RESUMO
Alternative splicing (AS) may increase the number of proteoforms produced by a gene. Alzheimer's disease (AD) is a neurodegenerative disease with well-characterized AS proteoforms. In this study, we used a proteogenomics strategy to build a customized protein sequence database and identify orthologous AS proteoforms between humans and mice on publicly available shotgun proteomics (MS/MS) data of the corpus callosum (CC) and olfactory bulb (OB). Identical proteotypic peptides of six orthologous AS proteoforms were found in both species: PKM1 (gene PKM/Pkm), STXBP1a (gene STXBP1/Stxbp1), Isoform 3 (gene HNRNPK/Hnrnpk), LCRMP-1 (gene CRMP1/Crmp1), SP3 (gene CADM1/Cadm1), and PKCßII (gene PRKCB/Prkcb). These AS variants were also detected at the transcript level by publicly available RNA-Seq data and experimentally validated by RT-qPCR. Additionally, PKM1 and STXBP1a were detected at higher abundances in a publicly available MS/MS dataset of the AD mouse model APP/PS1 than its wild type. These data corroborate other reports, which suggest that PKM1 and STXBP1a AS proteoforms might play a role in amyloid-like aggregate formation. To the best of our knowledge, this report is the first to describe PKM1 and STXBP1a overexpression in the OB of an AD mouse model. We hope that our strategy may be of use in future human neurodegenerative studies using mouse models.
Assuntos
Processamento Alternativo/genética , Doença de Alzheimer/genética , Encéfalo/metabolismo , Proteogenômica , Sequência de Aminoácidos , Animais , Bases de Dados de Proteínas , Modelos Animais de Doenças , Éxons/genética , Humanos , Masculino , Camundongos Endogâmicos C57BL , Peptídeos/química , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA-Seq , Transcriptoma/genéticaRESUMO
Selective stimulation of carotid chemoreceptors by intravenous infusion of low doses of potassium cyanide (KCN) produces short-lasting escape responses that have been proposed as a model of panic attack. In turn, preclinical studies suggest that facilitation of the endocannabinoid system attenuate panic-like responses. Here, we compared the effects of cannabinoid-related compounds to those of alprazolam, a clinically effective panicolytic, on the duration of the escape reaction induced by intravenous infusion of KCN (80µg) in rats. Alprazolam (1, 2, 4mg/kg) decreased escape duration at doses that did not alter basal locomotor activity. URB597 (0.1, 0.3, 1mg/kg; inhibitor of anandamide hydrolysis), WIN55,212-2 (0.1, 0.3, 1mg/kg; synthetic cannabinoid), arachidonoyl-serotonin (1, 2.5, 5mg/kg; dual TRPV1 and anandamide hydrolysis inhibitor), and cannabidiol (5, 10, 20, 40mg/kg; a phytocannabinoid) did not decrease escape duration. Alprazolam also prevented the increase in arterial pressure evoked by KCN, while bradycardia was unchanged. This study reinforces the validity of the KCN-evoked escape as a model of panic attack. However, it does not support a role for the endocannabinoid system in this behavioral response. These results might have implications for the screening of novel treatments for panic disorder.
