共查询到20条相似文献,搜索用时 15 毫秒
1.
Toledo E Gurevitz O Hod H Eldar M Akselrod S 《American journal of physiology. Regulatory, integrative and comparative physiology》2003,284(4):R1079-R1091
Myocardial infarction (MI) is known to elicit activation of the autonomic nervous system. Reperfusion, induced by thrombolysis, is thus expected to bring about a shift in the balance between the sympathetic and vagal systems, according to the infarct location. In this study, we explored the correlation between reperfusion and the spectral components of heart rate (HR) variability (HRV), which are associated with autonomic cardiac control. We analyzed the HR of patients during thrombolysis: nine anterior wall MI (AW-MI) and eight inferoposterior wall MI (IW-MI). Reperfusion was determined from changes in ST levels and reported pain. Reocclusion was detected in four patients. HRV was analyzed using a modified continuous wavelet transform, which provided time-dependent versions of the typically used low-frequency (LF) and high-frequency (HF) peaks and of their ratio, LF/HF. Marked alterations in at least one of the HRV parameters was found in all 18 reperfusion events. Patterns of HRV, compatible with a shift toward relative sympathetic enhancement, were found in all of the nine reperfusion events in IW-MI patients and in three AW-MI patients. Patterns of HRV compatible with relative vagal enhancement were found in six AW-MI patients (P < 0.001). Significant changes in HRV parameters were also found after reocclusion. Time-dependent spectral analysis of HRV using the wavelet transform was found to be valuable for explaining the patterns of cardiac rate control during reperfusion. In addition, examination of the entire record revealed epochs of markedly diminished HRV in two patients, which we attribute to vagal saturation. 相似文献
2.
Waldén TB Hansen IR Timmons JA Cannon B Nedergaard J 《American journal of physiology. Endocrinology and metabolism》2012,302(1):E19-E31
Mainly from cell culture studies, a series of genes that have been suggested to be characteristic of different types of adipocytes have been identified. Here we have examined gene expression patterns in nine defined adipose depots: interscapular BAT, cervical BAT, axillary BAT, mediastinic BAT, cardiac WAT, inguinal WAT, retroperitoneal WAT, mesenteric WAT, and epididymal WAT. We found that each depot displayed a distinct gene expression fingerprint but that three major types of depots were identifiable: the brown, the brite, and the white. Although differences in gene expression pattern were generally quantitative, some gene markers showed, even in vivo, remarkable depot specificities: Zic1 for the classical BAT depots, Hoxc9 for the brite depots, Hoxc8 for the brite and white in contrast to the brown, and Tcf21 for the white depots. The effect of physiologically induced recruitment of thermogenic function (cold acclimation) on the expression pattern of the genes was quantified; in general, the depot pattern dominated over the recruitment effects. The significance of the gene expression patterns for classifying the depots and for understanding the developmental background of the depots is discussed, as are the possible regulatory functions of the genes. 相似文献
3.
Nakamura K Morrison SF 《American journal of physiology. Regulatory, integrative and comparative physiology》2007,292(1):R127-R136
Control of thermoregulatory effectors by the autonomic nervous system is a critical component of rapid cold-defense responses, which are triggered by thermal information from the skin. However, the central autonomic mechanism driving thermoregulatory effector responses to skin thermal signals remains to be determined. Here, we examined the involvement of several autonomic brain regions in sympathetic thermogenic responses in brown adipose tissue (BAT) to skin cooling in urethane-chloralose-anesthetized rats by monitoring thermogenic [BAT sympathetic nerve activity (SNA) and BAT temperature], metabolic (expired CO(2)), and cardiovascular (arterial pressure and heart rate) parameters. Acute skin cooling, which did not reduce either rectal (core) or brain temperature, evoked increases in BAT SNA, BAT temperature, expired CO(2), and heart rate. Skin cooling-evoked thermogenic, metabolic, and heart rate responses were inhibited by bilateral microinjections of bicuculline (GABA(A) receptor antagonist) into the preoptic area (POA), by bilateral microinjections of muscimol (GABA(A) receptor agonist) into the dorsomedial hypothalamic nucleus (DMH), or by microinjection of muscimol, glycine, 8-OH-DPAT (5-HT(1A) receptor agonist), or kynurenate (nonselective antagonist for ionotropic excitatory amino acid receptors) into the rostral raphe pallidus nucleus (rRPa) but not by bilateral muscimol injections into the lateral/dorsolateral part or ventrolateral part of the caudal periaqueductal gray. These results implicate the POA, DMH, and rRPa in the central efferent pathways for thermogenic, metabolic, and cardiac responses to skin cooling, and suggest that these pathways can be modulated by serotonergic inputs to the medullary raphe. 相似文献
4.
