Mestrado em Ciências Fisiológicas Multicêntrico (ICB)
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Navegando Mestrado em Ciências Fisiológicas Multicêntrico (ICB) por Assunto "Cardiovascular system"
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Item Avaliação dos efeitos de peptídeos isolados de veneno de serpentes no sistema cardiovascular de ratos(Universidade Federal de Goiás, 2016-03-22) Alves, Pedro Henrique; Ianzer, Danielle Alves; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4760882T6; Alves, Carlos Henrique; http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4758015Z0; Castro, Carlos Henrique de; Ianzer, Danielle Alves; Ghedini, Paulo CesarThe proline-riche-oligopeptides (PROs) were identified in the crude venom of snakes Bothrops jararaca (Bj), Bothrops cotiara (Bc) and Bothrops fonsecai (Bf). Previous studies have shown hypotensive/antihypertensive effects of the PROs in normotensive and hypertensive (SHR) rats. However, the direct effect of PROs in the aorta and heart isolated, as well as, the action mechanisms involved in these effects is unknown. In the presenty study, were evaluated the cardiovascular effect of six PROs, Bj-PRO-5a,-7a,-10c, Bc-PRO-10e, Bf-PRO-10d,-10f. The aortic rings, with (E+) or without (E-) endothelium, were preconstricted with phenylephine (Phe, 0.1 μmol/L), following increasing concentrations of PROs (0.1 nmol/L – 1 μmol/L) in presence or absence of a nonselective antagonist muscarinic receptors (Atropine, 3µmol/L), M1 muscarinic receptor antagonist (Pirenzepine, 1 µmol/L), synthase nitric oxide inhibitor (L-NAME, 1 µmol/L), adenylyl cyclase inhibitor (MDL 12.330A, 3 µmol/L), guanylyl cyclase inhibitor (ODQ, 3µmol/L) or argininosuccinate synthetase inhibitor (MDLA, 1 µmol/L). To evaluated the coronary and cardiac contractility effects of PROs, the hearts were perfused according Langendorff technique. The hearts were perfused for a basal period with Krebs Ringer solution containing the PROs (0.05 or 5 nmol/L) in presence or absence of L-NAME (10 nmol/L), ODQ (200 nmol/L) or MDL (1 µmol/L). The PROs utilized in this study induced endothelium-dependend vasorelaxation in aortic rings of Wistars and SHRs. Atropine and pirezenpine blocked the vasorelaxant effect of Bj-PRO-7a in isolated aorta from Wistar and SHR. L-NAME, ODQ or MDL inhibited the aortic vasorelaxation induced by Bj-PRO-7a and Bj-PRO-10c in both strains. MDLA inhibited the Bj-PRO-10c-induced vasorelaxation in aortic rings of SHR, but not in Wistar. Just the peptides Bj-PRO-7a and Bj-PRO-10c promoted a significant coronary vasodilatation in isolated heart from Wistar and SHR rats. The coronary vasodilatation induced by Bj-PRO-7a was inhibited in the presence of L-NAME in isolated heart from Wistar. Already in isolated heart from SHR this effect was abolished by L-NAME, ODQ or MDL. The Bc-PRO-10e and Bf-PRO-10f did not induce significant effects on cardiac contractility. However, the Bj-PRO-5a, -7a, -10c and Bf-PRO-10f promoted negative inotropic effect in the isolated hearts from Wistar and/or SHR. This effect in isolated hearts perfused by Bj-PRO-7a was inhibited in the presence of L-NAME in Wistars. Differently, the effect of Bj-PRO-10c was blocked by L-NAME, ODQ or MDL in both strains. Sumarizing, the PROs utilized in this study induced endothelium-dependend vasorelaxation. The data demonstrated participation of pathways NO/GCs/GMPc and AC/AMPc in the vasorelaxant effect of peptides Bj-PRO-7a and Bj-PRO-10c. In addition, the muscarinic receptors are involved in the vasorelaxant effects induced by peptide Bj-PRO-7a in aortic rings from Wistar and SHR rats. Moreover, the negative inotropic effect induced by Bj-PRO-7a and Bj-PRO-10c is linked with activation of NO in cardiomyocyte of normotensive and hypertensive rats.Item Avaliação das respostas cardiovasculares e eletroencefalográficas após crises epilépticas induzidas pelo abrasamento elétrico da amígdala em diferentes fases do ciclo sono-vigília de ratos(Universidade Federal de Goiás, 2016-09-21) Ghazale, Poliana Peres; Pansani, Aline Priscila; http://lattes.cnpq.br/6385679829734771; Colugnati, Diego Basile; http://lattes.cnpq.br/3875833705952056; Colugnati, Diego Basile; Blanch, Graziela Torres; Oliveira, André Henrique Freiria; Pansani, Aline PriscilaIntroduction: Cardiovascular alterations have been identified as the main cause of Sudden Unexpected Death in Epilepsy (SUDEP). There is an intimate relationship between epilepsy and sleep. Most cases of SUDEP occurs during sleep and the NREM sleep is a facilitator factor for the occurence of seizures. Aim: To evaluate