Tags : :
So SWIM for a few months now has been looking into the Muscarinic receptors as SWIM has been fascinated with their potential for helping Parkinson's patients and also for the odd effects from the Datura + Cramp Bark combination.
Something wasn't adding up for the longest time so SWIM went looking for answers. SWIM is still looking into it further but feels they should at least report what they have found out so far.
The reason SWIM is rehashing all this again is because SWIM thought the Muscarinic receptors had to deal soley with acetylcholine levels, but SWIM has been potentially viewing this situation wrong.
Scopolamine and other chemicals from datura affect the Muscarinic receptors. They (chemicals from datura) are antagonists of the muscarinic receptors.
Scopolamine receptor targets:
Not only that, but antagonizing M2 and M3 receptors upregulate the receptors (with atropine)
So datura is naturally increasing M2 and M3 receptors and antagonizing them.
Then comes the interesting bit. The synergy between two receptors..... M1 / M2 and D1 / D2 respectively!!
Note that in the article they state the Dopamine and Muscarinic receptors act in a synergistic fashion when it comes to dopamine, but separate when it comes to other systems (such as cholinergic systems)
So with the trail so far, we see that datura will upregulate M2, antagonize M2, and now there is a synergy between M2 and D2 receptors. D2 being the receptor that Toastus has stated / claimed is responsible for hallucinations.
Some missing pieces of the puzzle:
1) Does antagonizing or agonizing M2 increase D2 receptor activity?
2) 69Ron mention serotonin receptors play a role in this a well, do they? and / or does it affect D2 receptors?
(Claim about 69Ron talking about serotonin playing a role in the combination http://herbs.maxforum.org/2010/09/03/cramp-bark-datura-inoxia-closed-eye-visuals/page2/#post30 )
SWIM is speculating that the Datura + Cramp Bark combo may creating the hallucinations in such fashion as described above. SWIM needs to look into it more though.
That is it for now.
P.S. SWIM would like to thank Medievil from Longecity with this further insight into Muscarinic receptors
P.P.S @ alyssum, So SWIM may have been half right on the reason to use Galantamine to help SWIY's persistent problems from their abuse of diphenhydramine. But the reason it would work isn't because of the increase of Acetylcholine directly, but because they agonize Alpha7-Nicotinic and Muscarinic receptors downstream. SWIM will try to come to a better conclusion why this would work when more information presents itself. Example, the reason some hospitals use Physostigmine to treat datura poisoning is because it increases acetlycholine levels, which indirectly affect nicotinic and muscarinic receptors downstream.
Links to some of SWIM's digging: