Effects of taurine on cardiovascular and autonomic nervous functions in cold exposed rats

Exposure to cold temperature might affect on cardiovascular and autonomic nervous function. Although there are a lot of studies on physiological and pathophysiological responses of taurine, it was poorly understood the effects of taurine on cardiovascular and autonomic nervous function during cold circumstances. Therefore, the purpose of this study was to clarify the possible role of taurine on cardiovascular and autonomic nervous function in rats exposed to cold temperature. For this purpose, heart rate, blood pressure and locomotive activity were recorded from conscious and unrestrained rats using a telemetry system. Moreover, the autonomic nervous function was investigated by power spectral analysis of heart rate variability. After the recovery period of implantation of transmitter, 1% taurine was supplied during experimental period ad libitum. After the 7 days control period, both taurine administrated and control groups of rats were exposed a cold temperature. There were no differences in heart rate, blood pressure and locomotive activity between taurine and control groups before cold exposure. However, parasympathetic nervous function was somewhat predominant in taurine group. Heart rate and blood pressure in both groups increased greatly by cold exposure. Heart rate in taurine group was much higher than that in control group. LF and HF powers were decreased by cold exposure in both groups. Although no differences were observed in LF, decrease of HF in taurine group was greater than that in control group. These results suggested that taurine might provide some reservoir for cardiovascular and autonomic nervous function to cold stress in rats.