| Abstract: | ABSTRACT. In 19 men aged 50 with essential hypertension, 18 weeks' treatment with atenolol (n=9) or oxprenolol (n=10) increased supine plasma free dopamine concentrations by 78% (p<0.05) and 121 % (p<0.001) respectively. Increments in plasma dopamine were observed in all patients except for one treated with atenolol. Supine peripheral venous adrenaline and noradrenaline concentrations were not influenced by β-blockade. The mechanism and significance of the present elevation of plasma free dopamine by β-blockade are unknown. However, increased plasma free dopamine may be involved in the hypotensive effect of chronic β-adrenergic blockade, both β-1 selective and non-selective, and may lend further support to decreased dopaminergic activity in essential hypertenison. |