Manish Goyal Arun Goel Ruchi Singh Nilotpal Chowdhury Narsingh Verma Sunita Tiwari 《Chronobiology international》2020,37(6):845-855
ABSTRACT The autonomic nervous system (ANS) is one of the effector pathways for circadian variation of many physiological parameters. Autonomic tone and airways caliber have been reported to exhibit circadian variation in separate studies. A simultaneous investigation of heart rate variability (HRV) and airway caliber might ascertain how airway caliber is modulated by autonomic tone. This study was planned to identify the variations in airway caliber and autonomic function tone during a 24-hour span. A total of 56 healthy male subjects with almost similar daily routines were studied. Time domain, frequency domain and nonlinear analysis of R-R interval from 5 min electrocardiogram (ECG) was done seven times during the daytime wake span at 3-hour intervals starting at 05:00 h in the morning until 23:00 h in the night. Simultaneously peak expiratory flow rate (PEFR) was determined using a mini Wright’s peak flow meter. Rhythmometric analysis was done for PEFR and HRV parameters. Significant circadian variation in low frequency (LF) and high frequency (HF) variance was identified in this group of healthy subjects. The circadian rhythm of LF variance was characterized by a gradual increase and corresponding reciprocal change in HF variance from morning until night. The LF/HF ratio and SD2/SD1 ratio reflecting sympatho-vagal balance showed low to high values from morning to evening. The acrophase of the PEFR temporal pattern is similar to that of LF power and almost opposite in phase to that of HF power. PEFR is positively correlated with LF power. The circadian rhythm of airway caliber co-varies with cardiac autonomic tone. It appears that the temporal pattern of cardiac autonomic tone precedes in time that of airways caliber, thereby suggesting the latter operates under the modulatory effect of the 24-hour pattern in sympatho-vagal balance. 相似文献
5.
We established characteristics of power spectral analysis of heart rate variability, and assessed the diurnal variations of autonomic nervous function in guinea pigs. For this purpose, an electrocardiogram (ECG) was recorded for 24 hr from conscious and unrestrained guinea pigs using a telemetry system. There were two major spectral components, at low frequency (LF) and high frequency (HF) bands, in the power spectrum of HR variability. On the basis of these data, we defined two frequency bands of interest: LF (0.07-0.7 Hz) and HF (0.7-3.0 Hz). The power of LF was higher than that of HF in the normal guinea pigs. Atropine significantly reduced power at HF. Propranolol also significantly reduced power at LF. Furthermore, the decrease in the parasympathetic mechanism produced by atropine was reflected in a slight increase in the LF/HF ratio. The LF/HF ratio appeared to follow the reductions of sympathetic activity produced by propranolol. Autonomic blockade studies indicated that the HF component reflected parasympathetic activity and the LF/HF ratio seemed to be a convenient index of autonomic balance. Nocturnal patterns, in which the values of heart rate in the dark phase (20:00-06:00) were higher than those in the light phase (06:00-20:00), were observed. However, the HF, LF and the LF/HF ratio showed no daily pattern. These results suggest that the autonomic nervous function in guinea pigs has no clear circadian rhythmicity. Therefore, this information may be useful for future studies concerning the autonomic nervous function in this species. 相似文献
6.
