Respiratory sinus arrhythmia in freely moving and anesthetized rats

2004 ◽  
Vol 97 (4) ◽  
pp. 1431-1436 ◽  
Author(s):  
Evguenia Bouairi ◽  
Robert Neff ◽  
Cory Evans ◽  
Allison Gold ◽  
Michael C. Andresen ◽  
...  
Keyword(s):  
Heart Rate ◽  
Respiratory Sinus Arrhythmia ◽  
Vagal Activity ◽  
General Anesthetics ◽  
Sinus Arrhythmia ◽  
Lung Inflation ◽  
Pentobarbital Sodium ◽  
Freely Moving Rats ◽  
Anesthetized Rats ◽  
Freely Moving

Heart rate increases during inspiration and slows during postinspiration; this respiratory sinus arrhythmia helps match pulmonary blood flow to lung inflation and maintain an appropriate diffusion gradient of oxygen in the lungs. This cardiorespiratory pattern is found in neonatal and adult humans, baboons, dogs, rabbits, and seals. Respiratory sinus arrhythmia occurs mainly due to inhibition of cardioinhibitory parasympathetic cardiac vagal neurons during inspiration. Surprisingly, however, a recent study in anesthetized rats paradoxically found an enhancement of cardiac vagal activity during inspiration, suggesting that rats have an inverted respiratory sinus arrhythmia (Rentero N, Cividjian A, Trevaks D, Pequignot JM, Quintin L, and McAllen RM. Am J Physiol Regul Integr Comp Physiol 283: R1327–R1334, 2002). To address this controversy, this study examined respiratory sinus arrhythmia in conscious freely moving rats and tested whether the commonly used experimental anesthetics urethane, pentobarbital sodium, or ketamine-xylazine alter respiratory sinus arrhythmia. Heart rate significantly increased 21 beats/min during inspiration in conscious rats, a pattern similar to the respiratory sinus arrhythmia that occurs in other species. However, anesthetics altered normal respiratory sinus arrhythmia. Ketamine-xylazine (87 mg/kg and 13 mg/kg) depressed and pentobarbital sodium (60 mg/kg) abolished normal respiratory sinus arrhythmia. Urethane (1 g/kg) inverted the cardiorespiratory pattern so that heart rate significantly decreased during inspiration. Our study demonstrates that heart rate normally increases during inspiration in conscious, freely moving rats, similar to the respiratory sinus arrhythmia pattern that occurs in other species but that this pattern is disrupted in the presence of general anesthetics, including inversion in the case of urethane. The presence and consequences of anesthetics need to be considered in studying the parasympathetic control of heart rate.

scholarly journals Does respiratory sinus arrhythmia occur in fishes?

2005 ◽  
Vol 1 (4) ◽  
pp. 484-487 ◽  
Author(s):  
Hamish A Campbell ◽  
Edwin W Taylor ◽  
Stuart Egginton
Keyword(s):  
Heart Rate ◽  
Respiratory Sinus Arrhythmia ◽  
Selection Pressure ◽  
Vagal Activity ◽  
Sinus Arrhythmia ◽  
Antarctic Species ◽  
Power Spectral ◽  
Spectral Statistics ◽  
Respiratory Modulation ◽  
Environmental Temperatures

The hypothesis that respiratory modulation of heart rate variability (HRV) or respiratory sinus arrhythmia (RSA) is restricted to mammals was tested on four Antarctic and four sub-Antarctic species of fish, that shared close genotypic or ecotypic similarities but, due to their different environmental temperatures, faced vastly different selection pressures related to oxygen supply. The intrinsic heart rate ( f H ) for all the fish species studied was ∼25% greater than respiration rate ( f V ), but vagal activity successively delayed heart beats, producing a resting f H that was synchronized with f V in a progressive manner. Power spectral statistics showed that these episodes of relative bradycardia occurred in a cyclical manner every 2–4 heart beats in temperate species but at >4 heart beats in Antarctic species, indicating a more relaxed selection pressure for cardio-respiratory coupling. This evidence that vagally mediated control of f H operates around the ventilatory cycle in fish demonstrates that influences similar to those controlling RSA in mammals operate in non-mammalian vertebrates.

