Raul Aguilar-Roblero

National Autonomous University of Mexico | UNAM · Department of Cognitive Neuroscience, Instituto de Fisiologia Celular

The available guidelines recommend the use of CPAP or APAP for ongoing treatment of OSA in adults. While Auto-Adjusting CPAP (Auto) provides therapeutic effectiveness at a lower mean pressure, outcome studies have not provided clear therapeutic advantages when compared to fixed-pressure CPAP (FP). The purpose of this study is to evaluate therapeuti...

The episodes of cerebral dysfunction, known as encephalopathy, are usually coinci-dent with liver failure. The primary metabolic marker of liver diseases is the increase in blood ammonium, which promotes neuronal damage. In the present project, we used an experimental model of hepatic encephalopathy in male rats by portacaval anastomosis (PCA) surg...

Introduction EDS represents a cardinal symptom in SM. Use of subjective scales are prevalent, which have a modest correlation with the MSLT. While the Clinical Global Impression has been used in research, reports of clinical impression (CI) in medical practice are lacking. We report on the CI of EDS in a convenience sample of patients undergoing in...

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impairment in communication and social interaction, repetitive or stereotypical behaviors, altered sensory perception, and sleep disorders. In general, the causes of ASD remain unknown, but in Phelan–McDermid syndrome, it is known that the disorder is related to the ha...

The suprachiasmatic nucleus (SCN) is the main brain clock that regulates circadian rhythms in mammals. The SCN synchronizes to the LD cycle through the retinohypothalamic tract (RHT), which projects to ventral SCN neurons via glutamatergic synapses. Released glutamate activates N-methyl-D-aspartate (NMDA) receptors, which play a critical role in th...

The suprachiasmatic nucleus (SCN) is the main brain clock that regulates circadian rhythms in mammals. The SCN synchronizes to the LD cycle through the retinohypothalamic tract (RHT), which projects to ventral SCN neurons via glutamatergic synapses. Released glutamate activates N-methyl-D-aspartate (NMDA) receptors, which play a critical role in th...

locomotion, body temperature, blood and intraocular pressure, corticosteroid secretion, and sleep. Control of several circadian rhythms involves a light‐entrained circadian clock and a food‐entrained oscillator. Nursing periodicity, however, relies on a suckling stimulation threshold. Brain structures regulating this activity include the paraventri...

Eating behavior is controlled by the energy needs of the organism. The need to provide a constant supply of energy to tissues is a homeostatic drive that adjusts feeding behavior to the energetic condition of the organism. On the other hand, food intake also shows a circadian variation synchronized to the light-dark cycle and food availability. Thu...

As we all know, the 2017 Nobel Prize in Physiology or Medicine was awarded in the field of Chronobiology. This was received with great excitement by all those who study different aspects of Biological Rhythms. In this brief essay, I would like to address the question, how shall we proceed after such great accomplishment from our esteemed colleagues...

Growth arrest-specific 1 (Gas1) is a pleiotropic protein that induces apoptosis of tumor cells and has important roles during development. Recently, the presence of two forms of Gas1 was reported: one attached to the cell membrane by a GPI anchor; and a soluble extracellular form shed by cells. Previously, we showed that Gas1 is expressed in differ...

Rationale: The amygdala plays a paramount role in the modulation of anxiety and numerous studies have shown that arginine vasopressin (AVP) elicits anxiogenic effects following either its systemic or septal administration. Objectives: The aim of this paper was to study the involvement of vasopressinergic neurotransmission in the amygdaloid modul...

Calcium-regulated chloride channel (CaCC) anoctamin-1 has been recently identified in neurons. In neurons, which express the Na-K-2Cl cotransporter, activation of CaCCs increases firing frequency, by reversion between the Cl equilibrium potential and the membrane resting potential, leading to membrane depolarization by Cl extrusion from the cell. A...

Rabbit maternal behavior begins in late pregnancy as the doe constructs a maternal nest where she will deliver the litter and nurse the kits throughout lactation (González-Mariscal et al., 1994, 2016). Nursing occurs only once a day, inside the maternal nest, (González-Mariscal et al., 2013 a; Jilge, 1995) and lasts around three min (González-Maris...

Continuous incorporation of nutrients into the organism is a requirement for all living beings. For complex entities such as invertebrate and vertebrate animals, feeding has evolved as a physiological task that is sustained by a spectrum of metabolic, endocrine, and behavioral activities. Feeding also involves the coordinated function of diverse sy...

