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17 Cards in this Set
- Front
- Back
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What is the definition of a receptive substance ? |
Drugs must bind to a specific constituents of a cell to produce their effect ie. Receptors |
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What do drugs that bind to receptors often resemble? |
Often resemble the natural or endogenous ligand structurally and have specific affinity for specific receptors |
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What is affinity? |
Is the property of an agonist or any drug to bind to a binding site including a specific receptor |
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What is efficacy? |
A measure of the ability of an agonist to activate the receptor and produce a response |
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What is an agonist? |
Drugs or naturally occurring body substances that directly cause a measurable response |
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What are the two responses a agonist can have? |
Excitatory or inhibitory |
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How is Emax reached for an agonist? |
Increasing the concentration of an agonist leads to larger and larger responses until a maximum response is reached |
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What are the properties of an agonist? |
Response is concentration dependent There is a finite number of receptors Usually agonist can be washed away- binding is relatively weak |
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What is a sigmoid curve? |
It is an s shaped curve |
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What are concentration response curves used to compare? |
To compare the potencies of different drugs qualitatively similar response |
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What is inverse agonist |
Receptors can either be on, partially on or off. The idea is that agonists could push the receptor into a fully off state |
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What is the definition of inverse antagonists? |
Are drugs that can be described as negative efficacy as opposed to agonists that have positive efficacy and antagonists have zero efficacy |
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When are the effects of inverse antagonists observed? |
Only observed when receptors are active even in the absence of an agonist |
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What is a two state model? |
For receptor activation cells to explain the relationships between receptor state and response |
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What happens to the conformational state when there is a partial or full antagonist? |
The equilibrium will move towards R* The greater the affinity for the R* state over R the greater the efficacy of the agonist |
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What happens to the conformational state of a receptor when in the presence of an inverse agonist? |
There is a greater affinity for the R state over the R* state Most receptors will be at rest |
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Where state are most receptors in? |
R state |