cardiovascular and electroencephalographic responses of rats submitted to kindling model induced at diferente stages of sleep-wake cycle. Methods: The experimental protocol was approved by Ethics Commitee of the Universidade Federal de Goiás (CEUA-035/2015). Wistar rats (250-350 g) were separeted into 4 groups and seizures were induced according to sleep-wake cycle (Wake, NREM sleep and REM sleep) or no seizure (SHAM). We used the kindling model for induction of seizures. The animals was submitted to stereotactic surgery to implant electrodes in the right amygdala, for electrical stimulation, and in the cortex, for electroencephalographic record (EEGc). Electrodes for electromyographic (EMG) and electrocardiographic (ECG) recordings were also implanted. The detection of sleep phase was based on algorithms described by Louis et al. (2003). The electrical stimulus was induced one time per day and consisted in a biphasic wave during 2 seconds (60 Hz). The seizures evolution was analyzed according to Racine’s scale (E1: orofacial movements; E2: mastigatory movements and head clonus; E3: forelimb clonus; E4: rearing; E5: rearing and falling). Three E5 seizures was induced in each animal. We evaluated heart rate (HR), heart rate variability (HRV) arrhythmias and EEGc in vivo, cardiac function and vascular reactivity ex vivo. Results: The time fully kindling in NREM group was lower compared to Wake group. The NREM group presents postictal tachycardia in the early stages of process. The duration of postictal generalized electroencephalogram supression (PGES) is larger in REM group. The PGES in Wake group was accompanied by a decrease in HR compared to the final period of seizures. The muscle cell in aortic artery of Wake group had greater contraction capacity than the other groups, while the REM group had a higher endothelium-dependent relaxatio. Parameters such as after-discharge duration (AD), HR and HRV after kindling process, arrhythmias, bradycardia followed by tachycardia during the ictal period of E5 seizures and ex vivo cardiac funtion were similar in all groups. Conclusion: Our results suggest that kindling process per se was able to induce an increase in post-ictal HR in NREM group, an increase in PGES duration in REM group, and an impairment on vascular reactivity of NREM (higher contraction percentage) and REM (lower relaxation percentage) groups.Item Caracterização das alterações hemodinâmicas ocasionadas pelo reflexo pressórico ao exercício em ratos normotensos e hipertensos: participação do RVLM e possíveis mecanismos periféricos(Universidade Federal de Goiás, 2019-06-28) Silveira, Laíla Milhomem; Rosa, Daniel Alves; http://lattes.cnpq.br/5848020104921718; Rosa, Daniel Alves; Mendes, Elizabeth Pereira; Ferreira Neto, Marcos LuizStatic muscle contraction promotes an increase in blood pressure (BP) and heart rate (HR) by means of a peripheral neural reflex of muscular origin, the " exercise reflex pressure" (EPR). It is well established in the literature that cardiovascular adjustments in responses to physical exercise are altered in hypertensive individuals, and some of these alterations are attributed to the central mechanisms - associated with mismatches in the autonomic sympathetic component - as well as the peripheral mechanisms characterized by vascular endothelial dysfunction. The rostralventrolateral region of the medulla (RVLM) is the main efferent arm of vasomotor neurons for tonic maintenance and BP reflex. Experimental evidence indicates the participation of RVLM in HR and BP increase induced by EPR. However, little is known about its participation in this reflex, regarding hemodynamic adjustments, such as alteration in blood flow (BF) and aortic (AVC) and renal vascular conductance (RVC), of normotensive and hypertensive animals. Objective: investigate the central role of RVLM and peripheral vasodilator mechanisms in hemodynamic changes resulting from EPRevocated by the static muscle contraction of the sural triceps by tibial nerve electrical stimulation (TNES) in WISTAR and spontaneously hypertensive rats(SHR). Methodology: Wistars (n = 10) and SHR (n = 6) (250-350g) were anesthetized and instrumented to record BP, HR, ABF, RBF, AVC and RVC. The left sural triceps tendon was attached to a force transducer to measure the developed muscle tension. The tibial nerve was stimulated by electrical current for 30 s at a frequency of 40Hz, 0.1 ms pulse duration and 5x motor threshold. The TNES was performed before and after quinurenic acid nanoinjection (KYN, 50 nL) in the contralateral RVLM to the stimulated nerv. The injection site was targed, and