Posted by sowhysosad on April 6, 2009, at 14:41:18
In reply to Re: How are reuptake ratios expressed?, posted by desolationrower on April 6, 2009, at 8:55:41
> larry explained that well, the only thing i'd add is that the binding is http://en.wikipedia.org/wiki/Sigmoid_function sigmoidal. this is relevant when the drug binds to two different receptors, like velafaxine. that rapid increase in the middle of the curve means that the first receptor gets almost full before the other one really gets going, which is why you only start to get a little bit of NA effect at a high dose of venlafaxine, especially since the binding is quite different. i think there is a article on this on preskorn's site, if you search there.
>
> -d/rSo, with that in mind, it could explain why I get such a strong noradrenergic effect from imipramine but no discernible serotonergic effect.
Perhaps I didn't push the dose high enough to reach "saturation point" at the norepinephrine transporter.
The concept of sigmoid function also lends further weight to Ken Gillman's idea that an SRI+NRI combo like sertraline + nortriptyline is better than a dual action drug,
poster:sowhysosad
thread:888069
URL: http://www.dr-bob.org/babble/20090330/msgs/889006.html