Patterns of renal and splanchnic sympathetic vasomotor activity in an animal model of survival to experimental sepsis

Sepsis causes long-term disability, such as immune dysfunction, neuropsychological disorders, persistent inflammation, catabolism, and immunosuppression, leading to a high risk of death in survivors, although the contributing factors of mortality are unknown. The purpose of this experimental study in rats was to examine renal (rSNA) and splanchnic (sSNA) sympathetic nerve activity, as well as baroreflex sensitivity, in acute and chronic post-sepsis periods. The rats were divided into two groups: control group with naïve Wistar rats and sepsis group with 2-mL intravenous inoculation of Escherichia coli at 108 CFU/mL. Basal mean arterial pressure, heart rate, rSNA, sSNA, and baroreflex sensitivity were evaluated in all groups at the acute (6 h) and chronic periods (1 and 3 months). Basal rSNA and sSNA were significantly reduced in the surviving rats, as was their baroreflex sensitivity, for both pressor and hypotensive responses, and this effect lasted for up to 3 months. A single episode of sepsis in rats was enough to induce long-term alterations in renal and splanchnic sympathetic vasomotor nerve activity, representing a possible systemic event that needs to be elucidated. These findings showed that post-sepsis impairment of sympathetic vasomotor response may be one of the critical components in the inability of sepsis survivors to respond effectively to new etiological illness factors, thereby increasing their risk of post-sepsis morbidity.

Electroacupuncture at "Neiguan"(PC6) decreased cardiac sympathetic hyperactivity and improved cardiac function in chronic myocardial ischemia model rats / 针刺研究

OBJECTIVE: To investigate the autonomic nervous mechanism of acupuncture therapy in the treatment of ischemic cardiomyopathy by observing the influence of electroacupuncture (EA) at "Neiguan"(PC6) on the superior cervical cardiac nerve activity and cardiac function in chronic myocardial ischemia (CMI) rats. METHODS: Male SD rats were randomly divided into control, model and EA groups (n＝8 in each group). The CMI model was established by ligating the anterior descending branch of the left coronary artery. EA (15 Hz, 1.5 mA) was applied to bilateral PC6 for 20 min, once a day for 28 consecutive days. Cardiac sympathetic nerve electrical activities (CSNEA), electrocardiogram (ECG) of the standard limb lead Ⅱ and ultrasonic cardiogram (UCG) were recorded for observing changes of ST segment height, left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS)．. RESULTS: The CSNEA was significantly increased(P<0.001), and the hight of ECG-STⅡ， LVEF and LVFS were considerably decreased in the model group relevant to the control group (P<0.01, P<0.001), while after the intervention, modeling induced increase of CSNEA and decrease of ECG-STⅡ， LVEF and LVFS were obviously suppressed in the EA group in comparison with the model group (P<0.01, P<0.05, P<0.001). CONCLUSION: EA of PC6 can improve cardiac function and myocardial ischemia in CMI rats, which is possibly related to its effect in decreasing cardiac sympathetic hyperactivity.

Angiotensin Type 1 Receptors and Superoxide Anion Production in Hypothalamic Paraventricular Nucleus Contribute to Capsaicin-Induced Excitatory Renal Reflex and Sympathetic Activation / 神经科学通报·英文版

Chemical stimulation of the kidney increases sympathetic activity and blood pressure in rats. The hypothalamic paraventricular nucleus (PVN) is important in mediating the excitatory renal reflex (ERR). In this study, we examined the role of molecular signaling in the PVN in mediating the capsaicin-induced ERR and sympathetic activation. Bilateral PVN microinjections were performed in rats under anesthesia. The ERR was elicited by infusion of capsaicin into the cortico-medullary border of the right kidney. The reflex was evaluated as the capsaicin-induced changes in left renal sympathetic nerve activity and mean arterial pressure. Blockade of angiotensin type 1 receptors with losartan or inhibition of angiotensin-converting enzyme with captopril in the PVN abolished the capsaicin-induced ERR. Renal infusion of capsaicin significantly increased NAD(P)H oxidase activity and superoxide anion production in the PVN, which were prevented by ipsilateral renal denervation or microinjection of losartan into the PVN. Furthermore, either scavenging of superoxide anions or inhibition of NAD(P)H oxidase in the PVN abolished the capsaicin-induced ERR. We conclude that the ERR induced by renal infusion of capsaicin is mediated by angiotensin type 1 receptor-related NAD(P)H oxidase activation and superoxide anion production within the PVN.

