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1.
Environmental Health and Preventive Medicine ; : 45-45, 2020.
Article in English | WPRIM | ID: wpr-826287

ABSTRACT

High salt intake increases blood pressure, and dietary salt intake has been clearly demonstrated to be associated with hypertension incidence. Japanese people consume higher amounts of salt than Westerners. It has been reported that miso soup was one of the major sources of daily salt intake in Japanese people. Adding salt is indispensable to make miso, and therefore, in some cases, refraining from miso soup is recommended to reduce dietary salt intake. However, recent studies using salt-sensitive hypertensive models have revealed that miso lessens the effects of salt on blood pressure. In other word, the intake of miso dose not increase the blood pressure compared to the equivalent intake of salt. In addition, many clinical observational studies have demonstrated the absence of a relationship between the frequency of miso soup intake and blood pressure levels or hypertension incidence. The mechanism of this phenomenon seen in the subjects with miso soup intake has not been fully elucidated yet. However, in basic studies, it was found that the ingredients of miso attenuate sympathetic nerve activity, resulting in lowered blood pressure and heart rate. Therefore, this review focused on the differences between the effects of miso intake and those of the equivalent salt intake on sympathetic nerve activity, blood pressure, and heart rate.


Subject(s)
Humans , Blood Pressure , Physiology , Heart Rate , Physiology , Soy Foods , Sympathetic Nervous System , Physiology
2.
Japanese Journal of Physical Fitness and Sports Medicine ; : 165-170, 2020.
Article in Japanese | WPRIM | ID: wpr-782004

ABSTRACT

It is well known that elderly patients with heart failure have low tolerance to exercise. Heart disease increases the cardiac load and causes severe arrhythmias due to an increase in the afferent stimuli from peripheral tissues such as skeletal muscle and from the sympathetic nervous system. Managing risk during exercise from the peripheral factors is essential to improve the quality of life of this patient population. Previous research involved utilizing high-intensity exercise and invasive methods, but it is necessary to perform at a safe intensity to evaluate the tolerance to exercise during rehabilitation. Therefore, the purpose of this study was to assess the changes in ventilatory and circulatory indices caused by venous ischemia after moderate-intensity exercise. The participants comprised ten healthy men randomly assigned to either a venous blood flow shut off task (task1) or the venous blood flow task (task 2). After 2 days or more the tasks were switched. The protocol was performed using a moderate intensity of rest for a while and performing a 4-min cycling exercise at 200 mmHg while occluding venous outflow of the left leg. Immediately after the termination, both groups took 5 min of rest. Task 1 involved occlusion of the venous outflow using 90 mmHg applied to the left thigh. The result showed that in normal subjects, shutting off the venous blood flow did not change the ventilatory response after moderate-intensity exercise but it changed the circulation index.

3.
Neuroscience Bulletin ; (6): 67-78, 2019.
Article in English | WPRIM | ID: wpr-775464

ABSTRACT

The rostral ventrolateral medulla (RVLM) is a key region in cardiovascular regulation. It has been demonstrated that cholinergic synaptic transmission in the RVLM is enhanced in hypertensive rats. Angiotensin-converting enzyme 2 (ACE2) in the brain plays beneficial roles in cardiovascular function in hypertension. The purpose of this study was to determine the effect of ACE2 overexpression in the RVLM on cholinergic synaptic transmission in spontaneously hypertensive rats (SHRs). Four weeks after injecting lentiviral particles containing enhanced green fluorescent protein and ACE2 bilaterally into the RVLM, the blood pressure and heart rate were notably decreased. ACE2 overexpression significantly reduced the concentration of acetylcholine in microdialysis fluid from the RVLM and blunted the decrease in blood pressure evoked by bilateral injection of atropine into the RVLM in SHRs. In conclusion, we suggest that ACE2 overexpression in the RVLM attenuates the enhanced cholinergic synaptic transmission in SHRs.


