Posted by Ritch on February 2, 2003, at 14:53:02
In reply to Re: Neurontin spin, posted by not exactly on February 2, 2003, at 13:15:11
> > the intentional use of spin on GABA in the Gabapentin name
>
> The "gabapentin" name is justifiable chemically, since gabapentin [http://biopsychiatry.com/gabapentin] is effectively GABA [http://biopsychiatry.com/gaba] with a 5-carbon chain added (thereby forming a cyclohexane ring). However, its in-vivo functional relationship to GABA is questionable. Pfizer's "prescribing information" monograph [http://www.Pfizer.com/download/uspi_neurontin.pdf] admits:
>
> "Gabapentin is structurally related to the neurotransmitter GABA (gamma-aminobutyric acid) but it does not modify GABA-A or GABA-B radioligand binding, it is not converted metabolically into GABA or a GABA agonist, and it is not an inhibitor of GABA uptake or degradation."
>
> In fact, they go on to say:
>
> "Gabapentin was tested in radioligand binding assays at concentrations up to 100 µM and did not exhibit affinity for a number of other common receptor sites, including benzodiazepine, glutamate, N-methyl-D-aspartate (NMDA), quisqualate, kainate, strychnine- insensitive or strychnine-sensitive glycine, alpha 1, alpha 2, or beta adrenergic, adenosine A1 or A2, cholinergic muscarinic or nicotinic, dopamine D1 or D2, histamine H1, serotonin S1 or S2, opiate mu, delta or kappa, cannabinoid 1, voltage-sensitive calcium channel sites labeled with nitrendipine or diltiazem, or at voltage-sensitive sodium channel sites labeled with batrachotoxinin A 20-alpha-benzoate. Furthermore, gabapentin did not alter the cellular uptake of dopamine, noradrenaline, or serotonin."
>
> Creating a medication that affects *none* of the neurochemical receptors is quite a trick in itself. One might conclude gabapentin is just a placebo, albeit a convincing one simply because it happens to have a GABA molecule imbedded within it. At best, we're left with the all-too-familiar disclaimer:
>
> "The mechanism by which gabapentin exerts its anticonvulsant action is unknown..."
>
> - Bob
>
There is some speculation about calcium channels, and it appears that might be the case:http://www.physoc.org/Proceedings/Abstracts/528P/Aberdeen/Files/S37.html
http://lrc.bcm.tmc.edu/mmd/neuro/syllabus.html
poster:Ritch
thread:136541
URL: http://www.dr-bob.org/babble/20030130/msgs/138936.html