Selective Imidazoline Receptor Agonists: redefining the role of centrally acting agents in management of hypertension

Hypertension, often referred to as ‘The silent killer’, is christened so, as it is seldom preceded by any warning signs or symptoms. With the new ACC/AHA guidelines lowering the Blood Pressure (BP) threshold values, it has resulted in a 140% relative increase in the hypertension prevalence in India, which is 3 times higher than that of in United States. Imidazoline receptor agonists control BP effectively with minimal adverse effects of sedation and mental depression that are usually associated with centrally acting antihypertensives. While having a low affinity to the α2-adrenergic receptors, these new generation centrally acting antihypertensive agents are highly selective for imidazoline receptor. Moxonidine, a second-generation centrally acting antihypertensive drug having selective agonist activity on imidazoline I1 receptors and minor activity on imidazoline α2 adrenoceptors, reduces the activity of Sympathetic Nervous System (SNS) by activating I1 imidazoline receptors in Rostral Ventrolateral Medulla (RVLM). Studies of moxonidine have shown equal effectiveness in lowering BP like other well-established antihypertensive drugs such as nifedipine, atenolol or angiotensin-converting enzyme inhibitors, with minimal adverse events. At doses of 0.2-0.6 mg, moxonidine induces satisfactory BP reduction in patients with mild-to-moderate essential hypertension. In patients with mild-to-moderate hypertension, moxonidine (0.2-0.4 mg o.d.) significantly decreased Systolic Blood Pressure/Diastolic Blood Pressure (SBP/DBP), respectively, by 19.5/11.6 mmHg. In obese, non-controlled hypertensive patients, there is a 14% and 13.5% reduction in the mean SBP and DBP, respectively, from the baseline value after moxonidine treatment and during the follow-up with an additional reduction in body weight, plasma leptin levels and Body Mass Index (BMI) (p<0.01). Thus, moxonidine could be considered as a therapeutic option in obese patients with metabolic syndrome.

Sympathetic activity is negatively associated to uremic state and hemodynamic instability during hemodialysis sessions / La actividad simpática está negativamente asociada al estado urémico y a la inestabilidad hemodinámica durante las sesiones de hemodiálisis

INTRODUCTION: Hemodynamic instabilities, characterized by oscillations of blood pressure, are common during hemodialysis sessions (HD), culminating in intradialytic hypotension owing to volume withdrawal from the cardiovascular system. The ability to carry out immediate adjusts in cardiovascular system, mainly mediated by the autonomic nervous system, is essential to the maintenance of hemodynamic stability during HD. OBJECTIVE: This study aimed to investigate the relationship between the sympathetic activity, and the hemodynamic stability from chronic kidney disease (CKD) patients during the HD, as well as the relationship between sympathetic activity and the uremic state. METHODS: Fourteen CKD patients (08 women and 06 men) with no history of recurrent ID episodes had the successive RR intervals recorded during HD. Blood pressure measurements were recorded at regular intervals of 30 minutes along 4 hours of each session. Hemodynamic stability was established by the standard deviation (SD), coefficient of variation (CV) and the Delta (difference between the highest and the lowest measure) of systolic (SBP), diastolic (DBP), and mean (MBP) blood pressures, as well as the pulse pressure (PP) from the 8 recordings obtained during each session. As a measure of autonomic heart control, the log-transformed low frequency (lnLFnu) spectral band was used. The uremic state was established by the mean of uremia from the last 12 months. Pearson's correlation was used to analyze the correlation between the studied variables. RESULTS: The lnLFnu values were negatively associated SD (SBP [r = -0.480; p = 0.010], PP [r = -0.504; p = 0.006] and MBP [r = -0.449; p = 0.017]), CV (SBP [r = -0.390; p = 0.040]) and delta (SBP [r = -0.438; p = 0.020], PP [r = -0.490; p = 0.008] and MBP [r = -0.382; p = 0.045]). lnLFnu was also negatively associated to the uremic state (r = -0.601; p = 0.01). CONCLUSIONS: Our results indicate that higher values of the lnLFnu are associated with better hemodynamic stability (i.e., smaller blood pressure oscillations) during HD sessions, in turn, the mean of blood urea concentration in the last 12 months, defined here as the uremic state, was associated with lower values of the lnLFnu during HD sessions

