Effect of acute tobacco smoke inhalation on the mechanical responses of isolated rat cardiac muscle

Abstract

To evaluate the effects of acute inhalation of tobacco smoke upon the intrinsic properties of cardiac muscle, rats were exposed to cigarette smoke from 2R1 Kentucky reference cigarettes in special smoking chambers for periods of 10Min/hr for 5 hr. Animals were sacrificed, and the mechanical properties of isolated left ventricular papillary and columnar carneae preparations were studied. Mean COHb concentration of animals exposed to tobacco smoke was 13.2 ± 0.9 vol%. No significant difference was found in rats exposed to tobacco smoke when compared to shams in (1) cardiac chamber weight or chamber wet-to-dry weight ratios, (2) cardiac muscle performance in oxygenated Krebs-Henseleit solution (95% O 2, 5% CO 2), (3) muscle performance during 60 min of hypoxia (95% N 2, 5% CO 2) followed by 30 min of reoxygenation, (4) muscle performance during graded hypoxia with and without glycolytic blockade (iodoacetic acid 10 −4 m), or (5) sensitivity of myocardial performance to isoproterenol. Thus, after acute exposure to tobacco smoke, no effects on the intrinsic mechanical properties of rat cardiac muscle were demonstrable.