Ontogeny of cardiac rate regulation and brown fat thermogenesis in golden hamsters (Mesocricetus auratus) 总被引:2,自引:0,他引:2
M. S. Blumberg 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1997,167(8):552-557
It was shown previously in infant rats (Rattus norvegicus) that the ability to produce heat in the cold using brown adipose tissue (BAT) is closely related to the ability to maintain
cardiac rate. When the limits of BAT thermogenesis were exceeded, interscapular temperature (which reflects the temperature
of the interscapular BAT depot) and cardiac rate fell together. As an extension of this earlier study, the relation between
BAT thermogenesis and cardiac rate was examined here in the golden hamster (Mesocricetus auratus), a species whose young do not exhibit BAT thermogenesis until the end of the 2nd week postpartum. It was found that 3 to
12-day-old hamsters were unable to increase shivering or nonshivering thermogenesis in the cold and exhibited decreases in
cardiac rate that proceeded in lock-step with decreases in interscapular temperature. In contrast, as the thermogenic capability
of hamsters increased after 12 days of age, cardiac rate was maintained within narrow limits across a wide range of air temperatures.
These results support the hypothesis that heat produced by BAT helps to warm the heart and thus aids in the maintenance of
cardiac rate during cold exposure.
Accepted: 16 August 1997 相似文献
7.
Davrath LR Goren Y Pinhas I Toledo E Akselrod S 《American journal of physiology. Heart and circulatory physiology》2003,285(4):H1697-H1704
One of the primary pathologies associated with hypertension is a complex autonomic dysfunction with evidence of sympathetic hyperactivity and/or vagal withdrawal. We investigated the possibility for early detection of essential hypertension on the basis of the analysis of heart rate (HR) and blood pressure fluctuations, which reflect autonomic control. Young adult normotensive offspring of one hypertensive parent (KHT; n = 12) and normotensive offspring of two normotensive parents (YN; n = 14) participated in this study. ECG, continuous blood pressure, and respiration were recorded during steady-state conditions and under various autonomic challenges. Time-frequency decomposition of these signals was performed with the use of a continuous wavelet transform. The use of the wavelet transform enables the extension of typical HR variability analysis to non-steady-state conditions. This time-dependent spectral analysis of HR allows time-dependent quantification of different spectral components reflecting the sympathetic and parasympathetic activity during rapid transitions, such as an active change in posture (CP). During an active CP from the supine to standing position, KHT demonstrated a significantly greater increase in the low-frequency fluctuations in HR than YN, indicating enhanced sympathetic involvement in the HR response to CP, and a reduced alpha-index, indicating decreased baroreceptor sensitivity. On recovery from handgrip, vagal reactivation was more sluggish in KHT. These results indicate the early existence of malfunctions in both branches of autonomic control in individuals at increased risk of hypertension. 相似文献
8.
O. N. Krysyuk 《Human physiology》2007,33(5):577-584
A study of quick adaptation of the myocardium of subjects operating a computer, depending on the adaptive capacities of the body, was conducted in 100 children with ages varying between 10 and 11 years using the electrocardiography method for the analysis of heart rate variability. Significant differences in the bioelectrical processes in the myocardium and autonomic nervous regulation of the cardiac rhythm (CR) were found in children with different adaptive capacities of the body. Quick adaptation to the operator activity in children with a good adaptive capacity is characterized by intensification of atrial activity and metabolic processes in the myocardium, as well as by a shortened duration of the cardiac cycle due to a shorter diastolic time, determined by increased sympathetic influences on the CR. In children with a decreased adaptive capacity, a decrease in the atrial excitability and myocardial metabolism, an increase in the systolic time, a decrease in the diastolic time, and an increase in parasympathetic influences on the CR are observed. 相似文献
9.
