Abstract
Previous studies from our laboratory demonstrated that the vestibular system has a significant role in controlling arterial pressure during gravitational stress. The vestibular system is thought to be stimulated not only by gravitational change but also by postural change. Thus, the vestibular system might have a significant role in controlling arterial pressure during postural change. To examine this, arterial pressure was measured during 60°head-up tilt in conscious rats with or without intact vestibular system. Rats were divided into 3 groups: intact, sinoaortic denervation (SAD), and SAD+vestibular lesion (VL). The posture change did not alter arterial pressure in intact group. In SAD group, however, arterial pressure was increased by the posture change. This increase in arterial pressure was completely abolished by additional VL. Thus, the vestibular system has a significant role in an increase in arterial pressure during posture change in SAD group. The increased arterial pressure induced by the vestibular system is buffered by baroreflex, thus arterial pressure is well maintained during posture change in intact group. [J Physiol Sci. 2006;56 Suppl:S133]