Assuntos
Alprazolam/uso terapêutico , Canabinoides/uso terapêutico , Hipnóticos e Sedativos/uso terapêutico , Transtorno de Pânico/tratamento farmacológico , Analgésicos/uso terapêutico , Animais , Ácidos Araquidônicos/uso terapêutico , Benzamidas/uso terapêutico , Benzoxazinas/uso terapêutico , Pressão Sanguínea/efeitos dos fármacos , Carbamatos/uso terapêutico , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/toxicidade , Reação de Fuga/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Locomoção/efeitos dos fármacos , Masculino , Camundongos , Morfolinas/uso terapêutico , Naftalenos/uso terapêutico , Transtorno de Pânico/induzido quimicamente , Cianeto de Potássio/toxicidade , Ratos Wistar , Serotonina/análogos & derivados , Serotonina/uso terapêuticoRESUMO
NEW FINDINGS: What is the central question of this study? In this study, we sought to investigate whether cardiovascular responses to peripheral chemoreflex activation of rats recovered from protein restriction are related to activation of AT1 receptors. What is the main finding and its importance? This study highlights the fact that angiotensinergic mechanisms activated by AT1 receptors do not support increased responses to peripheral chemoreflex activation by KCN in rats recovered from protein restriction. Also, we found that protein restriction led to increased resting ventilation in adult rats, even after recovery. The effects of a low-protein diet followed by recovery on cardiorespiratory responses to peripheral chemoreflex activation were tested before and after systemic angiotensin II type 1 (AT1 ) receptor antagonism. Male Fischer rats were divided into control and recovered (R-PR) groups after weaning. The R-PR rats were fed a low-protein (8%) diet for 35 days and recovered with a normal protein (20%) diet for 70 days. Control rats received a normal protein diet for 105 days (CG105 ). After cannulation surgery, mean arterial pressure, heart rate, respiratory frequency, tidal volume and minute ventilation were acquired using a digital recording system in freely moving rats. The role of angintensin II was evaluated by systemic antagonism of AT1 receptors with losartan (20 mg kg-1 i.v.). The peripheral chemoreflex was elicited by increasing doses of KCN (20-160 µg kg min-1 , i.v.). At baseline, R-PR rats presented increased heart rate and minute ventilation (372 ± 34 beats min-1 and 1.274 ± 377 ml kg-1 min-1 ) compared with CG105 animals (332 ± 22 beats min-1 and 856 ± 112 ml kg-1 min-1 ). Mean arterial pressure was not different between the groups. Pressor and bradycardic responses evoked by KCN (60 µg kg-1 ) were increased in R-PR (+45 ± 13 mmHg and -77 ± 47 beats min-1 ) compared with CG105 rats (+25 ± 17 mmHg and -27 ± 28 beats min-1 ), but no difference was found in the tachypnoeic response. These differences were preserved after losartan. The data suggest that angiotensin II acting on AT1 receptors may not be associated with the increased heart rate, increased minute ventilation and acute cardiovascular responses to peripheral chemoreflex activation in rats that underwent postweaning protein restriction followed by recovery.
Assuntos
Sistema Cardiovascular/metabolismo , Sistema Cardiovascular/fisiopatologia , Células Quimiorreceptoras/metabolismo , Células Quimiorreceptoras/fisiologia , Receptor Tipo 1 de Angiotensina/metabolismo , Reflexo/fisiologia , Angiotensina II/farmacologia , Bloqueadores do Receptor Tipo 1 de Angiotensina II/farmacologia , Animais , Pressão Arterial/efeitos dos fármacos , Pressão Arterial/fisiologia , Bradicardia/metabolismo , Sistema Cardiovascular/efeitos dos fármacos , Células Quimiorreceptoras/efeitos dos fármacos , Dieta com Restrição de Proteínas/métodos , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Losartan/farmacologia , Masculino , Ratos , Ratos Endogâmicos F344 , Reflexo/efeitos dos fármacos , Taquicardia/metabolismo , Volume de Ventilação Pulmonar/efeitos dos fármacos , Volume de Ventilação Pulmonar/fisiologiaRESUMO
INTRODUCTION: The angiotensin-converting enzyme 2 (ACE2)/angiotensin (Ang)-(1-7)/Mas axis could modulate the heart rate (HR) and blood pressure variabilities (BPV) which are important predictors of cardiovascular risk and provide information about the autonomic modulation of the cardiovascular system. Therefore we investigated the effect of Mas deficiency on autonomic modulation in wild type and Mas-knockout (KO) mice. METHODS: Blood pressure was recorded at high sample rate (4000 Hz). Stationary sequences of 200-250 beats were randomly chosen. Frequency domain analysis of HR and BPV was performed with an autoregressive algorithm on the pulse interval sequences and on respective systolic sequences. RESULTS: The KO group presented an increase of systolic arterial pressure (SAP; 127.26±11.20 vs 135.07±6.98 mmHg), BPV (3.54±1.54 vs 5.87±2.12 mmHg(2)), and low-frequency component of systolic BPV (0.12±0.11 vs 0.47±0.34 mmHg(2)). CONCLUSIONS: The deletion of Mas receptor is associated with an increase of SAP and with an increased BPV, indicating alterations in autonomic control. Increase of sympathetic vascular modulation in absence of Mas evidences the important role of Ang-(1-7)/Mas on cardiovascular regulation. Moreover, the absence of significant changes in HR and HRV can indicate an adaptation of autonomic cardiac balance. Our results suggest that the Ang-(1-7)/Mas axis seems more important in autonomic modulation of arterial pressure than HR.
