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Some studies relate the use of pyriproxyfen (PPF) in drinking water with damage to embryonic neurodevelopment, including a supposed association with cases of microcephaly. However, the effects on neural cells and skull ossification in embryos remain unclear. This study aims to investigate the effects of PPF on the structure and ultrastructure of brain cells and its influence on the skull ossification process during embryonic development. Chicken embryos, used as an experimental model, were exposed to concentrations of 0.01 and 10 mg/l PPF at E1. The findings demonstrated that PPF led to notable ultrastructural alterations such as reduced cilia and microvilli of ependymal cells and damage to mitochondria, endoplasmic reticulum, Golgi bodies, and cell membranes in neural cells. The frequency of changes and the degree of these cell damage between the forebrain and midbrain were similar. PPF induced a reduction in fox3 transcript levels, specific for differentiation of neurons, and a reduction in the NeuN protein content related to mature neurons and dendritic branches. PPF impacted the ossification process of the skull, as evidenced by the increase in the ossified area and the decrease in inter-bone spacing. In conclusion, this study highlights the ability of PPF to affect neurodevelopmental processes by inducing ultrastructural damage to neural cells, concomitant with a reduction in NeuN and fox3 expression. This detrimental impact coupled with deficiencies in skull ossification can prevent the proper growth and development of the brain.
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Insecticidas , Osteogénesis , Piridinas , Embrión de Pollo , Animales , Cráneo , NeuronasRESUMEN
Information storage in the brain involves different memory types and stages that are processed by several brain regions. Cholinergic pathways through acetylcholine receptors actively participate on memory modulation, and their disfunction is associated with cognitive decline in several neurological disorders. During the last decade, the role of α7 subtype of nicotinic acetylcholine receptors in different memory stages has been studied. However, the information about their role in memory processing is still scarce. In this review, we attempt to identify brain areas where α7 nicotinic receptors have an essential role in different memory types and stages. In addition, we discuss recent work implicating-or not-α7 nicotinic receptors as promising pharmacological targets for memory impairment associated with neurological disorders.
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BACKGROUND: Fragile X syndrome, the major cause of inherited intellectual disability among men, is due to deficiency of the synaptic functional regulator FMR1 protein (FMRP), encoded by the FMRP translational regulator 1 (FMR1) gene. FMR1 alternative splicing produces distinct transcripts that may consequently impact FMRP functional roles. In transcripts without exon 14 the translational reading frame is shifted. For deepening current knowledge of the differential expression of Fmr1 exon 14 along the rat nervous system development, we conducted a descriptive study employing quantitative RT-PCR and BLAST of RNA-Seq datasets. RESULTS: We observed in the rat forebrain progressive decline of total Fmr1 mRNA from E11 to P112 albeit an elevation on P3; and exon-14 skipping in E17-E20 with downregulation of the resulting mRNA. We tested if the reduced detection of messages without exon 14 could be explained by nonsense-mediated mRNA decay (NMD) vulnerability, but knocking down UPF1, a major component of this pathway, did not increase their quantities. Conversely, it significantly decreased FMR1 mRNA having exon 13 joined with either exon 14 or exon 15 site A. CONCLUSIONS: The forebrain in the third embryonic week of the rat development is a period with significant skipping of Fmr1 exon 14. This alternative splicing event chronologically precedes a reduction of total Fmr1 mRNA, suggesting that it may be part of combinatorial mechanisms downregulating the gene's expression in the late embryonic period. The decay of FMR1 mRNA without exon 14 should be mediated by a pathway different from NMD. Finally, we provide evidence of FMR1 mRNA stabilization by UPF1, likely depending on FMRP.
