Long-term effects of ethanol on coronary microvessels of rats

To study the hitherto unknown long-term effects of ethanol on the contractile activity of wall cells of coronary microvessels (mv.), 21 experimental and 21 control animals were investigated, using a new histomorphometric method. The pair-fed rats of the experimental group were given a diet containing ethanol which replaced 36% of the total calories for 4 weeks. This resulted in an increase of wall thickness of mv. in all segments of the microvasculature and an augmentation of the number of ATP-hydrolyzing small-calibered mv. The increase of wall thickness of muscularized mv. was interpreted as a structural adaptation to a long-term predominance of vasotonic influences, which were apparently likewise responsible for the increase of ATP-hydrolysis in the smallest mv. The possible reasons for this predominance are discussed and the necessity to include myocardial metabolic factors in pathogenic considerations on ethanol-induced coronary affections is indicated. Such mv. reactions as observed may be considered as a potential contributive pathogenic factor in ethanol-induced cardiomyopathies and hypertension.