Assuntos
Vasos Sanguíneos/metabolismo , Proteínas Proto-Oncogênicas/deficiência , Receptores Acoplados a Proteínas G/deficiência , Sistema Nervoso Simpático/metabolismo , Animais , Hemodinâmica , Masculino , Camundongos Knockout , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , SístoleRESUMO
This study evaluated the effect of blockade of the excitatory amino acid (EAA) receptors in the dorsomedial hypothalamic (DMH) area on the ventilatory and cardiovascular responses of the chemoreflex activation in conscious rats. Bilateral microinjection of kynurenic acid (2.7 nmol, n = 6) into the DMH area reduced the tachypneic (+ 264 ± 13 versus + 204 ± 14 cpm, P < 0.05) and pressor (+ 52 ± 5 versus + 31 ± 6 mmHg, P < 0.05) components of chemoreflex but had no effect on the bradycardic component (-214 ± 7 versus -244 ± 17 bpm) of the chemoreflex. The magnitudes of the reduction in pressor and tachypneic chemoreflex responses were not significantly correlated (r = 0.308, P = 0.330). These data indicate that neurons located in the DMH area are activated by chemoreflex; that this activation is mediated via EAA receptors; and that it is essential for the full expression of the respiratory component of the chemoreflex.
Assuntos
Núcleo Hipotalâmico Dorsomedial/metabolismo , Receptores de Glutamato/metabolismo , Respiração , Taquipneia/metabolismo , Análise de Variância , Animais , Pressão Sanguínea/efeitos dos fármacos , Pressão Sanguínea/fisiologia , Núcleo Hipotalâmico Dorsomedial/efeitos dos fármacos , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Ácido Cinurênico/farmacologia , Masculino , Pletismografia , Cianeto de Potássio/farmacologia , Ratos , Ratos Wistar , Respiração/efeitos dos fármacos , Taquipneia/induzido quimicamente , Fatores de TempoRESUMO
Peripheral sympathetic overdrive in young obese subjects contributes to further aggravation of insulin resistance, diabetes, and hypertension, thus inducing worsening clinical conditions in adulthood. Exercise training has been considered a strategy to repair obesity autonomic dysfunction, thereby reducing the cardiometabolic risk. Therefore, the aim of this study was to assess the effect of early exercise training, starting immediately after weaning, on cardiac autonomic control in diet-induced obese rats. Male Wistar rats (weaning) were divided into four groups: (i) a control group (n = 6); (ii) an exercise-trained control group (n = 6); (iii) a diet-induced obesity group (n = 6); and (iv) an exercise-trained diet-induced obesity group (n = 6). The development of obesity was induced by 9 weeks of palatable diet intake, and the training program was implemented in a motor-driven treadmill (5 times per week) during the same period. After this period, animals were submitted to vein and artery catheter implantation to assess cardiac autonomic balance by methylatropine (3 mg/kg) and propranolol (4 mg/kg) administration. Exercise training increased running performance in both groups (p < 0.05). Exercise training also prevented the increased resting heart rate in obese rats, which seemed to be related to cardiac pacemaker activity preservation (p < 0.05). Additionally, the training program preserved the pressure and bradycardia responses to autonomic blockade in obese rats (p < 0.05). An exercise program beginning at weaning age prevents cardiovascular dysfunction in obese rats, indicating that exercise training may be used as a nonpharmacological therapeutic strategy for the treatment of cardiometabolic diseases.