INTRODUCCIÓN: La inestabilidad hemodinámica, que se caracteriza por las oscilaciones de la presión arterial, es frecuente durante las sesiones de hemodiáilisis (HD) y tiene como resultado la hipotensión intradialítica, causada por una disminución en el volumen sanguíneo del sistema cardiovascular. Es esencial poder realizar ajustes inmediatos en el sistema cardiovascular, mediados principalmente por el sistema nervioso autónomo, a fin de mantener la estabilidad hemodinámica durante la hemodiálisis. OBJETIVO: El objetivo de nuestro estudio fue investigar la relación entre la actividad del sistema nervioso simpático y la estabilidad hemodinámica en pacientes con enfermedad renal crónica (ERC) durante las sesiones de hemoterapia; asimismo, se indagó sobre la relación entre la actividad del sistema nervioso simpático y el estado urémico. MATERIAL Y MÉTODOS: Se registraron, durante las sesiones de hemodiálisis, los intervalos RR sucesivos de 14 pacientes con enfermad renal crónica (8 mujeres y 6 hombres) sin antecedentes de episodios recurrentes de hipotensión intradialítica (HI). Se realizaron registros de la tensión arterial en intervalos regulares de 30 minutos durante 4 horas en cada sesión. La estabilidad hemodinámica se estableció mediante la desviación estándar, el coeficiente de variación (CV) y delta (diferencia entre la medida más alta y la más baja) de la tensión arterial sistólica (TAS), la diastólica (TAD) y la media (TAM), así como la tensión diferencial (TD) a partir de los ocho registros obtenidos durante cada sesión. Se utilizó el análisis espectral de transformaciones logarítmicas de baja frecuencia (LnLFnu, por su sigla en inglés) expresados en unidades normalizadas mediante transformación logarítmica. El estado urémico se determinó a través del promedio de los valores de uremia obtenidos durante los últimos doce meses. Se utilizó el coeficiente de correlación de Pearson para analizar las variables estudiadas. RESULTADOS: Mediante los distintos cálculos, se hallaron las siguientes correlaciones negativas con los valores de lnLFnu : SD (TAS [r = -0,480; p = 0,010]; TD [r = -0,504; p = 0,006] , y TAM [r = -0,449; p = 0,017]); CV (TAS [r = -0,390; p = 0,040]); y delta (TAS [r = -0,438; p = 0,020]; TD [r = -0,490; p = 0,008], y TAM [r = -0,382; p = 0,045]). También se observó una correlación negativa entre lnLFnu y el estado urémico (r = -0,601; p = 0,01). CONCLUSIONES: Nuestros resultados indican que los valores más elevados de LnLFnu se asocian con una mejor estabilidad hemodinámica, es decir, menor oscilación de la tensión arterial, durante las sesiones de hemodiálisis. A su vez, el promedio de concentración de urea en sangre registrado durante los últimos doce meses, al cual definimos como el estado urémico, se relacionó con valores más bajos de LnLFnu durante las sesiones de hemodiálisis

Sympathetic activity of S-(+)-ketamine low doses in the epidural space / Atividade simpática de cetamina S-(+) em doses baixas no espaço epidural / Actividad simpática de la ketamina S(+)-en dosis bajas en el espacio epidural

BACKGROUND AND OBJECTIVES: S-(+)-ketamine is an intravenous anaesthetic and sympathomimetic with properties of local anaesthetic. It has an effect of an analgetic and local anaesthetic when administered epidurally, but there are no data whether low doses of S-(+)-ketamine have sympathomimetic effects. The aim of this study was to determine whether low doses of S-(+)-ketamine, given epidurally together with local anaesthetic, have any effect on sympathetic nervous system, both systemic and below the level of anaesthetic block. METHODS: The study was conducted on two groups of patients to whom epidural anaesthesia was administered to. Local anaesthesia (0.5% bupivacaine) was given to one group (control group) while local anaesthesia and S-(+)-ketamine were given to other group. Age, height, weight, systolic, diastolic and mean arterial blood pressure were measured. Non-competitive enzyme immunochemistry method (Cat Combi ELISA) was used to determine the concentrations of catecholamines (adrenaline and noradrenaline). Immunoenzymometric determination with luminescent substrate on a machine called Vitros Eci was used to determine the concentration of cortisol. Pulse transit time was measured using photoplethysmography. Mann-Whitney U-test, Wilcoxon test and Friedman ANOVA were the statistical tests. Blood pressure, pulse, adrenaline, noradrenaline and cortisol concentrations were measured in order to estimate systemic sympathetic effects. RESULTS: 40 patients in the control group were given 0.5% bupivacaine and 40 patients in the test group were given 0.5% bupivacaine with S-(+)-ketamine. Value p < 0.05 has been taken as a limit of statistical significance. CONCLUSIONS: Low dose of S-(+)-ketamine administered epidurally had no sympathomimetic effects; it did not change blood pressure, pulse, serum hormones or pulse transit time. Low dose of S-(+)-ketamine administered epidurally did not deepen sympathetic block. Adding 25 ...

JUSTIFICATIVA E OBJETIVOS: cetamina S-(+) é um anestésico intravenoso e simpaticomimético com propriedades de anestésico local. Tem efeito analgésico e de anestésico local quando administrada por via epidural, mas não há dados que relatem se cetamina S-(+) em doses baixas tem efeitos simpaticomiméticos. O objetivo deste estudo foi determinar se cetamina S-(+) em doses baixas, administrada por via epidural em combinação com anestésico local, tem algum efeito sobre o sistema nervoso simpático, tanto sistêmico quanto abaixo do nível do bloqueio anestésico. MÉTODOS: o estudo foi conduzido com dois grupos de pacientes submetidos à anestesia epidural. Anestesia local (bupivacaína a 0,5) foi administrada a um grupo (controle), enquanto anestesia local em combinação com cetamina S-(+) foi administrada ao outro grupo (teste). Idade, altura, peso, pressão arterial sistólica e diastólica e pressão arterial média foram medidos. O método imunoquímico de inibição enzimática não competitiva (Cat Combi Elisa) foi usado para determinar as concentrações de catecolaminas (adrenalina e noradrenalina). O ensaio imunoenzimométrico com substrato luminescente em uma máquina chamada Vitros Eci foi usado para determinar a concentração de cortisol. O tempo de transição do pulso foi medido com fotopletismografia. Para análise estatística, os testes de Wilcoxon, U de Mann-Whitney e Anova de Friedman foram usados. Pressão arterial, pulso e concentrações de adrenalina, noradrenalina e cortisol foram medidos para estimar os efeitos simpáticos sistêmicos. RESULTADOS: receberam bupivacaína a 5% 40 pacientes do grupo controle e 40 do grupo teste receberam bupivacaína a 0,5% com cetamina S-(+). Um valor de p < 0,05 foi ...