Respiratory Sinus Arrhythmia in Blood Phobic Subjects

1997 ◽  
Vol 84 (2) ◽  
pp. 505-506 ◽  
Author(s):  
Alessandro Angrilli ◽  
Michela Sarlo ◽  
Daniela Palomba ◽  
Micaela Schincaglia ◽  
Luciano Stegagno
Keyword(s):  
Heart Rate ◽  
Respiratory Sinus Arrhythmia ◽  
Vagal Activity ◽  
Sinus Arrhythmia ◽  
Control Subjects ◽  
Paced Respiration ◽  
Autonomic Index ◽  
Vagal Influence

12 blood-phobic subjects, selected according to the Feat Survey Schedule and the Mutilation Questionnaire, and 50 control subjects performed a paced respiration task during which heart rate and respiration were recorded. Respiratory Sinus Arrhythmia (RSA) was analyzed as an autonomic index of vagal influence on the heart. Analysis showed a larger RSA in the blood-phobic group than the controls and points to a difference in vagal activity at rest between the groups.

A Theoretical Appraisal of the Dependence of Respiratory Sinus Arrhythmia on Gradual Vagal Blockade

2004 ◽  
Vol 43 (01) ◽  
pp. 52-55 ◽  
Author(s):  
E. Pyetan ◽  
S. Akselrod
Keyword(s):  
Heart Rate ◽  
Respiratory Sinus Arrhythmia ◽  
Vagal Tone ◽  
Vagal Activity ◽  
Theoretical Evaluation ◽  
Sinus Arrhythmia ◽  
Cardiac Vagal Tone ◽  
Closed Set ◽  
Vagal Blockade ◽  
The Relationship

Summary Motivation: The high frequency (HF) indices of heart rate variability (HRV), which reflect the magnitude of respiratory sinus arrhythmia (RSA), have been repeatedly used as measures of cardiac vagal tone. Recent studies, however, have shown experimentally that variations in these indices do not necessarily reflect proportional changes in cardiac parasympathetic outflow. Objective: The goal of this study was to obtain a physiological-based theoretical evaluation of the relationship between RSA and cardiac vagal tone, which will help explain conflicting experimental results previously published. Methods: We derived a theoretical model for heart rate (HR) response to gradual vagal blockade. The model implements the integral-pulse-frequency-modulation (IPFM) approach to sinoatrial (SA) node physiology. The level of vagal blockade was simulated by the addition of a cardio-selective muscarinic antagonist. Results and Conclusion: The derivations of the model lead to a closed set of equations, from which the dependence of the HF indices on the level of vagal blockade is deduced. It is shown that several aspects of the physiological condition may have a substantial effect on this relationship: the level of baseline vagal activity, the relationship between vagal tone and the fluctuations in its traffic, the level of sympathetic activity, etc… Hence, changes in the HF indices of HRV provide a plausible assessment of the changes in cardiac vagal tone only under a specific range of physiological conditions.

Respiratory sinus arrhythmia: noninvasive measure of parasympathetic cardiac control

1975 ◽  
Vol 39 (5) ◽  
pp. 801-805 ◽  
Author(s):  
P. G. Katona ◽  
F. Jih
Keyword(s):  
Heart Rate ◽  
Correlation Coefficient ◽  
Respiratory Sinus Arrhythmia ◽  
Rate Control ◽  
Spontaneous Respiration ◽  
Vagal Activity ◽  
Heart Period ◽  
Heart Rate Control ◽  
Sinus Arrhythmia ◽  
Cardiac Control

