Cardiovascular and respiratory changes during slow-wave sleep in rats are associated with electrocorticogram desynchronization.

J.R Dias-Dos-Santos,B.H Machado

doi:10.1590/s0100-879x1997001100018

J.R Dias-Dos-Santos, B.H Machado

Open Access

https://doi.org/10.1590/s0100-879x1997001100018

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Abstract

In awake rats a single recurrent larger tidal volume (deep breaths) occurs at regular intervals, followed by oscillations in arterial pressure and heart rate. In the present study we recorded the changes in blood pressure, heart rate and ventilation during the wakefulness-sleep cycle identified by electrocorticographic records in order to determine whether the deep breaths and cardiovascular oscillations were associated with changes in the electrocorticogram. During several episodes of slow-wave sleep (SWS) in 7 rats the deep breaths and oscillations in arterial pressure and heart rate were preceded by SWS desynchronization. The interval between deep breaths during SWS was 71 +/- 4 s, the period between initial desynchronization and the generation of deep breaths was 3.98 +/- 0.45 s and the duration of SWS desynchronization was 11 +/- 0.65 s. Hypotension (-16 +/- 1 mmHg) and tachycardia (+15 +/- 5 bpm) were observed during deep breaths in the SWS state. These data indicate that the oscillations in arterial pressure and heart rate during SWS are associated with deep breaths, which in turn are preceded by desynchronization of the electrocorticogram in this state of sleep.

Highlights

Studies on cardiovascular changes in the wakefulness-sleep cycle have shown that short episodes of electrocortical desynchronization occur during slow-wave sleep (SWS) in which arterial pressure exhibits rapid oscillations [1]
The results of the present study indicate that all micro-awake episodes during the SWS are associated with deep breaths and that the transition from SWS to wakefulness as well as from desynchronized sleep (REM) to wakefulness is associated with deep breaths and cardiovascular changes
The cardiovascular changes observed during the SWS desynchronization and simultaneous to the deep breaths were not greater probably because of the buffering role played by the arterial baroreceptors [2,3]

Summary

Introduction

Studies on cardiovascular changes in the wakefulness-sleep cycle have shown that short episodes of electrocortical desynchronization occur during slow-wave sleep (SWS) in which arterial pressure exhibits rapid oscillations [1]. In previous studies we observed that awake normal rats present deep breath events at regular intervals associated with oscillations in arterial blood pressure and heart rate [2,3]. These studies showed that in rats with sino-aortic deafferentation the deep breath events were consistently accompanied by substantial and abrupt reductions of arterial pressure, whereas this effect was markedly lower in intact rats. John et al [5,6,7,8] in decerebrated cats

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