Effects of systemic hypoxia on R-R interval  and blood pressure variabilities in conscious rats

Murasato, Yoshinobu; Hirakawa, Haruhisa; Harada, Yuji; Nakamura, Tadashi; Hayashida, Yoshiaki

doi:10.1152/ajpheart.1998.275.3.h797

Cited by 47 publications

(54 citation statements)

References 12 publications

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“…First, extrapolations of observations on an anaesthetized adult rat model for non-anaesthetized human foetuses should be performed with extreme caution. Second, the same prudence should also be taken into consideration regarding the anoxia model used, particularly when it is known that this model can dramatically change the HR responses (Murasato et al 1998). These limitations do not allow full direct application of the observations of this study to foetal heart-rate monitoring.…”

Section: Discussionmentioning

confidence: 99%

“…The Wistar rat model has been used for heart-rate analysis research by some centres (Moraru et al 2004, Murasato et al 1998, and it is a model particularly well known at our institution in cardiovascular research (Henriques-Coelho et al 2004, Lourenço et al 2006. Moraru et al (2004) have studied linear and nonlinear HR dynamics in rats recovering from an episode of cardiac arrest.…”

Section: Introductionmentioning

confidence: 99%

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The Obestatin/Ghrelin System as a Novel Regulatory Mechanism of Iris Muscle Contraction

Rocha‐Sousa

Falcão‐Reis

Leite‐Moreira

2008

Current Eye Research

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The objective of this study was the assessment of heart-rate (HR) dynamics with linear and nonlinear methods during episodes of mechanical ventilation and acute anoxia in rats. Namely, to assess whether linear and nonlinear HR analysis was able to discriminate acute anoxia from baseline in rats and if this was consistent with human foetal and adult studies. Five HR segments of 1 min duration, during baseline recording, mechanical ventilation and first, second and third minutes of induced acute anoxia, were analysed in ten adult Wistar rats. Linear time and frequency domain and nonlinear methods were used, namely mean HR (mHR), long-term irregularity (LTI), interval index (II), low frequency (LF) and high frequency (HF), approximate entropy (ApEn) and sample entropy (SampEn). New parameters for the entropy indices are proposed for the analysis of rats' HR. Bootstrap percentile confidence intervals and nonparametric statistical tests were used in the evaluation of the differences between segments. During mechanical ventilation a clear spectral band was detectable at the ventilation rate, but mHR, II and the 'new' entropy indices were the only significantly changed indices. In the transition from baseline-mechanical-ventilation to mechanical-ventilationinduced anoxia, a statistically significant decrease of mHR, II and entropy indices was observed, clearly discriminating these two instances, whereas most linear indices increased. With continued anoxia, most linear indices decreased significantly, whereas entropy remained stably low. These results are consistent with other foetal human and non-human studies and evidence that the rat model may be used for further research on linear and nonlinear analysis of heart-rate dynamics. The transition from baseline to acute anoxia was encompassed by signs of increased activation of the autonomic nervous system sympathetic branch, and decreased or blunted activity of the HR complexity regulatory centres.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Obestatin/Ghrelin System as a Novel Regulatory Mechanism of Iris Muscle Contraction

Rocha‐Sousa

Falcão‐Reis

Leite‐Moreira

2008

Current Eye Research

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“…13,14 However, haemodynamic parameters are totally different in each animal, 15 -17 and optimal animal models for studying HRV corresponding to human HRV are still unclear. Furthermore, there are no published comparative species studies of HRV.…”

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confidence: 99%

Comparative study of heart rate variability between healthy human subjects and healthy dogs, rabbits and calves

Manzo

Ootaki

et al. 2009

Lab Anim

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Several studies have been performed to assess heart rate variability (HRV) in several species such as humans, dogs, pigs, calves, rabbits and rats. However, haemodynamic parameters are totally different in each animal, and optimal animal models for studying HRV corresponding to human HRV are still unclear. The purpose of this study was to assess HRV in human subjects and to compare those HRV data with canine, bovine and rabbit HRV data. The heart rate in the human subjects (62.8 + 7.4 bpm) was significantly lower than that in dogs (124.2 + 18.8 bpm, P , 0.001), calves (73.4 + 10.5 bpm, P , 0.05), and rabbits (217.3 + 21.5 bpm, P , 0.001). The low-frequency waves (LF) (57.

