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Autonomic Regulation (autonomic + regulation)
Selected AbstractsBrainstem mechanisms underlying the sudden infant death syndrome: Evidence from human pathologic studiesDEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2009Hannah C. Kinney Abstract The brainstem hypothesis is one of the leading hypotheses concerning the sudden infant death syndrome (SIDS). It states that SIDS, or an important subset of SIDS, is due to abnormal brainstem mechanisms in the control of respiration, chemosensitivity, autonomic regulation, and/or arousal which impairs the infant's response to life-threatening, but often occurring, stressors during sleep (e.g., hypoxia, hypercarbia, asphyxia, hyperthermia) and leads to sudden death in a vulnerable developmental period. In this review, we summarize neuropathologic evidence from SIDS cases that support this hypothesis, beginning with the seminal report of subtle brainstem gliosis three decades ago. We focus upon recent neurochemical studies in our laboratory concerning the neurotransmitter serotonin (5-HT) and its key role in mediating protective responses to homeostatic stressors via medullary circuits. The possible fetal origin of brainstem defects in SIDS is reviewed, including evidence for adverse effects of prenatal exposure to maternal cigarette smoking and alcohol upon the postnatal development of human brainstem 5-HT pathways. © 2009 Wiley Periodicals, Inc. Dev Psychobiol 51: 223,233, 2009 [source] Cardiac Autonomic Control in Patients with Refractory Epilepsy before and during Vagus Nerve Stimulation Treatment: A One-Year Follow-up StudyEPILEPSIA, Issue 3 2006Eija Ronkainen Summary:,Purpose: To elucidate possible effect of vagus nerve stimulation (VNS) therapy on interictal heart rate (HR) variability in patients with refractory epilepsy before and after 1-year VNS treatment. Methods: A 24-hour electrocardiogram (ECG) was recorded at the baseline and after 12 months of VNS treatment in 14 patients with refractory epilepsy, and once in 28 healthy age- and sex-matched control subjects. Time and frequency domain measures, along with fractal and complexity measures of HR variability, were analyzed from the ECG recordings. Results: The mean value of the RR interval (p = 0.008), standard deviation of N-N intervals (SDNN) (p < 0.001), very-low frequency (VLF) (p < 0.001), low-frequency (LF) (p = 0.001), and high-frequency (HF) (p = 0.002) spectral components of HR variability, and the Poincaré components SD1 (p = 0.005) and SD2 (p < 0.001) of the patients with refractory epilepsy were significantly lower than those of the control subjects before VNS implantation. The nocturnal increase in HR variability usually seen in the normal population was absent in patients with refractory epilepsy. VNS had no significant effects on any of the HR-variability indexes despite a significant reduction in the frequency of seizures. Conclusions: HR variability was reduced, and the nocturnal increase in HR variability was not present in patients with refractory epilepsy. One-year treatment with VNS did not have a marked effect on HR variability, suggesting that impaired cardiovascular autonomic regulation is associated with the epileptic process itself rather than with recurrent seizures. [source] Impact of body fat mass extent on cardiac autonomic alterations in womenEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 8 2009J. Sztajzel Abstract Background, Obesity has been associated with significant abnormalities of the cardiac autonomic regulation. However, the precise impact of increasing body weight on cardiac autonomic function and the metabolic and hormonal contributors to these changes are presently unclear. The aim of our study was to explore in subjects with increasing values of body mass index (BMI) the alterations of cardiac autonomic function and to establish the potential role of various metabolic and hormonal contributors to these alterations. Materials and methods, We investigated time and frequency domain heart rate variability (HRV) parameters taken from 24-h Holter recordings, and several anthropometric, metabolic and hormonal parameters (plasma glucose, insulin, triglycerides, free fatty acids, leptin and adiponectin) in 68 normoglycaemic and normotensive women (mean age of 40 ± 3 years), subdivided according to their BMI into 15 normal body weight (controls), 15 overweight, 18 obese and 20 morbidly obese. Results, Heart rate was increased and HRV was decreased in the morbidly obese group as compared with controls. In overall population, a negative association linked body fat mass (FM) to HRV indices. None of the metabolic and hormonal parameters were significantly related to the HRV indices, after they were adjusted for the body FM. Conclusions, Morbidly obese, normoglycaemic and normotensive young women have increased HR and low HRV, indicating an abnormal cardiac autonomic function and representing a risk factor for adverse cardiovascular events. A decrease of HRV parameters is associated with a progressive increase of body FM. Other metabolic and hormonal factors, characterising obesity, do not show an independent influence on these HRV alterations. [source] Autonomic Blockade Unmasks Maturational Differences in Rate-Dependent Atrioventricular Nodal Conduction and Facilitation in the MouseJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2003SAMIR SABA M.D. Maturational Differences in Murine AVN Conduction. Introduction: In large animals, rate-dependent AV nodal (AVN) properties of conduction are modulated by autonomic inputs. In this study, we investigated whether the properties of AVN conduction and facilitation are altered by autonomic blockade in the mouse and whether this effect is age dependent. Methods and Results: Young (age 4,6 weeks; n = 11) and adult (age 8,9 months; n = 11) female mice underwent in vivo electrophysiologic testing, before and after autonomic blockade. After autonomic blockade, the adult mice had significantly longer AVN effective refractory period (AVNERP; 67 ± 14 msec vs 56 ± 4 msec, P = 0.05) and functional refractory period (AVNFRP; 81 ± 10 msec vs 72 ± 4 msec, P = 0.05). With autonomic blockade, the increase from baseline of AVN Wenckebach cycle length (,AVW; 1.8 ± 8.1 msec vs 8.8 ± 3.3 msec, P = 0.04), as well as of AVNERP (,AVNERP; 3.5 ± 3.5 msec vs 21.4 ± 12.6 msec, P = 0.002) and AVNFRP (,AVNFRP; 2.3 ± 3.2 msec vs 12.8 ± 9.0 msec, P = 0.008), was significantly larger in adult than in young mice. Compared with young mice, adult mice were less likely to exhibit AVN facilitation (44% vs 90%, P = 0.03) and had smaller maximal shortening of AVN conduction times after the "test beat" for any coupling of the "facilitating beat" (4 ± 4 msec vs 7 ± 3 msec, P = 0.05). Conclusion: Complete autonomic blockade significantly increases AVN conduction times and refractory periods in adult but not in young mice. Adult mice also exhibit less AVN facilitation. Our results confirm that, like in larger animals, rate-dependent murine AVN properties of conduction are under autonomic regulation. Adult mice have higher sympathetic AVN inputs at baseline, leading to slower conduction after autonomic blockade. (J Cardiovasc Electrophysiol, Vol. 14, pp. 191-195, February 2003) [source] Role of calcium in the gating of isoproterenol-induced arylalkylamine N- acetyltransferase gene expression in the mouse pineal glandJOURNAL OF PINEAL RESEARCH, Issue 1 2006Mathieu Chansard Abstract:, Melatonin and its autonomic regulation serve important physiological functions. We recently demonstrated that stimulation of beta-adrenergic receptors only increases nighttime arylalkylamine N- acetyltransferase (Aa-Nat, the rate-limiting enzyme in melatonin synthesis) mRNA levels in mouse pineal gland in vitro, which suggests that pineal clocks may gate Aa-Nat gene expression. In the present study, our data reveal that cAMP analog increased Aa-Nat at any time of day but only in the presence of ionomycin. Using Fura-2AM in ratiometric calcium measurements, we show that isoproterenol stimulation increased intracellular free calcium levels at night, contrary to previous reports. Further, intra- or extracellular calcium depletion suppressed the isoproterenol-induced calcium responses as well as Aa-Nat gene expression. These results suggest calcium may be a critical factor in isoproterenol-induced Aa-Nat gene expression, which may be limited in the daytime. We also found that basal intracellular calcium levels were lower during the night and responses to isoproterenol and KCl depolarization were more robust. In addition, pineals of Cryptochrome mutant mice exhibited no significant difference between day and nighttime basal calcium or isoproterenol response. Together, these results suggest that basal