N&PD Moderators: Skorpio | someguyontheinternet
Ibogaine doesn't sound to be dissociative? All the reports of flood doses I read sound like deep dissociative state and wandering around your mind, actually sounds a lot like Salvia Divinorum experience but much much longer lasting. It could be a result of both dissociative effect caused via NMDA receptors and/or sigma receptors and serotonin reuptake inhibition. I experienced similar states after DXM though they were mostly abstract at moderate doses rather than making up long stories that you take part in. Certain arylcyclohexanamines produce similar effects too. Still, that's what dissociation is in my experience, losing contact with your environment and experiencing deep continuous introspection however it is effected.
Are there other a3b4 nicotinic agents known that could be compared?.
Are there other a3b4 nicotinic agents known that could be compared?
My gut feeling is that it probably wouldn't. Apparenty dextromethorphan, bupropion, and mecamylamine can also bind to the same nicotinic receptor to some extent, but they don't really mimic the effects of ibogaine. However, Glick was able to produce an anti-addictive effect by combining low doses of a few different ligands. That makes me think that there have to be pretty high levels of blockade.Does a little blockade of a3b4 day by day function the same as a massive blockade akin to an ibogaine flood dose?
I recall a study showing rodents can display increased locomotion up to one year after a single amphetamine dose. Do you think a3b4 antagonists would have utility for former addicts who are currently abstaining but still having issues with hyper-excitability?
Is it possible that addicting drugs and behaviors stimulate a3b4, and thus a3b4 blockade is not just a means to an end that is unrelated to the original cause?
I managed to find this study http://www.ncbi.nlm.nih.gov/m/pubmed/24750073/ regarding genetic models but it seems hard to interpret because you would think that even modifying the basal level of a3b4 input to the VTA (or knocking it out) would change the dynamics of the VTA (and therefore withdrawal) regardless of whether the drugs were stimulating a3b4 (I hope that makes sense). In other words, are drugs/behaviors actually affecting the a3b4, or is the a3b4 this somewhat "static" input that doesn't get affected too much by the surrounding brain activity?
You can't necessarily assume there is increased excitability. Another possibility is that alpha3beta4 plays a role in the function of the circuits responsible for expression of the somatic signs of withdrawal.Do we have any idea what's providing input to or increasing the excitability of these a3b4 receptors?
Sort of, yes.Regarding the variable mechanics of nicotinic blockade, is this similar to a slow dissossociating NMDA antagonist vs. something like memantine?
The values for ibogaine are in uM. For DXM, it looks like some values are in nM while others are in uM (I doubt the SERT affinity is 20 pM). You are almost certainly correct about DXO. Some people think desmethyl = nor but that is obviously wrong.The top values for DXM look like they're in nM (?). Also, isn't nor-DXM meant to be DXO? The value for NMDA receptors looks like that of dextrorphan's (which is ~200-400 nM depending on the source). I've never really seen any affinities for nor-DXM. The affinities of ibogaine and noribogaine at SERT are 0.55 and 0.04 uM respectively (source).
The primary mechanism of action of ibogaine isn't blocking drug-induced reward
To give a brief answer, the habenula receives input from PFC, meaning it can receive input with multisensory integration.
In terms of how the brain disentangles the stimulus causing craving, someone who is addicted to cocaine (as an example) and experiences craving in a particular environment will also have formed strong sensory associations between that environment and cocaine. The integration of all of these things is done in the same way as sensory binding -- ie, the brain has to be able to process all of the features of a complex stimulus individually but somehow link everything back together.
Interesting... I wonder what to make of the increased excitability observed in MDMA user's lateral geniculate nucleus then, because it sounds like the medial geniculate nucleus (" audio hypothalamus") is pretty much the relay for audio, and it's right next to the lateral geniculate nucleus??? Hmmmmmmm.
You're absolutely right: DXM and DXO's NMDA/OP/sigma Ki values are in nM (instead of uM). So should read:The top values for DXM look like they're in nM (?). Also, isn't nor-DXM meant to be DXO? The value for NMDA receptors looks like that of dextrorphan's (which is ~200-400 nM depending on the source). I've never really seen any affinities for nor-DXM. The affinities of ibogaine and noribogaine at SERT are 0.55 and 0.04 uM respectively (source).