The effect of prolonged administration of CGS 10078B on systemic and regional haemodynamics in normotensive and spontaneously hypertensive rats.

The effects of 3 weeks treatment with CGS 10078B (30 mg/kg orally) on systemic and regional haemodynamics and cardiac mass were studied in normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. The significant decrease in mean arterial pressure (MAP) (174 +/- 3 versus 156 +/- 4 mmHg, P less than 0.002) in SHR was associated with a significantly slower heart rate. No significant alteration in systemic haemodynamics was observed in WKY rats. The reduced MAP in SHR was related to the preserved blood flow to the vital organs, and therefore reduced renal and cerebrovascular resistances. Left ventricular mass index was reduced in both rat strains of treated animals. Therefore, the reduced MAP and heart rate in the SHR without haemodynamic changes in the WKY indicates that CGS 10078B was an effective antihypertensive agent that decreased cardiac mass in rats through mechanisms that may be dissociated from their haemodynamic effects.