Subject(s)
Animals , Male , Rats , Acetylcholine , Metabolism , Blood Pressure , Physiology , Cardiovascular System , Metabolism , Cholinergic Neurons , Metabolism , Hypertension , Metabolism , Peptidyl-Dipeptidase A , Metabolism , Rats, Inbred SHR , Metabolism
4.
Neuroscience Bulletin ; (6): 79-90, 2019.
Article in English | WPRIM | ID: wpr-775433

ABSTRACT

Chronic intermittent hypobaric hypoxia (CIHH) is known to have an anti-hypertensive effect, which might be related to modulation of the baroreflex in rats with renal vascular hypertension (RVH). In this study, RVH was induced by the 2-kidney-1-clip method (2K1C) in adult male Sprague-Dawley rats. The rats were then treated with hypobaric hypoxia simulating 5000 m altitude for 6 h/day for 28 days. The arterial blood pressure (ABP), heart rate (HR), and renal sympathetic nerve activity (RSNA) were measured before and after microinjection of L-arginine into the nucleus tractus solitarii (NTS) in anesthetized rats. Evoked excitatory postsynaptic currents (eEPSCs) and spontaneous EPSCs (sEPSCs) were recorded in anterogradely-labeled NTS neurons receiving baroreceptor afferents. We measured the protein expression of neuronal nitric oxide synthase (nNOS) and endothelial NOS (eNOS) in the NTS. The results showed that the ABP in RVH rats was significantly lower after CIHH treatment. The inhibition of ABP, HR, and RSNA induced by L-arginine was less in RVH rats than in sham rats, and greater in the CIHH-treated RVH rats than the untreated RVH rats. The eEPSC amplitude in NTS neurons receiving baroreceptor afferents was lower in the RVH rats than in the sham rats and recovered after CIHH. The protein expression of nNOS and eNOS in the NTS was lower in the RVH rats than in the sham rats and this decrease was reversed by CIHH. In short, CIHH treatment decreases ABP in RVH rats via up-regulating NOS expression in the NTS.


Subject(s)
Animals , Male , Baroreflex , Physiology , Blood Pressure , Hypertension , Metabolism , Hypoxia , Kidney , Metabolism , Nitric Oxide Synthase Type I , Metabolism , Rats, Sprague-Dawley , Solitary Nucleus , Metabolism
5.
Journal of Shanghai Jiaotong University(Medical Science) ; (12): 230-233, 2017.
Article in Chinese | WPRIM | ID: wpr-507669

ABSTRACT

Objective · To explore the effects of brisk walking on blood pressure, body mass index (BMI), and autonomic nerve activity of male elderly with hypertension in community-based health centers in Shanghai. Methods · A total of 630 elderly men received brisk walking treatment (>10000 steps/d) voluntarily, who were selected from six community-based health centers in Pudong New Area of Shanghai. Among them, 210 people stick to training for 12 weeks. According to whether suffering from hypertension, the people were assigned to hypertension intervened group (intervention group, n=110) and normal intervened group (control group 1, n=100). Blood pressure, BMI, heart rate and autonomic nerve activity before and after the training were compared. Results · After 12 weeks of training, systolic blood pressure (SBP), diastolic blood pressure (DBP) and sympathetic nerve activity of intervention group were significantly lower than those before the training (P0.05). Conclusion · Brisk walking treatment lasting for 12 weeks can decrease blood pressure and sympathetic nerve activity in elderly men with hypertension. It is worthy to be popularized in the community.

6.
Journal of Interventional Radiology ; (12): 1113-1118, 2015.
Article in Chinese | WPRIM | ID: wpr-485103

ABSTRACT

Transcatheter renal sympathetic denervation with radiofrequency ablation has become a new treatment for refractory hypertension.Recent studies have showed that renal sympathetic denervation can also treat the diseases that are related to increased sympathetic nerve activity, such as metabolic diseases, cardiac disfunction, arrhythmia, obstructive sleep apnea syndrome, polycystic ovary syndrome, renal failure, etc. This paper aims to make a general review on the recent clinical research progress about renal sympathetic denervation with radiofrequency ablation.

