PHRM 100 Lecture Notes - Lecture 12: Partial Agonist, Agonist, Conformational Change
Document Summary
Three key principles: receptors determine the relations between drug dose and pharmacologic effect, receptors are responsible for the selectivity of drug action, receptors mediate action of agonist and antagonists. Antagonist: causes no action but prevents action from going on (of agonist. Competitive : competes for enzyme active site to block natural substrate. Non-competitive: binds to enzyme on another site (causes conformational change) Uncompetitive: binds to receptor-agonist complex (stimulus is not released) Ec50: concentration of substrate required to achieve 50% of emax. Coupling : transduction process between receptor binding and drug response. Efficiency of coupling determined by initial receptor change. Does not fully occupy receptor (not a great fit due to shape, size or charge) Chemical antagonism: one drug binds and inactivates the other. Physiological antagonism: physiological pathway has opposite effect to drug. Commonly act by binding dna and changing transcription. Long action time (several hours: transmembrane protein, tyrosine kinases (transmembrane protein) Ligand binding causes conformational change in receptor activates enzyme.