JUSTIFICACIÓN Y OBJETIVOS: la ketamina S(+) es un anestésico intravenoso y simpaticomimético con propiedades de anestésico local. Posee un efecto analgésico y de anestésico local cuando se administra por vía epidural, pero no existen datos que informen si la ketamina S(+) en bajas dosis tiene efectos simpaticomiméticos. El objetivo de este estudio fue determinar si la ketamina S(+) en bajas dosis y administrada por vía epidural en combinación con el anestésico local tiene algún efecto sobre el sistema nervioso simpático, tanto sistémico como por debajo del nivel del bloqueo anestésico. MÉTODOS: el estudio fue realizado con 2 grupos de pacientes sometidos a anestesia epidural. A un grupo (grupo control) se le administró la anestesia local (bupivacaína al 0,5), mientras que a otro se le administró la anestesia local en combinación con la ketamina S(+). La edad, altura, peso, presión arterial sistólica y diastólica y la presión arterial media se midieron. El método inmunoquímico de inhibición enzimática no competitiva (Cat Combi ELISA) se usó para determinar las concentraciones de catecolaminas (adrenalina y noradrenalina). El ensayo inmunoenzimométrico con sustrato lumínico en una máquina llamada Vitros Eci fue usado para determinar la concentración de cortisol. El tiempo de transición del pulso fue medido usando la fotopletismografía. Para el análisis estadístico se usaron los test de Wilcoxon, U de Mann-Whitney y ANOVA de Friedman. La presión arterial, pulso y concentraciones de adrenalina, noradrenalina y cortisol fueron medidos para estimar los efectos simpáticos sistémicos. RESULTADOS: cuarenta pacientes del grupo control recibieron bupivacaína al 5% y 40 pacientes del grupo test recibieron bupivacaína al 0,5% con ketamina ...

Effects of acute administration of selective serotonin reuptake inhibitors on sympathetic nerve activity

Serotonergic mechanisms have an important function in the central control of circulation. Here, the acute effects of three selective serotonin (5-HT) reuptake inhibitors (SSRIs) on autonomic and cardiorespiratory variables were measured in rats. Although SSRIs require 2-3 weeks to achieve their full antidepressant effects, it has been shown that they cause an immediate inhibition of 5-HT reuptake. Seventy male Wistar rats were anesthetized with urethane and instrumented to record blood pressure, heart rate, renal sympathetic nerve activity (RSNA), and respiratory frequency. At lower doses, the acute cardiovascular effects of fluoxetine, paroxetine and sertraline administered intravenously were insignificant and variable. At middle and higher doses, a general pattern was observed, with significant reductions in sympathetic nerve activity. At 10 min, fluoxetine (3 and 10 mg/kg) reduced RSNA by -33±4.7 and -31±5.4%, respectively, without changes in blood pressure; 3 and 10 mg/kg paroxetine reduced RSNA by -35±5.4 and -31±5.5%, respectively, with an increase in blood pressure +26.3±2.5; 3 mg/kg sertraline reduced RSNA by -59.4±8.6%, without changes in blood pressure. Sympathoinhibition began 5 min after injection and lasted approximately 30 min. For fluoxetine and sertraline, but not paroxetine, there was a reduction in heart rate that was nearly parallel to the sympathoinhibition. The effect of these drugs on the other variables was insignificant. In conclusion, acute peripheral administration of SSRIs caused early autonomic cardiovascular effects, particularly sympathoinhibition, as measured by RSNA. Although a peripheral action cannot be ruled out, such effects are presumably mostly central.

Effect of pre-acclimatization training under hypoxic environment for one week on work capacity and physiological responses under hypoxic environment / 体力科学

We examined the effect of pre-acclimatization training under hypoxia for competition or training at high altitude on work capacity and physiological responses in hypoxia. Eight healthy male university students performed pre-acclimatization training under normobaric hypoxia (equivalent to about 2500 m; 15.4% inspired oxygen) for a week. Each student was exposed for a total of 90 minutes. During the exposure, each student rested for 60 minutes and pedaled at a workload of lactate threshold (LT) under normobaric hypoxia (equivalent to about 2500 m) for 30 minutes. In the result, workload of LT under normobaric hypoxia significantly increased after pre-acclimatization training (+15%). In physiological responses, arterial oxygen saturation at rest and exercise and peak ventilatory volume significantly increased after pre-acclimatization training. Arterial oxygen saturation at rest during pre-acclimatization training significantly increased. In addition, the ratio of low- and high-frequency power in heart rate variability significantly decreased after pre-acclimatization training. These results suggest that pre-acclimatization training is able to bring in acclimatization to high altitude on cardiopulmonary function and prevent decline of work capacity in high altitude. The ratio of low- and high-frequency power in heart rate variability as well as arterial oxygen saturation may reflect degree of acclimatization to high altitude.