Assuntos
Coração/fisiologia , Obesidade/fisiopatologia , Condicionamento Físico Animal/fisiologia , Desmame , Fatores Etários , Animais , Dieta , Masculino , Obesidade/etiologia , Ratos , Ratos WistarRESUMO
The present study aimed to investigate whether running performance in different environments is dependent on intact arterial baroreceptor reflexes. We also assessed the exercise-induced cardiovascular and thermoregulatory responses in animals lacking arterial baroafferent signals. To accomplish these goals, male Wistar rats were subjected to sinoaortic denervation (SAD) or sham surgery (SHAM) and had a catheter implanted into the ascending aorta to record arterial pressure and a telemetry sensor implanted in the abdominal cavity to record core temperature. After recovering from these surgeries, the animals were subjected to constant- or incremental-speed exercises performed until the voluntary interruption of effort under temperate (25° C) and warm (35° C) conditions. During the constant-speed exercises, the running time until the rats were fatigued was shorter in SAD rats in both environments. Although the core temperature was not significantly different between the groups, tail skin temperature was higher in SAD rats under temperate conditions. The denervated rats also displayed exaggerated increases in blood pressure and double product compared with the SHAM rats; in particular, in the warm environment, these exaggerated cardiovascular responses in the SAD rats persisted until they were fatigued. These SAD-mediated changes occurred in parallel with increased variability in the very low and low components of the systolic arterial pressure power spectrum. The running performance was also affected by SAD during the incremental-speed exercises, with the maximal speed attained being decreased by approximately 20% in both environments. Furthermore, at the maximal power output tolerated during the incremental exercises, the mean arterial pressure, heart rate and double product were exaggerated in the SAD relative to SHAM rats. In conclusion, the chronic absence of the arterial baroafferents accelerates exercise fatigue in temperate and warm environments. Our findings also suggest that an augmented cardiovascular strain accounted for the early interruption of exercise in the SAD rats.
Assuntos
Artérias/fisiopatologia , Barorreflexo/fisiologia , Condicionamento Físico Animal/fisiologia , Corrida/fisiologia , Análise de Variância , Animais , Pressão Sanguínea/fisiologia , Regulação da Temperatura Corporal/fisiologia , Denervação , Frequência Cardíaca/fisiologia , Masculino , Ratos , Ratos Wistar , Nó Sinoatrial/inervação , Nó Sinoatrial/fisiopatologia , TemperaturaRESUMO
The present study investigated the role of the dorsomedial hypothalamus (DMH) on cardiovascular and behavioural responses of chemoreflex activation in conscious rats. The arterial chemoreflex was activated by potassium cyanide (KCN, 40 µg, i.v.) before and after bilateral microinjection of lidocaine (2%) or kynurenic acid (2.7 nmol) into the DMH. Locomotor activity was measured to assess the chemoreflex behavioural response. Bilateral microinjection of lidocaine into the DMH produced a significant reduction in the pressor response induced by chemoreflex activation (+51 ± 4 versus +34 ± 5 mmHg, n = 5, P < 0.05). A similar reduction in the pressor chemoreflex response was also observed after microinjection of kynurenic acid into the DMH (+50 ± 3 versus +22 ± 5 mmHg, n = 6, P < 0.05). Strikingly, the behaviour/locomotor activity induced by chemoreflex activation was virtually abolished after blockade of excitatory amino acid receptors in the DMH with kynurenic acid (44 ± 6 versus 5 ± 4 cm, n = 6, P < 0.05). There was no correlation between the reduction in pressor and behavioural chemoreflex responses (r = -0.186, P > 0.05). The bradycardic response of the chemoreflex was not altered by lidocaine or kynurenic acid microinjected into the DMH. These results strongly suggest that the excitatory amino acid receptors in the DMH are essential for full expression of the behavioural response of the chemoreflex and participate, at least in part, in the integration of the pressor response of the chemoreflex in conscious rats.
