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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 16 of 16. This is the beginning of the thread.
Posted by B2chica on August 17, 2011, at 13:19:55
im reading and clinical effects mention MAO-B (such as emsam) is irreversible inhibitor...
what is meant by that.
does that mean that once i go on an MAO-B that i can basically never go back?
that those amines (Dop, Norep,etc) will never 'naturally' be blocked again?can anyone explain a little more regarding this "Irreversible" process.
thank you.
b2c.
Posted by emmanuel98 on August 17, 2011, at 17:52:40
In reply to MAO-A vs MAO-B?, posted by B2chica on August 17, 2011, at 13:19:55
It just means that the oxidase inhibition doesn't go away as soon as you are off the drug. It takes about two weeks off for the brain to start producing oxidase again. That's why these drugs require a two week wash out period.
Posted by Phillipa on August 17, 2011, at 18:44:41
In reply to Re: MAO-A vs MAO-B?, posted by emmanuel98 on August 17, 2011, at 17:52:40
How come it seems that the A and B come up a lot on threads. I now understand that the B means no meds for two weeks unless compatible with the MAOI. Is this correct? Phillipa
Posted by linkadge on August 17, 2011, at 19:29:22
In reply to Re: MAO-A vs MAO-B?, posted by emmanuel98 on August 17, 2011, at 17:52:40
Your brain produces MAO at a steady rate. When you take an 'irreversable' MAOI, the drug grabs hold of each enzyme and that one no longer works (until a new ones are produced). The 'reversable' drug just hold onto the enzyme for a period of time, then let go, so that the MAO enzyme can go back to eating up the neurotransmitters.
Linkadge
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
Posted by Phillipa on August 17, 2011, at 21:03:01
In reply to Re: MAO-A vs MAO-B?, posted by policebox on August 17, 2011, at 20:24:48
Thanks reminds me of also how serotonin and other neurotransmitters work. Know what synapse is and used to teach when nursing that it's like a space ship landing in the snapse and the med makes it stay longer so you can soak up the medication and then it exits above. But the MAOI's stick around much longer.Phillipa
Posted by B2chica on August 18, 2011, at 10:29:22
In reply to Re: MAO-A vs MAO-B?, posted by policebox on August 17, 2011, at 20:24:48
thnx policebox.
that was a very understandable explanation.
i was just wondering if the body contantly produces something, and then is blocked (irreversibly) for many years, would your body then begin to evolve and slow or stop the production?
i know overly paranoid. but i had to ask.
the more i understand the less i worry.thnk u.
Posted by policebox on August 18, 2011, at 12:14:53
In reply to Re: MAO-A vs MAO-B? » policebox, posted by B2chica on August 18, 2011, at 10:29:22
It's a good question to have asked. And when it comes to your body and putting things like drugs into your body which changes it, it's especially important for you to get all of your concerns addressed.
While I've never heard of a case where an individual has previously produced a sufficient amount of MAO and then stopped doing so (such as after taking an MAOi), I am just a lay person, so I can't say with 100% certainty that it's never happened.
Your question got me curious though and apparently there is a rare genetic disorder called Brunner syndrome which causes an MAO-A deficiency. From what I can tell from reading, the mutation in the MAO-A gene is present at birth, so I don't think it would apply to you.
The more I think about your question, the more interested in it I get. Perhaps it's already been research, but I'm curious about the possibility of gene mutation as a cause for depression and whether the genes which have mutated are like that from birth or if something can happen during your adult life to cause them.
> thnx policebox.
> that was a very understandable explanation.
> i was just wondering if the body contantly produces something, and then is blocked (irreversibly) for many years, would your body then begin to evolve and slow or stop the production?
> i know overly paranoid. but i had to ask.
> the more i understand the less i worry.
>
> thnk u.
