β-blocker effects on 24-h activity in normotensive and renovascular hypertensive baboons

Spontaneous motor activity of normotensive and renovascular hypertensive baboons was measured during oral dosing with the β-adrenergic antagonists atenolol HCl (2.6 mg/kg/day) and d,l-propranolol HCl (6.8 mg/kg twice daily) in separate studies. Each study administered active drug for 21 consecutive days. Piezoelectric monitors sensitive to movement were worn continuously by the baboons. Propranolol decreased overall 24-h average activity during the third week of dosing in normotensive baboons but not in renovascular hypertensive baboons. The greatest reductions in activity averaged 20% at those times of day corresponding to the second daily drug dose both in normotensive baboons and, at this time of day only, in the majority of hypertensive baboons. Activity decreases reversed to baseline levels when propranolol was discontinued. For atenolol, most normotensive but no hypertensive baboons showed decreases in activity at the time of day corresponding to the daily drug dose.