Dependence of adrenoceptor regulation on oxidative stress in cardiac inju-ry induced by high sympathetic activity in rats / 中国病理生理杂志

AIM:To investigate the dependence of the adrenoceptor regulation on oxidative stress in the rats with cardiac injury induced by high sympathetic activity .METHODS: Healthy SD rats were randomly divided into 7 groups:control, model, propranolol (Pro), prazosin (Praz), Pro+Praz, vitamin E (VE) and Pro+Praz+VE.The rats were intraperitoneally injected with norepinephrine ( NE) for continuous 16 d to reproduce cardiac injury , and treated with the respective drugs .During the experimental process , the body weight was recorded .At the end of the experiments , the following parameters were measured:the ventricular remodeling indexes ( cardiac index and hydroxyproline of the left ven-tricle), histopathologic examination , oxidative/antioxidative indexes [MDA, SOD, catalase (CAT), GSH-Px and total an-tioxidant capacity (T-AOC)], and energy metabolism (Na+-K+ATPase and Ca2+-Mg2+ATPase).RESULTS: The in-crease of body weight in model group was significantly slower than that in control group after 9 d of treatment (P<0.05). The cardiac index and left ventricular hypertrophy were significantly increased .Oxidation/antioxidation and energy metabo-lism were disturbed.In Pro, Praz, Pro+Praz and VE groups, the body weight, cardiac index, left ventricular fibrosis and oxidative/antioxidative dysfunction were ameliorated .Pro, Praz and Pro +Praz increased the activity of Na +-K+ATPase and Ca2+-Mg2+ATPase.Treatment with Pro+Praz showed the best result in all of the indexes (P<0.05).CONCLU-SION:The dependence of adrenoceptor regulation plays an important role in the formation of oxidative stress in the process of rat cardiac injury induced by high sympathetic activity .

The impact of metabolic syndrome on metabolic, pro-inflammatory and prothrombotic markers according to the presence of high blood pressure criterion

OBJECTIVES: We explored whether high blood pressure is associated with metabolic, inflammatory and prothrombotic dysregulation in patients with metabolic syndrome. METHODS: We evaluated 135 consecutive overweight/obese patients. From this group, we selected 75 patients who were not under the regular use of medications for metabolic syndrome as defined by the current Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults criteria. The patients were divided into metabolic syndrome with and without high blood pressure criteria (≥130/≥85 mmHg). RESULTS: Compared to the 45 metabolic syndrome patients without high blood pressure, the 30 patients with metabolic syndrome and high blood pressure had significantly higher glucose, insulin, homeostasis model assessment insulin resistance index, total cholesterol, low-density lipoprotein-cholesterol, triglycerides, uric acid and creatinine values; in contrast, these patients had significantly lower high-density lipoprotein-cholesterol values. Metabolic syndrome patients with high blood pressure also had significantly higher levels of retinol-binding protein 4, plasminogen activator inhibitor 1, interleukin 6 and monocyte chemoattractant protein 1 and lower levels of adiponectin. Moreover, patients with metabolic syndrome and high blood pressure had increased surrogate markers of sympathetic activity and decreased baroreflex sensitivity. Logistic regression analysis showed that high-density lipoprotein, retinol-binding protein 4 and plasminogen activator inhibitor-1 levels were independently associated with metabolic syndrome patients with high blood pressure. There is a strong trend for an independent association between metabolic syndrome patients with high blood pressure and glucose levels. CONCLUSIONS: High blood pressure, which may be related to the autonomic dysfunction, is associated with metabolic, inflammatory and prothrombotic dysregulation ...

Cardiac autonomic activity in young females with primary dysmenorrhea.