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Empalme Alternativo , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil , Prosencéfalo , Empalme Alternativo/genética , Animales , Desarrollo Embrionario , Exones/genética , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/genética , Proteína de la Discapacidad Intelectual del Síndrome del Cromosoma X Frágil/metabolismo , Prosencéfalo/embriología , ARN Helicasas/genética , ARN Helicasas/metabolismo , ARN Mensajero/metabolismo , Ratas , Transactivadores/genética , Transactivadores/metabolismoRESUMEN
While most patients with depression respond to pharmacotherapy and psychotherapy, about one-third will present treatment resistance to these interventions. For patients with treatment-resistant depression (TRD), invasive neurostimulation therapies such as vagus nerve stimulation, deep brain stimulation, and epidural cortical stimulation may be considered. We performed a narrative review of the published literature to identify papers discussing clinical studies with invasive neurostimulation therapies for TRD. After a database search and title and abstract screening, relevant English-language articles were analyzed. Vagus nerve stimulation, approved by the U.S. Food and Drug Administration as a TRD treatment, may take several months to show therapeutic benefits, and the average response rate varies from 15.2-83%. Deep brain stimulation studies have shown encouraging results, including rapid response rates (> 30%), despite conflicting findings from randomized controlled trials. Several brain regions, such as the subcallosal-cingulate gyrus, nucleus accumbens, ventral capsule/ventral striatum, anterior limb of the internal capsule, medial-forebrain bundle, lateral habenula, inferior-thalamic peduncle, and the bed-nucleus of the stria terminalis have been identified as key targets for TRD management. Epidural cortical stimulation, an invasive intervention with few reported cases, showed positive results (40-60% response), although more extensive trials are needed to confirm its potential in patients with TRD.
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Based on the rationale that neural hypersynchronization underlies epileptic phenomena, nonperiodic stimulation (NPS) was designed and successfully tested as an electrical stimulus with robust anticonvulsant action. Considering the scale-free temporal structure of NPS mimics natural-like activity, here we hypothesized its application to the amygdala would induce minor to none impairment of neural function in treated animals. Wistar rats underwent gold-standard behavioral tests such as open field (OF), elevated plus-maze (EPM), novel object recognition, and social interaction test in order to evaluate the functions of base-level anxiety, motor function, episodic memory, and sociability. We also performed daily (8 days, 6 h per day) electrophysiological recordings (local field potential/LFP and electromyography) to assess global forebrain dynamics and the sleep-wake cycle architecture and integrity. All animals displayed an increased proportion of time exploring new objects, spent more time in the closed arms of the EPM and in the periphery of the OF arena, with similar numbers of crossing between quadrants and no significant changes of social behaviors. In the sleep-wake cycle electrophysiology experiments, we found no differences regarding duration and proportion of sleep stages and the number of transitions between stages. Finally, the power spectrum of LFP recordings and neurodynamics were also unaltered. We concluded that NPS did not impair neural functions evaluated and thus, it may be safe for clinical studies. Additionally, results corroborate the notion that NPS may exert an on-demand only desynchronization effect by efficiently competing with epileptiform activity for the physiological and healthy recruitment of neural circuitry. Considering the very dynamical nature of circuit activation and functional activity underlying neural function in general (including cognition, processing of emotion, memory acquisition, and sensorimotor integration) and its corruption leading to disorder, such mechanism of action may have important implications in the investigation of neuropsychological phenomena and also in the development of rehabilitation neurotechnology.
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Amígdala del Cerebelo , Epilepsia , Amígdala del Cerebelo/fisiología , Animales , Ansiedad , Estimulación Eléctrica/métodos , Epilepsia/terapia , Ratas , Ratas Wistar , ConvulsionesRESUMEN
The peroxisome proliferator-activated receptor alpha (PPARα) is a nuclear receptor that has been linked to the modulation of several physiological functions, including the sleep-wake cycle. The PPARα recognizes as endogenous ligands the lipids oleoylethanolamide (OEA) and palmitoylethanolamide (PEA), which in turn, if systemically injected, they exert wake-promoting effects. Moreover, the activation of PPARα by the administration of OEA or PEA increases the extracellular contents of neurotransmitters linked to the control of wakefulness; however, the role of PPARα activated by OEA or PEA on additional biochemicals related to waking regulation, such as acetylcholine (ACh) and 5-hydroxytryptamine (5-HT), has not been fully studied. Here, we have investigated the effects of treatments of OEA or PEA on the contents of ACh and 5-HT by using in vivo microdialysis techniques coupled to HPLC means. For this purpose, OEA or PEA were systemically injected (5, 10 or 30 mg/kg; i.p.), and the levels of ACh and 5-HT were collected from the basal forebrain, a wake-related brain area. These pharmacological treatments significantly increased the contents of ACh and 5-HT as determined by HPLC procedures. Interestingly, PPARα antagonist MK-886 (30 mg/kg; i.p.) injected before the treatments of OEA or PEA blocked these outcomes. Our data suggest that the activation of PPARα by OEA or PEA produces significant changes on ACh and 5-HT levels measured from the basal forebrain and support the conclusion that PPARα is a suitable molecular element involved in the regulation of wake-related neurotransmitters.
