Sympathomimetic drug Adrenergic receptor

Derivatives of phenylethanolamine substituted by a phenolic hydroxyl on the para position have been known for some time to exhibit 0-adrenergic agonist activity. As a consequence of this property, the compounds have proven useful as bronchodilators for the treatment of asthma (see Chapter 3). Since such sympathomimetic drugs tend to have undesired activity on the cardiovascular system in addition to the desired activity on the bronchii, considerable work has been devoted to the preparation of compounds that would show selectivity for the adrenergic receptors (02> that predominate in the lung. Attachment of the side chain to a heterocyclic aromatic phenol has been one avenue that has shown promise for achieving this selectivity. 

Esmolol hydrochloride is a competitive p-adrenergic receptor antagonist it is selective for pT adrenoceptors. In contrast to pindolol, esmolol has little intrinsic sympathomimetic activity, and it differs from propranolol in that it lacks membrane stabilizing activity Of all of the p-adrenergic blocking drugs, this compound has the shortest duration of action because it is an ester, it is hydrolyzed rapidly by plasma esterases and must be used by the intravenous route Esmolol is approved only for the treatment of supraventricular arrhythmias... 

As drugs of mixed action, amphetamines activate adrenergic receptors and simultaneously release endogenic catecholamines (norepinephrine and dopamine) from neurons of the brain and periphery. Sympathomimetic effects on the periphery are very similar to those of ephedrine. Amphetamine elevates systolic and diastolic blood pressure and has weakly expressed, broncholytic action. These effects are more prolonged, yet less expressed, than with epinephrine. The distinctive feature of amphetamines is their psychostimulatory activity. Larger doses can cause hallucinations and mental conditions similar to paranoid schizophrenia. As a sympathomimetic, amphetamine is sometimes used for uterine inertia. Synonyms of amphetamine are phenamine and benzedrine. 

Weiner, N. (1991) Drugs that inhibit adrenergic nerves and block adrenergic receptors. In Gilman, A. and Goodman, L., eds. Norepinephrine, Epinephrine and the Sympathomimetic Amines, 7th ed. New York The Pharmacological Basis of Therapeutics, pp. 145-180. 

Hoffman BB. Catecholamines, sympathomimetic drugs, and adrenergic receptor antagonists. In Hardman JG, et al, eds. The Pharmacological Basis of Therapeutics. 10th ed. New York McGraw-Hill 2001. 

HKR has been used in a short synthesis of (R)-(-)-phenylephrine hydrochloride (9), an adrenergic agent and P-receptor sympathomimetic drug (Scheme 9.14).117... 

Hoffman B, Lefkowitz R 1996 Catechoiamines, sympathomimetic drugs and adrenergic receptor antagonists. In Hardman J, Limbird L, Molinoff P et al (eds) Goodman Gilman s the pharmacological basis of therapeutics, 9th edn. McGraw-Hiil, New York, pp. 199-248... 

The basic pharmacological action of Ephedrine is that of a sympathomimetic. It does not contain a catechol moiety and is effective after oral administration. The drug stimulates heart rate and cardiac output and variably increases peripheral resistance as a result, ephedrine usually increases blood pressure. Stimulation of the a-adrenergic receptors of smooth muscle cells in the bladder base may increase resistance to the outflow of urine. Activation of S-adrenergic receptors in the lungs promotes bronchodilation. Ephedrine stimulates the cerebral cortex and subcortical centers to produce its effects in narcolepsy and depressive states. 

To clarify some of the puzzling differential effects of sympathomimetic drugs on various tissues, in 1948 Ahlquist (76) introduced the concept of two distinct types of adrenergic receptors as defined by their responses to (1), (2), and (17), which he called alpha receptors and beta receptors. Alpha receptors were defined as those that responded in rank order of agonist potency as (2) > (1) (17). Beta receptors were defined as those responding in potency order of (17) > (2) > (1). Subsequently, /3-receptors were further divided into /3i-receptors, located primarily in cardiac tissue, and /32-adrenoceptors, located in smooth muscle and other tissues, given that (1) and (2) are approximately equipotent at cardiac... 

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