Marijke A. K. A. Braeken Andrew H. Kemp Tim Outhred Renée A. Otte Geert J. Y. J. Monsieur Alexander Jones Bea R. H. Van den Bergh 《PloS one》2013,8(12)
Objective
Active anxiety disorders have lasting detrimental effects on pregnant mothers and their offspring but it is unknown if historical, non-active, maternal anxiety disorders have similar effects. Anxiety-related conditions, such as reduced autonomic cardiac control, indicated by reduced heart rate variability (HRV) could persist despite disorder resolution, with long-term health implications for mothers and children. The objective in this study is to test the hypotheses that pregnant mothers with a history of, but not current anxiety and their children have low HRV, predicting anxiety-like offspring temperaments.Methods
The participants in this case-control study consist of 56 women during their first trimester and their offspring (15 male, 29 female). Women had a history of an anxiety disorder (n=22) or no psychopathology (n=34) determined using the Mini-International Neuropsychiatric Interview. The main outcome measures were indices of autonomic cardiac control including root mean square of successive differences (RMSSD) and high frequency (HF) variability. Children’s fearfulness was also assessed using the Laboratory Temperament Assessment Battery (Lab-TAB)-Locomotor Version.Results
HRV was lower in women and children in the past anxiety group compared to controls. HRV measures for mothers and children were positively correlated in the anxiety group only. In all children, low HRV measures at 2-4 months were associated with a higher chance of fearful behavior at 9-10 months.Conclusions
Pregnant women with previous but not current anxiety and their children have low HRV. Children with low HRV tend to show more fearfulness. These findings have implications for identifying children at risk of anxiety disorders and point to possible underlying mechanisms of child psychopathology. 相似文献10.
11.
I. P. Lukashevich R. I. Machinskaya V. M. Shklovskii G. P. Venikova A. V. Danilov E. V. Ziborova T. V. Fridman 《Human physiology》2004,30(4):418-420
The neurophysiological mechanisms of convulsions were studied in the stammering syndrome. Electrophysiological, neurological, neuropsychological, and logopedic examinations were performed for 23 children aged 9–10 years with stammering. For comprehensive analysis, a neurophysiological classification was used to divide the stammering children into two groups: group I, which included patients with paroxysmal patterns recorded in the EEG, and group II, which included patients without paroxysmal EEG patterns. The analysis revealed a correlation of specific features of the autonomic regulation with the character of convulsions. Predominant malfunction of the parasympathetic part of the autonomic nervous system and tonic convulsions in stammering were found in the group I children. Malfunction of the sympathetic part of the autonomic nervous system and clonic convulsions in stammering were characteristic of group II children. 相似文献
12.
Brown adipose tissue (BAT) dysfunction is associated with obesity and its comorbidities, such as hypertension, and the improvement of BAT function seems important for obesity management. Here we investigated the effects of dietary calcium supplementation on BAT autonomic nerve activity, sympathoadrenal function and cardiovascular parameters in adult obese rats that were raised in small litters (SL group). Three days after birth, SL litters were adjusted to three pups to induce early overfeeding. The control group remained with 10 pups/litter until weaning (NL group). At PN120, the SL group was randomly divided into the following: rats fed with standard chow (SL) and rats fed with dietary calcium carbonate supplementation (SL-Ca, 10 g/kg chow). Animals were killed either at PN120 or PN180. At both ages, SL rats had higher BAT autonomic nervous system activity, mass and adipocyte area, as well as increased heart rate and blood pressure (systolic and diastolic); 2 months of calcium supplementation normalized these parameters. At PN180 only, UCP1 and TRβ1 in BAT were decreased in SL rats. These changes were also prevented by calcium treatment. Also at PN180, the SL group presented higher tyrosine hydroxylase and adrenal catecholamine contents, as well as lower hypothalamic POMC and MC4R contents. Calcium supplementation did not revert these alterations. Thus, we demonstrated that dietary calcium supplementation was able to improve cardiovascular parameters and BAT thermogenesis capacity in adult animals that were early overfed during lactation. 相似文献
13.
