On the antihypertensive mechanisms of beta-adrenoceptor antagonists in relation to intrinsic sympathomimetic activity, cardioselectivity and hydrophilicity.

A review of the relevant literature indicates that the effects of beta-blockers on cardiac output and plasma renin or penetration of these drugs into the brain and cerebrospinal fluid are not essential for their antihypertensive effect. Reduction in blood pressure during long-term beta-blocker therapy is always associated with reduction of total peripheral resistance. Evidence is presented which suggests that blockade of presynaptic beta-receptors underlies this vasodilator effect of beta-blockers.