Various studies have reported the effect of different phases of normal menstrual cycle on the autonomic control over the cardiac activity using heart rate variability (HRV) analysis. However, information on cardiac autonomic activity in young females suffering from primary dysmenorrhea (PD) is scant. Hence, the aim of the present study was to assess the HRV and blood pressure (BP) in different phases of menstrual cycle in women with PD and to compare these findings with eumenorrheic females. Sixty healthy unmarried female subjects (30 females with PD and 30 control subjects), in the age group of 18-25 years, having regular 28-32 days menstrual cycle were recruited for the study. Anthropometric measurements such as height, weight, BMI and WHR were measured. Blood pressure was measured with automatic blood pressure monitor and lead II ECG recordings were done to obtain HRV, during menstrual, follicular and luteal phases of menstrual cycle in both groups. The data recorded were subjected to time and frequency domain analysis. The results showed that dysmenorrheic women had significantly high BMI (P<0.05). Analysis of HRV during the different phases of the menstrual cycle between two groups revealed significantly increased (P<0.01) mean HR and significantly reduced (P<0.01) mean RR and RMSSD in all the 3 examined phases, SDNN significantly less (P<0.05) and systolic BP significantly higher (P<0.001) during the luteal phase in study group compared to control. Also, we observed a statistically significant decrease in TP and LF ms2 (P<0.05), HF ms2 & nu (P<0.01) in menstrual phase, HF ms2 (P<0.05) and HF nu (P<0.01) in luteal phase, while LF nu and LF-HF ratio were found to be significantly higher (P<0.01) in menstrual and luteal phases in women with PD compared to control group. This study has shown decreased HRV in the form of increased sympathetic tone and decreased parasympathetic activity in dysmenorrheic women which may be considered an important cardiovascular risk factor.

Mecanismos fisiopatológicos cardiovasculares en sujetos con privación de sueño / Cardiovascular physiopathological mechanisms in patients with sleep deprivation

Muchos factores relacionados con el medio laboral, los hábitos higiénicos alimentarios y estilos de vida influyen sobre la duración del sueño y traen aparejado un desequilibrio en la homeostasis del organismo, con la aparición de factores de riesgo que incrementan la morbilidad y mortalidad por enfermedades cardiovasculares. El presente trabajo tiene el objetivo de actualizar y sintetizar los mecanismos fisiopatológicos cardiovasculares en sujetos con privación de sueño parcial y total. Para ello se consultaron las bases de datos Pubmed, Ebsco, Medline e Hinari, seleccionando artículos sobre el tema, publicados fundamentalmente en los últimos 5 años. Se ha encontrado una asociación significativa entre la privación de sueño y las enfermedades cardiovasculares que se explican por diferentes mecanismos, que incluyen: desequilibrio autonómico con predominio de la actividad simpática, incremento de catecolaminas circulantes, disminución de la sensibilidad del baroreflejo, los bajos niveles de magnesio intracelular, la inhibición de la secreción de melatonina y la acción de diversos precursores de la inflamación. Se concluye que estos mecanismos producen aumento del tono vascular, hipertensión arterial, entre otras variaciones que incrementan los factores de riesgo y la morbilidad y mortalidad cardiovasculares.

There are many factors which are related to work, nutritional and hygienic habits and lifestyle that influence on sleep duration and bring about disequilibrium in the body homeostasis and lead to the appearance of risk factors that increase morbidity and mortality due to cardiovascular diseases. This work is aimed at updating and synthesizing the cardiovascular physiopathological mechanisms in patients with partial or total sleep deprivation. To achieve this aim, we consulted electronic databases (Pubmed, Ebsco, Medline and Hinari), and selected articles about the topic which have been published during the last five years. We found a significant association between sleep deprivation and cardiovascular diseases, explained by different mechanisms which include: autonomic disequilibrium with prevalence of sympathetic activity, increase of circulating catecholamines, diminished baroreflex sensitivity, low levels of intracellular magnesium, inhibition of melatonin secretion, and the action of diverse inflammation precursors. We conclude that, these mechanisms produce an increase in the vascular tone and high blood pressure among other variations that increase cardiovascular risk factors, morbidity and mortality.

Reduction of superoxide in the nucleus of solitary tract improves baroreflex control of sympathetic activity in chronic heart failure rats / 第二军医大学学报

Objective To determine the role of the nucleus tractus solitarii (NTS) superoxide in mediating the chronic heart failure (CHF)-induced reduction in baroreflex control of sympathetic activity. Methods CHF model was produced by coronary ligation in SD rats, and rats receiving sham operation (Sham) served as controls. Changes in renal sympathetic nerve activity (RSNA) and baroreflex sensitivity control of sympathetic activity were observed after microinjections of SOD mimic Tempol into the NTS in Shamand CHF rats. Results In anesthetized rats, the baseline level of sympathetic nerve activity was significantly higher in CHF group than in Sham group (P<0. 05), whereas the baroreflex sensitivity control of sympathetic activity was lower in CHF group than in Sham group. Bilateral microinjection of Tempol (10 nmol in 50 nL) into the NTS had no effect on baseline RSNA and baroreflex sensitivity in the Sham group. In contrast, injection of Tempol notably reduced the baseline RSNA and increased baroreflex sensitivity in CHF group. Conclusion Superoxide in the NTS contributes to sympathetic overactivity and baroreflex impairment in rats with CHF, suggesting that increased oxidative stress in the NTS is responsible for cardiovascular dysfunctions in CHF.

To evaluate the involvement of autonomic nervous system during pre and post menstrual phases in young women.