calcium levels in the pineal may be controlled by the endogenous pineal clock, which may influence calcium dynamics, cellular homeostasis and sensitivity to external stimulation. Although the mechanism underlying Aa-Nat gene expression has been well studied, the role of calcium as a link between the pineal clock and Aa-Nat gene expression has been underestimated in rodent pineals. [source] Altered Autonomic Cardiac Control Predicts Restenosis After Percutaneous Coronary InterventionPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2006MATTHIAS GOERNIG Background: Early and late restenosis in up to 30% remains a major problem for long-term success after percutaneous coronary intervention (PCI). Compared to bare metal stents, the use of drug-eluting stents reduces restenosis below 10%, but implant coasts have to be considered. In restenosis noninvasive testing lacks diagnostic power. We applied a new approach to identify patients with a high risk for restenosis after PCI by combining heart rate (HR) and blood pressure variability (BPV) analyses. Methods: In 52 patients with clinical suspicion of restenosis and history of PCI, we investigated patterns of cardiovagal autonomic regulation prior to cardiac catheterization. The patients were separated in (i) patients with restenosis (CAD+R) and (ii) patients without restenosis (CAD,R), where restenosis is defined as a stenosis greater than 75% of luminal diameter in at least one main vessel. The following parameters/methods were evaluated: Canadian Cardiovascular Society grade (CCS-grade), vessel disease score (CAD-level), left ventricular ejection fraction (LVEF), heart rate variability (HRV), BPV, baroreflex sensitivity (BRS), as well as HR turbulence and blood pressure (BP) potentiation caused by premature ventricular complexes. Results: Whereas age, LVEF, CAD-level, CCS-grade, and mean BP did not differ between CAD+R and CAD,R, significant differences were found in (i) BPV: diastolic LF/P, systolic, and diastolic UVLF, (ii) in BRS: slope of tachycardic sequences, and (iii) in extrasystolic parameters: heart rate turbulence onset (HRTO) and potentiation of systolic BP (SBPP). Standard HRV parameters did not show significant differences between the groups. Using the two parameters diastolic LF/P (threshold >0.2) and HRTO (threshold >0) restenosis were predicted in 83.4%. Conclusions: These results demonstrate that indicators of sympathetic activation or vagal depression identify restenosis in patients after PCI, thus opening a perspective for a new noninvasive monitoring. [source] The impact of menstrual cycle phase on cardiac autonomic regulationPSYCHOPHYSIOLOGY, Issue 4 2009Paula S. Mckinley Abstract This study investigated menstrual cycle phase differences in heart rate (HR) and RR interval variability (RRV) in 49 healthy, premenopausal, eumenorrheic women (age 30.2±6.2 years). HR and RRV were computed from ambulatory 24-h electrocardiogram, collected for up to 6 days, with at least 1 day each during early to midfollicular and midluteal menstrual phases. Phase effects on HR and RRV were assessed using linear mixed effects models with a random intercept to account for the correlation of observations within each subject as well as intrasubject variation. During follicular phase monitoring, women had significantly lower average HR (,2.33 bpm), and higher standard deviation, the root mean squared successive difference, and high frequency (0.04,0.15 Hz) and low frequency (0.15,0.40 Hz) RRV than during the luteal phase. These results provide strong support for the influence of menstrual phase on cardiac autonomic regulation in premenopausal women. [source] Atypical autonomic regulation in perpetrators of violent domestic abusePSYCHOPHYSIOLOGY, Issue 2 2002John C. Umhau Perpetrators of domestic violence describe symptoms that are compatible with exaggerated autonomic arousal at the time of the domestic violence. This inappropriate arousal may be reflected in altered heart rate regulation. If heart rate is systematically regulated by vagal mechanisms, then increases in heart rate should correlate with decreases in cardiac vagal activity, as indexed by respiratory sinus arrhythmia (RSA). We hypothesized that perpetrators of domestic violence have an alteration in heart rate regulation. To test this hypothesis we compared the results of a postural shift performed on perpetrators, healthy volunteers, and