The main aim of this study was to clarify the general morphology of the autonomic cardiac nervous system in macaque monkeys. A submacroscopic comparative anatomical study of the autonomic cardiac nervous system was performed by examining 22 sides of 11 bodies of four species of macaque monkeys, including some previously unreported species (pig-tailed and stump-tailed monkeys), under a surgical stereomicroscope. The following results were obtained. 1) The basic arrangement of the autonomic cardiac nervous system is constant in all examined macaques. 2) A superior cardiac nerve originating from the superior cervical ganglion was not observed, whereas the thoracic cardiac nerve originating from the sympathetic trunk/ganglia under the cervicothoracic ganglion was rarely observed in all the examined macaques. 3) The main cardiac nerve is the middle cardiac nerve originating from the middle cervical ganglion, similar to the situation in humans. 4) Although the superior, inferior, and thoracic cardiac branches of the vagus nerve were consistently observed, the left thoracic cardiac branch is rarely absent because of its lower origin to the heart. 5) The cranial autonomic nerves tend to distribute into the heart medially (arterial porta), and the caudal autonomic nerves tend to distribute into the heart laterally (venous porta). To comprehend the comparative morphological and evolutionary changes more completely, these results were compared with our previous studies and some references. Consequently, differences in the sympathetic cardiac nerves of macaques and humans are recognized, in spite of the similar morphologies of the vagal cardiac branches. These differences include the composition of the cervicothoracic ganglion, the lower positions of the middle cervical and cervicothoracic ganglia, and the narrow range for the origin of the cardiac nerves in macaques compared to that in humans. 相似文献
14.
Franco Rabbia Bernard Silke Andrea Conterno Tiziana Grosso Barbara De Vito Ivana Rabbone Livio Chiandussi Franco Veglio 《Obesity (Silver Spring, Md.)》2003,11(4):541-548
Objective: To investigate the cardiovascular autonomic function in pediatric obesity of different duration by using standard time domain, spectral heart rate variability (HRV), and nonlinear methods. Research Methods and Procedures: Fifty obese children (13.9 ± 1.7 years) were compared with 12 lean subjects (12.9 ± 1.6 years). Obese children were classified as recent obese (ROB) (<4 years), intermediate obese (IOB) (4 to 7 years), and long‐term obese (OB) (>7 years). In all participants, we performed blood pressure (BP) measurements, laboratory tests, and 24‐hour electrocardiogram/ambulatory BP monitoring. The spectral power was quantified in total power, very low‐frequency (LF) power, high‐frequency (HF) power, and LF to HF ratio. Total, long‐term, and short‐term time domain HRV were calculated. Poincaré plot and quadrant methods were used as nonlinear techniques. Results: All obese groups had higher casual and ambulatory BP and higher glucose, homeostasis model assessment, and triglyceride levels. All parameters reflecting parasympathetic tone (HF band, root mean square successive difference, proportion of successive normal‐to‐normal intervals, and scatterplot width) were significantly and persistently reduced in all obese groups in comparison with lean controls. LF normalized units, LF/HF, and cardiac acceleration (reflecting sympathetic activation) were significantly increased in the ROB group. In IOB and OB groups, LF, but not nonlinear, measures were similar to lean controls, suggesting biphasic behavior of sympathetic tone, whereas nonlinear analysis showed a decreasing trend with the duration of obesity. Long‐term HRV measures were significantly reduced in ROB and IOB. Discussion: Autonomic nervous system changes in adolescent obesity seem to be related to its duration. Nonlinear methods of scatterplot and quadrant analysis permit assessment of autonomic balance, despite measuring different aspects of HRV. 相似文献
15.
Porta A Tobaldini E Guzzetti S Furlan R Montano N Gnecchi-Ruscone T 《American journal of physiology. Heart and circulatory physiology》2007,293(1):H702-H708
Two symbolic indexes, the percentage of sequences characterized by three heart periods with no significant variations (0V%) and that with two significant unlike variations (2UV%), have been found to reflect changes in sympathetic and vagal modulations, respectively. We tested the hypothesis that symbolic indexes may track the gradual shift of the cardiac autonomic modulation during an incremental head-up tilt test. Symbolic analysis was carried out over heart period variability series (250 cardiac beats) derived from ECG recordings during a graded head-up tilt test (0, 15, 30, 45, 60, 75, and 90 degrees ) in 17 healthy subjects. The percentage of subjects showing a significant linear correlation (Spearman rank-order correlation) with tilt angles was utilized to evaluate the performance of symbolic analysis. Spectral analysis was carried out for comparison over the same series. 0V% progressively increased with tilt angles, whereas 2UV% gradually decreased. The decline of 2UV% was greater than the increase of 0V% at low tilt angles. Linear correlation with tilt angles was exhibited in a greater percentage of subjects for 0V% and 2UV% than for any spectral index. Our findings suggest that symbolic analysis performed better than spectral analysis and, thus, is a suitable methodology for assessment of the subtle changes of cardiac autonomic modulation induced by a graded head-up tilt test. Moreover, symbolic analysis indicates that the changes of cardiac sympathetic and vagal modulations observed during this protocol were reciprocal but characterized by different absolute magnitudes. 相似文献
16.
