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Dr. Bob is Robert Hsiung, MD,
[email protected]Shown: posts 1 to 6 of 6. This is the beginning of the thread.
Posted by psychobot5000 on May 29, 2012, at 1:41:57
My whimsy and curiousity leads me to ask this question:
Nomifensine and methylphenidate are both norepinephrine and dopamine reuptake inhibitors, without a lot of other known action on other binding sites. However, the one is thought of primarily as an antidepressant (and was apparently quite effective for that purpose), while the other is a psychostimulant with positive effects on mood, but not an antidepressant per se. Why? What difference might there be between the two molecules?
To some extent they're similar, i.e. it's usually presumed nomifensine had some positive effect on attention and that sort of thing, as a stimulant would, but on mood they seem to act differently, despite the marked similarity in their pharmacological profiles.
Thoughts?
pb5000
Posted by SLS on May 29, 2012, at 20:36:17
In reply to theoretical question: nomifensine vs ritalin/methy, posted by psychobot5000 on May 29, 2012, at 1:41:57
> My whimsy and curiousity leads me to ask this question:
>
> Nomifensine and methylphenidate are both norepinephrine and dopamine reuptake inhibitors, without a lot of other known action on other binding sites. However, the one is thought of primarily as an antidepressant (and was apparently quite effective for that purpose), while the other is a psychostimulant with positive effects on mood, but not an antidepressant per se. Why? What difference might there be between the two molecules?
>
> To some extent they're similar, i.e. it's usually presumed nomifensine had some positive effect on attention and that sort of thing, as a stimulant would, but on mood they seem to act differently, despite the marked similarity in their pharmacological profiles.
>
> Thoughts?
> pb5000
Perhaps there are regional differences in where each drug exerts its effects. I don't know.Methylphenidate is a bit heavier on dopamine than it is on norepinephrine. I believe nomifensine exerts a more balanced effect. Also, methylphenidate increases the release of dopamine, albeit to a lesser extent via a different mechanism of action than amphetamine. Nomifensine does not. I think the bottom line is to compare the long-term changes these drugs produce in downstream signalling. Methylphenidate increases neural tone and signal-to-noise ratio in certain dopamine circuits almost immediately. With antidepressants, increases in signal-to-noise takes two or more weeks to manifest, at least in glutamatergic circuits.
- Scott
Posted by psychobot5000 on May 29, 2012, at 23:22:16
In reply to Re: theoretical question: nomifensine vs ritalin/methy » psychobot5000, posted by SLS on May 29, 2012, at 20:36:17
> > My whimsy and curiousity leads me to ask this question:
> >
> > Nomifensine and methylphenidate are both norepinephrine and dopamine reuptake inhibitors, without a lot of other known action on other binding sites. However, the one is thought of primarily as an antidepressant (and was apparently quite effective for that purpose), while the other is a psychostimulant with positive effects on mood, but not an antidepressant per se. Why? What difference might there be between the two molecules?
> >
> > To some extent they're similar, i.e. it's usually presumed nomifensine had some positive effect on attention and that sort of thing, as a stimulant would, but on mood they seem to act differently, despite the marked similarity in their pharmacological profiles.
> >
> > Thoughts?
> > pb5000
>
>
> Perhaps there are regional differences in where each drug exerts its effects. I don't know.
>
> Methylphenidate is a bit heavier on dopamine than it is on norepinephrine. I believe nomifensine exerts a more balanced effect. Also, methylphenidate increases the release of dopamine, albeit to a lesser extent via a different mechanism of action than amphetamine. Nomifensine does not. I think the bottom line is to compare the long-term changes these drugs produce in downstream signalling. Methylphenidate increases neural tone and signal-to-noise ratio in certain dopamine circuits almost immediately. With antidepressants, increases in signal-to-noise takes two or more weeks to manifest, at least in glutamatergic circuits.
>
>
> - Scott
>
>
>Wow. A much better answer than I could reasonably have expected.
Didn't know that methylphenidate was a releasing agent, or that it acted more heavily on DA. Very interesting, all of it. Will have to look up 'neural tone.'
Posted by linkadge on May 30, 2012, at 16:40:23
In reply to Re: theoretical question: nomifensine vs ritalin/methy, posted by psychobot5000 on May 29, 2012, at 23:22:16
I didn't know that methyphenidate was a releasing agent either.
Nomifenisine might act at other receptors (aka bupropion at nicotinergic receptors).
Linakdge
Posted by rjlockhart04-08 on June 4, 2012, at 11:02:02
In reply to Re: theoretical question: nomifensine vs ritalin/methy, posted by linkadge on May 30, 2012, at 16:40:23
i have to say i rerember reading about this years ago....nomifensine is maybe not as direct in behavior changes as methyphendiate and takes longer to take effect.....
SLS...i think its amphetamine that is the releaser...not methyphendiate...its a reputake inhibitor, like cocaine...that's why its less common for it cause schizophenia like symptoms when over used....but with methamphetamine...you bet, it releases and will cause paranoia, and bizarre like thinking.
anyways i found this that may have some awnsers...
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2957786/
rj
Posted by SLS on June 5, 2012, at 7:30:18
In reply to Re: theoretical question: nomifensine vs ritalin/methy, posted by rjlockhart04-08 on June 4, 2012, at 11:02:02
> i have to say i rerember reading about this years ago....nomifensine is maybe not as direct in behavior changes as methyphendiate and takes longer to take effect.....
>
> SLS...i think its amphetamine that is the releaser...not methyphendiate...its a reputake inhibitor, like cocaine...that's why its less common for it cause schizophenia like symptoms when over used....but with methamphetamine...you bet, it releases and will cause paranoia, and bizarre like thinking.
>
> anyways i found this that may have some awnsers...
>
> http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2957786/
>
> rj
That's a great article. Thanks for posting it.
- Scott
This is the end of the thread.
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