Posted by MB on December 28, 2001, at 14:28:34
In reply to Re: Gabitril and benzos » Cmatt, posted by Elizabeth on December 28, 2001, at 13:39:19
> Gabitril (tiagabine) doesn't interact with benzo receptors at all. It is a GABA reuptake inhibitor (blocking the GABA transporter to increase the amount of available extracellular GABA, just as SSRIs block the serotonin transporter). Benzos (which are benzodiazepine receptor agonists) work by increasing the effectiveness of GABA at its receptor. Benzos don't directly act at the GABA receptor or increase the amount of GABA.
>
> Another anticonvulsant, Sabril (vigabatrin), works by blocking an enzyme called GABA transaminase which is involved in the metabolism of GABA. This is analogous to the action of MAOIs on monoamines. (Nardil is also a GABA transaminase inhibitor, BTW.)
>
> Ambien is an example of a drug that works selectively at a particular subtype of benzodiazepine receptor; it lacks many of the effects of the benzos (such as their anticonvulsant and muscle relaxant effects).
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> There are two types of GABA receptors, GABA-A and GABA-B receptors. Baclofen, a medication used for spasticity, is a selective GABA-B agonist and has little effect on anxiety.
>
> -elizabeth
Elizabeth,
Thanks for the info...very interesting. I guess I just figured that both a) increasing the effectiveness of GABA (benzos) and b) increasing the presence of GABA (tiagabine, vigabatrin) would have similar end results (i.e., I figured increase in GABA activity would *feel* the same no matter what route was taken to get there).When you mentioned that benzodiazepines bind to the "benzodiazepine receptors" it made me wonder why we have those receptors. Do we know of an endogenous brain-chemical for which these receptors are meant to be recetpive?
So, since the vinyl-GABA and the Gabitril both increase GABA in the brain, does this mean that these drugs affect both types of GABA receptors? I felt no anxiety relief from the Gabitril.
MB
poster:MB
thread:87498
URL: http://www.dr-bob.org/babble/20011222/msgs/88056.html