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PPAR alfa , Serotonina , Acetilcolina , Amidas , Encéfalo/metabolismo , Endocannabinoides , Etanolaminas , Ácidos Oléicos , PPAR alfa/metabolismo , Ácidos PalmíticosRESUMEN
The clinicoanatomic cases of acquired pedophilia that have been published in the medical and forensic literature up to 2019 are reviewed. Twenty-two cases fit our inclusion criteria. All but one were men, and in only one case the injury was localized to the left hemisphere. Hypersexuality was present in 18 cases. The damaged areas fell within the frontotemporoinsular cortices and related subcortical nuclei; however, the anterior hypothalamus was spared. Damage to parts of the right frontotemporoinsular lobes with sparing of the anterior hypothalamus seems to be critical for the emergence of acquired pedophilia.
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Encefalopatías/patología , Corteza Cerebral/patología , Hipotálamo Posterior/patología , Haz Prosencefálico Medial/patología , Pedofilia/etiología , Disfunciones Sexuales Fisiológicas/etiología , Adulto , Anciano , Anciano de 80 o más Años , Encefalopatías/complicaciones , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
BACKGROUND: Myelomeningocele (MMC) is often related to hydrocephalus and Chiari malformation (CM) type 2; however, other brain abnormalities have been reported in this population. In order to better understand and quantify other forebrain abnormalities, we analyzed magnetic resonance imaging (MRI) of MMC patients treated in utero or postnatal. METHODS: Between January 2014 and March 2017, 59 MMC were treated in our hospital. Thirty-seven patients (32 postnatal and 5 intrautero repair) had brain MRI and were enrolled at the study. MRI was analyzed by two experienced neuroradiologists to identify the supra and infratentorial brain abnormalities. RESULTS: A wide range of brain abnormalities was consistently identified in MMC patients. As expected, the most common were hydrocephalus (94.5%) and CM type II (89.1%). Of note, we found high incidence of corpus callosum abnormalities (86.4%), mostly represented by dysplasia (46%). CONCLUSIONS: The data are consistent with the concept that brain abnormalities related to MMC can be both infratentorial and supratentorial, cortical, and subcortical. More studies are needed to correlate these forebrain abnormalities to long-term functional outcome and their prognostic value for these patients.
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Malformación de Arnold-Chiari , Hidrocefalia , Meningomielocele , Malformación de Arnold-Chiari/complicaciones , Malformación de Arnold-Chiari/diagnóstico por imagen , Encéfalo/diagnóstico por imagen , Humanos , Hidrocefalia/diagnóstico por imagen , Hidrocefalia/etiología , Meningomielocele/complicaciones , Meningomielocele/diagnóstico por imagen , Estudios RetrospectivosRESUMEN
Cholinergic activation of the medial septal area (MSA) with carbachol produces thirst, natriuresis and antidiuresis. Hydrogen peroxide (H2O2) injected into the medial septal area (MSA) impairs behavioral and renal responses induced by carbachol at the same site, suggesting the exogenous H2O2 may modulate the responses to cholinergic activation in the MSA. In the present study, we investigated if the accumulation of endogenous H2O2 in the MSA after the injection of the catalase inhibitor 3-amino-1,2,4-triazole (ATZ) also affects cholinergic responses. In addition, the effects of the combination of ATZ with a non-effective dose of H2O2 in the MSA were also tested. Male Holtzman rats (280-320 g) with stainless steel cannulas implanted in the MSA were used. The treatment with ATZ (10 nmol) into the MSA partially reverted the antidiuretic effect of carbachol (10.5 ± 0.7, vs. saline + carbachol: 7.3 ± 0.6 ml/120 min), without changing carbachol-induced water intake (9.5 ± 1.9, vs. saline + carbachol: 10.7 ± 1.6 ml/60 min). The combination of a low dose of ATZ (2.5 nmol) with an ineffective dose of H2O2 (0.5 µmol) into the MSA reduced carbachol-induced thirst (7.5 ± 2.0, vs. saline + carbachol: 14.9 ± 1.2 ml/15 min) and reverted the antidiuresis (8.1 ± 1.1, vs. saline + carbachol: 5.3 ± 0.9 ml/120 min). Sodium and potassium excretion were not modified regardless the treatment. Although exogenous H2O2 injected in the MSA may affect most of the responses to cholinergic activation of the MSA, the antidiuresis is the response clearly modulated by endogenous H2O2.
