EFFECTS OF RIBOFLAVIN ANALOGS AND DIURETICS ON THE SPONTANEOUSLY HYPERTENSIVE RAT-HEART

The chronic treatment of spontaneously hypertensive rats (SHR) with 7,8-dimethyl-10-(3-chlorobenzyl) isoalloxazine [CBI], 7,8-diethyl-10-aminol isoalloxazine [DEAI], enduron (methyclothiazide) and amiloride were studied for their effects on blood pressure and cardiac contractile protein ATPasc activities. After 35 weeks of treatment all the above antihypertensive agents showed a decrease in blood pressure in the SHR (p<0.01). Chronic treatment with CBI, DEAI, enduron, and amiloride significantly improved the myofibrillar ATPasc activity at all pCa2+ concentrations (p<0.01). Furthermore, CBI, DEAI, enduron, and amiloride drug treatments enhanced actin-activated myosin ATPase activity (p<0.01). The Ca2+-activated myosin ATPase activity was significantly elevated after treating with CBI and DEAI (p<0.01). These results suggest that the antihypertensive agents used in this study helped in reducing the blood pressure with a subsequent increase in myocardial contractile protein ATPase activity. © 1990 Dr. Dietrich Steinkopff Verlag.