7.
Braz. j. med. biol. res ; 47(7): 554-559, 07/2014. tab, graf
Article in English | LILACS | ID: lil-712973

ABSTRACT

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.


Subject(s)
Animals , Male , Fluoxetine/administration & dosage , Kidney/drug effects , Paroxetine/administration & dosage , Selective Serotonin Reuptake Inhibitors/administration & dosage , Sertraline/administration & dosage , Sympathetic Nervous System/drug effects , Antidepressive Agents/administration & dosage , Antidepressive Agents/pharmacology , Arterial Pressure/drug effects , Baroreflex/drug effects , Cardiovascular Physiological Phenomena/drug effects , Fluoxetine/pharmacology , Heart Rate/drug effects , Kidney/innervation , Kidney/surgery , Paroxetine/pharmacology , Rats, Wistar , Respiratory Rate/drug effects , Selective Serotonin Reuptake Inhibitors/pharmacology , Sertraline/pharmacology , Vital Signs/drug effects
8.
Chinese Journal of Behavioral Medicine and Brain Science ; (12): 237-239, 2013.
Article in Chinese | WPRIM | ID: wpr-434666

ABSTRACT

Objective To study the effect of autonomic nerve activity on emotion experience.Methods 71 healthy males were asked to see a neutral film STICK and conduct a computer game,then evaluated emotion experience.All participants were recorded skip temperature,skin conduction,heart rate,LF and HF during baseline and game periods.Results (1) There was significant difference in fear experience among high,middle and low synchronous groups (2.64 ± 2.05,2.50 ± 2.01,4.46 ± 2.41; P< 0.01),and low synchronous group was significantly higher than high synchronous group (P < 0.01).The main effects of three periods were significant in basis of three response types of autonomic nerve activity(skin conduction:F(2.68) =76.083,P<0.01; heart rate:F(2.68) =71.692,P < 0.01),and skip temperature,skin conduction and heart rate were no significant difference among three response types.Types and periods had no significant interaction.(2) Different response modes of autonomic nervous system has different distributions in high fear and low fear groups (x2 =9.763,P < 0.01).Skip temperature,skin conduction and heart rate were no significant difference between high fear group and low fear group.Conclusion The modes of autonomic nervous system have an effect on intensity of fear experience,but not the same in skip temperature,skin conduction and heart rate.

9.
Braz. j. med. biol. res ; 45(1): 43-48, Jan. 2012. ilus
Article in English | LILACS | ID: lil-610542

ABSTRACT

The objective of the present study was to determine the antihyperalgesic effect of sertraline, measured indirectly by the changes of sciatic afferent nerve activity, and its effects on cardiorespiratory parameters, using the model of formalin-induced inflammatory nociception in anesthetized rats. Serum serotonin (5-HT) levels were measured in order to test their correlation with the analgesic effect. Male Wistar rats (250-300 g) were divided into 4 groups (N = 8/per group): sertraline-treated group (Sert + Saline (Sal) and Sert + Formalin (Form); 3 mg·kg-1·day-1, ip, for 7 days) and saline-treated group (Sal + Sal and Sal + Form). The rats were injected with 5 percent (50 µL) formalin or saline into the right hind paw. Sciatic nerve activity was recorded using a silver electrode connected to a NeuroLog apparatus, and cardiopulmonary parameters (mean arterial pressure, heart rate and respiratory frequency), assessed after arterial cannulation and tracheotomy, were monitored using a Data Acquisition System. Blood samples were collected from the animals and serum 5-HT levels were determined by ELISA. Formalin injection induced the following changes: sciatic afferent nerve activity (+50.8 ± 14.7 percent), mean arterial pressure (+1.4 ± 3 mmHg), heart rate (+13 ± 6.8 bpm), respiratory frequency (+4.6 ± 5 cpm) and serum 5-HT increased to 1162 ± 124.6 ng/mL. Treatment with sertraline significantly reduced all these parameters (respectively: +19.8 ± 6.9 percent, -3.3 ± 2 mmHg, -13.1 ± 10.8 bpm, -9.8 ± 5.7 cpm) and serum 5-HT level dropped to 634 ± 69 ng/mL (P < 0.05). These results suggest that sertraline plays an analgesic role in formalin-induced nociception probably through a serotonergic mechanism.


