Western pharmacology is a relatively new scientific discipline, having originated around 150 years ago. It can be divided into two broad categories: pharmacodynamics (the effect drugs have on the body) and pharmacokinetics (the effect the body has upon the drug). This review is concerned with the former: the way drugs exert their pharmacological action. The keystone of Western pharmacology is based on the Receptor Theory, where the drug acts as a “key” to undo a “lock in specific parts of the body”. The receptor is a membrane-located macromolecule with both binding and activity sites. The pharmaceutical drug attaches to the binding site, and either stimulates (as an agonist) or blocks (as an antagonist) the receptor, initiating or inhibiting the receptor’s dedicated action. Some drugs (partial agonists) combine both effects. Receptors are normally acted upon by natural ligands, such as hormones, neurotransmitters, and growth factors. Receptors, of which there are many types, are spread throughout the body’s tissues, and in the case of antimicrobial agents, within viruses and bacteria. Receptors are also present in ligand ion channels, where they are involved in nerve transmission and hormone secretion.
