Binding Affinities for Endogenous Opioids

[romealone]

Hey guys,
I was wondering if anyone had any info regarding the binding affinities of human endogenous opioids. I am interested in the question of whether high affinity antagonists (such as naltrexone), as well as the maintenance drug buprenorphine, would theoretically displace the endogenous opioids produced in the brain. Does anyone have any info on this subject or aware of any studies that have looked at this? Thanks.

 

[Nagelfar]

I'm fairly sure it has been proven that they do. Someone else will have to cite a source to that effect to be certain, but it is logical enough to extrapolate the reasons for that being the case.

 

[romealone]

I'm fairly sure it has been proven that they do. Someone else will have to cite a source to that effect to be certain, but it is logical enough to extrapolate the reasons for that being the case.

Well I agree it's logical to assume that these antagonists and bupe would displace/block endogenous opioids IF they have a greater affinity than the endogenous opioids, however that is my major question here. Do antagonists like naltrexone as well as mixed antagonist/agonist like bupe have higher affinities than endogenous opioids.

 

[Coolwhip]

I've never seen the binding affinity of an endogenous opioid anywhere, let alone directly compared to naltrexone and bupe. But I think it is pretty safe to say the answer is yes, otherwise naltrexone wouldn't do anything or cause any upregulation right? If it kindly excused itself from the receptor every time an endogenous compound wanted to bind to it then our bodies wouldn't even know it was there. And bupe has a higher binding affinity than naltrexone.

 

[ebola?]

Naltrexone and buprenorphine have very high binding affinities in comparison to most exogenous ligands, so they likely significantly have higher affinities than endorphins.

ebola