Subject(s)
Animals , Male , Rats , Formaldehyde/antagonists & inhibitors , Nociception/drug effects , Selective Serotonin Reuptake Inhibitors/pharmacology , Sertraline/pharmacology , Arterial Pressure/drug effects , Formaldehyde/pharmacology , Heart Rate/drug effects , Neurons, Afferent/drug effects , Pain Measurement/drug effects , Rats, Wistar , Respiratory Rate/drug effects , Sciatic Nerve/drug effects , Serotonin/blood
10.
Braz. j. med. biol. res ; 44(9): 883-889, Sept. 2011. ilus
Article in English | LILACS | ID: lil-599666

ABSTRACT

The arterial partial pressure (P CO2) of carbon dioxide is virtually constant because of the close match between the metabolic production of this gas and its excretion via breathing. Blood gas homeostasis does not rely solely on changes in lung ventilation, but also to a considerable extent on circulatory adjustments that regulate the transport of CO2 from its sites of production to the lungs. The neural mechanisms that coordinate circulatory and ventilatory changes to achieve blood gas homeostasis are the subject of this review. Emphasis will be placed on the control of sympathetic outflow by central chemoreceptors. High levels of CO2 exert an excitatory effect on sympathetic outflow that is mediated by specialized chemoreceptors such as the neurons located in the retrotrapezoid region. In addition, high CO2 causes an aversive awareness in conscious animals, activating wake-promoting pathways such as the noradrenergic neurons. These neuronal groups, which may also be directly activated by brain acidification, have projections that contribute to the CO2-induced rise in breathing and sympathetic outflow. However, since the level of activity of the retrotrapezoid nucleus is regulated by converging inputs from wake-promoting systems, behavior-specific inputs from higher centers and by chemical drive, the main focus of the present manuscript is to review the contribution of central chemoreceptors to the control of autonomic and respiratory mechanisms.


Subject(s)
Humans , Adrenergic Neurons/physiology , Cardiovascular Physiological Phenomena , Chemoreceptor Cells/physiology , Respiratory Physiological Phenomena , Brain Stem/physiology , Carbon Monoxide/metabolism , Central Nervous System/physiology , Medulla Oblongata/physiology , Pons/physiology , Sympathetic Nervous System/physiology
11.
An. acad. bras. ciênc ; 81(3): 589-603, Sept. 2009. ilus
Article in English | LILACS | ID: lil-523983

ABSTRACT

Several forms of experimental evidence gathered in the last 37 years have unequivocally established that the medulla oblongata harbors the main neural circuits responsible for generating the vasomotor tone and regulating arterial blood pressure. Our current understanding of this circuitry derives mainly from the studies of Pedro Guertzenstein, a former student who became Professor of Physiology at UNIFESP later, and his colleagues. In this review, we have summarized the main findings as well as our collaboration to a further understanding of the ventrolateral medulla and the control of arterial blood pressure under normal and pathological conditions.


Numerosas formas de evidência experimental obtidas nos últimos 37 anos demonstraram inequivocamente que a medula oblongata contém os principais circuitos responsáveis pela geração e manutenção do tono vasomotor e a regulação da pressão arterial. A visão atual que possuímos destes circuitos deriva em grande parte dos estudos de Pedro Guertzenstein, um estudante e mais tarde Professor de Fisiologia da UNIFESP e seus colaboradores. Nesta revisão nós sumarizamos os seus principais resultados assim como a nossa colaboração para uma melhor compreensão da regulação da pressão arterial em condições normais e patológicas.


