ACUTE AND CHRONIC EFFECTS OF ETHANOL ON PAPILLARY-MUSCLES FROM SPONTANEOUSLY HYPERTENSIVE RATS

The effects of chronic ethanol ingestion (12 weeks) on the mechanical properties of hyper trophied papillary muscle and the in vitro effects of ethanol (80-640 mg/dl) was studied. Papillary muscles from spontan eously hypertensive rats (SHRs) and their normotensive controls, the W istar-Kyoto rat (WKY), were used in this study. Peak-developed tension was significantly less in muscles obtained from SHR compared with WKY even when normalized for muscle cross-sectional area. Chronic ethanol ingestion resulted in a significant shortening of both contraction an d relaxation duration in muscles from SHR and WKY. In muscles from SHR and WKY, acute in vitro ethanol exposure produced concentration-depen dent negative inotropic effects thai were associated with a reduction in the duration of contraction and relaxation and marked slowing in th e maximum velocities of tension development and decay. These findings suggest that the contractile response to ethanol exposure, in vitro, i s not modified by either chronic ethanol ingestion or hypertension.