Posted by Racer on February 25, 2006, at 3:22:53
In reply to provigil mechanism of action?, posted by mike99 on February 24, 2006, at 17:33:54
When I looked it up, back when the earth's crust was still cooling, I got the impression that it affected GABA, rather than any of the Big Three MAOs. Never heard it affected dopamine at all.
Here's rxlist.com
"At pharmacologically relevant concentrations, modafinil does not bind to most potentially relevant receptors for sleep/wake regulation, including those for norepinephrine, serotonin, dopamine, GABA, adenosine, histamine-3, melatonin, or benzodiazepines. Modafinil also does not inhibit the activities of MAO-B or phosphodiesterases II-V.
Modafinil is not a direct- or indirect-acting dopamine receptor agonist and is inactive in several in vivo preclinical models capable of detecting enhanced dopaminergic activity. In vitro, modafinil binds to the dopamine reuptake site and causes an increase in extracellular dopamine, but no increase in dopamine release. In a preclinical model, the wakefulness induced by amphetamine, but not modafinil, is antagonized by the dopamine receptor antagonist haloperidol."
"Modafinil does not appear to be a direct or indirect alpha-adrenergic agonist. Although modafinil-induced wakefulness can be attenuated by the a1-adrenergic receptor antagonist, prazosin, in assay systems known to be responsive to a1-adrenergic agonists, modafinil has no activity."
Best I can make out, doesn't seem to do anything... ;-) I know I've read, though, that it decreases GABA, and that's what makes it work. Guess that's wrong, according to this.
Hope that helps.
poster:Racer
thread:612884
URL: http://www.dr-bob.org/babble/20060219/msgs/613019.html