its medulla was removed for histological analysis. In a later protocol, SHRs (treated SHR, n = 7) were treated with Nebivolol Hydrochloride (NBL, 10mg / kg) or distilled water (control SHR, n = 5) for 15 days by gavage. They were then submitted to the same experimental procedures as the initial protocol, except for the central nanoinjection. Data were expressed as mean +/- SEM and Student's t-test and One-way ANOVA tests were used. P ≤ 0.05.RESULTS: In WISTARs and SHRs, EPR evocated byTNES increased BP and HR, which were reduced after KYNnanoinjection in RVML. In WISTARs, EPR caused increase in ABF and AVC, IX butafter the injection in the contralateral RVLM, we noticed a reduction in this response. In SHR, there were no changes of ABF or AVC during contractions, before and after glutamatergic blockade. In WISTAR animals, EPR produced RBF and RVC reduction during TNES. After the glutamatergic blockade in RVLM, however, the RBF and RVC responses were not altered. The EPR in SHR did not trigger RBF and RVC reduction, as well KYN in RVLM. The 15-day NBL treatment did not alter the SHRs AVC and RVC changes. CONCLUSION: BP and HR responses induced by TNES were reduced with glutamatergic blockade in RVLM in WISTARs and SHRs. In WISTARs, TNES was associated with aortic vasodilation and renal vasoconstriction. This response differs in SHRs, where we did not observe ABF and AVC changes (CONTROL or POST-KYN). Thus, we demonstrate that in the EPR, ABF, RBF, AVC, and RVC responses of normotensive and spontaneously hypertensive rats are distinct, and contralateral RVLM to the active musculature of these animals, participates in the responses of aortic vasodilation and renal vasoconstriction in normotensive rats, but does not significantly influence BF variations in SHR. In addition, the 15-day treatment with the nitric oxide (NO) donor and NBL selective beta blocker was also not able to alter the hemodynamic responses in SHRs.Item Avaliação de alterações cardiovasculares relacionadas ao efeito de drogas antiepilépticas em ratos submetidos ao modelo de indução de epilepsia pela pilocarpina(Universidade Federal de Goiás, 2018-05-18) Souza, Beatriz Pacheco de; Colugnati, Diego Basile; http://lattes.cnpq.br/3875833705952056; Lino Júnior, Ruy de Souza; Castro, Carlos Henrique de; Colugnati, Diego BasileEpilepsy is one of the most common problems in the neurological clinic, affecting up to 1% of the world population, moreover, individuals with epilepsy have a higher mortality than the general population. Thus, the interest in investigating cardiac changes in patients with epilepsy has been increasing, and some studies have associated the use of antiepileptic drugs (AEDs) with cardiovascular disorders. In this context, there are hypotheses that patients using specific AEDs, sodium channel blockers, have an increased risk of cardiovascular disease (CVD). In our study, we sought to evaluate cardiovascular responses in epileptic rats submitted to chronic administration of carbamazepine (CBZ) or lamotrigine (LTG). Baseline cardiovascular parameters [Systolic blood pressure (SBP); Diastolic blood pressure (DBP); Mean arterial pressure (MAP) and heart rate (HR)] were recorded through cannulation of the femoral artery and electrode implant after sixty days of treatment with AED or vehicle [(150mg / kg (vo)]. The animals were submitted to a baroreflex test with bolus administration of phenylephrine (PHE - 5μg) and sodium nitroprusside (NPS - 10μg) via cannulation of the femoral vein and later submitted to a challenge with isoproterenol. Through the recording of baseline cardiovascular parameters, we also analyzed the heart rate variability (HRV) and the number of extrasystoles. After all procedures in vivo, samples of the heart were retained for histological analyzes of cardiac tissue. The division of the groups was performed in controls without epilepsy (CNT), epileptics (EP), epileptics treated with CBZ (CBZ) and epileptics treated with LTG (LTG). In our results the epileptic rats presented all the baseline cardiovascular parameters higher than the parameters of animals without epilepsy. CBZ treatment reduced resting HR, SBP and MAP compared to untreated epileptic animals. Treatment with LTG also reduced resting HR compared to the EP group. We also observed that the EP group had a greater cross-sectional area (CSA) of cardiomyocytes when compared to the other groups and an increased accumulation of perivascular collagen in comparison to CNT and CBZ groups. In this way, we can suggest that chronic use of AEDs may influence cardiovascular responses and cardiac microstructure.