in the driest Chilean plantation, whereas in the wettest and coolest plantation, such correlation was found in winter and summer. A negative impact of summer temperature was found only in one of the five Chilean plantations and in a Spanish site. The correlation between SPEI and tree-ring width indices showed different patterns between and within countries. Overall, exotic plantations showed lower sensitivity to climate variability than native stands. Therefore, stone pine plantations may be useful to assist in mitigating climate change.
Effect of thinning on growth and shape of Castanea sativa adult tree plantations for timber production in Chile
(2023) Benedetti-Ruiz, Susana; Loewe-Munoz, Veronica; Del Rio, Rodrigo; Delard, Claudia; Barrales, Luis; Balzarini, Monica
Chestnut (Castanea sativa Mill.) is an interesting species for high-quality timber production. It is well known that the species responds to early thinning, but there is no information on the impact of late interventions. The objective of this study was to assess the effect of a late thinning on the performance of unmanaged adult chestnut plantations in Chile. Future-tree selective thinning and control were compared in adult plantations using a randomized complete block design with three replicates at three sites, Minas, Pillo-Pillo and Pumillahue. Tree growth was evaluated periodically during the first 7 years after thinning in all plantations. Additionally, almost 20 years after the intervention, the Pumillahue plantation was measured for growth and tree shape variables. In this case study, the effect of thinning on tree growth decreased considerably after 5 years, with a maximum DBH increment in the third year after the intervention (45.8 %, 68.6 %, and 42.2 % in Minas, Pillo-Pillo and Pum-illahue, respectively). In all plantations, basal area was smaller in the thinned plots in the first years after the intervention, but in Pumillahue, 19 years after thinning, no differences were found among treatments. Height was statistically greater under thinning seven years after the intervention; this effect was also found in Pum-illahue plantation 19 years after thinning. Most trees showed high vigor, and were straight and healthy, even in control plots. Late effect of thinning was observed 19 years after thinning on tree shape, with a reduction in the proportion of bifurcated trees from 16 % to 8 %. The results suggest that late thinning is an effective silvicultural intervention to produce high-quality chestnut timber in unmanaged adult plantations. Progressive and frequent thinning should be used to increase growth and improve timber production in chestnut.
Exercise intolerance in volume overload heart failure is associated with low carotid body mediated chemoreflex drive
(2021) Andrade, David C.; Diaz-Jara, Esteban; Toledo, Camilo; Schwarz, Karla G.; Pereyra, Katherin V.; Diaz, Hugo S.; Marcus, Noah J.; Ortiz, Fernando C.; Rios-Gallardo, Angelica P.; Ortolani, Domiziana; Del Rio, Rodrigo
Mounting an appropriate ventilatory response to exercise is crucial to meeting metabolic demands, and abnormal ventilatory responses may contribute to exercise-intolerance (EX-inT) in heart failure (HF) patients. We sought to determine if abnormal ventilatory chemoreflex control contributes to EX-inT in volume-overload HF rats. Cardiac function, hypercapnic (HCVR) and hypoxic (HVR) ventilatory responses, and exercise tolerance were assessed at the end of a 6 week exercise training program. At the conclusion of the training program, exercise tolerant HF rats (HF+EX-T) exhibited improvements in cardiac systolic function and reductions in HCVR, sympathetic tone, and arrhythmias. In contrast, HF rats that were exercise intolerant (HF+EX-inT) exhibited worse diastolic dysfunction, and showed no improvements in cardiac systolic function, HCVR, sympathetic tone, or arrhythmias at the conclusion of the training program. In addition, HF+EX-inT rats had impaired HVR which was associated with increased arrhythmia susceptibility and mortality during hypoxic challenges (similar to 60% survival). Finally, we observed that exercise tolerance in HF rats was related to carotid body (CB) function as CB ablation resulted in impaired exercise capacity in HF+EX-T rats. Our results indicate that: (i) exercise may have detrimental effects on cardiac function in HF-EX-inT, and (ii) loss of CB chemoreflex sensitivity contributes to EX-inT in HF.
