Drug-receptor interactions principles

It is thus a higher form of molecular "behaviour than selective com-plexation alone and involves two stages of information input. Enzyme reactions are examples of such processes, as well as, for instance, drug-receptor interactions. Two substrates could, in principle, display very similar thermodynamic and kinetic complexation behaviour (no selection) but still only one of them may be able to undergo a specific reaction (because of geometrical differences, for instance) and thus be recognized. 

The SAR is also determined at the level of stereochemistry of interaction. In principle, three limiting situations can apply to the stereochemistry of drug-receptor interactions the enantiomers may not differ in activity the species may differ quantitatively or they may differ qualitatively. 

PD, on the other hand, describes the effect of the drug on the body and is based on the fundamental principles founded on the receptor occupancy theory (see Fig. 1) [1]. PD is driven by the nature of the drug-receptor interaction, which is affected by the number and affinity of receptors, as well as the drug concentration at the receptor site. This underlies the importance of achieving a sustained steady-state effective concentration of drugs in the ffuids bathing... 

Fig. 4.8. Major classes of drug receptors. (A) Transmembrane ligand-gated ion channel receptor. (B) Transmembrane G protein-coupled receptor (GPCR). (C) Transmembrane catalytic receptor or enzyme-coupled receptors. (D) Intracellular cytoplasmic/nuclear receptor. (From Simon JB, Golan DE, Tashjian A, Armstrong E, et al., eds. Chapter 1, Drug-Receptor Interactions. In Principles of Pharmacology The Pathophysiologic Basis of Drug Therapy. Baltimore Lippincott Williams Wilkins, 2004, pp. 3-16, with permission.)...

From Simon JB, Golan DE, Tashjian A, Armstrong E, et al., eds. Chapter 1, Drug-Receptor Interactions. In Principles of Pharmacology The Pathophysiologic Basis of Drug Therapy. Baltimore Lippincott Williams Wilkins, 2004, pp. 3-16, with permission.)... 

In principle, various targets for therapeutic intervention exist. A successful drug can interact with viral receptors, virally encoded enzymes, viral structural components, viral genes or transcripts, or cellular factors required for viral replication. In recent years, attention has been given to small molecules that can target viral-specific RNA sites and prevent the formation of key RNA-protein and RNA-RNA complexes. Aminoglycoside antibiotics have provided the impetus for this approach as discussed below. 

There is ample documentation of the generality of chirality of drug interactions at receptors. In principle. 

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