Information AboutAgonist |
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In Pharmacology an agonist is a substance that binds to a specific Receptor and triggers a response in the Cell . It mimics the action of an Endogenous Ligand (such as Hormone or Neurotransmitter ) that binds to the same receptor. A partial agonist (such as Buspirone , Aripiprazole , bifeprunox or nor Clozapine ) activates a receptor, but only produces a partial physiological response compared to a '''full agonist'''. They may also be considered as a ligand which displays both agonistic and antagonistic effects. A '''co-agonist''' works with other co-agonists to produce the desired effect together. An Antagonist blocks a receptor from activation by agonists. Receptors can be activated or inactivated either by endogenous (such as Hormone s and Neurotransmitter s) or exogenous (such as Drugs ) agonists and antagonists, resulting in stimulating or inhibiting the cell. To see how an agonist may activate a receptor see this link . New findings that broaden the conventional definition of pharmacology demonstrate that ligands can concurrently behave as agonist ''and'' antagonists at the same receptor, depending on effector pathways. Terms that describe this phenomenon are " Functional Selectivity " or "protean agonism".Kenakin T. (2001). Inverse, protean, and ligand-selective agonism: matters of receptor conformation. ''FASEB J.'' 15:598-611. PMID 11259378. Fulltext Urban J.D. et al. (2007). Functional selectivity and classical concepts of quantitative pharmacology. ''J. Pharmacol. Exp. Ther. 320:1-13. PMID 16803859. ETYMOLOGY From the Greek αγωνιστής (agōnistēs), contestant; champion; rival < '''αγων''' (agōn), contest, combat; exertion, struggle < '''αγω''' (agō), I lead, lead towards, conduct; drive SEE ALSO
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