Receptors & Receptor Binding Flashcards
Ligands that bind to the effector site on a receptor and activate it
Agonists
Full Agonists
Fully activate receptor
Partial Agonists
Cause partial activation of receptors
Inverse Agonists
Bind to the effector site but produce a response opposite to that of a normal agonist
Ligands that bind to receptors but do not activate them
Antagonists
Competitive Antagonists
Compete with agonists for the same binding site
Noncompetitive Antagonists
Bind to the receptor at a different site than the agonist
Suicide Antagonists
Bind irreversibly to a receptor and remains bound for the rest of that receptor’s lifetime
Modulators
Alter the affinity and/or efficacy of a drug
Total Ligands [L] is equal to
amount of free ligands [F] + amount of bound ligands [B]
[L] = [F] + [B]
Association Constant
Ka; the rate at which a ligand becomes bound to a receptor
Dissociation Constant
Kd; the rate at which a ligand becomes unbound from a receptor
Modulating the affinity of a drug will affect the _______ of the drug.
Efficacy
Bmax
The maximum number of sites a specific ligand can bind to; equivalent to the number of free receptors [R] + ligand-receptor complex [B]
Dose-Response Curves
Concentration of drug (x) vs. efficacy (y)
Affinity
Likelihood of drug will blind to a receptor (inverse of Kd)
Tolerance shifts the dose-response curves to the ______.
Right
Sensitization shifts the dose-response curve to the ______.
Left
Time-dependent (kinetic) plots
Association, dissociation, and drug clearance plots are all time dependent plots
Hill Coefficient
Number of binding sites per receptor for a receptor-ligand interaction (slope of hill plot)
Saturation Curves
Show how much drug is needed to saturate a system
Scatchard Plot Slope
Inverse of dissociation constant and affinity
Scatchard plot x-intercept
Bmax
What is the Hill coefficient of most ionotropic receptors?
2
Ligands only have a biological effect after becoming a _______ .
Ligand-receptor complex
