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33 Cards in this Set
- Front
- Back
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What is a receptor?
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The component of a cell that interacts with a drug and initiates the chain of biochemical events leading to the drug's observed effects (protein located on the cell surface or within)
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What are 3 functions of a receptor?
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1) Determines relations between dose and effect
2) Responsible for drug selectivity 3) Mediators of agonists and antagonists |
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What is pharmodynamics?
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What the drug does to the body or the drug's mechanism of action
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What are 4 types of surface receptors?
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1) Surface receptors linked directly to ion channels
2) Surface receptors linked directly to enzymes 3) Surface receptors linked to regulatory (G) 4) Intracellular receptors |
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What 2 things do surface receptors linked directly to ion channels do?
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1) Drug binds to receptor to activate and open pore
2) Changes membrane permeability |
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What is an example of a surface receptor linked directly to an ion channel?
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Ach receptors that bind to allow K+ to go through
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What do surface receptors linked directly to enzymes affect?
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Drug binds to receptor site causing conformational changes allowing phosphates to become active (has binding domain and catalytic domain)
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How do surface receptors linked to regulatory G proteins operate? (2)
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1) Receptor links to G protein to activate
2) Activated G protein alters activity of an intracellular effector which breaks down something else |
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What surface receptors can facilitate and inhibit ATP?
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Surface receptors linked to G proteins
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How do intracellular receptors work?
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Endogenous hormone (or hormone-like drug) binds to receptor in cytoplasm, then the complex moves to the nucleus to affect gene expression
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What affects drug interaction?
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Drug's size, shape and affinity
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What 4 things affect drug affinity?
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1) Binding is graded
2) Measured by amount of drug needed to bind to unoccupied receptors 3) Allosteric modulators 4) Other factors can affect affinity |
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What are allosteric modulators?
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Proteins bind to receptor to change affinity of the drug to the receptor (could increase or decrease)
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What is a selective drug?
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100% goes to target with no side effects
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What does drug-receptor interactions affect?
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Dose-response curves
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How are the dose-response curves affected by drug-receptor interactions?
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Response is somewhat proportional to the # of receptors bound (within a given drug concentration)
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What is an agonist?
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Drug that binds to receptor causing functional response
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What is a partial agonist?
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Drug binds to receptor but does not cause full functional response (partial response)
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What is an antagonist?
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Drug binds to receptor but does not cause functional response
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What are 2 types of antagonists?
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1) Competitive antagonist
2) Noncompetitive antagonist |
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What is a competitive antagonist?
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Drug has equal opportunity to bind to the receptor as a agonist
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What is a noncompetitive antagonist?
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Increased affinity that the agonist can't compete to bind and antagonist does not release from site
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What is a mixed agonist-antagonist?
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Drug acts as agonist on some receptors and antagonist on other receptors
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What is an inverse agonist?
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Drug binds to receptor, but has opposite effect of an agonist (decrease activity)
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What are 3 types of receptor regulation?
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1) Desensitization
2) Down-regulation 3) Supersensitivity |
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What is desensitization?
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Decreased receptor responsiveness of no changes in the # of receptor sites ?(fast process)
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What is down-regulation?
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Decrease in # of receptor sites (slow process)
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What is supersensitivity
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Increase in # of receptor sites available
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How does down-regulation affect drug dosing?
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Increase stimulus to get the same effect
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How does supersensitivity affect drug dosing?
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Decrease stimulus to get the same effect
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T or F: All drugs exert effects by binding to a specific component of the cell (receptor)
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False--some drugs do not exert effects by binding to a specific receptor
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What are 4 things non-receptor drugs do?
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1) Alter synthesis of cell components
2) Direct chemical reactions 3) Direct alteration of enzyme function 4) Chelation of harmful agents (heavy metals) |
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What is an example of non-receptor dug?
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Chemotherapy
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