Cardiovascular and respiratory responses to microinjection of L-glutamate into the caudal pressor area in conscious and anesthetized rats

The role of the caudal pressor area (CPA) in the maintenance of vasomotor tonus in anesthetized and decerebrate animals has been clearly established. In conscious animals, however, the participation of CPA in the cardiovascular control remains to be fully elucidated. In the present study, unilateral L-glutamate (L-Glu) (10 and/or 20 nmol/70 nl) microinjection into CPA, in conscious male Wistar rats (250-280 g) caused a significant increase in mean arterial blood pressure (MAP; control: 112 ± 1.9 mmHg; after 20 nmol L-Glu: 139 ± 4.5 mmHg, N = 12, P<0.05) and respiratory rate (control: 81 ± 3.5 breaths/min; after 10 nmol L-Glu: 92 ± 3 breaths/min, P<0.05; after 20 nmol L-Glu: 104 ± 5 breaths/min, N = 6, P<0.05). The subsequent anesthesia with urethane caused a significant increase in basal respiratory frequency (conscious: 81 ± 3.5 breaths/min; under urethane: 107 ± 1.3 breaths/min, N = 6, P<0.05). Anesthesia also significantly attenuated L-Glu-evoked pressor (conscious: deltaMAP = +27 mmHg; anesthetized: deltaMAP = +18 mmHg, P<0.05) and respiratory responses. These results suggest that glutamatergic receptors in the CPA are involved in cardiovascular and respiratory modulation in conscious rats.Universidade Federal do Espírito Santo Centro Biomédico Departamento de Ciências FisiológicasFAESA Faculdade de Saúde de VitóriaUniversidade Federal de São Paulo (UNIFESP) Disciplina de Fisiologia CardiovascularUNIFESP, Disciplina de Fisiologia CardiovascularSciEL

Revealing the role of the autonomic nervous system in the development and maintenance of Goldblatt hypertension in rats

Despite extensive use of the renovascular/Goldblatt model of hypertension-2K-1C, and the use of renal denervation to treat drug resistant hypertensive patients, autonomic mechanisms that underpin the maintenance of this hypertension are important yet remain unclear. Our aim was to analyse cardiovascular autonomic function by power spectral density analysis of both arterial pressure and pulse interval measured continuously by radio telemetry for 6 weeks after renal artery clipping. Mean arterial pressure increased from 106 +/- 5 to 185 +/- 2 mm Hg during 5 weeks post clipping when it stabilized. A tachycardia developed during the 4th week, which plateaued between weeks 5 and 6. the gain of the cardiac vagal baroreflex decreased immediately after clipping and continued to do so until the 5th week when it plateaued (from -2.4 +/- 0.09 to -0.8 +/- 0.04 bpm/mm Hg; P < 0.05). A similar time course of changes in the high frequency power spectral density of the pulse interval was observed (decrease from 13.4 +/- 0.6 to 8.3 +/- 0.01 ms(2); P < 0.05). There was an increase in both the very low frequency and low frequency components of systolic blood pressure that occurred 3 and 4 weeks after clipping, respectively. Thus, we show for the first time the temporal profile of autonomic mechanisms underpinning the initiation, development and maintenance of renovascular hypertension including: an immediate depression of cardiac baroreflex gain followed by a delayed cardiac sympathetic predominance; elevated sympathetic vasomotor drive occurring after the initiation of the hypertension but coinciding during its mid-development and maintenance. (C) 2014 the Authors. Published by Elsevier B.V.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)British Heart FoundationNIHUniv Bristol, Sch Physiol & Pharmacol, Bristol BS8 1TD, Avon, EnglandUniversidade Federal de São Paulo, UNIFESP, Dept Physiol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, UNIFESP, Dept Physiol, BR-04023062 São Paulo, BrazilWeb of Scienc

Treadmill Exercise Training Prevents Myocardial Mechanical Dysfunction Induced by Androgenic-Anabolic Steroid Treatment in Rats