The suprachiasmatic nuclei (SCN) contain the major circadian clock responsible for generation of circadian rhythms in mammals. The time measured by the molecular circadian clock must eventually be translated into a neuronal firing rate pattern in order to transmit a meaningful signal to other tissues and organs in the animal. Previous observations...

The suprachiasmatic nucleus (SCN) in mammals is the master clock which regulates circadian rhythms. Neural activity of SCN neurons is synchronized to external light through the retinohypothalamic tract (RHT). The paraventricular thalamic nucleus (PVT) is a neural structure that receives synaptic inputs from, and projects back to, the SCN. Lesioning...

The suprachiasmatic nucleus (SCN) is the master clock, which regulates circadian rhythms, in mammals. Neural activity of SCN neurons is synchronized to external light through the retinohypothalamic tract (RHT). The paraventricular thalamic nucleus (PVT) is a neural structure that receives synaptic inputs from, and projects back to, the SCN. Lesioni...

In mammals, the major circadian clock is located in the suprachiasmatic nuclei (SCN). The molecular oscillator in these neurons is driven by transcriptional– translational feedback loops (TTL) among clock genes that generate a circadian periodicity. To fulfi ll its role as pacemaker, the molecular oscillation must be translated to an electrical sig...

Even though the biological relevance of circadian rhythmicity has been recognized since the middle of the past century, the majority of the medical community has remained unaware of the circadian rhythms or their relevance during most of this time, perhaps because of their apparent opposition to homeostasis. It was not until the 1980s that circadia...

From conception to death, life encompasses innumerable processes in continuous change and in many instances repetition; after all, life on earth has to cope from its origin with a highly cyclic environment. Thus, it is not surprising that cyclic phenomena are found in all living organisms and at all levels of organization. When this processes repea...

Well known experts in the field of Chronobiology from around the world, provide an integrative view of the state of the art of circadian biology. At present, genetic and epigenetic interaction of regulatory pathways among circadian oscillators, metabolic networks, cellular differentiation and neuronal communication are subject of intense scrutiny....

A female rabbit (does) nurse once a day for three min with circadian periodicity. This timing is controlled by the amount of suckling stimulation received as small litters (2-4 kits) disrupt nursing periodicity and increase the duration of nursing bouts. Yet, as suckling induces: a) the secretion of oxytocin and prolactin and b) milk ejection, the...

The suprachiasmatic nucleus (SCN) is the main and major biological clock in mammals and is responsible for the synchronization of the pineal gland to the light/darkness cycle through a polysynaptic pathway. The neuroendocrine feedback loop effect is carried out by melatonin. This study was carried out to demonstrate that the pineal gland adjusts th...

The suprachiasmatic nuclei (SCN) constitute a circadian clock in mammals, where -amino-butyric acid (GABA) neurotransmission prevails and participates in different aspects of circadian regulation. Evidence suggests that GABA has an excitatory function in the SCN in addition to its typical inhibitory role. To examine this possibility further, we det...

Individual differences in cognitive performance are partly dependent, on genetic polymporhisms. One of the single-nucleotide polymorphisms of the CNR1 gene, which codes for cannabinoid receptor 1 (CB1R), is the rs2180619, located in a regulatory region of this gene (6q14-q15). The alleles of the rs2180619 are A > G; the G allele has been associated...

Intracellular calcium is a biochemical messenger that regulates part of the metabolic adaptations in the daily fed-fast cycle. The aim of this study was to characterize the 24-h variations of the liver ryanodine and IP3 receptors (RyR and IP3R) as well as of the endoplasmic-reticulum and plasma-membrane Ca2+-ATPases (SERCA and PMCA) in daytime rest...

Growth arrest specific 1 (GAS1) is a pleiotropic protein that induces apoptosis and cell arrest in different tumors, but it is also involved in the development of the nervous system and other tissues and organs. This dual ability is likely caused by its capacity to interact both by inhibiting the intracellular signaling cascade induced by glial cel...

Nursing in rabbits occurs inside the nest with circadian periodicity. To determine the contribution of suckling stimulation in regulating such periodicity, we varied the size of the litters provided (1, 2, 4, or 6-8 pups). Nursing does, kept under a 14:10 (L:D) photoperiod, were continuously videotaped from parturition into lactation day 15. Althou...

