[Effect of non-depolarizing muscle relaxants on autonomic nervous system activity--assessment by heart rate...

We investigated the effect of d-tubocurarine (d-Tc), pancuronium (PAN), vecuronium (VEC), and rocuronium (ROC) on the autonomic nervous system in cats by measuring changes in the invasive mean arterial pressure (MAP), heart rate (HR), and heart rate variability following four administrations of each drug at 2.ED95. Heart rate variability analysis was used to assess the effects of the drugs on sympathetic and parasympathetic nervous system function using low-frequency (0.04-0.22 Hz) component (LF) and high-frequency (0.22-0.60 Hz) component (HF). Comparisons of the HR, MAP, LF, HF, and LF/HF ratio before and after drug administration were made for each drug. The administration of d-Tc caused a significant decrease in MAP and a significant increase in HR accompanied by increase in LF, HF, and LF/HF ratio. The increases in the LF, HF and LF/HF ratio appeared to be related to the mean abrupt enhancement of sympathetic and parasympathetic nervous system function caused by changes in circulatory dynamics. PAN caused a significant increase in HR, and a significant decrease in the HF, which we thought were related to suppression of cardiac parasympathetic function. Neither VEC nor ROC produced a significant change in any of the parameters and were considered to have no significant effect on the autonomic nervous system.