nonviolent alcoholics. Results showed there were no significant differences in heart rate, RSA, or catecholamines. However, the significant inverse relationship between posture-elicited changes in RSA and heart rate present in the healthy volunteers was not found in perpetrators. These differences in the covariation between heart rate and RSA may represent differences in the neural regulation of heart rate and may be related to difficulties in controlling autonomic state. [source] Heart rate variability in type 2 spinocerebellar ataxiaACTA NEUROLOGICA SCANDINAVICA, Issue 5 2010J. Montes-Brown Montes-Brown J, Sánchez-Cruz G, García AM, Báez ME, Velázquez-Pérez L. Heart rate variability in type 2 spinocerebellar ataxia. Acta Neurol Scand: 2010: 122: 329,335. © 2010 The Authors Journal compilation © 2010 Blackwell Munksgaard. Objectives,,, To explore cardiovascular autonomic regulation in Spinocerebellar ataxia type 2 (SCA2) patients, using heart rate variability (HRV) analysis and neurophysiologic autonomic reflex tests, and determine relations and causal related factors of dysautonomia in SCA2. Materials and methods,,, Heart rate variability indices for 5 min series of RR intervals were analyzed in 97 SCA2 patients, assessed quantitatively for somatic and autonomic nervous system complaints applying the International Cooperative Ataxia Rating Scale and Scales for Outcomes in Parkinson's disease (SCOPA-AUT), respectively. Autonomic testing included: resting control, standing, Valsalva maneuver and deep breathing. Results,,, Mean RR, long- and short-term variability indices and spectral density power (LF, HF) indices were lower in the patients group, whereas LF/HF ratio and LF (nu) were higher. Highly differences between groups were observed for seven diagnostic autonomic test indices. Significant correlations were found between different clinical and demographic indices and between clinical indices and some HRV indices. Conclusions,,, We confirm the presence of cardiovascular autonomic dysfunction in a large group of SCA2 patients. [source] Chronic fatigue in adolescence,autonomic dysregulation and mental health: an exploratory studyACTA PAEDIATRICA, Issue 8 2009Helene Gjone Abstract Aim:, The present study investigates associations between autonomic cardiovascular dysregulation, psychosocial load and mental health in adolescents presenting with chronic fatigue. Method:, Twenty-two adolescents, mean age 15.7 years (12.7,19.1), underwent a clinical mental health examination as part of a broad medical investigation which included autonomic tests. Adolescents and their parents were also interviewed with regard to psychosocial stress factors, family health and previous illnesses. A count of psychosocial load was made for each adolescent based on the interview. Results:, Of 22 fatigued adolescents in the present sample, 14 had psychiatric diagnoses. There was no significant difference in psychosocial load for the fatigued adolescents classified with normal autonomic regulation compared to those with deviant or borderline autonomic regulation. The present psychiatric diagnosis did not differ between the two groups. In a subsample, there was a significant negative association between depressive symptoms and abnormal blood pressure responses during orthostatic challenge. Conclusion:, No significant psychiatric or psychosocial differences between fatigued adolescents with or without autonomic dysregulation were found in this study. The trends towards higher psychosocial load and greater burden of depressive symptoms in fatigued adolescents with normal autonomic regulation warrant further studies. [source] HTR2A variation and sudden infant death syndrome: a case,control analysisACTA PAEDIATRICA, Issue 1 2009Casey M Rand Abstract Aim: The serotonergic (5-HT) system functions in central autonomic regulation with homeostatic roles in cardiorespiratory control, thermoregulation, arousal and sleep-wake cycling. Altered function and development of this system in cases of sudden infant death syndrome (SIDS) have been established, but the aetiology of these disturbances remains unclear. The serotonin receptor, HTR2A, functions within this system with roles in the homeostatic response to hypoxia including excitatory effects on respiration, gasping and rhythm generation, all functions potentially compromised in SIDS. The objective of this study was to examine