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Fármacos Antidiuréticos/administración & dosificación , Carbacol/administración & dosificación , Agonistas Colinérgicos/administración & dosificación , Diuresis , Peróxido de Hidrógeno/metabolismo , Núcleos Septales/metabolismo , Amitrol (Herbicida)/administración & dosificación , Animales , Conducta de Ingestión de Líquido/efectos de los fármacos , Masculino , Ratas Sprague-Dawley , Núcleos Septales/efectos de los fármacos , Micción/efectos de los fármacosRESUMEN
The cyclic alternating pattern (CAP) encompasses the pseudoperiodic appearance of synchronized brain waves and rhythms and is considered a regulator of the nonrapid eye movement (NREM) sleep vigilance level, reflecting sleep instability. To determine the brain regions responsible for this phenomenon, we scored and analyzed sleep functional magnetic resonance imaging data acquired with simultaneous electroencephalography (EEG-fMRI). Group analysis revealed a set of brain areas showing statistically significant blood oxygen-level dependent signal correlated positively with the synchronization phase of the CAP, most prominent being the insula, the middle cingulate gyrus, and the basal forebrain. These areas may form a network acting as a synchronization pacemaker, controlling the level of NREM sleep vigilance and the sleeper's arousability.
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Prosencéfalo Basal/fisiología , Ondas Encefálicas/fisiología , Fases del Sueño/fisiología , Sueño/fisiología , Adulto , Electroencefalografía/métodos , Femenino , Hemodinámica/fisiología , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Polisomnografía/métodos , Vigilia/fisiologíaRESUMEN
This study aimed to investigate the protective effect of salvinorin A on the cerebral pial artery after forebrain ischemia and explore related mechanisms. Thirty Sprague-Dawley rats received forebrain ischemia for 10 min. The dilation responses of the cerebral pial artery to hypercapnia and hypotension were assessed in rats before and 1 h after ischemia. The ischemia reperfusion (IR) control group received DMSO (1 µL/kg) immediately after ischemia. Two different doses of salvinorin A (10 and 20 µg/kg) were administered following the onset of reperfusion. The 5th, 6th, and 7th groups received salvinorin A (20 µg/kg) and LY294002 (10 µM), L-NAME (10 μM), or norbinaltorphimine (norBIN, 1 μM) after ischemia. The levels of cGMP in the cerebrospinal fluid (CSF) were also measured. The phosphorylation of AKT (p-AKT) was measured in the cerebral cortex by western blot at 24 h post-ischemia. Cell necrosis and apoptosis were examined by hematoxylin-eosin staining (HE) and TUNEL staining, respectively. The motor function of the rats was evaluated at 1, 2, and 5 days post-ischemia. The dilation responses of the cerebral pial artery were significantly impaired after ischemia and were preserved by salvinorin A treatment. In addition, salvinorin A significantly increased the levels of cGMP and p-AKT, suppressed cell necrosis and apoptosis of the cerebral cortex and improved the motor function of the rats. These effects were abolished by LY294002, L-NAME, and norBIN. Salvinorin A preserved cerebral pial artery autoregulation in response to hypercapnia and hypotension via the PI3K/AKT/cGMP pathway.