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“…Particular challenges, such as hypercapnia which enhances respiratory sinus arrhythmia and variations in oxygen level, which alter heart rate variation at slower frequencies (17), should differentiate cardiovascular and respiratory responses in CCHS cases over controls and provide insights into deficient mechanisms.…”

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confidence: 99%

Temporal Trends of Cardiac and Respiratory Responses to Ventilatory Challenges in Congenital Central Hypoventilation Syndrome

et al. 2004

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Congenital central hypoventilation syndrome (CCHS) patients exhibit respiratory deficits to ventilatory challenges, diminished breathing drive during sleep, and reduction of respiratoryrelated heart rate variation, but at least partially preserved peripheral chemoreception. We hypothesized that integration of afferent activity with respiratory motor output is deficient in CCHS, rather than chemoreceptor failure, and that examination of trends in heart and breathing rates and variabilities following ventilatory challenges may clarify the deficient mechanisms. Twelve children with CCHS and 12 age-and gender-matched control cases were subjected to hyperoxic hypercapnic, poikylocapnic hypoxic, and hyperoxic challenges while supine. Heart and respiratory rates and variabilities during 60-s baseline and 120-s challenge periods were assessed. Hypoxia and hypercapnia enhanced breathing rate in control subjects; in CCHS cases, the rise differed during hypercapnia and did not occur to hypoxia. Hyperoxia showed initial transient patterns in breathing rate that differed between groups. A heart rate increase to hypoxia and late decline to hyperoxia were muted in CCHS patients. In hypercapnia, heart rate followed similar rising patterns in both groups. Overall CCHS heart rate variability was lower in baseline and challenge periods, principally due to diminished respiratoryrelated variation, especially during hypercapnia. No heart rate variability group differences emerged in hypoxia, and only a late increase for CCHS cases developed in hyperoxia. The findings indicate retention of aspects of chemoreceptor sensitivity in CCHS cases. The heart rate alterations to ventilatory challenges suggest specific compensatory responses of a slower nature remain intact in CCHS, whereas other rapidly changing components are deficient. A number of alterations in respiratory and cardiovascular control characterize CCHS (also known as "Ondine's curse"), including diminished ventilatory responses to CO 2 and hypoxia (1-4), a reduced drive to breathe during sleep (5), greatly diminished high frequency contributions) to heart rate variability (6, 7), and abolition of cold pressor-induced respiratory changes (8). Despite these deficiencies, other respiratory and cardiovascular functions remain intact. CCHS patients can increase ventilation voluntarily in response to exercise, and to passive motion of the extremities, even during sleep (9 -12). Preservation of cardiovascular-related patterns include the slower heart rate variation induced by cold pressor stimulation, or induced by slower respiratory efforts accompanying Valsalva maneuvers (8). In addition, the spontaneous slow variation of heart rate that normally occurs in response to multiple sources during sleep is also present (5, 7), despite loss of faster respiratory-related influences.The classical description of CCHS focuses on central chemoreceptor dysfunction (5, 13), however, components of both peripheral and central chemoreception appear to remain at least partially intact in CCHS. Resp...

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Effects of systemic hypoxia on R-R interval and blood pressure variabilities in conscious rats

Cited by 47 publications

References 12 publications

The Obestatin/Ghrelin System as a Novel Regulatory Mechanism of Iris Muscle Contraction

The Obestatin/Ghrelin System as a Novel Regulatory Mechanism of Iris Muscle Contraction

Comparative study of heart rate variability between healthy human subjects and healthy dogs, rabbits and calves

Temporal Trends of Cardiac and Respiratory Responses to Ventilatory Challenges in Congenital Central Hypoventilation Syndrome

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