How Drugs and Receptors Interact Essay Example | Topics and Well Written Essays - 1000 words

How Drugs and Receptors Interact - Essay Example GABAA receptors are also ligand-gated and ionotropic channels. Upon binding of the drug, such hormones are automatically triggered. Examples of drugs that bind through this mechanism include bicuculline, muscimol, and gaboxadol. b) Ligand-Regulated Transmembrane Enzymes Ligand-Regulated Transmembrane Enzymes are receptor molecules that mediate the early steps of signaling by insulin, growth factor, epidermal growth factor, platelet-derived, transforming growth factor, atrial natriuretic peptide, and many more trophic hormones. They are a type of receptors that are polypeptides in nature and comprise of extra-cellular-hormone-binding domains that bind to a cytoplasmic enzyme. The enzyme can be a tyrosine kinase, a guanylate cyclase or serine. In all these receptors, the two are linked by a polypeptide, a hydrophobic domain that cuts across the lipid layers. Upon binding of the drug (ligand) to the extracellular receptor, the receptor activates monomers to dimmers and the two receptor polypeptides bind strongly to the membrane. The cytoplasmic domains are then phosphorylated on tyrosine residues and their particular enzymatic activities or effects are activated. The tyrosine kinase receptor signaling pathway begins with binding of the drug or ligand to the external domain of the receptor. For example, monoclonal antibodies that act as antagonists of the tyrosine kinase receptors are effective in the management of breast cancer-related with over-expression of the growth factor receptor.