Medicinal Chemistry Chapter 8 - Agonists, Antagonists - PDF
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University of South Florida
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Summary
Chapter 8 of this medicinal chemistry document defines and explains the roles of agonists and antagonists in receptor activation and blocking, respectively. The document explores features of agonists, including binding interactions, and delves into partial agonists. The concepts of sensitization and desensitization in the context of drug exposure are also explored.
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Chapter g 1 Define agonist and antagonist and the effect each has on a receptor agonist : drugs designed to mimic the natural messenger of a receptor. Agonists bind reversibly to the binding site...
Chapter g 1 Define agonist and antagonist and the effect each has on a receptor agonist : drugs designed to mimic the natural messenger of a receptor. Agonists bind reversibly to the binding site natural and produce the same induced fit as a receptor is then activated. messenger - antagonist drugs designed to block the natural messenger. : Antagonists bind to the binding site but fail to , correct not activated. produce the fit-receptor is 2 Describe features of an agonist including: binding interactions, structure compared to natural messenger. Including partial agonists and inverse agonists binding interactions of agonist : agonist bind reversibly to the · site produce induced fit of the binding a the same natural Similar intermolecular bonds messenger. as If 1 Functional groups capable of same interactions structure agonists have similar natural : structure to the messenger. Partia binds Agonist induced but does not produce the ideal fit for maximum effect site different modes the binds to binding in two , one where it agent acts as an agonist and one where acts as an antagonist binds as an agonist to one receptor subtype , but as an antagonist to another receptor subtype. Inverse Agonist * bind to receptor binding sites with different a induced fit from normal messenger Define and discuss allosteric antagonists including umbrella antagonists allosteric antagonists binds reversibly to an allosteric binding site intermolecular bonds formed between antagonists and binding site alters shape of receptor and binding site is distorted is not recognized by the messenger concentration does not increasing messenger reverse - antagonism Umbrella Antagonist binds reversibly to binding site a neighboring intermolecular bonds formed between antagonist and binding site antagonist overlaps messenger bonding place and messenger is blocked * 3 Describe desensitization, sensitization, tolerance, and dependence and discuss how they occur and the overall biological effect. Desensitization become desensitized term Receptors on long exposure to agonists. prolonged binding of agonist leads to phosphorylation of receptor lead long exposure may to the receptor-drug complex being removed from the cell membrane through endocytosis also result long exposure may in the cell reducing the Synthesis of the receptor protein Sensitization antagonist tend to add slowly and be more slow to leave than agonist therefore they can induce sensitization receptors become sensitized on long term exposure to antagonists synthesizes more receptors to compensate for blocked receptors & cells become sensitive to natural more messenger can result in tolerance and dependence. cells to normal neurotransmitters are supersensitive causes withdrawal symptoms when antagonists withdrawn leads to dependence
