Physiology 3140A Lecture Notes - Lecture 18: Retina, Endosome, Diglyceride
28 Dec 2017
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Document Summary
Cells must adapt to the amount of receptor that they need at the cell surface. ~1/2 drugs prescribed to patients are ligands that bind to gpcrs. Regulation of gpcr involves desensitization and down regulation. If there is a lot floating around the cell, the cell has already does its thing and it does not want to do it again: = receptors no longer responds. Desensitization is when the receptor is no longer sensitive to the ligand/agonist: mechanism for protecting cells against receptor overstimulation, down regulation is the process by which this takes place. Desensitization can occur through many processes which involve down regulation. Receptor inactivation: exposure of gpcrs to agonists often results in a rapid attenuation of receptor responsiveness. If there is a lot of ligand present, must go into desensitization mode: g protein uncouples and is not able to recouple to the receptor. Exposure of gpcrs to agonists results in rapid attenuation (loss) of receptor responsiveness.
