AJP - Heart and Circulatory Physiology, Vol 261, Issue 3 707-H713, Copyright © 1991 by American Physiological Society
Cerebrovascular effects produced by electrical stimulation of fastigial nucleus
W. T. Talman, D. M. Dragon, D. D. Heistad and H. Ohta
Department of Neurology, Department of Veterans Affairs Medical Center, Iowa City, Iowa.
We used the microsphere technique and laser flowmetry to assess cerebral
blood flow in 43 anesthetized rats. Cerebral blood flow did not increase
significantly when the fastigial nucleus was stimulated 15 min after
administration of alpha-chloralose. In animals that received maintenance
doses of alpha-chloralose, the modest (50%) increase in cerebral blood flow
that did occur returned toward control during stimulation despite a
continued stable elevation of arterial pressure. Stimulation of fastigial
nucleus 2 h after alpha-chloralose elicited a 20 +/- 3 mmHg increase in
arterial pressure; cerebral blood flow increased gradually for 30-60 s
after the rise in arterial pressure and reached a peak that was
approximately 90% (P less than 0.05) above baseline. The stimuli did not
significantly reduce vascular resistance or impair autoregulation. We did
not stimulate the fastigial nucleus for more than 2 h after administration
of alpha-chloralose because anesthesia was effective for only 2 h. This
study demonstrates that stimulation of the fastigial nucleus in rat
produces a delayed increase in cerebral blood flow that is blocked by
alpha-chloralose anesthesia. The delay in increases of cerebral blood flow
suggests that a metabolic mechanism, not a direct neurogenic vascular
effect, may account for increases in flow with fastigial stimulation.