Exercise training reduces brainstem oxidative stress and restores normal breathing function in heart failure
(2021) Diaz-Jara, Esteban; Diaz, Hugo S.; Rios-Gallardo, Angelica; Ortolani, Domiziana; Andrade, David C.; Toledo, Camilo; V. Pereyra, Katherin; Schwarz, Karla; Ramirez, Gigliola; Ortiz, Fernando C.; Andia, Marcelo E.; Del Rio, Rodrigo
Enhanced central chemoreflex drive and irregular breathing are both hallmarks in heart failure (HF) and closely related to disease progression. Central chemoreceptor neurons located within the retrotrapezoid nucleus (RTN) are known to play a role in breathing alterations in HF. It has been shown that exercise (EX) effectively reduced reactive oxygen species (ROS) in HF rats. However, the link between EX and ROS, particularly at the RTN, with breathing alterations in HF has not been previously addressed. Accordingly, we aimed to determine: i) ROS levels in the RTN in HF and its association with chemoreflex drive, ii) whether EX improves chemoreflex/breathing function by reducing ROS levels, and iii) determine molecular alterations associated with ROS generation within the RTN of HF rats and study EX effects on these pathways. Adult male Sprague-Dawley rats were allocated into 3 experimental groups: Sham (n = 5), volume overloaded HF (n = 6) and HF (n = 8) rats that underwent EX training for 6 weeks (60 min/day, 25 m/min, 10% inclination). At 8 weeks post-HF induction, breathing patterns and chemoreflex function were analyzed by unrestrained plethysmography. ROS levels and anti/pro-oxidant enzymes gene expression were analyzed in the RTN. Our results showed that HF rats have high ROS levels in the RTN which were closely linked to the enhanced central chemoreflex and breathing disorders. Also, HF rats displayed decreased expression of antioxidant genes in the RTN compared with control rats. EX training increases antioxidant defense in the RTN, reduces ROS formation and restores normal central chemoreflex drive and breathing regularity in HF rats. This study provides evidence for a role of ROS in central chemoreception in the setting of HF and support the use of EX to reduce ROS in the brainstem of HF animals and reveal its potential as an effective mean to normalize chemoreflex and breathing function in HF.
Integrating a collaboration script and group awareness to support group regulation and emotions towards collaborative problem solving
(Taylor and Francis, 2022) Rojas, Matias; Nussbaum, Miguel; Guerrero, Orlando; Chiuminatto Munoz Pablo Andres; Greiff, Samuel; Del Rio, Rodrigo; Alvares, Danilo
The research landscape displays increasing awareness of the important role of self-regulation and emotions in the process of acquiring Collaborative Problem-Solving skills (CPS), which are considered essential in almost all areas of life. However, there is still a dearth of research on developing CPS skills among elementary-school students. Our research therefore looks at how elementary school students' regulation skills and emotions are supported by a collaborative game using a collaboration script to scaffold group awareness. An intervention was carried out with a sample of 223 students aged between 10 and 13. The experimental group worked collaboratively in sub-groups, scaffolded by the game, while the control group attended regular lessons. The students' attitudes towards collaboration were evaluated before and after the intervention. In addition to this, a focus group was held a week after the intervention, which involved 32 students from both groups. The quantitative analysis revealed that attitudes towards collaboration improved significantly among students in the experimental group. This difference can be explained by a combination of the intervention, the students' initial attitudes, and their respective GPAs. The qualitative analysis provided evidence of the regulation processes and emotions that emerge when combining a collaboration script with group awareness tools during CPS activities. Furthermore, the results highlighted the relationship between these tools and positive emotions (i.e., satisfaction), co-regulation, and shared regulation. These findings suggest that there is a relationship between the co-regulation process required by the game and a shift in emotions from frustration to satisfaction. This work provides evidence of how scaffolding group awareness using a collaboration script supports regulation skills and emotions, thus promoting the development of Collaborative Problem-Solving skills.
