AJP - Heart and Circulatory Physiology, Vol 253, Issue 6 1335-H1341, Copyright © 1987 by American Physiological Society
Hemodynamic monitoring for 24 h in unanesthetized rats
T. L. Smith, T. G. Coleman, K. A. Stanek and W. R. Murphy
Department of Physiology and Pharmacology, Bowman Gray School of Medicine of Wake Forest University, Winston-Salem, North Carolina 27103.
A new technique is described that allows minute-to-minute recordings of
cardiac output and arterial pressure in unanesthetized rats for periods of
24 h and longer. Rats were instrumented with electromagnetic flow probes
and arterial catheters. An electrical and hydraulic swivel was interposed
between the rat and recording apparatus to allow free range of movement.
Data were collected and analyzed once each minute by computer. Average 24-h
values (mean +/- SD) for the following hemodynamic variables were
determined in eight rats [expressed where appropriate as a function of body
weight (BW)]: cardiac output (98.1 +/- 14.7 ml/min), cardiac index (29.2
+/- 4.4 ml.min-1.100 g BW-1), mean arterial pressure (92.5 +/- 7.8 mmHg),
heart rate (347 +/- 45 beats/min), peak aortic flow (403 +/- 32 ml/min),
stroke volume (282 +/- 26 microliters), stroke volume index (84.4 +/- 8.1
microliters/100 g BW), and total peripheral resistance index (3.26 +/- 0.46
mmHg.ml-1.min.100 g BW). These results provide a data base of hemodynamic
values for unanesthetized adult, Sprague-Dawley male rats, which has not
been previously available. In addition, cardiac index, mean arterial
pressure, and total peripheral resistance index demonstrated diurnal
variation. Diurnal variation contributed substantially to the overall
variance observed within these variables. Hourly variance was also
substantial and indicates the use of continuous recordings for short-term
experiments.
