Posted by Larry Hoover on November 8, 2002, at 8:15:29
In reply to Re: Opiates = very weird, Britt? » Larry Hoover, posted by BrittPark on November 7, 2002, at 20:00:54
> You may be right that opiates are the devils work. Morphine and friends were not evolved for our benefit. More probably as pest control for Papaver Somniferum. Of course that doesn't mean we can't make use of and learn from opiates.
Gotcha. Just like delta-9 tetrahydrocannabinol.
> The biochemistry of opiods does seem to be exceedingly complex. I'm a biochemist by training and still find myself perplexed.
Me too on both counts. Too much contradiction. There are obviously regulatory pathways of which we remain totally unaware.
>What I do know is that in some cells there are mu-opiate receptors attatched to both inhibitory and excitatory G proteins. Two phenomena support this. At low concentrations pure agonists like morphine can act as antagonist and result in hyperalgesia rather than analgesia. The other is the ability of low doses of opioid antagonists like naltrexone to enhance the analgesic properties of agonists and further stop or at least delay the development of opioid tolerance.
Well, there are theorists arguing that this is a receptor-conformational process....that changes in sensitivity occur due to meta-stable re-arrangements in binding sites.
>Then there are the studies that have found that opiates cause clustering of opiate receptors but prevent endocytosis of the clusters.
I haven't found a good answer yet on what happens *after* endocytosis. Both antagonists and agonists can act as chaperones for 'immature' receptors at the endoplasmic reticulum. Is this from endocytized ligands?
>When a compound that stimulates endocystosis is added tolerance development is lowered, at least in vitro.
I thought tolerance required endocytosis. In any case, there seems to be something peculiar about morphine as a ligand, when compared to others.
> There is much to learn.Ya. No kidding.
> Cheers,
>
> Britt
>
>
> I think of the complex biochemistry of opioids as a good thing because it means new drug targets are likely to be found, both for pain relief and, I hope, depression.The trend towards co-administration of different opiate ligands looks very promising. There's no reason to believe that this is any different than how the body naturally regulates the 'opiate' system.
Lar
poster:Larry Hoover
thread:126471
URL: http://www.dr-bob.org/babble/20021108/msgs/126941.html