Davi JA Moraes

Davi JA Moraes
University of São Paulo | USP · Department of Physiology (Ribeirão Preto)

PhD.

About

98
Publications
11,460
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,453
Citations
Citations since 2016
47 Research Items
1204 Citations
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150

Publications

Publications (98)
Article
Aims: Stimulation of peripheral chemoreceptors, as during hypoxia, increases breathing and respiratory-related sympathetic bursting. Activation of catecholaminergic C1 neurones induces sympatho-excitation, while its ablation reduces the chemoreflex sympatho-excitatory response. However, no study has determined the respiratory phase(s) in which the...
Article
Purinergic signaling involving adenosine triphosphate (ATP) acting on P2X2/3 receptors modulates physiological carotid body (CB) afferent discharge and chemoreflex activation however, the upregulation of P2X3 receptors on petrosal sensory neurons is partly responsible for aberrant CB tonicity and hyperreflexia, and the increase in blood pressure in...
Article
The Dorsal Motor Nucleus of the Vagus (DMNV) is the main parasympathetic output from CNS as part of the brain-liver axis that participates on glucose homeostasis. Previously, we have shown that icv injection of insulin elicited a decrease the hepatic vein glucose concentration (HVGC) of Wistar, but not in SHR. Here we aimed to investigate whether t...
Article
Full-text available
Twenty-five years ago, a new physiological preparation called the working heart-brainstem preparation (WHBP) was introduced with the claim it would provide a new platform allowing studies not possible before in cardiovascular, neuroendocrine, autonomic and respiratory research. Herein, we review some of the progress made with the WHBP, some advanta...
Article
Full-text available
Aims: The carotid bodies (CB) of spontaneously hypertensive (SH) rats exhibit hypertonicity and hyperreflexia contributing to heightened peripheral sympathetic outflow. We hypothesized that CB hyperexcitability is driven by its own sympathetic innervation. Methods and results: To test this, the chemoreflex was activated (NaCN 50-100 µL, 0.04%) in...
Article
Key points: Hypercapnia induces active expiration in rats and the recruitment of a specific population of expiratory neurones in the lateral parafacial (pFL ) region. Post-synaptic GABAergic and glycinergic inhibition both suppress the activity of glutamatergic pFL neurones during inspiratory and expiratory phases in normocapnia. Hypercapnia reduc...
Article
A neural circuit between the paraventricular nucleus of the hypothalamus (PVN) and the dorsal motor nucleus of the vagus (DMNV) constitutes part of an important parasympathetic autonomic pathway that controls hepatic glucose production. Intracerebroventricular injection of insulin activates oxytocinergic neurones in the PVN and elicits the release...
Article
Full-text available
Key points: Carotid bodies (CBs) chemoreceptors are hyperactive in hypertension, and their acute activation produces bronchoconstriction. We show that the respiratory-modulated bronchiolar tone, pulmonary parasympathetic efferent activity, as well as the firing frequency and synaptic excitation of bronchoconstrictor motoneurones in the nucleus amb...
Article
Full-text available
Key points Dysfunctions in the hypoglossal control of tongue extrinsic muscles are implicated in obstructive sleep apnoea (OSA) syndrome. Chronic intermittent hypoxia (CIH), an important feature of OSA syndrome, produces deleterious effects on the motor control of oropharyngeal resistance, but whether the hypoglossal motoneurones innervating the to...
Article
New findings: What is the central question of this study? Do mice submitted to sustained hypoxia present autonomic and respiratory changes similarly to rats? What is the main finding and its importance? Arterial pressure in the normal range, reduced baseline heart rate and tachypnoea were observed in behaving sustained hypoxia mice. Recordings in...
Article
Short-term sustained hypoxia (SH) elicits active expiration, augmented late-expiratory (late-E) sympathetic activity, increased arterial pressure and ventilation, and amplified sympathetic and abdominal expiratory responses to chemoreflex activation in rats of the Wistar-Ribeirão Preto (WRP) strain. Herein, we investigated whether SH can differenti...
Article
The carotid body's glomus cells are the primary sensors of hypoxia in mammals. Previous studies suggested that the glomus cells' hypoxia sensitivity is mediated by lactate in mice. This molecule increases the intracellular [Ca2+] and induces exocytosis in glomus cells, activating the carotid sinus nerve (the axons of chemoreceptive petrosal neurons...
Article
Full-text available
New findings: What is the central question of this study? Physical exercise requires ventilatory adjustments to maintain arterial gas homeostasis and pH. The carotid bodies (CBs) are sensory organs that modulate pulmonary ventilation during exercise. However, the CBs contribution to the active inspiratory and expiratory responses to exercise has n...
Article
Full-text available
New findings: What is the central question of this study? Active expiration is mediated by the parafacial Respiratory Group (pFRG). We hypothesised that pFRG recruits nasofacial and oral motoneurons to coordinate motor activities that engage muscles controlling airways in rats while actively expiring. What is the main finding and its importance? H...
Article
Full-text available
New findings: What is the central question of this study? Do A6 neurons modulate active expiratory and airway responses evoked by hypercapnia/acidosis? What is the main finding and its importance? Acute inhibition of A6 neurons reduced active expiratory, inspiratory and the associated oropharyngeal and laryngeal motor responses to hypercapnia/acid...
