[Vibration-induced morphological changes in the brain stem and spinal cord of the guinea pig].

Some disorders of the brain stem and spinal cord microcirculation were observed in male adult guinea pigs exposed to vertical vibration of frequency 40 Hz and amplitude 1 mm for 3 hours daily during 7, 14, 30 days. These changes after 7 days of vibration were seen as congestion with single small haemorrhages and after 14 days as diffuse spongiosis of the brain stem and spinal cord. After 30 days both congestion with haemorrhages and spongiosis were noted but the first predominated.