Since the pioneering work of Gadea-Ciria (Gadea-Ciria M, Stadler H, Lloyd KG, Bartholini G. Acetylcholine release within the cat striatum during the sleep-wakefulness cycle. Nature 1973; 243:518-519) indicating pointing to the involvement of acetylcholine and basal ganglia in sleep regulation; extensive literature has suggested that this brain comp...

In rabbit pups, nursing by the mother is the prevailing entraining signal for their circadian rhythms during at least the first two weeks of life. Therefore, they are considered a natural model of food anticipatory activity. However, the photic entrainment of the circadian system in rabbit pups during this developmental stage is not well understood...

Alcohol use disorder is a compulsive behavior driven by motivational systems and by a poor control of consummatory behavior. The entopeduncular nucleus (EP) seems to be involved in the regulation of executive mechanisms, hence, in the expression of behavior. Endocannabinoids (eCB) are involved in alcohol intake mechanisms. The eCB receptor name can...

The anterior paraventricular thalamus (aPVT) projects to the SCN, and a lesion of the aPVT leads to phase delays of circadian rhythms, instead of advances, produced by light pulses at CT23. As a first step to understanding the underlying mechanism, the authors characterized the monosynaptic responses of SCN neurons to aPVT in whole-cell recordings...

We propose that the mammalian timing system is formed by constitutive clocks, such as the suprachiasmatic nucleus, and emerging clocks build up from the coordinated activity of peripheral oscillators, such as the food entrained oscillator (FEO). This timing system underlies a general regulatory process that modulates the set point of physiological...

A restricted schedule of food access promotes numerous metabolic and physiological adaptations to optimize the biochemical handling of nutrients. The restricted feeding activates responses in hypothalamic and midbrain areas, as well as in peripheral organs involved in energy metabolism. A restricted feeding schedule (RFS) is associated with marked...

Electrophysiological and calcium mobilization experiments have suggested that the intracellular calcium release channel ryanodine receptors (RyRs) are involved in the circadian rhythmicity of the suprachiasmatic nucleus (SCN). In the present report the authors provide behavioral evidence that RyRs play a specific and major role in the output of the...

Ryanodine-sensitive intracellular Ca2+ channels (RyRs) are present in suprachiasmatic nuclei (SCN) neurons, but the functions served by these channels are not known. Here we addressed whether mobilization of intracellular Ca2+ stores through the RyRs may be a link between the molecular clock and the firing rate in SCN neurons. Activation of the RyR...

To analyse the data and concepts that have been produced in relation to one of the functions that have been suggested for sleep, namely, neuronal recovery. Sleep is a state of consciousness that is different to that of arousal. Mammals devote an important part of their lives to sleeping; for example, as humans, we sleep for a third of our lives, bu...

Food anticipatory activity (FAA) is an output of the food-entrained oscillator (FEO), a conspicuous biological clock that expresses when experimental animals are under a restricted food schedule (RFS). We have shown that the liver is entrained by RFS and exhibits an anticipatory response before meal time in its oxidative and energetic state. The pr...

Even though the rabbit has been widely used for circadian studies, very little information is available in this species about the morphology and physiology of the suprachiasmatic nucleus (SCN). The aim of the present study was to characterize expression of the Fos protein by immunocytochemistry in the rabbit's SCN under two conditions: light – dark...

Circadian rhythms are fluctuations with a period around 24 hrs and the most remarkable in humans is the awake-sleep cycle. In mammals these rhythms are under control of a master clock in the suprachiasmatic nucleus (SCN), in the brain. However these rhythms are endogenous, need to be synchronized to the external light-dark cycles in order to have a...

Digestive and metabolic processes are entrained by restricted feeding (RFS) schedules and are thought to be potential elements of a food-entrained oscillator (FEO). Due to the close relationship of leptin with metabolic regulation and because leptin is a relevant communication signal of the individual's peripheral metabolic condition with the centr...

The present study aimed to identify the hypothalamic nuclei involved with food entrainment by using c-Fos-like immunoreactivity (c-Fos-IR) as a marker of functional activation. We studied rats entrained 3 wk to restricted feeding schedules (RF), their ad libitum (AL) controls, and the persistence of c-Fos-IR temporal patterns in entrained-fasted ra...

Low protein malnourished rats held in 12:12 light-dark conditions exhibit two bouts of drinking activity, which resemble a "splitting" pattern. These findings have suggested a weak coupling force between the light-(LEO) and the food-entrainable oscillators (FEO). Food restriction to a few hours daily exerts a strong entraining influence on FEO and...

