Substances that stimulate adrenergic receptors, i.e. acting like norepinephrine and adrenaline are called adrenergic agonists. Those of them that excite both alpha and beta adrenergic receptors fully reproduce the effects of the above mediators. There are adrenergic agonists that selectively interact with either alpha or beta adrenergic receptors, or with their individual subtypes (for example, betaone– or beta2-).