Sabrina G. V. Dutra Ana Paula M. Pereira Geisa C. S. V. Tezini José H. Mazon Marli C. Martins-Pinge Hugo C. D. Souza 《PloS one》2013,8(10)
Background
Aerobic physical capacity plays an important role in reducing morbidity and mortality rates in subjects with cardiovascular diseases. This action is often related to an improvement in the autonomic modulation of heart rate variability (HRV). However, controversies remain regarding the effects of physical training on cardiac autonomic control in healthy subjects. Therefore, our objective was to investigate whether aerobic capacity interferes with the autonomic modulation of HRV and whether gender differences exist.Methods
Healthy men and women (N=96) were divided into groups according to aerobic capacity: low (VO2: 22-38 ml/kg-1 min-1), moderate (VO2: 38-48 ml/kg-1 min-1) and high (VO2 >48 ml/kg-1 min-1.) We evaluated the hemodynamic parameters and body composition. The autonomic modulation of HRV was investigated using spectral analysis. This procedure decomposes the heart rate oscillatory signal into frequency bands: low frequency (LF=0.04-0.15Hz) is mainly related to sympathetic modulation, and high frequency (HF=0.15-0.5Hz) corresponds to vagal modulation.Results
Aerobic capacity, regardless of gender, determined lower values of body fat percentage, blood pressure and heart rate. In turn, the spectral analysis of HRV showed that this parameter did not differ when aerobic capacity was considered. However, when the genders were compared, women had lower LF values and higher HF values than the respective groups of men.Conclusion
The results suggest that aerobic physical capacity does not interfere with HRV modulation; however, the cardiac modulatory balance differs between genders and is characterized by a greater influence of the autonomic vagal component in women and by the sympathetic component in men. 相似文献17.
Using spectral Granger causality (GC) we identified distinct spatio-temporal causal connectivity (CC) patterns in groups of control and epileptic children during the execution of a one-back matching visual discrimination working memory task. Differences between control and epileptic groups were determined for both GO and NOGO conditions. The analysis was performed on a set of 19-channel EEG cortical activity signals. We show that for the GO task, the highest brain activity in terms of the density of the CC networks is observed in α band for the control group while for the epileptic group the CC network seems disrupted as reflected by the small number of connections. For the NOGO task, the denser CC network was observed in θ band for the control group while widespread differences between the control and the epileptic group were located bilaterally at the left temporal-midline and parietal areas. In order to test the discriminative power of our analysis, we performed a pattern analysis approach based on fuzzy classification techniques. The performance of the classification scheme was evaluated using permutation tests. The analysis demonstrated that, on average, 87.6 % of the subjects were correctly classified in control and epileptic. Thus, our findings may provide a helpful insight on the mechanisms pertaining to the cognitive response of children with well controlled epilepsy and could potentially serve as “functional” biomarkers for early diagnosis. 相似文献
18.
