Coronary vasoconstriction and catecholamine XXXX .

@entity296 @entity26 @entity5521 @entity95 @entity1063
@entity1063 (NE) causes extensive @entity296 in the @entity95 . To investigate a potential mechanism we measured coronary blood flow with radioactive microspheres. Coronary resistance and @entity26 demand (heart rate-blood pressure double product) were calculated. Severity of injury was determined by semiquantitative histologic evaluation. Changes resulting from NE infusion were determined in animals with or without alpha-receptor blockade with @entity5521 (10 mg). In all animals @entity26 demand remained constant. Coronary blood flow (ml/gm/min) was 2.66 at the beginning of the experiment, rose to 3.46 after 3 minutes of NE infusion (p less than 0.05), then declined to baseline values (2.33) after 10 minutes. However, coronary blood flow was sharply lower than baseline (1.51; p less than 0.05) after 40 minutes of infusion. Coronary resistance rose progressively from baseline values of 40.9 (units) to 74.8 at 40 minutes (p less than 0.05). Animals given @entity5521 manifested none of these changes. Control subjects infused with saline solution showed no significant changes in coronary blood flow or coronary resistance. Animals pretreated with @entity5521 had minimal histologic damage at 48 hours compared with NE alone (p less than 0.01). We conclude that NE induces sustained coronary vasoconstriction in the @entity95 and that reduced coronary blood flow may contribute to the pathogenesis of NE @entity296 in this species.