Subject(s)
Animals , Humans , Rats , Blood Pressure/physiology , Hypertension/physiopathology , Medulla Oblongata/physiology , Sympathetic Nervous System/physiology , Vasomotor System/physiology , Baroreflex/physiology
12.
Braz. j. phys. ther. (Impr.) ; 12(6)Nov.-Dec. 2008. ilus, graf
Article in English, Portuguese | LILACS | ID: lil-504886

ABSTRACT

CONTEXTUALIZAÇÃO: Relatos clínicos sugerem que a associação terapêutica entre crioterapia (CRIO) e estimulação elétrica transcutânea (TENS) favorece analgesia local. OBJETIVO: Avaliar a atividade elétrica do nervo femoral (ANF), em repouso e durante a aplicação isolada, e associada de TENS e CRIO em ratos. MÉTODOS: Foram utilizados nove ratos (Wistar) adultos com peso de ±300g. Após anestesia (Uretana, 1mg/g i.p.), o nervo femoral direito foi isolado para registro da ANF basal e durante as modalidades analgésicas. Depois da fixação dos eletrodos no terço inferior da coxa direita, foram aplicadas TENS (50Hz, 10mÅ) por cinco minutos, CRIO isolada e terapia associada (TA) por dez minutos. Os registros contínuos da ANF foram realizados por meio de um amplificador de potenciais de ação, avaliados posteriormente no primeiro, quinto e décimo minuto em unidades arbitrárias (Ua). Utilizaram-se a análise de variância (ANOVA) uma via e o teste de Dunnett como post-hoc. Valores expressos como média ±EPM e as diferenças fixadas em p<0,05. RESULTADOS: A atividade do nervo femoral aumentou (p<0,01) na TENS (0,358±0,09Ua) e na TA (0,230±0,07Ua) e ficou inalterada após CRIO (0,063±0,003Ua), em relação ao basal inicial (0,009±0,0003Ua). No quinto minuto, observou-se uma significante (p<0,05) atenuação da ANF na modalidade TA (0,144±0,027Ua) versus TENS isolada (0,324±0,089Ua). CONCLUSÕES: A associação entre as modalidades analgésicas não-invasivas CRIO e TENS atenua significativamente os efeitos produzidos pela TENS isoladamente sobre a ANF de ratos anestesiados.


BACKGROUND: Clinical reports suggest that the therapeutic association between cryotherapy (CRYO) and transcutaneous electrical stimulation (TENS) favors local analgesia. OBJECTIVE: To evaluate the electrical activity of the femoral nerve (FNA), at rest and during single and combined application of TENS and CRYO, in rats. METHODS: Nine adult Wistar rats weighting ±300g were used in this study. After inducing anesthesia (Urethane, 1mg/g i.p.), the right femoral nerve was isolated in order to record the FNA at baseline and during the therapeutic modalities. After attaching the electrodes to the lower third of the right thigh, TENS (50Hz, 10mÅ) was applied for five minutes, and CRYO and the combined therapy (CT) for ten minutes. The FNA was recorded continuously by means of an action potential amplifier and the recordings from the first, fifth and tenth minutes were subsequently evaluated using arbitrary units (aU). One-way analysis of variance (ANOVA) was used, with Dunnett's test as post-hoc analysis. The values were expressed as the mean ±SEM and differences were established at p<0.05. RESULTS: The femoral nerve activity increased (p<0.01) after TENS (0.358±0.09aU) and CT (0.230±0.07aU) and was unchanged after CRYO (0.063±0.003aU), in relation to the baseline (0.009±0.0003aU). In the fifth minute, we observed significant (p<0.05) attenuation of FNA in the CT (0.144±0.027aU) in relation to TENS alone (0.324±0.089aU). CONCLUSIONS: The association between CRYO and TENS noninvasive analgesia significantly attenuates the effects produced by TENS alone on the FNA of anesthetized rats.

