Power spectral analysis of short-term RR interval and arterial blood pressure oscillations in the lizard,Gallotia galloti: Effects of sympathetic blockade

Vera, Luis De; González, José M.

doi:10.1002/(sici)1097-010x(19990201)283:2<113::aid-jez1>3.0.co;2-3

Cited by 9 publications

(1 citation statement)

References 17 publications

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“…Overall, cholinergic tone predominates in determining f H in reptiles though the prepared but unrestrained green iguana has similar levels of cholinergic and adrenergic tone on the heart (Figs 1, 2). A series of experiments using power spectral analysis to analyse HRV in the lizard Gallotia galloti showed that it included oscillations at low frequency that were abolished by adrenergic antagonists (De Vera and González, 1999). A high frequency peak appeared whenever the lizards exhibited a pronounced regular respiratory pattern (De Vera et al, 2012).…”

Section: Reviewmentioning

confidence: 84%

The phylogeny and ontogeny of autonomic control of the heart and cardiorespiratory interactions in vertebrates

Taylor

Leite

Sartori

et al. 2014

Journal of Experimental Biology

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Heart rate in vertebrates is controlled by activity in the autonomic nervous system. In spontaneously active or experimentally prepared animals, inhibitory parasympathetic control is predominant and is responsible for instantaneous changes in heart rate, such as occur at the first air breath following a period of apnoea in discontinuous breathers like inactive reptiles or species that surface to air breathe after a period of submersion. Parasympathetic control, exerted via fast-conducting, myelinated efferent fibres in the vagus nerve, is also responsible for beat-to-beat changes in heart rate such as the high frequency components observed in spectral analysis of heart rate variability. These include respiratory modulation of the heartbeat that can generate cardiorespiratory synchrony in fish and respiratory sinus arrhythmia in mammals. Both may increase the effectiveness of respiratory gas exchange. Although the central interactions generating respiratory modulation of the heartbeat seem to be highly conserved through vertebrate phylogeny, they are different in kind and location, and in most species are as yet little understood. The heart in vertebrate embryos possesses both muscarinic cholinergic and β-adrenergic receptors very early in development. Adrenergic control by circulating catecholamines seems important throughout development. However, innervation of the cardiac receptors is delayed and first evidence of a functional cholinergic tonus on the heart, exerted via the vagus nerve, is often seen shortly before or immediately after hatching or birth, suggesting that it may be coordinated with the onset of central respiratory rhythmicity and subsequent breathing.

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Section: Reviewmentioning

confidence: 84%

The phylogeny and ontogeny of autonomic control of the heart and cardiorespiratory interactions in vertebrates

Taylor

Leite

Sartori

et al. 2014

Journal of Experimental Biology

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Relationship between cortical electrical and cardiac autonomic activities in the awake lizard,Gallotia galloti

2000

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ECG and EEG signals were simultaneously recorded in lizards, Gallotia galloti, both in control conditions and under autonomic nervous system (ANS) blockade, in order to evaluate possible relationships between the ANS control of heart rate and the integrated central nervous system activity in reptiles. The ANS blockers used were prazosin, propranolol, and atropine. Time-domain summary statistics were derived from the series of consecutive R-R intervals (RRI) of the ECG to measure beat-to-beat heart rate variability (HRV), and spectral analysis techniques were applied to the EEG activity to assess its frequency content. Both prazosin and atropine did not alter the power spectral density (PSD) of the EEG low frequency (LF: 0.5-7.5 Hz) and high frequency (HF: 7.6-30 Hz) bands, whereas propranolol decreased the PSD in these bands. These findings suggest that central β-adrenergic receptor mechanisms could mediate the reptilian waking EEG activity without taking part any α 1 -adrenergic and/or cholinergic receptor systems. In 55% of the lizards in control conditions, and in ~43% of the lizards under prazosin and atropine, a negative correlation between the coefficient of variation of the series of RRI value (CV RRI ) and the mean power frequency (MPF) of the EEG spectra was found, but not under propranolol. Consequently, the lizards' HRV-EEG-activity relationship appears to be independent of α 1 -adrenergic and cholinergic receptor systems and mediated by β-adrenergic receptor mechanisms.

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Integration of autonomic and local mechanisms in regulating cardiovascular responses to heating and cooling in a reptile (Crocodylus porosus)

Seebacher

Franklin

2004

J Comp Physiol B

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Reptiles change heart rate and blood flow patterns in response to heating and cooling, thereby decreasing the behavioural cost of thermoregulation. We tested the hypothesis that locally produced vasoactive substances, nitric oxide and prostaglandins, mediate the cardiovascular response of reptiles to heat. Heart rate and blood pressure were measured in eight crocodiles (Crocodylus porosus) during heating and cooling and while sequentially inhibiting nitric-oxide synthase and cyclooxygenase enzymes. Heart rate and blood pressure were significantly higher during heating than during cooling in all treatments. Power spectral density of heart rate and blood pressure increased significantly during heating and cooling compared to the preceding period of thermal equilibrium. Spectral density of heart rate in the high frequency band (0.19-0.70 Hz) was significantly greater during cooling in the saline treatment compared to when nitric-oxide synthase and cyclooxygenase enzymes were inhibited. Cross spectral analysis showed that changes in blood pressure preceded heart rate changes at low frequencies (< 0.1 Hz) only. We conclude that the autonomic nervous system controls heart rate independently from blood pressure at higher frequencies while blood pressure changes determine heart rate at lower frequencies. Nitric oxide and prostaglandins do not control the characteristic heart rate hysteresis response to heat in C. porosus, although nitric oxide was important in buffering blood pressure against changes in heart rate during cooling, and inhibition caused a compensatory decrease in parasympathetic stimulation of the heart.

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Power spectral analysis of short-term RR interval and arterial blood pressure oscillations in the lizard,Gallotia galloti: Effects of sympathetic blockade

Cited by 9 publications

References 17 publications

The phylogeny and ontogeny of autonomic control of the heart and cardiorespiratory interactions in vertebrates

The phylogeny and ontogeny of autonomic control of the heart and cardiorespiratory interactions in vertebrates

Relationship between cortical electrical and cardiac autonomic activities in the awake lizard,Gallotia galloti

Integration of autonomic and local mechanisms in regulating cardiovascular responses to heating and cooling in a reptile (Crocodylus porosus)

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