Elevated concentrations of testosterone and its synthetic analogs may induce changes in cardiovascular function. However, the effects of the combination of anabolic/androgenic steroid (AAS) treatment and exercise training on systolic and diastolic cardiac function are poorly understood. in the present study, we aimed to investigate the effects of low-dose steroid treatment (stanozolol) on cardiac contractile parameters when this steroid treatment was combined with exercise training in rats and the effects of chronic steroid treatment on the Frank-Starling (length-tension curves) relationship. Male Wistar rats were randomly assigned to one of four groups: U (untrained), US (untrained and treated with stanozolol 5 mg/kg/week), T (trained, 16 m/min/1 h) and TS (trained and treated with stanozolol 5 mg/kg/week). Continuous exercise training was conducted 5 days/week for 8 consecutive weeks. the speed of the treadmill was gradually increased to a final setting of 16 m/min/1 h. Experiments were divided into two independent series: 1) central hemodynamic analysis for mean arterial blood pressure (MAP) and cardiac output (CO) measurements and 2) isolated papillary muscle preparation in Krebs solution. Stanozolol treatment significantly increased the MAP and the heart size in untrained and trained rats (U 113 +/- 2; T 106 +/- 2; US 138 +/- 8 and TS 130 +/- 7 mmHg). Furthermore, stanozolol significantly decreased developed tension and dT/dt (maximal and minimal) in U rats. However, the developed tension was completely restored by training. the Frank/Starling relationship was impaired in rats treated with stanozolol; however, again, training completely restored diastolic function. Taken together, the present data suggest that AAS treatment is able to decrease cardiac performance (systolic and diastolic functions). the combination of stanozolol and physical training improved cardiac performance, including diastolic and systolic functions, independent of changes in central hemodynamic parameters. Therefore, changes in ventricular myocyte calcium transients may play a cardioprotective role.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ Sao Judas Tadeu, Dept Post Grad Phys Educ, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Physiol, Div Cardiovasc, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Med, Div Cardiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Physiol, Div Cardiovasc, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Med, Div Cardiol, São Paulo, BrazilWeb of Scienc

More than hormones: Sex differences in cardiovascular parameters after sleep loss in rats

Although the influence of sex on sleep pattern and cardiovascular parameters is well known, knowledge regarding the effects of sleep loss on heart responses in both sexes is scarce. the present study investigated the effects of paradoxical sleep deprivation (PSD) and chronic sleep restriction (SR) on cardiovascular parameters and adrenocorticotropic hormone (ACTH) levels in male and female rats. Both groups were randomly assigned to PSD for 96 h, SR for 21 days or home-cage control. Mean arterial pressure (MAP), heart rate (HR), baroreflex sensitivity (bradycardia and tachycardia responses) and ACTH levels were evaluated. the results showed that PSD induced a significant increase in HR and ACTH levels in both sexes, although male rats presented higher levels of ACTH hormone compared to females. in addition to sex-specific responses, PSD decreased the tachycardia only in male rats. SR, induced a significant increase in MAP and decrease in bradycardia in both sexes. Male rats were more affected by sleep deprivation protocols than females for MAP, bradycardia response, and ACTH levels. the results showed that the effects of sleep loss on cardiovascular parameters are associated with the protocol of sleep deprivation and that sex can modulate these effects. We suggested this experimental model as a suitable tool for further investigations of the relationship between cardiovascular parameters and sleep. (C) 2013 Elsevier Inc. All rights reserved.Associacao Fundo de Incentivo a PesquisaConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo, Dept Psicobiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Fisiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Psicobiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Fisiol, São Paulo, BrazilFAPESP: 10/15110-8FAPESP: 12/05396-7Web of Scienc

Chronic Sleep Restriction during Pregnancy - Repercussion on Cardiovascular and Renal Functioning of Male Offspring

Changes in the maternal environment can induce fetal adaptations that result in the progression of chronic diseases in the offspring. the objective of the present study was to evaluate the effects of maternal chronic sleep restriction on blood pressure, renal function and cardiac baroreflex response on male offspring at adult age. Female 3-month-old Wistar rats were divided in two experimental groups: control (C) and chronic sleep restricted (CSR). Pregnancy was confirmed by vaginal smear. Chronic sleep restricted females were subjected to sleep restriction by the multiple platform technique for 20 h daily, between the 1st and 20th day of pregnancy. After birth, the litters were reduced to 6 rats per mother, and were designated as offspring from control (OC) and offspring from chronic sleep restricted (OCSR). Indirect blood pressure (BPi tail cuff) was measured by plethysmography in male offspring at 3 months old. Following, the renal function and cardiac baroreflex response were analyzed. Values of BPi in OCSR were significantly higher compared to OC [OC: 127 +/- 2.6 (19); OCSR: 144 +/- 2.5 (17) mmHg]. the baroreflex sensitivity to the increase of blood pressure was reduced in OCSR [Slope: OC: -2.6 +/- 0.15 (9); OCRS: -1.6 +/- 0.13 (9)]. Hypothalamic activity of ACE2 was significantly reduced in OCSR compared to OC [OC: 97.4 +/- 15 (18); OSR: 60.2 +/- 3.6 (16) UAF/min/protein mg]. Renal function alteration was noticed by the increase in glomerular filtration rate (GFR) observed in OCSR [OC: 6.4 +/- 0.2 (10); OCSR: 7.4 +/- 0.3 (7)]. Chronic sleep restriction during pregnancy caused in the offspring hypertension, altered cardiac baroreflex response, reduced ACE-2 activity in the hypothalamus and renal alterations. Our data suggest that the reduction of sleeping time along the pregnancy is able to modify maternal homeostasis leading to functional alterations in offspring.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Associacao Fundo de Incentivo a Pesquisa (AFIP)Universidade Federal de São Paulo, Dept Fisiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Psicobiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biociencias, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Fisiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Psicobiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biociencias, São Paulo, BrazilFAPESP: FAPESP-10/51665-4Web of Scienc

