Effect of whole body vibration on the rat brain content of serotonin and plasma corticosterone.

To investigate the effects of whole body vibration on the central nervous system, rats were exposed to various whole body vibrations and changes in whole brain levels of Serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were then determined. Changes in plasma corticosterone levels were also determined and related to the changes in the whole brain levels of 5-HT and 5-HIAA. The dose-related changes in the 5-HT and 5-HIAA levels were observed as acceleration increased from 0.4G to 5.0G. Changes in vibration frequency also affected the 5-HT and 5-HIAA levels of brain: they were significantly elevated at a frequency of 20 Hz (P less than 0.05). Plasma corticosterone levels increased as acceleration increased from 0.4G to 5.0G. As the vibration frequency was changed from 5 Hz to 30 Hz, plasma corticosterone levels also rose significantly (P less than 0.05) but the extent of elevation was approximately the same at each frequency. The correlation between brain 5-HT and plasma corticosterone levels with increasing acceleration (r = 0.93, P less than 0.01) was significant.