Cardiovascular actions of a novel NO-independent guanylyl cyclase stimulator, BAY 41-8543:: in vivo studies

1 BAY 41-8543 is a novel non-NO-based stimulator of sGC. This study investigates the acute effects of BAY 41-8543 on haemodynamics in anaesthetized rats and dogs, its long-term effects in conscious hypertension rat models and its antiplatelet effects. 2 In anaesthetized dogs, intravenous injections of BAY 41-8543 (3- 100 mug kg(-1)) caused a dose-dependent decrease in blood pressure and cardiac oxygen consumption as well as an increase in coronary blood flow and heart rate. 3 In anaesthetized normotensive rats, BAY 41-8543 produced a dose-dependent and long-lasting blood pressure lowering effect after intravenous (3 - 300 mug kg(-1)) and oral (0. 1 - 1 mg kg(-1)) administration. A dose-dependent and long-lasting decrease in blood pressure was also observed in conscious spontaneously hypertensive rats with a threshold dose of 0.1 mg kg(-1) p.o. After 3 mg kg(-1) the antihypertensive effect lasted for nearly 24 h. After multiple dosages, BAY 41-8543 did not develop tachyphylaxis in SHR. 4 BAY 41-8543 prolonged the rat tail bleeding time and reduced thrombosis in the FeCl3 thrombosis model after oral administration. 5 In a low NO, high renin rat model of hypertension, BAY 41-8543 prevented the increase in blood pressure evoked by L-NAME and reveals a kidney protective effect. In this model, the overall beneficial effects of BAY 41-8543 manifested as both antiplatelet effect and vasodilatation were reflected in a significant reduction in mortality. 6 The pharmacological profile of BAY 41-8543 suggests therefore that this compound has the potential to be an important research tool for in vivo investigations in the sGC/cGMP field and it also has the potential of being a unique clinical utility for treatment of cardiovascular diseases.