Electroacupuncture and Moxibustion Decrease Renal Sympathetic Nerve Activity and Retard Progression of Renal Disease in Rats

Background/Aim: Chronic kidney disease (CKD) is an increasing major public health problem worldwide. the sympathetic nervous system and nitric oxide play an important role in the pathogenesis of CKD. Traditional Chinese medicine has accumulated thousands of years of therapeutic experiences. Electroacupuncture (EA) and moxibustion (MO) are two such therapeutic strategies. the aim of this study was to investigate the renal and hemodynamic effects of EA-MO in an experimental model of a CKD. Methods: Male Wistar rats submitted to 5/6th nephrectomy (5/6 NX) were studied for 8 weeks. There were four groups: (1) control, normal rats; (2) NX, 5/6 NX only; (3) NX-AS, 5/6 NX and EA-MO session using sham points, and (4) NX-AM, 5/6 NX and EA-MO session using real acupoints. Biochemical and blood pressure studies, renal sympathetic nerve activity measurements, nitric oxide levels and the histopathological indices were assessed. Results:The EA- and MO-treated group presented significant improvement in all measured functional and histopathological parameters. Conclusion: These findings suggest that EA-MO had beneficial effects on CKD. This effect was probably achieved by the modulation of the renal sympathetic nerve activity and nitric oxide levels, leading to decreased blood pressure, which is associated with less proteinuria. Copyright (c) 2012 S. Karger AG, BaselConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fed Univ São Paulo UNIFESP, Dept Med, Div Nephrol, São Paulo, BrazilFed Univ São Paulo UNIFESP, Dept Physiol, Cardiovasc Physiol Div, São Paulo, BrazilFed Univ São Paulo UNIFESP, Dept Pathol, São Paulo, BrazilFed Univ São Paulo UNIFESP, Chinese Med & Acupuncture Div, Dept Orthoped & Traumatol, São Paulo, BrazilFed Univ São Paulo UNIFESP, Dept Med, Div Nephrol, São Paulo, BrazilFed Univ São Paulo UNIFESP, Dept Physiol, Cardiovasc Physiol Div, São Paulo, BrazilFed Univ São Paulo UNIFESP, Dept Pathol, São Paulo, BrazilFed Univ São Paulo UNIFESP, Chinese Med & Acupuncture Div, Dept Orthoped & Traumatol, São Paulo, BrazilWeb of Scienc

Protective effects of kefir in the angiotensin II-dependent hypertension

Recently, we have reported cardiovascular protective effects of the probiotic kefir in a model of primary hypertension. Now, we evaluated the beneficial effects of kefir in a model of secondary hypertension under hyperactivation of the renin-angiotensin-system by partially clipping one kidney artery (2K1C) for 60 days and compared with Sham rats. Maximum levels of arterial pressure were reached 7–14 days post-clipping in both 2K1C and 2K1C-Kefir, but after that time the values were approximately 20% lower in 2K1C-Kefir rats. Also, kefir attenuated the angiotensin converting enzyme activity (intrarenal-40%/plasma-25%) preventing the increase of angiotensin II in both samples. Isolated aortic rings showed an impaired relaxation to acetylcholine in 2K1C (-38%) compared to the Sham group and this difference was attenuated in 2K1C-Kefir rats (~15%). Additional analysis revealed that kefir protected kidney and vascular endothelium against the synergistic oxidative stress/angiotensin II-axis. Thus, kefir is an effective nutraceutical therapy for prevention/treatment of hypertensionThis work was supported by the CNPq/FAPES -Brazil (PRONEX CNPq # 24/2018; Termo Outorga 569/2018); FAPES-Universal (# 21/2018, Termo Outorga 120/2019); FAPES (BPC 552/2018;120/2019) and CNPq (BVN 160990/2019-0; SSM 312056/2018-5, TMCP 309277/2019-1 and ECV 305740/2019-9)S