Present state of alpha and beta adrenergic drugs. II. The adrenergic blocking agents.
There are selective blocking agents (antagonists) for alpha receptors and beta receptors. These blocking agents prevent the response to injected agonists and neurogenically released norepinephrine. The principal cardiovascular response to alpha blockade is postural hypotension with reflexly induced cardiac stimulation. If neurogenic vasoconstriction is present, this will be removed. The principal cardiovascular response to beta blockade is bradycardia. If fast arrhythmias are present, these will be slowed. Beta blockade tends to increase peripheral resistance. Unless circulation is previously impaired this vasoconstrictive effect is insignificant.
Present state of alpha and beta adrenergic drugs. II. The adrenergic blocking agents. There are selective blocking agents (antagonists) for alpha receptors and beta receptors. These blocking agents prevent the response to injected agonists and neurogenically released norepinephrine. The principal cardiovascular response to alpha blockade is postural hypotension with reflexly induced cardiac stimulation. If neurogenic vasoconstriction is present, this will be removed. The principal cardiovascular response to beta blockade is bradycardia. If fast arrhythmias are present, these will be slowed. Beta blockade tends to increase peripheral resistance. Unless circulation is previously impaired this vasoconstrictive effect is insignificant.