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Animales , Masculino , Ratas , Arterias Cerebrales/efectos de los fármacos , Isquemia Encefálica/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Diterpenos de Tipo Clerodano/farmacología , Transducción de Señal , Arterias Cerebrales/fisiopatología , Isquemia Encefálica/tratamiento farmacológico , Morfolinas/administración & dosificación , Cromonas/administración & dosificación , Ratas Sprague-Dawley , GMP Cíclico/líquido cefalorraquídeo , GMP Cíclico/metabolismo , NG-Nitroarginina Metil Éster , Diterpenos de Tipo Clerodano/antagonistas & inhibidores , Modelos Animales de Enfermedad , Naltrexona/administración & dosificación , Naltrexona/análogos & derivadosRESUMEN
Study objective: To assess differences in gene expression in cholinergic basal forebrain cells between sleeping and sleep-deprived mice sacrificed at the same time of day. Methods: Tg(ChAT-eGFP)86Gsat mice expressing enhanced green fluorescent protein (eGFP) under control of the choline acetyltransferase (Chat) promoter were utilized to guide laser capture of cholinergic cells in basal forebrain. Messenger RNA expression levels in these cells were profiled using microarrays. Gene expression in eGFP(+) neurons was compared (1) to that in eGFP(-) neurons and to adjacent white matter, (2) between 7:00 am (lights on) and 7:00 pm (lights off), (3) between sleep-deprived and sleeping animals at 0, 3, 6, and 9 hours from lights on. Results: There was a marked enrichment of ChAT and other markers of cholinergic neurons in eGFP(+) cells. Comparison of gene expression in these eGFP(+) neurons between 7:00 am and 7:00 pm revealed expected differences in the expression of clock genes (Arntl2, Per1, Per2, Dbp, Nr1d1) as well as mGluR3. Comparison of expression between spontaneous sleep and sleep-deprived groups sacrificed at the same time of day revealed a number of transcripts (n = 55) that had higher expression in sleep deprivation compared to sleep. Genes upregulated in sleep deprivation predominantly were from the protein folding pathway (25 transcripts, including chaperones). Among 42 transcripts upregulated in sleep was the cold-inducible RNA-binding protein. Conclusions: Cholinergic cell signatures were characterized. Whether the identified genes are changing as a consequence of differences in behavioral state or as part of the molecular regulatory mechanism remains to be determined.
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Prosencéfalo Basal/citología , Neuronas Colinérgicas/metabolismo , Perfilación de la Expresión Génica , Privación de Sueño/metabolismo , Sueño/genética , Vigilia/genética , Acetilcolina/metabolismo , Animales , Proteínas CLOCK/genética , Colina O-Acetiltransferasa/genética , Masculino , Ratones , Pliegue de Proteína , Receptores de Glutamato Metabotrópico/genética , Privación de Sueño/patologíaRESUMEN
ABSTRACT The purpose of the present study was to investigate the effect of crocin on brain oxidative damage and memory deficits in a 6-hydroxydopamine (6-OHDA) model of Parkinson’s disease. Male Wistar rats were subjected to unilateral injection of 6-OHDA (16 µg) into the medial forebrain bundle and treated with crocin (30 and 60 mg/kg) for six weeks. The rats were tested for memory performance at six weeks after 6-OHDA infusion, and then were killed for the estimation of biochemical parameters. The increase in thiobarbituric acid reactive substances (TBARS) and nitrite levels in the hippocampus were observed in the 6-OHDA lesioned rats, which was accompanied by memory deficits in a passive avoidance test at the end of week 6. Moreover, treatment with crocin decreased TBARS and nitrite levels in the hippocampus, and improved aversive memory. The present study conclusively demonstrated that crocin acts as an antioxidant and anti-inflammatory agent in the hippocampus of parkinsonian rats and could improve aversive memory through its properties.
RESUMO O objetivo do presente estudo foi investigar o efeito da crocina no dano oxidativo cerebral e nos déficits de memória em um modelo 6-OHDA de doença de Parkinson. Ratos Wistar machos foram submetidos à injeção unilateral de 6-OHDA (16 μg) em MFB e tratados com crocina (30 e 60 mg/kg), durante 6 semanas. Os ratos foram testados quanto ao desempenho da memória 6 semanas após a infusão de 6-OHDA, e, em seguida, foram sacrificados para a estimativa dos parâmetros bioquímicos. O aumento nos níveis de TBARS e de nitrito no hipocampo foram observados em ratos 6-OHDA lesionados, acompanhado por déficits de memória em um teste de esquiva passiva no final da semana 6. Além disso, o tratamento com crocina diminuiu os níveis de nitrito e de TBARS no hipocampo e melhorou a memória aversiva. O presente estudo demonstrou conclusivamente que a crocina age como um antioxidante e um agente anti-inflamatório no hipocampo de ratos parkinsonianos e pode melhorar a memória aversiva através de suas propriedades.
