Measurement of intraventricular pressure and cardiac performance in
the intact closed-chest anesthetized mouse0.
Lorenz, John N., and Jeffrey Robbins.
Department of Molecular and Cellular Physiology, University of
Cincinnati and Department of Pediatrics, Children's Hospital Research
Foundation Cincinnati, OH 45267-0576
APStracts 3:0480H, 1996.
In order to fully utilize the potential of newly developed mouse
models with specific genetic mutations, it is necessary to study the
functional consequences of genetic manipulation in the fully intact
animal. To this end, the purpose of the present study was to develop
and validate a methodology for the study of myocardial performance in
the fully intact, closed-chest mouse. Left ventricular function was
evaluated in euthyroid, hypothyroid, and hyperthyroid mice, animals
with well-documented alterations in myocardial function. Mice were
anesthetized and instrumented with polyethylene catheters in the
right femoral artery and vein, and with Milllar mikro-tip transducer
in the left ventricle via the right carotid artery. Structural and
functional evidence suggested that the instrumentation procedure did
not cause myocardial damage, valvular insufficiency, or aortic
obstruction. Isovolumic indices of myocardial contractility derived
from the left ventricular pressure pulse and its first derivative
demonstrated a 40% increase in contractility in the hyperthyroid
animals and a 40% decrease in contractility in the hypothyroid
animals. Similar differences in indices of relaxation were observed.
Furthermore, isoproterenol dose-response relationships of these
contractile parameters were blunted in the hypothyroid animals, and
augmented in the hyperthyroid animals compared to euthyroid controls.
Given the small size of the mouse, and the high frequency of the
cardiac cycle, these data demonstrate the feasibilty of combining a
high-fidelity, micro-tip manometer with a high speed data acquisition
system to obtain faithful recordings of cardiac performance in the
fully intact mouse.
Received 17 July 1996; accepted in final form 9 October 1996.
APS Manuscript Number H639-6.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996