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Autonomic Nervous Activity (autonomic + nervous_activity)
Selected AbstractsCorrelation between electroencephalography and heart rate variability during sleepPSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 1 2003MMLSC , Mina Ako MT Abstract It is known that autonomic nervous activities change in correspondence with sleep stages. However, the characteristics of continuous fluctuations in nocturnal autonomic nerve tone have not been clarified in detail. The study aimed to determine the possible correlation between the electroencephalogram (EEG) and autonomic nervous activities, and to clarify in detail the nocturnal fluctuations in autonomic nerve activities. Overnight EEGs and electrocardiograms of seven healthy males were obtained. These EEGs were analyzed by fast Fourier transformation algorithm to extract delta, sigma and beta power. Heart rate and heart rate variability (HRV) were calculated in consecutive 5-min epochs. The HRV indices of low frequency (LF), high frequency (HF) and LF/HF ratio were calculated from the spectral analysis of R-R intervals. The sleep stages were manually scored according to Rechtschaffen and Kales' criteria. Low frequency and LF/HF were significantly lower during non-rapid eye movement (NREM) than REM, and were lower in stages 3 and 4 than in stages 1 and 2. Furthermore, delta EEG showed inverse correlations with LF (r = , 0.44, P < 0.001) and LF/HF (r = , 0.41, P < 0.001). In contrast, HF differed neither between REM and NREM nor among NREM sleep stages. Detailed analysis revealed that correlation was evident from the first to third NREM, but not in the fourth and fifth NREM. Delta EEG power showed negative correlations with LF and LF/HF, suggesting that sympathetic nervous activities continuously fluctuate in accordance with sleep deepening and lightening. [source] Influence of neurohumoral blockade on heart rate and blood pressure responses to haemorrhage in isoflurane anaesthetized ratsACTA PHYSIOLOGICA, Issue 3 2000UllmanArticle first published online: 24 DEC 200 Four groups of Sprague,Dawley rats were anaesthetized with isoflurane (ISO) (1.7% end-tidal concentration) in 40% oxygen, and mechanically ventilated. The animals were bled 15 mL kg,1 b.w. from the femoral vein over 10 min, followed by an observation period of 30 min. Ten minutes before haemorrhage each group of animals was pre-treated with intravenous injection/infusion of either: isotonic saline (Group B; CON; n=7), vasopressin V1 -receptor antagonist [d(CH2)5Tyr(Me)AVP; 10 ,g kg,1] (Group C; AVP-a; n=7), the non-selective angiotensin II receptor antagonist saralasin (10 ,g kg,1 min,1) (Group D; SAR; n=7) or hexamethonium (10 mg kg,1) (Group E; HEX; n=7). A separate group of conscious animals were pre-treated with isotonic NaCl and subjected to the same haemorrhage protocol (Group A; AW; n=7). Mean arterial pressure (MAP), heart rate (HR) and blood gases were observed during the experiments. Only pre-treatment with SAR and HEX reduced MAP significantly. The pre-haemorrhage HR was only affected by HEX, which caused a reduction by 17%. The HR was significantly lower at the end of haemorrhage compared with pre-haemorrhage levels in all groups except that group treated with HEX. In that group the HR changed in the opposite direction. The ability to maintain MAP during haemorrhage, and the post-haemorrhage period, was significantly impaired in the groups treated with AVP-a, SAR or HEX compared with the group receiving NaCl. It is concluded that autonomic nervous activity is of major importance for the maintenance of MAP during isoflurane anaesthesia, whereas circulating angiotensin II and vasopressin levels contribute to a much smaller degree in this regard. General anaesthesia in combination with different degrees of neurohumoral blockade impairs the haemodynamic responses to blood loss, seen in conscious individuals. The impairment involves both the early and late phases during haemorrhage, as well as the post-bleeding recovery period. All three neurohumoral systems (autonomic nervous activity, angiotensin II and vasopressin) are of importance for regulating MAP during and after haemorrhage, although the autonomic nervous outflow appears to contribute to a larger extent. [source] Is insulin resistance caused by defects in insulin's target cells or by a stressed mind?DIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 6 2005Jonas Burén Abstract The importance of understanding insulin action is emphasized by the increasing prevalence of insulin resistance in various populations and by the fact that it plays an important pathophysiological role in many common disorders, for example, diabetes, obesity, hypertension and dyslipidemia. The primary factors responsible for the development of insulin resistance are so