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Animales , Masculino , Enfermedad de Parkinson/tratamiento farmacológico , Carotenoides/farmacología , Corteza Cerebral/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Trastornos de la Memoria/prevención & control , Antioxidantes/farmacología , Enfermedad de Parkinson/fisiopatología , Enfermedad de Parkinson/metabolismo , Compuestos de Sulfhidrilo/análisis , Peroxidación de Lípido/efectos de los fármacos , Distribución Aleatoria , Corteza Cerebral/fisiopatología , Corteza Cerebral/metabolismo , Oxidopamina , Sustancias Reactivas al Ácido Tiobarbitúrico/análisis , Ratas Wistar , Modelos Animales de Enfermedad , Glutatión Peroxidasa/análisis , Glutatión Peroxidasa/efectos de los fármacos , Memoria/efectos de los fármacos , Memoria/fisiología , Trastornos de la Memoria/fisiopatología , Trastornos de la Memoria/metabolismo , Nitritos/análisisRESUMEN
Cholinergic activation of the medial septal area (MSA) with carbachol produces thirst, natriuresis, antidiuresis and pressor response. In the brain, hydrogen peroxide (H2O2) modulates autonomic and behavioral responses. In the present study, we investigated the effects of the combination of carbachol and H2O2 injected into the MSA on water intake, renal excretion, cardiovascular responses and the activity of vasopressinergic and oxytocinergic neurons in the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei. Furthermore, the possible modulation of carbachol responses by H2O2 acting through K+ATP channels was also investigated. Male Holtzman rats (280-320 g) with stainless steel cannulas implanted in the MSA were used. The pre-treatment with H2O2 in the MSA reduced carbachol-induced thirst (7.9±1.0, vs. carbachol: 13.2±2.0 ml/60 min), antidiuresis (9.6±0.5, vs. carbachol: 7.0±0.8 ml/120 min,), natriuresis (385±36, vs. carbachol: 528±46 µEq/120 min) and pressor response (33±5, vs. carbachol: 47±3 mmHg). Combining H2O2 and carbachol into the MSA also reduced the number of vasopressinergic neurons expressing c-Fos in the PVN (46.4±11.2, vs. carbachol: 98.5±5.9 c-Fos/AVP cells) and oxytocinergic neurons expressing c-Fos in the PVN (38.5±16.1, vs. carbachol: 75.1±8.5 c-Fos/OT cells) and in the SON (57.8±10.2, vs. carbachol: 102.7±7.4 c-Fos/OT cells). Glibenclamide (K+ATP channel blocker) into the MSA partially reversed H2O2 inhibitory responses. These results suggest that H2O2 acting through K+ATP channels in the MSA attenuates responses induced by cholinergic activation in the same area.
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Carbacol/farmacología , Fármacos del Sistema Nervioso Central/farmacología , Agonistas Colinérgicos/farmacología , Peróxido de Hidrógeno/farmacología , Tabique del Cerebro/efectos de los fármacos , Animales , Presión Arterial/efectos de los fármacos , Presión Arterial/fisiología , Catéteres de Permanencia , Diuresis/efectos de los fármacos , Diuresis/fisiología , Ingestión de Líquidos/efectos de los fármacos , Ingestión de Líquidos/fisiología , Ingestión de Alimentos/efectos de los fármacos , Ingestión de Alimentos/fisiología , Canales KATP/metabolismo , Masculino , Neuronas/efectos de los fármacos , Neuronas/fisiología , Oxitocina/metabolismo , Núcleo Hipotalámico Paraventricular/efectos de los fármacos , Núcleo Hipotalámico Paraventricular/fisiología , Proteínas Proto-Oncogénicas c-fos/metabolismo , Ratas Sprague-Dawley , Tabique del Cerebro/fisiología , Núcleo Supraóptico/efectos de los fármacos , Núcleo Supraóptico/fisiología , Sed/efectos de los fármacos , Sed/fisiología , Vasopresinas/metabolismoRESUMEN
The nucleus basalis (NB) is a cholinergic neuromodulatory structure that projects liberally to the entire cortical mantle and regulates information processing in all cortical layers. Here, we recorded activity from populations of single units in the NB as rats performed a whisker-dependent tactile discrimination task. Over 80% of neurons responded with significant modulation in at least one phase of the task. Such activity started before stimulus onset and continued for seconds after reward delivery. Firing rates monotonically increased with reward magnitude during the task, suggesting that NB neurons are not indicating the absolute deviation from expected reward amounts. Individual neurons also encoded significant amounts of information about stimulus identity. Such robust coding was not present when the same stimuli were delivered to lightly anesthetized animals, suggesting that the NB neurons contain a sensorimotor, rather than purely sensory or motor, representation of the environment. Overall, these results support the hypothesis that neurons in the NB provide a value-laden representation of the sensorimotor state of the animal as it engages in significant behavioral tasks.