Excessive plasma dopamine increase at rest and during exercise after long-term beta-adrenoreceptor blockade in hypertensive patients.

Sympathetic nervous system response to graded exercise: effect of beta-blockade.

This study compares the sympathetic nervous system response to graded exercise in normotensive and essential hypertensive subjects with and without beta-adrenergic blockade. Blood pressure (BP), heart rate, and plasma norepinephrine (NE), epinephrine (E), and dopamine (DA) were measured just before starting the exercise (Pre-Ex), in the submaximal exercise (Sub-max),and after 8 minutes rest (Po...

Cardiovascular and sympathetic response to exercise after long-term beta-adrenergic blockade.

The response to dynamic exercise was investigated in 21 patients receiving long-term treatment with beta-adrenoceptor antagonists and 22 controls. An electrocardiogram (ECG) and blood pressure were recorded before and after treadmill exercise, and plasma dopamine-beta-hydroxylase (DBH) activity was measured as an index of changes in sympathetic activity. Heart rate and blood pressure were lower...

Comparative beta-adrenoreceptor-blocking effects and pharmacokinetics or propranolol and pindolol in hypertensive Africans.

1. The beta-adrenoreceptor-blocking effects of pindolol were compared with those of propranolol and a placebo in a double-blind cross-over trial involving nine hypertensive African patients. 2. Heart rate, systolic blood pressure and diastolic blood pressure were measured at rest and immediately after exercise before and at intervals up to 6 h after oral administration of the drugs. In addition...

Haemodynamic adaptation at rest and during exercise to long-term antihypertensive treatment with combined alpha- and beta-adrenoreceptor blockade by labetalol.

Haemodynamic responses to exercise and acute beta-receptor blockade in renin sub-types of essential hypertension.

1. Haemodynamic and renin responses to dynamic exercise before and after intravenous beta-adrenoreceptor blockade with propranolol were compared in twenty-one patients with essential hypertension and either high (n = 7), normal (n = 7) or low plasma renin activity (n = 7). 2. Renin and heart-rate responses to exercise and beta-receptor blockade diminished from high-renin to normal and to low-re...