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Pregabalin/lyrica and nmda activation

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https://www.google.com/url?sa=t&sou...ggtMAE&usg=AFQjCNHT5B3yaUyQLQ7okMG_GdnZX5N72w

Pregabalin [S-[+]-3-isobutylGABA or (S)-3-(aminomethyl)-5-methylhexanoic acid, Lyrica] is an anticonvulsant and analgesic medication that is both structurally and pharmacologically related to gabapentin (Neurontin; Pfizer Inc., New York, NY). Previous studies have shown that pregabalin reduces the release of neurotransmitters in several in vitro preparations, although the molecular details of these effects are less clear. The present study was performed using living cultured rat hippocampal neurons with the synaptic vesicle fluorescent dye probe FM4-64 to determine details of the action of pregabalin to reduce neurotransmitter release. Our results indicate that pregabalin treatment, at concentrations that are therapeutically relevant, slightly but significantly reduces the emptying of neurotransmitter vesicles from presynaptic sites in living neurons. Dye release is reduced in both glutamic acid decarboxylase (GAD)-immunoreactive and GAD-negative (presumed glutamatergic) synaptic terminals. Furthermore, both calcium-dependent release and hyperosmotic (calcium-independent) dye release are reduced by pregabalin. The effects of pregabalin on dye release are masked in the presence of l-isoleucine, consistent with the fact that both of these compounds have a high binding affinity to the calcium channel alpha(2)-delta protein. *{The effect of pregabalin is not apparent in the presence of an N-methyl-d-aspartate (NMDA) antagonist [D(-)-2-amino-5-phosphonopentanoic acid], suggesting that pregabalin action depends on NMDA receptor activation.}* Finally, the action of pregabalin on dye release is most apparent before and early during a train of electrical stimuli when vesicle release preferentially involves the readily releasable pool.

I couldnt highlight cuz im on my phone but i put the relevant text in brackets. I found this interesting seeing as i enjoy both lyrica and nmda antagonists, thought id share. Any thoughts?
 
How is the exact relationship of NMDARs, Ca ion channels and a2d sub units - NMDARs contain a Ca channel which they control, but does then every Ca channel contain a a2d subunit, so pregabalin would bind to and block some site inside of the NMDAR complex, leading to, but not limited to, a modulation of NMDAR mediated excitation / Ca influx? And when the NMDAR is blocked, it doesn't matter anymore whether pregabalin is present or not - but it would still affect other Ca channels?
 
How is the exact relationship of NMDARs, Ca ion channels and a2d sub units - NMDARs contain a Ca channel which they control, but does then every Ca channel contain a a2d subunit, so pregabalin would bind to and block some site inside of the NMDAR complex, leading to, but not limited to, a modulation of NMDAR mediated excitation / Ca influx? And when the NMDAR is blocked, it doesn't matter anymore whether pregabalin is present or not - but it would still affect other Ca channels?
It is more accurate to say that NMDA receptors ARE an ion channel, not that they contain a channel that they control. However, NMDA-R isn't technically a "calcium channel" -- it is a nonspecific cation channel -- most of the current it passes is actually sodium and potassium. Although the NMDA-R is a channel that can pass calcium, it is not a member of the family of voltage-gated calcium channels that are targeted by pregabalin.
 
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Possibly explains why a decent number of anecdotal comparisons between pregablin and gabapentin, which should have about the same effects at equivalent doses, report that an equivalent dose of lyrica feels more inebriating than one of gabapentin.
 
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