Article
Full-text available
New findings: What is the central question of this study? Adrenomedullin in the rostral ventrolateral medulla (RVLM) increases sympathetic activity. Given that adrenomedullin is released during hypoxia, we explored its antagonism and agonism in the RVLM after chronic intermittent hypoxia (CIH) exposure. What is the main finding and its importance?...
Article
Full-text available
The carotid body has emerged as a therapeutic target for cardio-respiratory-metabolic diseases. With the expansive functions of the chemoreflex, we sought mechanisms to explain differential control of individual responses. We purport a remarkable correlation between phenotype of a chemosensory unit (glomus cell-sensory afferent) with a distinct com...
Article
Full-text available
New findings: What is the central question of this study? The traditional surgical approach for sinoaortic denervation in rats leads to simultaneous carotid baroreceptor and chemoreceptor deactivation, not allowing their individual study in different situations. What is the main finding and its importance? We have described a new surgical approach...
Article
Full-text available
New findings: What is the central question of this study? Chronic intermittent hypoxia (CIH) causes increased arterial pressure (AP), sympathetic overactivity, and changes in expiratory modulation of sympathetic activity. However, changes in short-term sleep-wake cycle pattern after CIH and their potential impact on cardiorespiratory parameters ha...
Article
Obstructive sleep apnea patients face episodes of chronic intermittent hypoxia (CIH), which has been suggested as a causative factor for increased sympathetic activity (SNA) and hypertension. Female rats exposed to CIH develop hypertension and exhibit changes in respiratory-sympathetic coupling, marked by an increase in the inspiratory modulation o...
Article
Full-text available
Key points: Acute hypoxia induces active expiration in rectus abdominis (RA) muscles in conscious freely moving rats, although its overall contribution is smaller than in internal oblique (IO) muscles. Tonically active and silent RA motoneurons were identified in in vitro preparations of rat spinal cords. Sustained hypoxia (SH) increased the synap...
Article
Full-text available
At rest, inspiration is an active process while expiration is passive. However, high chemical drive (hypercapnia or hypoxia) activates central and peripheral chemoreceptors triggering reflex increases in inspiration and active expiration. The Locus Coeruleus contains noradrenergic neurons (A6 neurons) that increase their firing frequency when expos...
Poster
Full-text available
The presented research aims to construct bio-inspired Very-large-scale integration (VLSI) neuron models of respiratory neurons based on large-scale nonlinear optimization. The employed statistical inference framework implements interior point line parameter search to estimate the parameters and unobserved state variables from the voltage responses...
Article
Full-text available
The carotid bodies are peripheral chemoreceptors and contribute to the homeostatic maintenance of arterial levels of O2, CO2 and [H+]. They have attracted much clinical interest recently because of the realisation that aberrant signalling in these organs is associated with several pathologies including hypertension. Herein, we describe data suggest...
Article
Full-text available
Key points: Essential hypertension is associated with hyperactivity of the sympathetic nervous system and hypoperfusion of the brainstem area controlling arterial pressure. Sympathetic and parasympathetic innervation of vertebrobasilar arteries may regulate blood perfusion to the brainstem. We examined the autonomic innervation of these arteries i...
Article
Full-text available
Sympathetic activity displays rhythmic oscillations generated by brainstem inspiratory and expiratory neurons. Amplication of these rhythmic respiratory-related oscillations is observed in rats under enhanced central respiratory drive or during the development of neurogenic hypertension. Herein, we evaluated the involvement of ventral medullary sym...
Article
Obstructive sleep apnea (OSA) is a complex disease in which humans face episodes of intermittent hypoxia and it affects men and women. Patients with OSA present hypertension and sympathetic overactivity among several other dysfunctions. Therefore, one important question remains: are the autonomic dysfunctions associated with OSA similar in male and...
Article
Full-text available
Recent studies demonstrated a critical functional connection between the autonomic (sympathetic and parasympathetic) nervous and the immune systems. The carotid sinus nerve (CSN) conveys electrical signals from the chemoreceptors of the carotid bifurcation to the central nervous system where the stimuli are processed to activate sympathetic and par...
Article
The activity of pre-sympathetic neurons is under respiratory modulation and changes in the central respiratory network may impact on the baseline sympathetic activity and mean arterial pressure (MAP). It is well known that after baroreceptor afferents removal (sino-aortic denervation, SAD), rats present an unexpected normal levels of MAP. We hypoth...
Article
Full-text available
In spite of recent advances on the knowledgement of the neural control of cardiovascular function, the cause of sympathetic overactivity in neurogenic hypertension remains unknown. Studies from our laboratory point out that rats submitted to chronic intermittent hypoxia (CIH), an experimental model of neurogenic hypertension, present changes in the...
Conference Paper
Full-text available
