ABSTRACT
This chapter discusses developmental aspects of adrenergic receptor physiology and endogenous catecholamine responses and reviews the pharmacology of catecholamines and highlights the cardiovascular actions, clinical indications, and toxicities of these agents. It also discusses the several important pharmacologic principles and also reviews basic principles of catecholamine pharmacokinetics. Pharmacokinetics is the mathematical expression of the time course of all processes leading to drug distribution and elimination. Pharmacodynamics is the relationship between drug concentration and drug effect. In the case of inotropic agents, measurable drug-induced physiologic action may be a change in cardiac output, blood pressure, and heart rate. In most species examined, myocardial a-adrenergic receptors produce a positive inotropic effect with little or no change in heart rate. The timing of myocardial sympthetic innervation in humans is unknown and it is difficult to relate findings in animals to humans. Even in the more mature lamb, adrenal catecholamines have important tonic effects on myocardial contractility.
