Long-term renal vasodilator effect of the beta-adrenoceptor blocker tertatolol in conscious spontaneously hypertensive rats.

In conscious spontaneously hypertensive rats (SHR), 5-day intravenous infusions with the beta-adrenoceptor blockers propranolol (5 mg/kg/day) or tertatolol (0.5 mg/kg/day) caused a chronic reduction of blood pressure (-12% +/- 1% and -28% +/- 1%, respectively, on day 5) and heart rate (-13% +/- 3% and -8% +/- 2%, respectively, on day 5). Propranolol infusion led to a 23%-31% reduction of blood flow through the renal, mesenteric, and hindquarter vascular bed. Tertatolol caused similar flow reductions, with the exception of the renal vascular bed, which was dilated. Tertatolol induced reduction of renal vascular resistance of 29% +/- 2% on day 5. These studies show a long-term renal vasodilatory activity of tertatolol during chronic administration to SHR.