Assuntos
Barorreflexo/fisiologia , Comportamento Animal/fisiologia , Pressão Sanguínea/fisiologia , Células Quimiorreceptoras/fisiologia , Hipotálamo/fisiologia , Atividade Motora/fisiologia , Receptores de Glutamato/metabolismo , Animais , Masculino , Ratos , Ratos WistarRESUMO
The present study investigated whether the effects of central cholinergic stimulation on thermoregulation during exercise are modulated by arterial baroreceptors. Wistar rats were submitted to sinoaortic denervation (SAD) or sham denervation (SHAM) and then fitted with a chronic guide cannula into the lateral cerebral ventricle. After 2 weeks, a catheter was implanted into the ascending aorta, and a temperature sensor was implanted into the peritoneal cavity. Two days later, the rats were submitted to exercise on a treadmill at 18 m/min until fatigued. Thermoregulatory and cardiovascular responses were measured after injection of 2 µL of 10mM physostigmine (Phy) or 0.15M NaCl solution (Sal) into the cerebral ventricle. In SHAM rats, Phy injection induced a greater exercise-induced increase in blood pressure and lower increase in heart rate than Sal treatment. In the SAD group, the attenuation of heart rate in response to Phy was blocked despite an exaggerated increase in blood pressure. SHAM rats treated with Phy had a higher increase in tail skin temperature compared to Sal injection (31.9 ± 0.4 °C Phy-SHAM vs. 30.1 ± 0.6 °C Sal-SHAM, 5 min after injection; p<0.05), resulting in a lower exercise-induced increase in core temperature. In contrast, SAD blocked the Phy injection effects in thermoregulatory responses during exercise (tail temperature: 30.1 ± 1.2 °C Phy-SAD vs. 29.5 ± 1.2 °C Sal-SAD, 5 min, p = 0.65). Therefore, we conclude that the enhancement of cutaneous heat loss induced by central cholinergic stimulation during exercise is mediated primarily by arterial baroreceptors.
Assuntos
Acetilcolina/metabolismo , Regulação da Temperatura Corporal/fisiologia , Condicionamento Físico Animal , Nó Sinoatrial/inervação , Análise de Variância , Animais , Sistema Nervoso Autônomo/cirurgia , Pressão Sanguínea/efeitos dos fármacos , Temperatura Corporal/efeitos dos fármacos , Temperatura Corporal/fisiologia , Regulação da Temperatura Corporal/efeitos dos fármacos , Inibidores da Colinesterase/administração & dosagem , Denervação/métodos , Relação Dose-Resposta a Droga , Teste de Esforço/métodos , Frequência Cardíaca/efeitos dos fármacos , Injeções Intraventriculares/métodos , Masculino , Fisostigmina/administração & dosagem , Ratos , Ratos Wistar , Estatística como AssuntoRESUMO
The aim of the present study was to investigate the effects of N(G)-nitro-L-arginine-methyl-ester (L-NAME) microinjected into the rostral nucleus tractus solitarius (NTS) on jejunal glucose, sodium and potassium absorption. Male Wistar rats (210-250 g, n=6-12) were anesthetized and submitted to midline laparotomy to expose and isolate 20 cm of jejunal loop and perform a subdiaphragmatic truncal vagotomy or sympathectomy. Either 0.9% NaCl or L-NAME (10 nmol 100 nl⻹) was microinjected into the rostral NTS using a stereotaxic instrument. Tyrode solution (pH 8) containing twice the usual concentrations of glucose, sodium and potassium was infused (0.5 ml min⻹) into the jejunal loop and samples were taken at 10-min intervals during the 40-min experiment. Results were expressed by the difference between influx and efflux. L-NAME into the NTS increased glucose absorption and decreased potassium absorption when compared to the saline group (38.8 ± 3.8 vs. 50.3 ± 3.3 mg/dl and 0.6±0.01 vs. 0.4 ± 0.03 mM, respectively; p<0.05). Sympathectomy inhibited the glucose absorption caused by L-NAME alone (50.3 ± 3.3 vs. 30.7 ± 4.6 mg/dl; p<0.05), whereas vagotomy inhibited the L-NAME effect on potassium absorption (0.40 ± 0.02 vs. 0.70 ± 0.05; p<0.05). Moreover, increased sodium absorption was observed only in the group that received 30 nmol of L-NAME into NTS (33.0 ± 4.2 vs. 48.4 ± 3.9). In conclusion, the results suggest the participation of endogenous nitric oxide (NO) in the NTS in modulating intestinal glucose and potassium absorption mediated by the autonomic nervous system.