Non-competitive Inhibitor

[acciddropping]

In this graph, I understand that the Vmax is decreased, indicating that it's the inhibitor used here is a Non-competitive or Irreversible antagonist. I can also say that the potency is unchanged because of the same point on the X axis. (Am I correct?).

In this graph, the Vmax is decreased, therefore it's efficacy of the partial agonist is less than full agonist. However, I don't understand why "potency is a different variable and can be increased or decreased" (according to FA) ==> Looking at the points on the X-axis, Km is decreased so Potency of the partial agonist is increased. Why does FA say that potency can be decreased as well? Please help. Thanks.!

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[CherryRedDracul]

View attachment 180712
In this graph, I understand that the Vmax is decreased, indicating that it's the inhibitor used here is a Non-competitive or Irreversible antagonist. I can also say that the potency is unchanged because of the same point on the X axis. (Am I correct?).

View attachment 180713
In this graph, the Vmax is decreased, therefore it's efficacy of the partial agonist is less than full agonist. However, I don't understand why "potency is a different variable and can be increased or decreased" (according to FA) ==> Looking at the points on the X-axis, Km is decreased so Potency of the partial agonist is increased. Why does FA say that potency can be decreased as well? Please help. Thanks.!

Which edition of FA are you using? In FA 2014, it says "Potency is an independent variable". What that means is that for partial agonists, potency can be higher, lower, or equivalent to that of the comparison full agonist.

Also, when discussing the pharmacology of drugs, we use Emax (maximum efficacy) rather than Vmax (maximum enzymatic reaction rate in Michaelis-Menten kinetics).

 

[acciddropping]

Which edition of FA are you using? In FA 2014, it says "Potency is an independent variable". What that means is that for partial agonists, potency can be higher, lower, or equivalent to that of the comparison full agonist.

Also, when discussing the pharmacology of drugs, we use Emax (maximum efficacy) rather than Vmax (maximum enzymatic reaction rate in Michaelis-Menten kinetics).

I am using 2013 FA. What I do not understand is how to see that increase/decrease potency in the given graph. Am I correct in that the graph #3 here only shows the increased potency of the partial agonist compared to the full agonist?

Thank you!

 

[syma]

I think it is in response to shifting the graph to the left or to the right and that will show a variable potency. Partial antagonists, (AFAIK) are defined by their reduced efficacy.

 

[CherryRedDracul]

I am using 2013 FA. What I do not understand is how to see that increase/decrease potency in the given graph. Am I correct in that the graph #3 here only shows the increased potency of the partial agonist compared to the full agonist?

Thank you!

View attachment 180730

Correct.

I think it is in response to shifting the graph to the left or to the right and that will show a variable potency. Partial antagonists, (AFAIK) are defined by their reduced efficacy.

This.