Journal of Applied Physiology, Vol 41, Issue 4 574-580, Copyright © 1976 by American Physiological Society
Cerebellar pressor response in the dog
K. J. Dormer and H. L. Stone
A fastigial pressor response has been elicited in the anesthetized mongrel
dog. Stimulation within the rostral portions of this nucleus results in
mean arterial pressure rises up to 150 mmHg above control. A proportional
tachycardia is simultaneously evoked which may rapidly attain heart rates
of 190 beats/min above control levels. Peak tachycardias immediately suside
and often the heart rate declines below control values during stimulation
while arterial pressure remains elevated. When either the carotid sinuses
were isolated by ligation or a bilateral vagotomy was performed, the
fastigial tachycardia was sustained. Thresholds for the response are near
0.05 mA and the stimulus intensity curve is linear to 0.4 mA whereupon the
pressure rise and tachycardia begin to approach a plateau value. The
response could still be attained when submaximal doses of alpha-chloralose
anesthesia or high levels of barbiturates (30-40 mg/kg) were given. Both
portions of the response result from widespread sympathetic activation;
however, buffering of the response through the baroreceptor reflexes is
only demonstrated in the cardiac segment of the response.
