Synchrony analysis between blood pressure and sympathetic nerve signal inhibited by atrial receptor stimulation in Wistar rats

Abstract

Recently attempts have been made to analyse blood pressure (BPI and renal sympathetic nerve activity (RSNA) to determine how patterns contained within them might reflect control by the autonomic nervous system. TO date, these studies have primarily used coherence analysis of BP and RSNA in the frequency domain. However, this analysis is unable to assess the non-linear properties of the underlying cardiovascular control system. In t h i s study we employed not only coherence analysis but also cross-entropy analysis using balloon inflation ('balloon-on') to assess the influence of nght atrial receptors on the relationship between BP and RSNA under two conditions in anaesthetised Wistar rats. Balloon-on stimulation alone inhibited RSNA by28 k 4 % in eight rats without changing BP. This effect on integrated nerve activity was not present when atrial stimulation was applied during stimulation of a site in the paraventricular nucleus (PVN) of the hypothalamus which increased RSNA by 158.7 f 58 YO and increased BP by 17.1 k 2.3 mmHg. However, the cross-entropy measurement was significantly decreased (P < 0.05) during balloon-on stimulation in both the conditions revealing that there is greater synchrony between the oscillating signals contained within the BP and RSNA time series. Thus during the enhanced RSNA elicited by stimulation of the PVN, the inhibitory influence of atrial receptors, although apparently blocked, was still effective in that it resulted in the energy of the RSNA spectrum becoming more evenly distributed over a range of frequencies. The data show that cross-entropy calculations are able to characterize the non-lineanties of underlying cardiovascular control. Experimental Physiology (2002) 87.4, 461-468.

Cross‐sample entropy statistic as a measure of complexity and regularity of renal sympathetic nerve activity in the rat

“…Thus, although the functional importance of the lack of synchrony remains to be established, the data suggest that the central brain circuits become more primed to defend the body against a decrease in blood volume. The opposite is likely to accompany an increase in blood volume, as we recently showed by applying the same non‐linear dynamic statistical method to a reduction in RSNA induced by stimulating cardiac atrial receptors (Yang et al 2002 b ).…”

Long-range correlation of renal sympathetic nerve activity in both conscious and anesthetized rats

“…In an attempt to address this issue, a number of investigations have applied mathematical methods to measure patterns of activity and one of the most developed approaches is power spectral analysis. Studies in experimental animals have revealed that, in the renal sympathetic nerve, major energy peaks occur at heart rate frequency, respiratory frequency and also at much lower frequencies (Persson et al, 1992;Malpas et al, 1998;Burgess et al, 1999;Yang et al, 2002).…”

Functional Brain Networks Formed Using Cross-Sample Entropy Are Scale Free

“…XSampEnt also assesses the pattern synchronization between time series rather than just strict nontemporal (zero lag) cross-relation (Richman and Moorman, 2000;Xie et al, 2010). XSampEnt has been successfully applied to the analysis of cardiovascular measures (Yang et al, 2002), renal sympathetic nerve activity (Zhang et al, 2007), fMRI data (Hu and Shi, 2006), EEG data (Vakorin et al, 2010;Xie et al, 2010), and financial data (Liu et al, 2010).…”