The degree of parasympathetic heart rate control, PC, was defined as the decrease in average heart period (RR interval) caused by the elimination of parasympathetically mediated influences on the heart while keeping sympathetic activity unchanged. By reviewing published results on the interaction of sympathetic and parasympathetic heart rate control, the prediction was made that PC should be directly proportional to VHP, the peak-to-peak variations in heart period caused by spontaneous respiration. In sevel chloralose/urethan-anesthetized dogs the vagi were reversibly blocked by cooling, and PC (the difference between average heart period before and after cooling) and VHP (without cooling) were determined under a variety of conditions that included a) increasing vagal activity by elevating the blood pressure b) sympathetic blockade, and c) parasympathetic blockade. The relationship between VHP and PC was linear with an average correlation coefficient of 0.969 +/- 0.024 (SD) and a PC-axis intercept of 15.2 +/- 25.9 ms. In each dog the correlation coefficient between VHP and PC was higher than between VHP and the average heart period (avg correlation coef: 0.914 +/- 0.044). These results suggest that the degree of respiratory sinus arrhythmia may be used as a noninvasive indicator of the degree of parasympathetic cardiac control.

Measures of RSA Suppression, Attentional Control, and Negative Affect Predict Self-Ratings of Executive Functions

2011 ◽  
Vol 25 (4) ◽  
pp. 164-173 ◽  
Author(s):  
Brian Healy ◽  
Aaron Treadwell ◽  
Mandy Reagan
Keyword(s):  
College Students ◽  
Heart Rate ◽  
Regression Analysis ◽  
Individual Differences ◽  
Negative Affect ◽  
Respiratory Sinus Arrhythmia ◽  
Attentional Control ◽  
Executive Processes ◽  
Sinus Arrhythmia ◽  
Low Levels

The current study was an attempt to determine the degree to which the suppression of respiratory sinus arrhythmia (RSA) and attentional control were influential in the ability to engage various executive processes under high and low levels of negative affect. Ninety-four college students completed the Stroop Test while heart rate was being recorded. Estimates of the suppression of RSA were calculated from each participant in response to this test. The participants then completed self-ratings of attentional control, negative affect, and executive functioning. Regression analysis indicated that individual differences in estimates of the suppression of RSA, and ratings of attentional control were associated with the ability to employ executive processes but only when self-ratings of negative affect were low. An increase in negative affect compromised the ability to employ these strategies in the majority of participants. The data also suggest that high attentional control in conjunction with attenuated estimates of RSA suppression may increase the ability to use executive processes as negative affect increases.

Assessment of parasympathetic control of heart rate by a noninvasive method

1984 ◽  
Vol 246 (6) ◽  
pp. H838-H842 ◽  
Author(s):  
F. M. Fouad ◽  
R. C. Tarazi ◽  
C. M. Ferrario ◽  
S. Fighaly ◽  
C. Alicandri
Keyword(s):  
Heart Rate ◽  
Respiratory Sinus Arrhythmia ◽  
Separate Group ◽  
Noninvasive Method ◽  
Sinus Arrhythmia ◽  
Beta Adrenergic ◽  
Normal Volunteers ◽  
Vagal Control ◽  
Parasympathetic Control ◽  
The Relationship

The degree of parasympathetic control of heart rate was assessed by the abolition of respiratory sinus arrhythmia with atropine. Peak-to-peak variations in heart periods (VHP) before atropine injection correlated significantly (r = 0.90, P less than 0.001) with parasympathetic control, indicating that VHP alone may be used as a noninvasive indicator of the parasympathetic control of heart rate. Pharmacologic blockade of beta-adrenergic supply in a separate group of normal volunteers did not alter the relationship between VHP and parasympathetic control, indicating that the condition of the experiment (complete rest in a quiet atmosphere) allows the use of VHP alone without pharmacologic interventions to characterize the vagal control of heart rate in humans.

Respiratory sinus arrhythmia in the denervated human heart

1989 ◽  
Vol 67 (4) ◽  
pp. 1447-1455 ◽  
Author(s):  
L. Bernardi ◽  
F. Keller ◽  
M. Sanders ◽  
P. S. Reddy ◽  
B. Griffith ◽  
...  
Keyword(s):  
Heart Rate ◽  
Respiratory Sinus Arrhythmia ◽  
Human Heart ◽  
Normal Subjects ◽  
Respiratory Frequency ◽  
Autonomic Tone ◽  
Sinus Arrhythmia ◽  
Transplant Patients ◽  
Myocardial Wall ◽  
Analysis Technique

