Effects of stimulation of fastigial nucleus on cerebral blood flow in cats

J. L. Williams, D. D. Heistad, J. L. Siems and W. T. Talman Department of Internal Medicine, Veterans Administration Medical Center, University of Iowa College of Medicine, Iowa City 52242. The goal of this study was to examine effects of electrical stimulation of the rostral fastigial nucleus on cerebral blood flow. Anesthetized cats were studied, and arterial pressure and blood gases were maintained at control levels during fastigial stimulation. In one group, we measured vessel diameter and velocity of blood flow through a pial artery with a Doppler probe and calculated blood flow as the product of cross-sectional area and velocity. Electrical stimulation of the fastigial nucleus produced a small increase in pial arterial flow of 16 +/- 6% (means +/- SE, P less than 0.05). Pial vascular resistance increased during moderate hypertension and decreased during decreases in arterial pressure, which indicates that cerebral vascular responses were not impaired. In a second group, cerebral blood flow was measured with microspheres. Blood flow to the pons and medulla increased 25 +/- 11 and 21 +/- 11%, respectively, during stimulation of the fastigial nucleus, but blood flow to the cerebral cortex did not increase significantly. Stimulation produced decreases in flow to the renal cortex and duodenum of 39 +/- 10 and 39 +/- 15%, respectively, and flow to the heart increased 48 +/- 22%, which indicates that the stimulus was efficacious. Thus electrical stimulation of the rostral fastigial nucleus in cats elicits only a small increase in cerebral blood flow.