Medullary astrocytes mediate irregular breathing patterns generation in chronic heart failure through purinergic P2X7 receptor signalling
(2022) Toledo, Camilo; Diaz-Jara, Esteban; Diaz, Hugo S.; Schwarz, Karla G.; Pereyra, Katherin, V; Las Heras, Alexandra; Rios-Gallardo, Angelica; Andrade, David C.; Moreira, Thiago; Takakura, Ana; Marcus, Noah J.; Del Rio, Rodrigo
Background Breathing disorders (BD) (apnoeas/hypopneas, periodic breathing) are highly prevalent in chronic heart failure (CHF) and are associated with altered central respiratory control. Ample evidence identifies the retrotrapezoid nucleus (RTN) as an important chemosensitivity region for ventilatory control and generation of BD in CHF, however little is known about the cellular mechanisms underlying the RTN/BD relationship. Within the RTN, astrocyte-mediated purinergic signalling modulates respiration, but the potential contribution of RTN astrocytes to BD in CHF has not been explored.
MODIFICATION OF BORON DOPED DIAMOND ELECTRODES WITH GLUCOSE OXIDASE, CHARACTERIZATION BY ELECTROCHEMICAL TECHNIQUES
(SOC CHILENA QUIMICA, 2011) Del Rio, Rodrigo; Armijo, Francisco; Schrebler, Ricardo; Del Canto, Gabriela; Vergara, Claudia; Gutierrez, Cesar
In this work, we report the effect of the direct successive modifications with Glucose oxidase onto boron doped diamond electrode (BDD). The modification due to the enzyme adsorption, on the potentiodynamic response of the electrode, was evaluated using Fe(CN)(6)(4-/3-) red-ox couple on the electrolyte and the Delta Ep variations were related with the number of modifications. Contact angle measurements and the electrochemical impedance spectra were also used to characterized the modifications and they showed variations in the same way that the potentiodynamic data.
Modification of composites of block copolymers-gold nanoparticles with enzymes and their characterization by electrochemical techniques
(SPRINGER, 2011) Del Rio, Rodrigo; Armijo, Francisco; Schrebler, Ricardo; Gutierrez, Cesar; Amaro, Andrea; Biaggio, Sonia R.
In this work, the poly(styrene-vynil pyridine) block copolymer was used as a porous pattern to study the electrodeposition of gold inside the pores, as a new method to obtain gold nanoparticles. The porous pattern left by the copolymer film onto a conductive glass surface was characterized by atomic force microscopy (AFM), evidencing pores of 30 nm diameter. After the electrodeposition, 30 nm diameter gold nanoparticles were obtained and they were characterized by cyclic voltammetry (CV) and AFM, and then used to study the adsorption of glucose oxidase enzyme. The adsorption process of glucose oxidase on gold nanowires was investigated by CV and electrochemical impedance spectroscopy. The morphological and capacitance results indicate that the block copolymer-gold nanoparticle composite seems to be a good candidate to design biosensors and immunosensors.
Poly-o-aminophenol obtained at high potentials by cyclic voltammetry on SnO2 : F electrodes. application in quantitative determination of ascorbic acid
(2009) Armijo Mancilla, Juan Francisco; Canales, Luis I.; Del Rio, Rodrigo; Valle de la Cortina, María Angélica del
Rostral ventrolateral medullary catecholaminergic neurones mediate irregular breathing pattern in volume overload heart failure rats
(2019) Toledo, Camilo; Andrade, David C.; Diaz, Hugo S.; Pereyra, Katherin V.; Schwarz, Karla G.; Diaz-Jara, Esteban; Oliveira, Luiz M.; Takakura, Ana C.; Moreira, Thiago S.; Schultz, Harold D.; Marcus, Noah J.; Del Rio, Rodrigo
Key points

Browsing by Author "Del Rio, Rodrigo"

Results Per Page

Sort Options