Relaxant effect of microtitan via regulation of autonomic nerve activity in mice

Aims: It has been shown that microtitan may possibly affect the nervous system. In the present study, we examined the effect of microtitan on spontaneous activity during the sleeping period and on autonomic nervous activity in mice. Main methods: Institute of Cancer Research (ICR) mice were divided into placebo and microtitan groups that were housed in chambers with rubber sheets impregnated with microtitan or placebo sheets. In both groups, spontaneous active movement, metabolic parameters, and heart rate variability (HRV) were measured. Key findings: Spontaneous activity during the light period was decreased for mice housed with microtitan sheets compared with placebo sheets. The urinary noradrenalin level was also reduced by microtitan. Heart rate variability was assessed by using a telemetry system and autonomic nervous activity was estimated. Power spectral analysis of R-R interval data revealed that the high frequency band, which shows parasympathetic activity, was significantly increased by microtitan, while the low frequency to high frequency power spectral ratio was decreased in the mice housed with microtitan sheets compared to the mice housed with placebo sheets. Significance: Microtitan promoted rest during the sleeping period by regulating autonomic nervous activity, which indicates that microtitan has a relaxant effect. (C) 2009 Elsevier Inc. All rights reserved.