Abstract
The effects on carotid artery blood flow of atenolol (a selective beta 1-adrenoceptor antagonist) and xamoterol (a beta 1-adrenoceptor partial agonist with 43% agonist activity) were measured using a Doppler technique in eight healthy volunteers. Atenolol produced a decrease in blood pressure and blood velocity flow, and tended to reduce volume flow. In contrast, there were no changes with xamoterol or placebo. Beta 1-adrenoceptor blockade may reduce cerebral blood flow but the partial agonist xamoterol does not appear to reduce carotid blood flow.