I. B. Kulagina 《Neurophysiology》2012,44(1):1-6
On models of motoneurons of the n. abducens nucleus with reconstructed dendritic arborizations having an active membrane, we investigated features of the relationships
between passive transfer properties and dynamics of excitation states of asymmetrical dendrites during generation of complex
periodical and stochastic impulse patterns (output neuronal codes). Various patterns were obtained by varying the intensity
of tonic synaptic excitation homogeneously distributed over the dendrites. The electrical states of sites belonging to branches
of the same dendrite or different dendrites were compared. For this comparison, branches were selected, which, according to
the earlier performed cluster analysis, were assigned to the groups (electrotonic clusters) with a high and a low effectiveness
of passive transfer of the somatopetal current. The selection took into account features of the dendritic structure of neurons
of the exemined type. These were: (i) the presence of groups of the asymmetrical branches differing from each other according
to their belonging to different clusters (high or low transfer effectiveness) in different dendrites, and (ii) the presence
of branches belonging to different dendrites characterized by significantly different orientations in three-dimensional space
of the brainstem within each electrical cluster. Comparative analysis showed that, in a given dendrite during generation of
a complex periodical pattern, the asymmetrical branches belonging to high- or low-efficiency clusters were characterized by
being in different states (high or low depolarization) in different phases of generation of repeated sequences of action potentials
(APs). This relationship was consistent with those previously detected in neurons of other types and in other specimens of
neurons of the above-mentioned type. During generation of such periodical spike patterns, the branches of different dendrites
belonging to the same electrotonic cluster were in similar states. Similar relationships between the states of the branches
of the same dendrite belonging to different clusters were also observed during generation of complex stochastic (non-periodical)
impulse patterns. In the latter case, however, the essential feature was that the branches of different dendrites belonging
to the same electrotonic cluster were often in opposite states. Thus, the number of combinations of discrete electrical states
of asymmetrical parts of the dendritic arborization was much greater. Probably, it is precisely this circumstance that determined
the quasi-stochastic nature of the output impulse pattern. 相似文献
19.
Janine J. Geerling Mari?tte R. Boon Sander Kooijman Edwin T. Parlevliet Louis M. Havekes Johannes A. Romijn Illiana M. Meurs Patrick C. N. Rensen 《Journal of lipid research》2014,55(2):180-189
Important players in triglyceride (TG) metabolism include the liver (production), white adipose tissue (WAT) (storage), heart and skeletal muscle (combustion to generate ATP), and brown adipose tissue (BAT) (combustion toward heat), the collective action of which determine plasma TG levels. Interestingly, recent evidence points to a prominent role of the hypothalamus in TG metabolism through innervating the liver, WAT, and BAT mainly via sympathetic branches of the autonomic nervous system. Here, we review the recent findings in the area of sympathetic control of TG metabolism. Various neuronal populations, such as neuropeptide Y (NPY)-expressing neurons and melanocortin-expressing neurons, as well as peripherally produced hormones (i.e., GLP-1, leptin, and insulin), modulate sympathetic outflow from the hypothalamus toward target organs and thereby influence peripheral TG metabolism. We conclude that sympathetic stimulation in general increases lipolysis in WAT, enhances VLDL-TG production by the liver, and increases the activity of BAT with respect to lipolysis of TG, followed by combustion of fatty acids toward heat. Moreover, the increased knowledge about the involvement of the neuroendocrine system in TG metabolism presented in this review offers new therapeutic options to fight hypertriglyceridemia by specifically modulating sympathetic nervous system outflow toward liver, BAT, or WAT. 相似文献
20.
The efficiency of baroreflex control depends on the baroreflex sensitivity (BRS), which is defined as the ratio of the change in the heart rate (HR) to the change in the blood pressure (BP). The BRS value may be used for assessing the autonomic control of the cardiovascular system and the degree of autonomic dysfunction. Until recently, the baroreflex had not been assessed in a large population of healthy subjects. In this study, the BRS was estimated by the ratio of the low-frequency component of the HR spectrum and the low-frequency component of the rhythm of the systolic BP. For assessing the arterial baroreflex in children, the BRSs for spontaneous and induced baroreflexes were compared. Sex-and age-related differences in BRS were found in 8-to-11-year-old children, and correlations between BRS and some spectral components of HR variability (HRV) and BP rhythm variability were determined. Cluster analysis of the BRS calculated for the spontaneous baroreflex at rest was used to distinguish three clusters of subjects (with high, medium, and low BRSs). These clusters differed in the variability of the basic parameter and size and showed sex-related differences. 相似文献