Introduction principles of drug action

ION CHANNELS Ca +channels (Ca channel Mockers) Na channels (local anaesthetics) 

Medical pharmacology is the science of chemicals (drugs) ihai interact with the human body. These interactions are divided into two classes  

The activation of receptors by an agonist or hormone is coupled to die physiological or biochemical responses by transduction mechanisms (lower figure) that often (hut not always) involve molecules called sec-itntl messengers (HI). 

s are prescribed to produce a therapeutic effect but they often produce additional unwanted effects (Chapter 4. i) that range from the trivial (e.g. slight nausea to the fatal (e.g. aplastic inaeniia). 

These are protein molecules that are normally activated by transmitters or hormones. Many receptors have now been cloned md their amino acid sequence.s determined. The four main types of receptor are listed below. 

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