AJP - Heart and Circulatory Physiology, Vol 246, Issue 6 806-H810, Copyright © 1984 by American Physiological Society
Effect of thiamylal on the response to carotid occlusion and mild hemorrhage in rabbits
T. Yamazaki and K. Sagawa
The effects of anesthesia (thiamylal, 30 mg/kg) on steady-state mean
arterial pressure responses to bilateral carotid occlusion (BCO) and rapid
8% hemorrhage were studied in 11 rabbits chronically instrumented with an
arterial pressure catheter and balloon occluders on the common carotid
arteries. The BCO was repeated in the conscious and anesthetized states
both before and after transecting the aortic nerves (AN). With the AN
intact, the BCO response was an increase in mean systemic arterial pressure
of 23.6 +/- 2.1 (SE) mmHg in the conscious state and 24.7 +/- 1.2 in the
anesthetized state. With the AN cut (AN) BCO response was 46.2 +/- 1.7 mmHg
in conscious state and 45.7 +/- 2.6 in anesthetized state. There was no
significant difference in BCO response between conscious and anesthetized
states, whether the AN was present or absent. The hemorrhage experiment was
repeated on separate days under various conditions, including carotid sinus
reflex elimination (CS). With AN intact the posthemorrhage fall in mean
arterial pressure (delta MAPh) was 3.2 +/- 0.6 mmHg in the conscious state.
Under anesthesia, delta MAPh was 3.4 +/- 0.6 mmHg in the AN intact
condition, 7.3 +/- 0.9 in AN, and 34.5 +/- 6.8 in (AN + CS). There was no
significant difference in delta MAP between the conscious and anesthetized
states under the intact AN condition. We conclude that, in the rabbit,
thiamylal anesthesia has little effect on the BCO response and the
restoration of arterial pressure after a mild hemorrhage.