far unknown, although both genetic and environmental factors are involved. The genetic defects responsible for the common forms of insulin resistance, for example, in type 2 diabetes, are largely unidentified. Some studies from our group as well as by other investigators suggest that cellular insulin resistance is reversible and that it may be secondary to factors in the in vivo environment. These may include insulin-antagonistic action of hormones like catecholamines, glucocorticoids, sex steroids and adipokines as well as dysregulation of autonomic nervous activity and they could contribute to the early development of insulin resistance. Some of these factors can directly impair glucose uptake capacity and this might be due to alterations in key proteins involved in insulin's intracellular signaling pathways. This article briefly summarizes proposed mechanisms behind cellular and whole-body insulin resistance. In particular, we question the role of intrinsic defects in insulin's target cells as primary mechanisms in the development of insulin resistance in type 2 diabetes and we suggest that metabolic and neurohormonal factors instead are the main culprits. Copyright © 2005 John Wiley & Sons, Ltd. [source] EXAMINATION OF RESPIRATORY AND CIRCULATORY DYNAMICS DURING EXAMINATION USING A THIN GASTROINTESTINAL ENDOSCOPE IN ADVANCED-AGE SUBJECTSDIGESTIVE ENDOSCOPY, Issue 2 2007Miyako Niki Background:, Endoscopic examination influences cardiovascular hemodynamics. Upper gastrointestinal examinations are currently performed with a thin endoscope. In the present study, respiratory and circulatory dynamics and autonomic nervous activity using a thin endoscope (XP260) or a standard endoscope (XQ240) were investigated. Methods:, The subjects were 25 healthy adults aged less than 60 years (middle-aged group) and 15 healthy adults aged 60 years or older (advanced-age group). Percutaneous oxygen saturation, tonometric blood pressure, heart rate, and autonomic nervous activity were evaluated before the examination. After the endoscopic procedure, a questionnaire survey regarding examination-related stress was conducted. Results:, In the questionnaire survey, the proportion of subjects who answered ,very stress free' in the thin endoscope group was significantly higher than that in the standard endoscope group. The low frequency power of blood pressure variability (LFBP), an indicator of sympathetic nervous activity, was significantly lower during the thin endoscopic procedure than during the standard endoscopic procedure. Moreover, the ratio of low frequency power to high frequency power of heart rate variability (LFRR/HFRR), an indicator of sympathetic nervous activity, was significantly lower during thin endoscopic procedure than during the standard endoscopic procedure. The maximum rates of change in the LFBP and HFRR powers in the advanced-age group using thin and standard endoscopic procedures were significantly lower than in the middle-aged group. Conclusions:, The findings, although not in cross-over study, suggest that a thin endoscope has a less marked influence on circulatory kinetics. Gastrointestinal endoscopic examinations using a thin endoscope might reduce complications related to endoscopic screening examinations in advanced-age subjects. [source] Role of mastication and swallowing in the control of autonomic nervous activity for heart rate in different posturesJOURNAL OF ORAL REHABILITATION, Issue 12 2003E. Nitta summary, Mastication and swallowing increase the heart rate, and posture change and respiration also modulate the heart rate. To clarify the role of mastication and swallowing in the modulation of the autonomic nervous activity, we investigated how they interact with modulation of the heart rate by changing body positions and respiration in young healthy subjects. R,R intervals of electrocardiogram at rest were significantly changed with different body positions, compared with supine and standing. A net shortening by mastication of a chewing gum base was similar in various postures. Respiration induced a periodic change in the R,R intervals, depending on the body postures, but mastication did not markedly change them in each posture. Dry swallowing at rest and spontaneous swallowing during the mastication in the sitting position induced a similar transient shortening and suppressed the respiration-induced changes after the swallowing. The net transient shortening by dry swallowing at rest was similar in the different postures. These results suggest that signals from mastication and swallowing are summated with those from body positions and respiration for shortening the R,R intervals and that signals from swallowing suppress the respiration-induced periodic changes. [source] Gastric motility and autonomic activity during obstructive sleep apneaALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 2006M. URATA Summary Background Patients with Obstructive Sleep Apnea Syndrome (OSAS) often experience gastroesophageal reflux disease (GERD). Aim To investigate gastric motility and autonomic nervous activity during sleep apnea. Methods The subjects of this study were 20 individuals with OSAS who experienced 10 or more sleep apnoea events per hour, as measured with a portable sleep polygraph. A percutaneous electrogastrography (EGG) and fast Fourier transformation analysis was carried out on the results. The mean amplitude was compared for bradygastria, normogastria and tachygastria. Spectral analysis of heart rate variability was performed, and low-frequency (LF) power, high-frequency (HF) power and the LF/HF ratio were measured. Oesophagogastroduodenal endoscopy was performed on each subject, and the presence of reflux oesophagitis (RE) was diagnosed according to the Los Angeles (LA) grade classification. Moreover, questionnaire for the diagnosis of reflux disease (QUEST) was carried out. Results Normogastria was significantly decreased, and brady-, tachygastria, or both were increased during sleep apnea (P < 0.01). There was no significant relation between LA grade classification of RE and severity of OSAS. The LF/HF ratio was significantly higher during sleep apnea for patients with RE and OSAS, but the opposite for those with RE without OSAS. Decreased percutaneous arterial oxygen saturation and normogastria were independent risk factors for the severity of RE. Conclusions The present study suggested that, in addition to decreased pressure on the pleural cavity, factors affecting the development of RE might include abnormal gastric motility, low oxygen, and increased sympathetic nervous activity during sleep apnea. [source] Left Atrial Catheter Ablation Promotes Vasoconstriction of the Right Coronary ArteryPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2007EIJI YAMASHITA M.D. Background: Multiple cardiac ganglia are present in the left atrial (LA) region, and marked changes in autonomic nervous activity can occur after left atrial catheter ablation (CA) for atrial fibrillation (AF). Vasospastic angina involving the inferior wall of the left ventricle has been reported as a complication shortly after LACA. Methods: We studied 20 patients with drug-refractory AF who underwent LACA, performed to encircle the left- and right-sided pulmonary veins, 1 to 2 cm from their ostia under fluoroscopic guidance. Quantitative coronary angiography was performed before and after LACA, and we analyzed the minimal lesion diameter (MLD) of the proximal segment of the coronary arteries, and the basal tone, the baseline percent constriction versus maximal dilation after nitroglycerin administration. Results: No significant difference was observed in MLD or basal tone of the left coronary arteries after LACA. However, in the right coronary artery (RCA), the basal MLD was smaller (P < 0.01) and the basal tone was greater (P< 0.05) after than before LACA. No correlation was found between the baseline MLD or tone of the RCA and total amount of radiofrequency energy delivered or procedure duration. In 75% of RCA, the baseline MLD was smaller after than before LACA, which was significantly higher (P < 0.01) than observed in the left coronary arteries (38%). Conclusion: Vasoconstriction was promoted in the RCA shortly after LACA, which may explain the variant angina reported after LACA. [source] Hormonal alterations in adolescent chronic fatigue syndromeACTA PAEDIATRICA, Issue 5 2010Vegard Bruun Wyller Abstract Aim:, The chronic fatigue syndrome is associated with alterations in the hypothalamus-pituitary-adrenal axis and cardiovascular autonomic nervous activity, suggesting a central dysregulation. This study explored differences among adolescent chronic fatigue syndrome patients and healthy controls regarding antidiuretic hormone, the renin-angiotensin-aldosterone-system, sex hormones and cardiac peptides. Methods:, We included a consecutive sample of 67 adolescents aged 12,18 years with chronic fatigue syndrome diagnosed according to a thorough and standardized set of investigations, and a volunteer sample of 55 healthy control subjects of equal gender and age distribution. Hormones were assayed with standard laboratory methods. Results:, Among patients, plasma antidiuretic hormone was significantly decreased and serum osmolality and plasma renin activity were significantly increased (p , 0.001). Serum concentration of aldosterone, cortisol, NT-proBNP and sex hormones were not significantly different in the two groups. Conclusion:, Chronic fatigue syndrome in adolescents is associated with alterations in hormonal systems controlling osmolality and blood volume, possibly supporting a theory of central dysregulation. [source] | ||||||||||