the relationship between SIDS risk and HTR2A variation. Methods: All coding regions, intron,exon boundaries and the promoter region of HTR2A were PCR amplified and analysed by standard sequencing in 96 SIDS cases and 96 matched controls. Results: Twenty-one HTR2A variations were identified in this case,control cohort, including four novel variations (c.C-1185A, c.T-923C, c.T-17C and c.C50T). None of the variations identified showed a significant association with SIDS. Conclusion: This report provides evidence that despite known alterations of the 5-HT system in SIDS, and the logical role for the HTR2A receptor, genetic variation of HTR2A as studied in our cohort is not responsible for these alterations. These results represent a further step in the investigation of the aetiology of the altered serotonin system in SIDS cases. [source] SPATIAL AND TEMPORAL ASPECTS OF cAMP SIGNALLING IN CARDIAC MYOCYTESCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 11 2008Radu V Iancu SUMMARY 1,1 -Adrenoceptor and M2 muscarinic receptor regulation of cAMP production plays a pivotal role in autonomic regulation of cardiac myocyte function. However, not all responses are easily explained by a uniform increase or decrease in cAMP activity throughout the entire cell. 2Adenovirus expression of fluorescence resonance energy transfer (FRET)-based biosensors can be used to monitor cAMP activity in protein kinase A (PKA) signalling domains, as well as the bulk cytoplasmic domain of intact adult cardiac myocytes. 3Data obtained using FRET-based biosensors expressed in different cellular microdomains have been used to develop a computational model of compartmentalized cAMP signalling. 4A systems biology approach that uses quantitative computational modelling together with experimental data obtained using FRET-based biosensors has been used to provide evidence for the idea that compartmentation of cAMP signalling is necessary to explain the stimulatory responses to ,1 -adrenoceptor activation as well as the complex temporal responses to M2 muscarinic receptor activation. [source] Decrease in heart rate variability with overtraining: assessment by the Poincaré plot analysisCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 1 2004Laurent Mourot Summary Numerous symptoms have been associated with the overtraining syndrome (OT), including changes in autonomic function. Heart rate variability (HRV) provides non-invasive data about the autonomic regulation of heart rate in real-life conditions. The aims of the study were to: (i) characterize the HRV profile of seven athletes (OA) diagnosed as suffering of OT, compared with eight healthy sedentary (C) and eight trained (T) subjects during supine rest and 60° upright, and (ii) compare the traditional time- and frequency-domain analysis assessment of HRV with the non-linear Poincaré plot analysis. In the latter each R-R interval is plotted as a function of the previous one, and the standard deviations of the instantaneous (SD1) and long-term R-R interval variability are calculated. Total power was higher in T than in C and OA both in supine (1158 ± 1137, 6092 ± 3554 and 2970 ± 2947 ms2 for C, T and OA, respectively) and in upright (640 ± 499, 1814 ± 806 and 1092 ± 712 ms2 for C, T and OA, respectively; P<0·05) positions. In supine position, indicators of parasympathetic activity to the sinus node were higher in T compared with C and OA (high-frequency power: 419·1 ± 381·2, 1105·3 ± 781·4 and 463·7 ± 715·8 ms2 for C, T and OA, respectively; P<0·05; SD1: 29·5 ± 18·5, 75·2 ± 17·2 and 37·6 ± 27·5 for C, T and OA, respectively; P<0·05). OA had a marked predominance of sympathetic activity regardless of the position (LF/HF were 0·47 ± 0·35, 0·47 ± 0·50 and 3·96 ± 5·71 in supine position for C, T and OA, respectively, and 2·09 ± 2·17, 7·22 ± 6·82 and 12·04 ± 10·36 in upright position for C, T and OA, respectively). The changes in HRV indexes induced by the upright posture were greater in T than in OA. The shape of the Poincaré plots allowed the distinction between the three groups, with wide and narrow shapes in T and OA, respectively, compared with C. As Poincaré plot parameters are easy to compute and associated with the ,width' of the scatter gram, they corroborate the traditional time- and frequency-domain analysis. We suggest that they could be used to indicate fatigue and/or prevent OT. [source] | |||||||||||||||||||