adrenergic-receptor-site specificity
a drug's affinity for only adrenergic receptor sites; cetain drugs may have specific affinity for only alpha- or only beta-adrenergic receptor sites
alpha1-selective adrenergic blocking agents
drugs that block the postsynaptic alpha1 - receptor sites, causing a decrease in vascular tone and a vasodilation that leads to a fall in blood pressure; these drugs do not block the presynaptic alpha2-receptor sites, and therefore the reflex tachycardia
beta-adrenergic blocking agents
drugs that, at therapeutic levels, selectively block the beta-receptors of the sympathetic nervous system
beta1-selective adrenergic blocking agents
drugs that, at therapeutic levels, specifically block the beta1-receptors in the sympathetic nervous system while not blocking the beta2-receptors and resultant effects on the respiratory system
bronchodilation
relaxation of the muscles in the bronchi, resulting in a widening of the bronchi, an effect of sympathetic stimulation
pheochromocytoma
a tumor of the chromaffin cells of the adrenal medulla that periodically releases large amounts of norepinephrine and eprinephrine into the system with resultant severe hypertension and tachycardia
sympatholytic
a drug that lyses, or blocks, the effects of the sympathetic nervous system