Alcohol and Alcoholism Vol. 36, No. 1, pp. 44-47, 2001
© 2001 Medical Council on Alcoholism
Long-term voluntary ethanol consumption induces impairment of the mechanical performance in the papillary muscle of Sardinian alcohol-preferring rats
Department of Applied Sciences for Biosystems, Division of Human Physiology and Nutrition, University of Cagliari, Via Porcell 4, I–09124 Cagliari and
1 Institute of Human Physiology, Catholic University, Largo F. Vito 1, I–00168 Rome, Italy
Received 25 April 2000; first review notified 26 July 2000; accepted 28 July 2000
— The effects of chronic (26 weeks) ethanol consumption on cardiac muscle contractility in Sardinian alcohol-preferring drinkers (sP-D) and Sardinian alcohol-preferring naive (sP-N) rats were investigated. Experiments were carried out 1 week after ethanol administration ceased. Length–tension and force–frequency responses in left ventricular papillary muscles from both sP-D and sP-N rats were recorded in vitro. Papillary muscles were gradually stretched in steps of 5% of the reference (initial) length (Lr) from 100 to 130% Lr. In sP-D rats, length–tension relationships showed a significant reduction in active tension: at optimal length for maximum active tension (130% Lr), the developed force value (1.38 ± 0.36 mN/mg, dry tissue) was 54% lower than that found in sP-N rats (3.16 ± 0.6 mN/mg, dry tissue). In sP-D papillary muscles, a decrease in contractile behaviour was also observed in force–frequency responses (0.03–120 pulse/min), when compared with sP-N rats; developed force was found to be reduced by about 2.5 times. These results indicate that long-term ethanol consumption impairs the mechanical performance of sP papillary muscle, inducing a negative inotropic effect.