Restricted feeding schedules (RFSs) produce a behavioral activation known as anticipatory activity, which is a manifestation of a food-entrained oscillator (FEO). The liver could be playing a role in the physiology of FEO. Here we demonstrate that the activity of liver selenoenzyme deiodinase type 1 (D1), which transforms thyroxine into triiodothyr...

Despite the fact that the circadian variations in the density of striatal dopaminergic D2 receptors are well documented, there are few reports concerning whether these variations may regulate the extrapyramidal symptoms produced by antipsychotic drugs. To test this hypothesis, we selected 18 male hospitalized schizophrenic subjects, who had been tr...

Peripheral oscillators, especially in the liver, are thought to be part of the food entrained oscillator (FEO). The internal mediating signals involved in food entrain-ment are unknown. Catecholamines may be one signal, since they increase their blood concentration immediately after feeding, and their intraperitoneal (IP) administration produces hy...

Food entrainment of clock genes in the liver suggests that this organ may underlie a food entrained oscillator (FEO), which manifests under restricted feeding schedule (RFS). In order to test the importance of a functional liver for the expression of FEO, chronic CCl4-treated cirrhotic rats and oil-treated controls were entrained to RFS and drinkin...

The reciprocal connections between the paraventricular thalamic nucleus (PVT) and the suprachiasmatic nuclei suggest that PVT may participate in the regulation of circadian rhythms. We studied in rats the effect of lesions of the anterior and midposterior regions of the PVT on phase shifts of drinking circadian rhythm induced by light pulses at cir...

The reciprocal connections between the paraventricu-lar thalamic nucleus (PVT) and the suprachiasmatic nuclei suggest that PVT may participate in the regulation of circa-dian rhythms. We studied in rats the effect of lesions of the anterior and midposterior regions of the PVT on phase shifts of drinking circadian rhythm induced by light pulses at c...

Evidence from several laboratories indicates that the anxiogenic effects of cholecystokinin (CCK) are mediated by CCKB receptors. However, it has been reported that CCKA receptors have been found in brain and CCKA antagonists have anxiolytic properties. The aim of this work was to study whether CCKA receptors are also involved in the modulation of...

ABSTRACT The present article is the adapted version of an electronic symposium organized by the Brazilian Society of Neuroscience and Behavior (SBNeC) which took place on June 14, 2000. The text is divided into three sections: I. The main issues, II. Chronodrugs, and III. Methods. The first section is dedicated to the perspectives of chronobiology...

Restricted feeding schedules entrain behavioral and physiological circadian rhythms, which depend on a food-entrainable oscillator (FEO). The mechanism of the FEO might depend on digestive and endocrine processes regulating energy balance. The present study characterizes the dynamics of circulating corticosterone, insulin, and glucagon and regulato...

Young rabbits (Oryctolagus cuniculus) are only nursed for 3-5 min every 24 h. They show a circadian increase in activity in anticipation of this, which is entrained by suckling. Our aim was to determine whether serum and liver metabolites show diurnal fluctuations which could act to regulate this circadian pattern. Stomach weight, liver glycogen an...

We examined the temporal modulation of intracellular calcium release channels in the suprachiasmatic nucleus (SCN). We found a circadian rhythm in [3H]ryanodine binding that was specific to the SCN. The peak in the rhythm occurred at CT 7 and was due to an increase in Bmax, which correlated well with immunoblots showing an increase in RyR-2 express...

Blood adenosine metabolism, including metabolites and metabolizing enzymes, was studied during the sleep period in human volunteers. Searching for significant correlations among biochemical parameters found: adenosine with state 1 of slow-wave sleep (SWS); activity of 5'-nucleotidase with state 2 of SWS; inosine and AMP with state 3-4 of SWS; and a...

This study examined how chronic protein malnutrition (6% casein diet) affected the electrocorticogram (ECoG) in young rats following 24 h of sleep deprivation. Baseline (basal day) ECoG-polygraphic recordings were obtained in Sprague-Dawley rats after which animals were sleep-deprived for 24 h by means of a slowly rotating cylinder. ECoG recordings...

Brief photic stimuli at different circadian times induce differential expression of c-Fos in the suprachiasmatic nuclei (SCN). Whether circadian modulation of light-induced c-Fos expression occurs in other visual projection areas is not known. We addressed this question by estimating the immunohistochemical expression of c-Fos induced by 60 min lig...