AJP - Heart and Circulatory Physiology, Vol 243, Issue 6 837-H843, Copyright © 1982 by American Physiological Society
Anesthetic depression of microcirculation, central hemodynamics, and respiration in decerebrate rats
J. E. Faber, P. D. Harris and D. L. Wiegman
The objectives of this study were the development of a skeletal muscle
microcirculatory preparation, in which the complications of drug anesthesia
were minimized, and the quantitation of the effects of urethan and
chloralose anesthesia on the microcirculation. Rats were initially
anesthetized with urethan and chloralose and decerebrated by a
midcollicular transection. The cremaster skeletal muscle, with intact
circulation and innervation, was prepared for intravital microscopy by
placement in a tissue bath. Arterioles (9-70 micrometers diam) at several
anatomic levels were observed during the initial period of
urethan-chloralose anesthesia (period 1), after recovery from the
anesthesia (period 2), and again following reanesthetization (period 3).
During period 2, respiratory rate, heart rate, and mean arterial pressure
were significantly greater than during periods 1 and 3. Smaller arterioles
(8-50 micrometers diam) exhibited vasomotion (mean amplitude 35% of mean
diameter; mean frequency 31 cycles/min) during period 2. Urethan-chloralose
anesthesia during periods 1 and 3 inhibited vasomotion and increased
arteriolar diameters by 16-36%. This study quantitates the depressant
effects of urethan-chloralose anesthesia on the cardiovascular system and
demonstrates the feasibility of using decerebration to circumvent the
necessity of continuous drug anesthesia for in vivo microvascular studies.
