Posted by policebox on August 17, 2011, at 20:24:48
In reply to MAO-A vs MAO-B?, posted by B2chica on August 17, 2011, at 13:19:55
Monoamine oxidase (MAO) breaks down neurotransmitters. There are two kinds of monamine oxidase: MAO-A and MAO-B. MAO-A mainly breaks-down seratonin, melatonin, norepinephrine, and epinephrine; MAO-B mainly breaks-down phenethylamine and benzylamine; both forms break down dopamine, tyramine, and tryptamine equally.
Since not having enough neurotransmitters in the synapses (to put it crudely) is believed to be responsible for depression (called the monoamine theory of depression) the goal of an antidepressant drug is to increase the amount of time that neurotransitters are available in the synapse.
What an MAO inhibitor does is to "latch" onto monoamine oxidase and "deactivate it". Since the MAO is deactivated, it can't break down neurotransmitters and thus this action increases the amount of time that neurotransitters are available in the synapse, hopefully leading to a remission of depressive symptoms.
When an MAOi is "irreversible" it means that it latches onto MAO permanantely, and thus disables it permanently. When an MAOi is "reversible" it means that it latches onto MAO for a while, but eventually will "unlatch", allowing the original MAO to function again.
When you take a non-selective irreversible MAOi, such as Parnate, Nardil, or many others, it just means that it will deactivate both the MAO-A and MAO-B that you currently have in your body permanantely. Of course, your body produces MAO all the time, so as long as you are taking an MAOi, it will seek-out the newly produced MAO and deactivate it. Once you stop taking an MAOi, then the new MAO your body produces will no longer get deactivated. However, it can take around two weeks for all of the MAOi drug to fully get out of your system, meaning it will still work to deactivate newly produced MAO for up to two weeks after you discontinue use of the MAOi.
To answer your original question in one sentence, taking an irreversible MAOi doesn't create any permament situation; it will only block the ability for monoamine oxidase to degrade neurotransmitters while you are actively taking it and then for up to two weeks after you stop taking it.
Hope this helps! All the best.
Policebox
poster:policebox
thread:994104
URL: http://www.dr-bob.org/babble/20110809/msgs/994156.html