Background: During reproductive life, Women undergo many types of behavioural and hormonal changes, which influence various functions of body. ANS provides physiological adaptive background for these changes. The main aim of this study is to carry out autonomic function tests during various phases of menstrual cycle. Method: Different Methods were used to evaluate sympathetic and Parasympathetic activity. This study was carried out in two different phases of menstrual cycle viz. premenstrual phase (late luteal phase-LL) and post menstrual phase (early follicular phase –EF). Results: The autonomic function tests and heart rate variables were recorded and data was tabulated for Statistical evaluation with student paired “t” test. P 0.05 was considered as statistically significant. The tests for sympathetic activity were compared during pre and post menstrual phases. It was observed that pulse rate, blood pressure and cold pressor test were statistically more significant (p<0.01), while orthostatic variation in arterial blood pressure was statistically significant (p<0.05) in premenstrual phase as compared to post menstrual phase of menstrual cycle. For parasympathetic activity it was observed that heart rate response, expiratory: inspiratory ratio and valsalva ratio were statistically not significant (p>0.05) in both pre and post menstrual phases of menstrual cycle. Conclusion: In this study the responses to various sympathetic tests were significantly altered in premenstrual phase as compare to that of postmenstrual phase, reflecting the significant increase in the sympathetic activity. These changes may be due to gonadal steroids imbalance during post menstrual phase (EF) and premenstrual phase (LL) of menstrual cycle which in turn affects HPA axis and ANS significantly. Significant increased sympathetic activity responses indicate an augmented stress system.

Differential brain angiotensin-II type I receptor expression in hypertensive rats

Blood-borne angiotensin-II (Ang-II) has profound effects in the brain. We tested the hypothesis that Ang-II-dependent hypertension involves differential Ang-II type I (AT1) receptors expression in the subfornical organ (SFO) and the rostral ventrolateral medulla (RVLM). Male Wistar rats were implanted with 14-day osmotic minipump filled with Ang-II (150 ng/kg/min) or saline. AT1 receptor mRNA levels were detected in the SFO and RVLM by reverse transcription-polymerase chain reaction (RT-PCR). Ang-II caused hypertension (134 +/- 10 mmHg vs. 98 +/- 9 mmHg, n = 9, p < 0.05). RT-PCR revealed that Ang-II infusion induced increased AT1 receptor mRNA levels in RVLM and decreased in SFO. Our data suggest that Ang-II-induced hypertension involves differential expression of brain AT1 receptors.

Role of cGMP and cAMP in the hemodynamic response to intrathecal sildenafil administration

INTRODUCTION: Results from our laboratory have demonstrated that intracerebroventricular administration of sildenafil to conscious rats promoted a noticeable increase in both lumbar sympathetic activity and heart rate, with no change in the mean arterial pressure. The intracerebroventricular administration of sildenafil may have produced the hemodynamic effects by activating sympathetic preganglionic neurons in the supraspinal regions and spinal cord. It is well documented that sildenafil increases intracellular cGMP levels by inhibiting phosphodiesterase type 5 and increases cAMP levels by inhibiting other phosphodiesterases. OBJECTIVE: To examine and compare, in conscious rats, the hemodynamic response following the intrathecal administration of sildenafil, 8-bromo-cGMP (an analog of cGMP), forskolin (an activator of adenylate cyclase), or dibutyryl-cAMP (an analog of cAMP) in order to elucidate the possible role of the sympathetic preganglionic neurons in the observed hemodynamic response. RESULTS: The hemodynamic responses observed following intrathecal administration of the studied drugs demonstrated the following: 1) sildenafil increased the mean arterial pressure and heart rate in a dose-dependent manner, 2) increasing doses of 8-bromo-cGMP did not alter the mean arterial pressure and heart rate, 3) forskolin did not affect the mean arterial pressure but did increase the heart rate and 4) dibutyryl-cAMP increased the mean arterial pressure and heart rate, similar to the effect observed following the intrathecal injection of the highest dose of sildenafil. CONCLUSION: Overall, the findings of the current study suggest that the cardiovascular response following the intrathecal administration of sildenafil to conscious rats involves the inhibition of phosphodiesterases other than phosphodiesterase type 5 that increase the cAMP level and the activation of sympathetic preganglionic neurons.

Short-term red wine consumption promotes differential effects on plasma levels of high-density lipoprotein cholesterol, sympathetic activity, and endothelial function in hypercholesterolemic, hypertensive, and healthy subjects

OBJECTIVES: To compare the metabolic, hemodynamic, autonomic, and endothelial responses to short-term red wine consumption in subjects with hypercholesterolemia or arterial hypertension, and healthy controls. METHODS: Subjects with hypercholesterolemia (n=10) or arterial hypertension (n=9), or healthy controls (n=7) were given red wine (250 mL/night) for 15 days. Analyses were performed before and after red wine intake. RESULTS: Red wine significantly increased the plasma levels of HDL-cholesterol in the controls, but not in the other groups. The effects on hemodynamic measurements were mild, non-significantly more prominent in healthy subjects, and exhibited high interindividual variability. Across all participants, mean blood pressure decreased 7 mmHg (p <0.01) and systemic vascular resistance decreased 7 percent (p = 0.05). Heart rate and cardiac output did not significantly change in any group. Red wine enhanced muscle sympathetic fibular nerve activity in hypercholesterolemic and hypertensive patients, but not in controls. At baseline, brachial artery flow-mediated dilation was impaired in patients with hypercholesterolemia and arterial hypertension; red wine restored the dilation in the hypercholesterolemic group but not in the hypertensive group. CONCLUSIONS: Red wine elicits different metabolic, autonomic, and endothelial responses among individuals with hypercholesterolemia or arterial hypertension and healthy controls. Our findings highlight the need to consider patient characteristics when evaluating the response to red wine.