Humans ascending to high altitudes are submitted to sustained hypoxia (SH), activating peripheral chemoreflex with several autonomic and respiratory responses. We analyzed the effect of short-term SH (24 hours, FIO210%) on the cardiovascular parameters in non-anesthetized rats and on the processing of cardiovascular and respiratory reflexes using i...
Article
Full-text available
Key points: Hypercapnia or parafacial respiratory group (pFRG) disinhibition at normocapnia evokes active expiration in rats by recruitment of pFRG late-expiratory (late-E) neurons. We show that hypercapnia simultaneously evoked active expiration and exaggerated glottal dilatation by late-E synaptic excitation of abdominal, hypoglossal and larynge...
Conference Paper
Full-text available
Respiratory movements in mammals are produced by the brainstem respiratory central pattern generator (CPG). Core structures of the respiratory CPG are the pre-Bötzinger (pre-BötC) and Bötzinger (BötC) complexes whose network interactions control respiratory oscillations. The normal breathing rhythm (eupnea) includes three phases of the cycle: inspi...
Article
Full-text available
Significance statement: Cells in our organism live in a liquid environment whose composition and osmolality are maintained within tight limits. Magnocellular neurons (MNCs) of the supra optic nucleus can sense osmolality and control the synthesis and secretion of vasopressin (VP) and oxytocin (OT) by the neurohypophysis. OT and VP act on the kidne...
Article
Full-text available
Despite several studies describing the electrophysiological properties of RVLM presympathetic neurons, there is no consensus in the literature about their pacemaking property, mainly due to different experimental approaches used for recordings of neuronal intrinsic properties. In this review we are presenting a historical retrospective about the pi...
Article
Full-text available
In view of the high proportion of individuals with resistance to antihypertensive medication and/or poor compliance or tolerance of this medication, new drugs to treat hypertension are urgently needed. Here we show that peripheral chemoreceptors generate aberrant signaling that contributes to high blood pressure in hypertension. We discovered that...
Article
Sino-aortic denervated (SAD) rats present mean arterial pressure (MAP) similar to control rats. Since respiration modulates MAP, we hypothesized that conscious SAD rats present respiratory changes associated with the normal MAP. In this study we evaluated the cardiovascular and respiratory activities and arterial blood gases in control and SAD rats...
Article
Chronic intermittent hypoxia (CIH) induces sympathetic overactivity and hypertension in male rats. Enhanced respiratory modulation of sympathetic activity in juvenile male rats exposed to CIH occurs in the expiratory phase of the respiratory cycle, characterizing changes in respiratory-sympathetic coupling. Different from other experimental models...
Article
Full-text available
Chronic intermittent hypoxia (CIH) produces respiratory-related sympathetic overactivity and hypertension in rats. In this study, we tested the hypothesis that the enhanced central respiratory modulation of sympathetic activity after CIH also decreases the sympathoinhibitory component of baroreflex of rats, which may contribute to the development o...
Article
Full-text available
Humans ascending to high altitudes are submitted to sustained hypoxia (SH), activating peripheral chemoreflex with several autonomic and respiratory responses. Here we analyzed the effect of short-term SH (24 h, FIO210%) on the processing of cardiovascular and respiratory reflexes using an in situ preparation of rats. SH increased both the sympatho...
Article
Full-text available
Why sympathetic activity raises in neurogenic hypertension remains unknown. It has been postulated that changes in the electrical excitability of medullary pre-sympathetic neurones are the main causal mechanism for the development of sympathetic over activity in experimental hypertension. Herein, we review recent data suggesting that enhanced sympa...
Article
Full-text available
New findings: What is the central question of this study? Chronic intermittent hypoxia (CIH) induces hypertension in male rats. There is evidence that the development of high blood pressure in females is attenuated in other models of hypertension. Due to the lack of information about the cardiovascular effect of CIH in female rats, we set out to d...
Article
Full-text available
The phenotypic differentiation between oxytocin (OT)- and vasopressin (VP)-secreting magnocellular neurosecretory cells (MNCs) from the supraoptic nucleus is relevant to understanding how several physiological and pharmacological challenges affect their electrical activity. Although the firing patterns of OT and VP neurons, both in vivo and in vitr...
Article
Full-text available
Key points: The respiratory control of the glottis by laryngeal motoneurones is characterized by inspiratory abduction and post-inspiratory adduction causing decreases and increases in upper airway resistance, respectively. Chronic intermittent hypoxia (CIH), an important component of obstructive sleep apnoea, exaggerated glottal abduction (before...
Article
The respiratory modulation of sympathetic activity relies on the balance between excitatory and inhibitory inputs from the brainstem respiratory network to presympathetic neurons of the rostral ventrolateral medulla. This central respiratory-sympathetic contributes for the generation of respiratory-related rhythmical oscillations in heart rate and...
Article
Full-text available
Major evolutionary trends in animal physiology have been heavily influenced by atmospheric O 2 levels. Amongst other important factors, the increase in atmospheric O 2 which occurred in the Pre-Cambrian and the development of aerobic respiration beckoned the evolution of animal organ systems that were dedicated to the absorption and transportation...