5/6- Drug Receptor Interactions Flashcards
What is a receptor
Cellular macromolecule that interacts with a drug that changes one or more ongoing processes
Do drugs initiate a new processs
No
What are receptors coupled with
Effectors or ion channels (enzymes)
Properties of receptors
Undergo synthesis and degradation
Number altered by diseases or chronic drug treatments
Properties of drug receptor interactions
Reversible
Very fast
What determines the concentration of the drug required to interact with receptor
Strength of interaction
What do drug receptor interactions exhibit
Saturable response Reversible Good potency Chemical sensitivity Competitive blockade by antagonists Amplified responses
What are the 4 categories for drug receptors
Ion channels
GPCR (Guanine nucleotide binding protein-coupled receptor)
Receptor tyrosine kinases (TRK)
Intracellular receptor
What types of drugs are GPCR
adrenegic Choline rain Dopaminergic Histamine Opiate Serotonergenic
Receptor ligands
Small molecules that interact with or bind to a cellular macromolecule
Properties of receptor ligands
Associate very rapidly with receptors
After dissasociating response diminishes
Prolonged stimulation leads to diminished response
Full agonist produces a max effect
2+ agonists are no more effective than one
What does a dose response curve for receptor agonists look like
Sigmoid
Semi-logarithmic
Need 2 orders or more of concentration to get a full range of responses
What is a partial agonist
Drug that produces a sub maximal effect
Can decrease the response of a full agonist when both are used in combo
Properties of receptor antagonists
Associate and disassociate slowly
Bind to receptor and block or prevent action of agonist
may be reversible or irreversible
Unable to elicit a response alone
What is the efficacy of antagonist
0
What are the 3 major antagonists used clinically
Competitive (most common)
Noncompetitive
Irreversible
Properties of competitive antagonists
Bind reversibly to a receptor
Binding occurs at agonist binding
Mutually competitive with agonist
Properties of non-competitive antagonists
Bind irreversibly or to alternate site of the receptor
Receptor blockade is fixed and related to the dose of antagonists
Cannot be overcome by raising the conc. Of the agonist
what are simple models for drug receptor reactions based on
Single drug binding to single receptor to find a bimolecular complex
Reversible
Dissociation constant (KD)
Predicts the relative conc. Of the drug receptor complex at any conc. Of the drug
Independent from any cell response
Can be determined for both agonists and antagonists
Relevance of KD
Indicates drug conc. That is required in order for a drug to bind to a receptor
Not related to efficacy
Potency
Dose of drug needed to produce a desired level of effect
affinity
Drug conc. Require to occupy a target receptor
Specificity
Measure of drug’s ability to produce a desirable effect relative to its ability to produce an undesirable effect
