Spectral heart rate variability and selected biochemical markers for autonomic activity in rats under pentobarbital anesthesia

Abstract

Abstract Introduction Autonomic nervous system (ANS) function can be evaluated by analysis of heart rate variability (HRV) and plasma concentration of noradrenaline (NA). Recent studies identified potential, biochemical markers of the ANS activity, including selected co-transmitters, released from either sympathetic (e.g. neuropeptide Y – NPY) or parasympathetic (e.g. vasoactive intestinal peptide – VIP) fibers. Aim The aim of the study was to analyze HRV recordings and to determine plasma level of NA, NPY and VIP in 3–12 months males and females rats under pentobarbital anesthesia. Moreover, our goal was to determine overall and gender-dependent correlation between the HRV indices and abovementioned compounds. Material and methods The experiment included 36 rats with different autonomic tone related to age and gender. Spectral HRV analysis was applied and NA, NPY and VIP were measured by ELISA. Results and discussion Male rats were characterized by significantly higher values of selected HRV indices: total power (TP), very low frequency (VLF) and high frequency (HF) and plasma concentrations of both analyzed neuropeptides comparing to female ones. Similar to the overall assessment, both males and females showed significant correlations between NA and TP, VLF and LF. Moreover, male rats (but not female ones) presented with significant moderate correlations between NPY and LF, VIP and TP, HF and normalized HF (nHF). Conclusions Our preliminary findings imply that NA correlates with global autonomic activity (TP) and with the values of sympathetically-driven components (VLF and LF). Furthermore, VIP seems to correlate with specific measures of parasympathetic drive (HF and nHF), but only in male rats.