ABSTRACT
This chapter covers the pharmacological actions and uses of agonists at the receptors: the sympathomimetic amines. The activity of a sympathomimetic at an organ or tissue is dependent upon the receptor type or types that are present and upon the selectivity and potency of the agonist for the receptor. The first indication that sympathomimetic amines could exert their effects by different pharmacological mechanisms was the observation that cocaine potentiated the effects of adrenaline but antagonized the effects of tyramine. The chapter discusses the structural requirements of sympathomimetic amines for direct and indirect activity. The pharmacological responses to sympathomimetic amines are generally the same as are the physiological responses to sympathetic nerve stimulation. Indirectly acting sympathomimetic amines exert their pharmacological response by release from sympathetic neurones of noradrenaline in active form so that it stimulates the α- and β-adrenoceptors.
