BMS 117: Intro to Pharmacodynamics I and Intro to Pharmacokinetics II

4 types of proteins that selectively bind ligands - ANSWER-1. Enzyme steroid receptor 2. Protein linked to a tyrosine kinase 3. Ligand-gated ion channel 4. Protein linked to a G protein agonist - ANSWER-exerts a direct downstream effect upon receptor binding antagonist - ANSWER-exerts NO direct downstream effect upon receptor binding in absence of agonist antagonist in presence of agonist - ANSWERantagonist displaces agonist = no effect What if there is a competitive reversible antagonist? - ANSWER-Flooding the system with an antagonist can "outcompete" a competitive but reversible antagonist (but if you ↑ antagonist, then no effect) What if there is a irreversible antagonist? - ANSWER-An irreversible antagonist cannot be outcompeted no matter how much agonist you add. True or false? Receptor-drug interactions are usually irreversible. - ANSWER-False (They are usually reversible) Kd, dissociation constant - ANSWER-Drug concentration at which 50% of maximum amount of drug is bound (Bmax) ↓ Kd means - ANSWER-↑ affinity of drug (inverse relationship) constant for reversible ligand binding - ANSWER-Kd (based on Bmax) constant for the EFFECT of reversible ligand binding - ANSWER-EC50 (based on Emax) EC50 - ANSWER-Concentration of the drug tha