>
Posted by B2chica on August 18, 2011, at 12:30:04
In reply to Re: MAO-A vs MAO-B?, posted by policebox on August 18, 2011, at 12:14:53
it would be interesting to see articles of research done in that area.
i've honestly had feelings of depression as long as i can remember.
i remember an exact time, when i was 9 when i first had thoughts of death. The fears and hopelessness, the welcome thoughts, the overwhelming feelings...though i did have some childhood "events" that would induce depressive feelings, i do always remember feeling this off and on throughout my entire life.
b2c
Posted by viper1431 on August 19, 2011, at 11:47:33
In reply to Re: MAO-A vs MAO-B? » policebox, posted by B2chica on August 18, 2011, at 10:29:22
Hmm it's not exactly blocked as i understand it as it keeps getting produced but just destoyed afterwards so as far as your brain is aware it's still producing and releasing the stuff the same as it was before taking the maoi.
if anything i would wonder if it tries to produce more, since whatever is involved in keeping the stuff at the needed level would be noticing that other trasmitters are higher than normal so would something in the brain go "oh no not enough mao"
UNless it only works by sensing the amount of moa floating around and it still detects it as normal even with the nardil/parnate clinging on and eactivating it.
> thnx policebox.
> that was a very understandable explanation.
> i was just wondering if the body contantly produces something, and then is blocked (irreversibly) for many years, would your body then begin to evolve and slow or stop the production?
> i know overly paranoid. but i had to ask.
> the more i understand the less i worry.
>
> thnk u.
>
Posted by B2chica on August 19, 2011, at 12:58:11
In reply to Re: MAO-A vs MAO-B? » B2chica, posted by viper1431 on August 19, 2011, at 11:47:33
Very interesting...good point.
and that comment actually really relieved a lot of my stress about the issue.
thnx.
Posted by linkadge on August 20, 2011, at 7:49:03
In reply to Re: MAO-A vs MAO-B?, posted by policebox on August 17, 2011, at 20:24:48
Posted by linkadge on August 20, 2011, at 7:51:52
In reply to Re: MAO-A vs MAO-B?, posted by policebox on August 18, 2011, at 12:14:53
There is some evidence that smoking is associated with increased gene expression for monoamine oxidase production. Whether this is a cause or effect is not known. However, it has been noted that when smokers stop smoking, there is an increased rate of MAO production compared to the general population. However, this may be a trait marker for smokers that preceeded smoking.
Linkadge
Posted by linkadge on August 20, 2011, at 7:56:57
In reply to Re: MAO-A vs MAO-B? » B2chica, posted by viper1431 on August 19, 2011, at 11:47:33
>UNless it only works by sensing the amount of >moa floating around and it still detects it as >normal even with the nardil/parnate clinging on >and eactivating it.
There may be a feedback loop for MAO production. I know for SSRIs, prenatal use is associated with elevated serotonin transporer levels in the offspring. Thus the offspring adapt to the drug's presence during development and decide to have a higher set point of serotonin transporter as the new "normal".
There are MAO inhibition level tests. One could have such a test over time with MAO therapy to see if an constant blood level results in steady MAO inhibition.
Linkadge
Posted by policebox on August 22, 2011, at 0:13:30
In reply to Re: MAO-A vs MAO-B? » policebox, posted by linkadge on August 20, 2011, at 7:51:52
That's an interesting finding. It seems consistent with the side-effects individuals experience when they stop smoking, such as depression and agitation. Higher levels of MAO in the synaptic cleft would theoretically correspond to higher levels of neurotransmitter degradation.
> There is some evidence that smoking is associated with increased gene expression for monoamine oxidase production. Whether this is a cause or effect is not known. However, it has been noted that when smokers stop smoking, there is an increased rate of MAO production compared to the general population. However, this may be a trait marker for smokers that preceeded smoking.
>
> Linkadge
Posted by SLS on August 22, 2011, at 6:15:06
In reply to Re: MAO-A vs MAO-B?, posted by policebox on August 22, 2011, at 0:13:30
> That's an interesting finding. It seems consistent with the side-effects individuals experience when they stop smoking, such as depression and agitation. Higher levels of MAO in the synaptic cleft would theoretically correspond to higher levels of neurotransmitter degradation.
I think that MAO is located in the cytosol; most of which is bound to mitochondria. It is COMT that is found in the synaptic gap and that is responsible for deamination.
- Scott
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