An electronic, negative feedback device to control arterial pressure.
Cardiovascular investigations frequently require manipulation of the arterial pressure for assessment of neural reflexes. This has largely been accomplished in the past by a bolus injection or constant infusion of a vasoactive drug. The purpose of the present investigation was to develop a proportional, integrative, negative feedback device capable of controlling arterial pressure in rats by modulating the infusion rate of the vasoconstrictor, phenylephrine. The device was designed to 1) maintain arterial pressure at a constant plateau level above the prevailing control pressure and 2) create linear ramp increases in arterial pressure. We have validated this system with conscious and urethan-anesthetized rats instrumented with arterial cannulas for arterial pressure measurement and aortic or venous cannulas for phenylephrine infusion. When used to create steady-state changes in blood pressure at 150 mmHg, the device maintained arterial pressure within +/- 7 mmHg of the desired level for the 20-min experimental periods. When used to create rising arterial pressure ramps (duration: 60 s; magnitude: 30 mmHg), regression analysis of the pressure vs. time relationship indicated that the correlation coefficient was greater than 0.99 in 90% of the trials, indicating a linear ramp. This device will aid in future cardiovascular protocols, especially in the analysis of baroreflex sensitivity.
Pardini
B J
BJ
Veterans Administration Medical Center, Iowa City, Iowa.
Lund
D D
DD
Wurster
R D
RD
Anderson
R H
RH
D000818:Animals; D001795:Blood Pressure Determination / Q000295:instrumentation*; D006339:Heart Rate / Q000187:drug effects; D006706:Homeostasis / Q000187:drug effects; D007260:Infusion Pumps; D010656:Phenylephrine / Q000008:administration & dosage / Q000494:pharmacology; D011311:Pressoreceptors / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D014662:Vasoconstrictor Agents / Q000008:administration & dosage
D014662:Vasoconstrictor Agents; D010656:Phenylephrine