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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 9 of 9. This is the beginning of the thread.
Posted by bulldog2 on November 16, 2007, at 19:29:58
The ssris eventually reduce the amount of dopamine in the brain. Nardil because it inhibits mao for all three neurotransmitters actually slightly increases the amount of ne and da in the brain. This could account for why ssri sexual sides get worse with time(dopamine steadily decreasing)while nardil sides sometime disappate with time..Here's the study..
This study investigated the effects of acute and chronic (one daily i.p. injection for 14 days) treatments with the non-selective irreversible monoamine-oxidase (MAO) inhibitor phenelzine (10 and 30 mg/kg) on defensive behaviors of Swiss mice in the mouse defense test battery (MDTB) which has been designed for screening anxiolytic and anti-panic drugs. In the MDTB, subjects were confronted with a natural threat (a rat) and situations associated with this threat. MAO-A and MAO-B activities and levels of brain monoamines (serotonin (5-HT), dopamine (DA) and norepinephrine (NE)) and their deaminated metabolites were subsequently measured. Behavioral results showed that acute administration of phenelzine did not specifically modify defensive behaviors. By contrast, after chronic treatment, phenelzine produced a significant reduction in avoidance distance when the rat was approaching, an effect which is consistent with an anti-panic-like action. In addition, phenelzine displayed weak anxiolytic-like effects as it increased risk assessment responses when mice were constrained in one part of the apparatus facing the rat which remained at a constant distance. No other specific drug effect was observed. These behavioral changes were associated with a dramatic increase in 5-HT levels, in particular after chronic treatment, while levels of DA and NE increased only slightly. Importantly, no significant differences in DA and NE levels between acute and chronic regimens were observed. Levels of deaminated metabolites of monoamines were markedly decreased. Measurements of MAO activity revealed substantial reductions in both type A and B forms with a full inhibition of both forms being observed only after chronic treatment with phenelzine. These results suggest that the effects of phenelzine may be due mainly to its effects on the 5-HT system and presumably related to the full inhibition of MAO-A and/or MAO-B.
Posted by mav27 on November 16, 2007, at 21:08:22
In reply to Mechanism Of Action Of Nardil, posted by bulldog2 on November 16, 2007, at 19:29:58
So if i understand that, it's saying it's mostly the seratonin systems that account for the results of nardil rather than NE or Dopamine which are only increased slightly ?
Do you have the source for that study by any chance?
Posted by bulldog2 on November 17, 2007, at 8:17:48
In reply to Re: Mechanism Of Action Of Nardil » bulldog2, posted by mav27 on November 16, 2007, at 21:08:22
I'd have to find the source again as I didn't keep it. Yes the implication is serotonin is the main player. But think of the implications of at least maintaining Ne and DA as opposed to a steady decline of DA. Dopamine is the pleasure chemical and at least with nardil you don't lose that. With the ssris you get a steady decline over time which might account for people saying they feel like zombies.
Posted by bulldog2 on November 17, 2007, at 8:25:12
In reply to Mechanism Of Action Of Nardil, posted by bulldog2 on November 16, 2007, at 19:29:58
Here's the nardil link.
Posted by Racer on November 17, 2007, at 12:26:30
In reply to Re: Mechanism Of Action Of Nardil, posted by bulldog2 on November 17, 2007, at 8:17:48
> With the ssris you get a steady decline over time which might account for people saying they feel like zombies.
Actually, most of what I've read says that the down-regulation of 5HT receptors on SSRIs actually increases the ratio of DA, rather than lowering it. I'd be interested in seeing the sources for this statement.
Posted by bulldog2 on November 17, 2007, at 13:14:42
In reply to Re: Mechanism Of Action Of Nardil » bulldog2, posted by Racer on November 17, 2007, at 12:26:30
> > With the ssris you get a steady decline over time which might account for people saying they feel like zombies.
>
> Actually, most of what I've read says that the down-regulation of 5HT receptors on SSRIs actually increases the ratio of DA, rather than lowering it. I'd be interested in seeing the sources for this statement.You would think that if the ratio of DA to SE were increased libido would be increased and people would have more of a pleasure response in general which people on ssris frequently complain they don't have.
Here's a excerpt from an article on ssris.
Sexual side effects
See also: Post SSRI Sexual Dysfunction
SSRIs can cause various types of sexual dysfunction such as anorgasmia, erectile dysfunction, and diminished libido. Initial studies found that such side effects occur in less than 10% of patients, but since these studies relied on unprompted reporting, the frequency was probably underestimated. In more recent studies, doctors have specifically asked about sexual difficulties, and found that they are present in between 17% [17] and 41% [18] of patients. This dysfunction occasionally disappears spontaneously without stopping the SSRI, and in most cases resolves after discontinuation. In some cases, however, it does not; this is known as Post SSRI Sexual Dysfunction (PSSD).It is believed that sexual dysfunction is caused by an SSRI induced reduction in dopamine. Stimulation of postsynaptic 5-ht2 and 5-ht3 receptors decreases dopamine release from the Substantia Nigra. Sexual dysfunction caused by SSRIs can sometimes be mitigated by several different drugs. These include:
bupropion (norepinephrine and dopamine reuptake inhibitor)
buspirone (serotonin receptor agonist)
methylphenidate (stimulant)
mirtazapine (noradrenergic and specific serotonergic antidepressant (NaSSA))
amphetamine (stimulant)
amantadine (antiviral)
pramipexole (dopamine agonist) and
ropinirole (dopamine agonist)
On the other hand, the effect of SSRIs to slow down sexual stimulation may be used as treatment; SSRIs have been proposed as a drug to treat premature ejaculation.[19]
Posted by FredPotter on November 17, 2007, at 18:12:45
In reply to Re: Mechanism Of Action Of Nardil, posted by bulldog2 on November 17, 2007, at 13:14:42
has anyone found a low dose of Nardil as maintenance works? That is after several months of the high dose phase
Posted by mav27 on November 17, 2007, at 21:45:34
In reply to Re: Mechanism Of Action Of Nardil, posted by bulldog2 on November 17, 2007, at 8:17:48
Cheers for the link (in the next post)
I found your first post interesting because i assumed nardil would have a big effect on Dopamine where as it says it only has a small effect(slight) on it. nardil has helped my SP but i'm still severly lacking in motivation which i believe is effected by Dopamine so if Nardil does only have a slight effect on Dopamine then boosting it with something may help... i had only just recently talked to my psych about adding a tiny amount of stimulant so i may be on the right track after all.
Posted by bulldog2 on November 19, 2007, at 9:57:26
In reply to Re: Mechanism Of Action Of Nardil » bulldog2, posted by mav27 on November 17, 2007, at 21:45:34
> Cheers for the link (in the next post)
> I found your first post interesting because i assumed nardil would have a big effect on Dopamine where as it says it only has a small effect(slight) on it. nardil has helped my SP but i'm still severly lacking in motivation which i believe is effected by Dopamine so if Nardil does only have a slight effect on Dopamine then boosting it with something may help... i had only just recently talked to my psych about adding a tiny amount of stimulant so i may be on the right track after all.Maybe a dopamine agonist would help.
This is the end of the thread.
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