Different effects of selective and nonselective beta adrenoceptor blockade on urinary catecholamine and creatinine excretion in stress.

We tested the hypothesis that (1) beta 1-selective and nonselective beta adrenoceptor blockades have a different influence on stress-induced catecholamine overshoot, and (2) beta 1-selective blockade shifts the epinephrine/norepinephrine ratio in favor of norepinephrine. Seven violinists were investigated; each performed four times in public after ingesting different beta blockers. A significantly greater urinary norepinephrine/creatinine excretion was found with selective beta blockade than with nonselective. In addition during selective beta blockade creatinine excretion decreased significantly in comparison with nonselective blockade. This might be due to a higher concentration of circulating norepinephrine, stimulating alpha receptors in the renal vasculature.