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Old 12-19-2012
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Drug Drug Agonist Curves!

Drug Agonist Curves!-drug-agonist-curve.jpg
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Graph show response elicited by different concentration of drug X in a system containing spare receptor in the absence (solid curve), presence (dashed curve) of 2 different concentrations of drug Y. Drug Y alone has no effect. Which of following best describe drug Y?

A competitive reversible agonist
B full agonist
C Inverse agonist
D non competitive antagonist
E partial agonist
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Old 12-19-2012
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Default NBME pharm

Can you please label questions if they are from NBME.
I have already answered one of your posted questions not realizing it was an NBME question that i have not taken.

When people take the NBME it will mess up their assessment score. For the sake of everyone in this forum please post proper title.

Thank you.
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Old 12-26-2012
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i think i couldnot properly unbderstand the qtn......but i would go with ans partial agonist...
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Old 12-26-2012
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I am think D) non competitive antagonist:not sure:
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Old 09-14-2013
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i answered: partial agonist and was wrong ans.

But im pretty confuse with it because this graph have Drug y acts as both: competitive and non competitive?
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Old 09-14-2013
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Default Spare receptors

to answer this question, we should know wat is spare receptors. spare receptors are the one that can produce maximal response even if not all of them are occupied.. in other words,spare receptors can produce a half maximal response even if less than 50% of them are bound. so wen u add a non competitive antag it binds the receptor and reduces the no of receptors available fr substrate.. but spare receptors can still produce a max response with reduction in potency, this is shown in the fig. if this is not a spare receptor, we can conclude antagonist is competitive! but wat happens wen more non comp antag is added..? there is a reduction in response because there is an additional drop in no of receptors say 75% are gone.. now it shows up as reduction in efficacy.. so conclusion : in the presence of spare receptors, response of the system to non comp antagonist is different.
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Old 09-14-2013
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Wao!! thank you for the explanation, for sure i will never figure this out!!


Quote:
Originally Posted by jayashree View Post
to answer this question, we should know wat is spare receptors. spare receptors are the one that can produce maximal response even if not all of them are occupied.. in other words,spare receptors can produce a half maximal response even if less than 50% of them are bound. so wen u add a non competitive antag it binds the receptor and reduces the no of receptors available fr substrate.. but spare receptors can still produce a max response with reduction in potency, this is shown in the fig. if this is not a spare receptor, we can conclude antagonist is competitive! but wat happens wen more non comp antag is added..? there is a reduction in response because there is an additional drop in no of receptors say 75% are gone.. now it shows up as reduction in efficacy.. so conclusion : in the presence of spare receptors, response of the system to non comp antagonist is different.
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