Increased sympathetic activity in normotensive offspring of malignant hypertensive parents compared to offspring of normotensive parents

Malignant hypertension seems to be the consequence of very high blood pressure. Furthermore, an increase in sympathetic and renin-angiotensin system activity is considered to be the main mechanisms producing malignant hypertension. In the present study, 10 offspring of malignant hypertensive (OMH) parents (age 28 ± 5 years, 7 males, 3 females, 2 white and 8 non-white) and 10 offspring of normotensive (ONT) parents (age 28 ± 6 years, 2 males, 8 females, 3 white and 7 non-white) were evaluated. The OMH group had significantly higher (P < 0.05) casual blood pressure (125 ± 10/81 ± 5 mmHg) compared with ONT (99 ± 13/67 ± 5 mmHg). The increase in blood pressure was greater in OMH (Ä SBP = 17 ± 2 vs Ä SBP = 9 ± 1 mmHg in ONT) during cold pressor testing, but they had a lower increase in heart rate (Ä HR = 13 ± 2 vs Ä HR = 20 ± 3 bpm in ONT) during isometric exercise (handgrip test). Sympathetic activity, measured by microneurography, was significantly higher (P < 0.05) before exercise in OMH (17 ± 6 vs 11 ± 4 burst/min in ONT) and exhibited a greater increase (Ä = 18 ± 10 vs Ä = 8 ± 3 burst/min in ONT) during isometric exercise. This study showed increased sympathetic activity in OMH before exercise and a greater response during isometric exercise, suggesting an autonomic abnormality before exercise and a greater sympathetic response to physical stress in OMH compared to ONT.

Attenuated Sympathetic Activity and Its Relation to Obesity in MSG Injected and Sympathectomized Rats

In order to characterize the role of sympathetic activity in obesity, we repeatedly assessed sympathetic activity via power spectral analyses of heart rate variability in the same subjects at 7, 11, 25, and 60 weeks, using monosodium glutamate (MSG)-induced obese and control rats. The effects of lower sympathetic activity on obesity were also evaluated. Fat mass in MSG rats was already higher at 7 weeks, but the sympathetic activity did not differ between 7 and 25 weeks. Between 25 and 60 weeks, the increase in fat mass, food efficiency, and body weight gain was higher in MSG rats. The increase in sympathetic activity between 25 and 60 weeks and sympathetic activity at 60 weeks were lower in MSG rats. Fat mass at 60 weeks was inversely correlated with changes in sympathetic activity between 25 and 60 weeks. Reduced plasma epinephrine levels by bilateral adrenal demedullation induced increase of fat mass. In summary, an attenuated increase of sympathetic activity with age may partly be responsible for aggravated obesity in MSG rats. Additionally, reduced sympathetic activity per se induced obesity in rats. These results suggest that lower sympathetic activity contributes to obesity in rats.

Circadian Variation of Cardiac Autonomic Function in Hypertensives

BACKGROUND: We addressed the problem of the circadian changes in neural control of the circulation in ambulant hypertensive subjects. With spectral analysis of heart rate variability the tonic sympathetic and vagal activities and their changes are respectively assessed by the power of 0.050 - 0.015Hz(low frequency, LF) and 0.150 - 0.350Hz(respiratory linked, high frequency, HF) components of the spectrum of the beat by beat variability of RR interval. METHODS: Heart rate variability(HRV) and its circadian rhythm were evaluated in 15 patients with hypertension. By using 24-h Holter monitoring, HRV and its spectral components were measured. Finding were compared with 15 age-matched normal controls. RESULTS: The 24-hour plot of the SDs revealed that heart rate variability was significantly lower in the hypertensive patients, and the differences reached statistical significance during hours 2, 3, 9, 13, 16, 18, 19, and 23(p<0.05). Spectral analysis showed that power in the high-frequency range(0.150 to 0.350Hz) was lower among the hypertensive patients than among the normal controls during 22 of 24 hours but that the difference was statistically significant only during 2 hours(p<0.05). Power in the low frequency range(0.050 to 0.150Hz) was low at night, increased in the morning, and high during the day among controls ; this circadian rhythm was absent among hypertensive patients. CONCLUSIONS: Among hypertensive patients, HRV is decreased with a partial withdrawal of parasympathetic tone, and the circadian rhythm of sympathetic/parasympathetic tone is altered.