How Drugs Act?
Introduction A drug can be defined as a chemical substance of known structure, other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect . 4 main kinds of regulatory protein are commonly involved as primary drug targets , namely: receptors, enzymes, ion channels and carrier molecules (transporters). For a drug to be useful as either a therapeutic or a scientific tool, it must act selectively on particular cells and tissues (i.e. high degree of binding site specificity). However, no drugs are completely specific in their actions . In many cases, increasing the dose of a drug will cause it to affect targets other than the principal one, and this can lead to side effects . NOTE: Many drugs bind (in addition to their primary targets) to plasma proteins and other tissue proteins, without producing any obvious physiological effect. Drug Receptors In pharmacology, receptor describes protein molecules whose function...