Cerebellar control of the cardiovascular responses during postural changes in conscious rabbits.

In conscious control rabbits, tilting the head 30 degrees up from a position 30 degrees down induced initially an inhibition in the renal sympathetic nerve activity (RSNA), however this inhibition immediately released and became a transient increase. Following these responses in RSNA, blood pressure (BP) initially decreased but recovered to the control level within 3-5 s. After bilateral destruction of the lateral nodulus-uvula in the cerebellum, in contrast, the same tilting of the head caused an immediate large increase in RSNA without early inhibition, which was sustained at a high level. BP increased transiently, but then decreased and remained at a level lower than the control. These results indicate that the timing and duration of this transient increase in RSNA during tilting the head up are controlled by the lateral nodulus-uvula and may be important in the rapid adaptation of blood pressure. In addition, this suggests that the lateral nodulus-uvula may play an important role in the cardiovascular control under conditions of consciousness during changes in head position and body posture.