Principles of Drug-Receptor Interactions

1. Drug exerts quantitative but not qualitative effect at the receptor site and can create new function.
   
   
2. Receptors have specific molecular conformation corresponding to certain kinds of drugs.
   
   
3. Forces must be present to attract and hold a drug in contact to a receptor so that a drug may exert an effect.
   
   
4. Drugs fitting the receptors may either to activate or inhibit them.
   
   
5. Not all receptors on a particular cell are needed to be occupied by a drugs to produce effect or intrinsic activity.