13.
Chinese Journal of Clinical Pharmacology and Therapeutics ; (12)2004.
Article in Chinese | WPRIM | ID: wpr-566657

ABSTRACT

AIM:Left coronary artery ligation(LAD)was used to induce heart failure.Losartan was microinjected into paraventricular nucleus(PVN),heart rate(HR),blood pressure(BP)and renal sympathetic nerve activity(RSNA)were measured.The mechanism of PVN in chronic heart failure was investigated.METHODS:Sprague-Dawley male rats were selected for LAD ligation for heart failure models,the variation of cardiac function was detected by echocardiography.Losartan was microinjected into PVN,the responses of HR,BP and RSNA were analyzed.RESULTS:Compared with sham group,the level of LV was increased(P

14.
Environmental Health and Preventive Medicine ; : 149-153, 2001.
Article in Japanese | WPRIM | ID: wpr-361567

ABSTRACT

Objectives: To determine the relationship between obesity and cardiac autonomic nerve activity in healthy children. Methods: 16 healthy male children comprising of 9 nonobese and 7 obese subjects (body mass index > 19.1 kg/m2) aged 8−9 years were selected. Electrocardiograms were measured for 10 min. under controlled ventilation (0.25 Hz) in the supine position. Consecutive 256-second RR interval data were transformed by the Fast Fourier Transform method into power spectral data. Very low frequency (VLF; 0.003−0.04 Hz), low frequency (LF; 0.04−0.15 Hz), high frequency (HF; 0.15−0.40 Hz), and total power (TP; 0.003−0.40 Hz) were calculated and transformed into a natural logarithm (ln). Normalized units (nu) were also calculated as follows: LFnu = LF / (TP - VLF) x 100. HFnu = HF / (TP - VLF) x 100. Low/high-frequency ratio (LHR) was calculated as LF divided by HF. Unpaired t test was performed to compare the 2 groups. Results: TP ln and HFnu, reflecting cardiac parasympathetic nerve activity, in obese children were significantly lower than those in nonobese children. In contrast, LFnu and LHF, reflecting cardiac sympathetic nerve activity, in obese children were significantly higher than those in nonobese children. Conclusions: These findings suggest that obese children have higher sympathetic nerve activity and lower parasympathetic nerve activity than nonobese children.


Subject(s)
Child
15.
The Korean Journal of Physiology and Pharmacology ; : 555-563, 1998.
Article in English | WPRIM | ID: wpr-727761

ABSTRACT

The renal function is under regulatory influence of central nervous system (CNS), in which various neurotransmitter and neuromodulator systems take part. However, a possible role of central GABA-benzodiazepine system on the central regulation of renal function has not been explored. This study was undertaken to delineate the renal effects of diazepam. Diazepam, a benzodiazepine agonist, administered into a lateral ventricle (icv) of the rabbit brain in doses ranging from 10 to 100 microgram/kg, elicited dose-related diuresis and natriuresis along with improved renal hemodynamics. However, when given intravenously, 100 mug/kg diazepam did not produce any significant changes in all parameters of renal function and systemic blood pressure. Diazepam, 100 mug/kg icv, transiently decreased the renal nerve activity (RNA), which recovered after 3 min. The plasma level of atrial natriuretic peptide (ANP) increased 7-fold, the peak coinciding with the natriuresis and diuresis. Muscimol, a GABAergic agonist, 1.0 mug/kg given icv, elicited marked antidiuresis and antinatriuresis, accompanied by decreases in systemic blood pressure and renal hemodynamics. When icv 0.3 microgram/kg muscimol was given 3 min prior to 30 mug/kg of diazepam icv, urinary flow and Na excretion rates did not change significantly, while systemic hypotension was produced. These results indicate that icv diazepam may bring about natriuresis and diuresis by influencing the central regulation of renal function, and that the renal effects are related to the increased plasma ANP levels, not to the decreased renal nerve activity, and suggest that the effects may not be mediated by the activation of central GABAergic system.