We performed this study to test whether the denervated human heart has the ability to manifest respiratory sinus arrhythmia (RSA). With the use of a highly sensitive spectral analysis technique (cross correlation) to define beat-to-beat coupling between respiratory frequency and heart rate period (R-R) and hence RSA, we compared the effects of patterned breathing at defined respiratory frequency and tidal volumes (VT), Valsalva and Mueller maneuvers, single deep breaths, and unpatterned spontaneous breathing on RSA in 12 normal volunteers and 8 cardiac allograft transplant recipients. In normal subjects R-R changes closely followed changes in respiratory frequency (P less than 0.001) but were little affected by changes in VT. On the R-R spectrum, an oscillation peak synchronous with respiration was found in heart transplant patients. However, the average magnitude of the respiration-related oscillations was 1.7–7.9% that seen in normal subjects and was proportionally more influenced by changes in VT. Changes in R-R induced by Valsalva and Mueller maneuvers were 3.8 and 4.9% of those seen in normal subjects, respectively, whereas changes in R-R induced by single deep breaths were 14.3% of those seen in normal subjects. The magnitude of RSA was not related to time since the heart transplantation, neither was it related to patient age or sex. Thus the heart has the intrinsic ability to vary heart rate in synchrony with ventilation, consistent with the hypothesis that changes, or rate of changes, in myocardial wall stretch might alter intrinsic heart rate independent of autonomic tone.

scholarly journals Assessment of Brain Functional Activity Using a Miniaturized Head-Mounted Scanning Photoacoustic Imaging System in Awake and Freely Moving Rats

Biosensors ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 429
Author(s):  
Yuhling Wang ◽  
Tsung-Sheng Chu ◽  
Yan-Ren Lin ◽  
Chia-Hui Tsao ◽  
Chia-Hua Tsai ◽  
...  
Keyword(s):  
Blood Vessel ◽  
Blood Vessels ◽  
Photoacoustic Imaging ◽  
T Test ◽  
Natural Behavior ◽  
Freely Moving Rats ◽  
Anesthetized Rats ◽  
Freely Moving ◽  
Paired T Test ◽  
Awake Rats

Understanding the relationship between brain function and natural behavior remains a significant challenge in neuroscience because there are very few convincing imaging/recording tools available for the evaluation of awake and freely moving animals. Here, we employed a miniaturized head-mounted scanning photoacoustic imaging (hmPAI) system to image real-time cortical dynamics. A compact photoacoustic (PA) probe based on four in-house optical fiber pads and a single custom-made 48-MHz focused ultrasound transducer was designed to enable focused dark-field PA imaging, and miniature linear motors were included to enable two-dimensional (2D) scanning. The total dimensions and weight of the proposed hmPAI system are only approximately 50 × 64 × 48 mm and 58.7 g (excluding cables). Our ex vivo phantom experimental tests revealed that a spatial resolution of approximately 0.225 mm could be achieved at a depth of 9 mm. Our in vivo results further revealed that the diameters of cortical vessels draining into the superior sagittal sinus (SSS) could be clearly imaged and continuously observed in both anesthetized rats and awake, freely moving rats. Statistical analysis showed that the full width at half maximum (FWHM) of the PA A-line signals (relative to the blood vessel diameter) was significantly increased in the selected SSS-drained cortical vessels of awake rats (0.58 ± 0.17 mm) compared with those of anesthetized rats (0.31 ± 0.09 mm) (p < 0.01, paired t-test). In addition, the number of pixels in PA B-scan images (relative to the cerebral blood volume (CBV)) was also significantly increased in the selected SSS-drained blood vessels of awake rats (107.66 ± 23.02 pixels) compared with those of anesthetized rats (81.99 ± 21.52 pixels) (p < 0.01, paired t-test). This outcome may result from a more active brain in awake rats than in anesthetized rats, which caused cerebral blood vessels to transport more blood to meet the increased nutrient demand of the tissue, resulting in an obvious increase in blood vessel volume. This hmPAI system was further validated for utility in the brains of awake and freely moving rats, showing that their natural behavior was unimpaired during vascular imaging, thereby providing novel opportunities for studies of behavior, cognition, and preclinical models of brain diseases.

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