Subject(s)
Rabbits , Atrial Natriuretic Factor , Benzodiazepines , Blood Pressure , Brain , Central Nervous System , Diazepam , Diuresis , Hemodynamics , Hypotension , Lateral Ventricles , Muscimol , Natriuresis , Neurotransmitter Agents , Plasma
16.
Japanese Journal of Physical Fitness and Sports Medicine ; : 101-112, 1997.
Article in Japanese | WPRIM | ID: wpr-371751

ABSTRACT

The purpose of this study was to assess an alteration of cardiac autonomic nerve activity during water immersion. Ten healthy young males (age : 21-28 yr.) were immersed in water at the temperatures of 25°C, 30°C and 34°C. Subjects sat calmly for 20 minutes in sitting position before water immersion, and then were immersed in water at subaxillary level in sitting position for 15 minutes, performing controlled breathing (15 cycle/min.) . Electrocardiograms were recorded continuously. Autonomic nerve activity was estimated with the analysis of power spectral by using the Fast Fourier Transformation (FFT) . High (HF ; 0.15-0.50 Hz) and low (LF ; 0.04-0.15 Hz) frequency areas and the ratio of LF to HF (LF/HF) were calculated as the indices of cardiac parasympathetic nerve activity, sympathetic nerve activity with parasympathetic modulation, and sympathetic nerve activity, respectively. During the water immersion at 25°C, 30°C and 34°C, HF was significantly increased, while the heart rate and LF/HF were significantly decreased. There were no statistically significant differences among both of HF and LF/HF during the immersion at 25°C, 30°C and 34°C, although the rate of change in HF at the temperature of 25°C appeared to be prominent compared to those at 30°C and 34°C and some subjects showed an exaggerated change in HF immediately after immersion. These results suggest that cardiac parasympathetic nerve activity is enhanced and cardiac sympathetic nerve activity is suppressed during a short time water immersion at the thermo-neutral temperature (34°C) and the temperatures of 25°C and 30°C, which are the usual temperatures found in indoor pools.

17.
Japanese Journal of Physical Fitness and Sports Medicine ; : 117-123, 1992.
Article in Japanese | WPRIM | ID: wpr-371549

ABSTRACT

A study was conducted to determine whether anticipation of exercise alters the responses of sympathetic nerve activity to muscle contraction. Sympathetic nerve activity leading to the skin (SSA) and muscle (MSA) was recorded from the tibial nerve in the left and right legs using tungsten microelectrodes. Heart rate and blood pressure (oscillometric method) were also measured during the experiment. Seven healthy subjects, who gave informed consent, participated in the experiment. They were asked to exert a static handgrip (SHG) for 2 min at a tension of 30% of maximal voluntary handgrip. Two different situations were set before the commencement of exercise. One was that after several minutes of controlled rest, a countdown was started 2 min before the exercise, and then the handgrip was applied (Cond. 1) . The other was that a preparation time of between 7 and 5 min was set prior to the handgrip exercise while no information regarding the starting time of exercise was given to the subjects (Cond. 2) . SSA for 30 s just before the exercise was increased in comparison with the control value at rest in Cond. 1, but not in Cond. 2. There was no difference in the SSA response patterns to SHG between the two conditions. Before the commencement of SHG, MSA did not alter from the control value at rest in either condition. The magnitudes of the increase in MSA during SHG were almost identical under both conditions. Heart rate for 30s before SHG in Cond. 1 was increased significantly from the control value, whereas there was no significant change in Cond. 2. The magnitude of the heart rate response to SHG was the same in both conditions. The mean blood pressure showed no significant change before SHG, but increased significantly during SHG in both conditions. The increases in SSA and heart rate prior to the commencement of exercise may be related to the anticipatory response to the exercise, although this response was not significant in MSA. These results confirm that anticipation of exercise increases sympathetic outflow to the skin. This may be advantageous in adapting the body to exercise.

18.
Journal of Chongqing Medical University ; (12)1987.
Article in Chinese | WPRIM | ID: wpr-571868

ABSTRACT

Objective:To measure the cardiac vagus nerve activity and its circadian rhythm in patients with essential hypertension(EH group) and normontensive controls (NC group),and to study the relationship between the cardiac vagus nerve activity and blood pressure.Methods:By dynamic electrocardiogram and ambulatory blood pressure monitoring,HF,PNN 50 and their circadian rhythm were compared between the EH group and NC group,and the relationship between HF,PNN 50 and blood pressure was analyzed.Results:During 24 hours,waking and sleeping hours,HF,PNN 50 were significantly lower(P

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