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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 12 of 12. This is the beginning of the thread.
Posted by KaraS on August 24, 2004, at 16:29:07
Role of serotonin in the paradoxical calming effect of psychostimulants on hyperactivity.
Gainetdinov RR, Wetsel WC, Jones SR, Levin ED, Jaber M, Caron MG.
Howard Hughes Medical Institute Laboratories, Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
The mechanism by which psychostimulants act as calming agents in humans with attention-deficit hyperactivity disorder (ADHD) or hyperkinetic disorder is currently unknown. Mice lacking the gene encoding the plasma membrane dopamine transporter (DAT) have elevated dopaminergic tone and are hyperactive. This activity was exacerbated by exposure to a novel environment. Additionally, these mice were impaired in spatial cognitive function, and they showed a decrease in locomotion in response to psychostimulants. This paradoxical calming effect of psychostimulants depended on serotonergic neurotransmission. The parallels between the DAT knockout mice and individuals with ADHD suggest that common mechanisms may underlie some of their behaviors and responses to psychostimulants.
PMID: 9888856 [PubMed - indexed for MEDLINE]
Could anyone tell me what that role of serotonin is in this case?
Posted by SLS on August 24, 2004, at 16:35:26
In reply to Paradoxical Stimulant Response Abstract, posted by KaraS on August 24, 2004, at 16:29:07
Did you know that amphetamine can sometimes have an anti-manic effect.
Pretty cool, huh?
- Scott
Posted by linkadge on August 24, 2004, at 17:05:23
In reply to Re: Paradoxical Stimulant Response Abstract, posted by SLS on August 24, 2004, at 16:35:26
I heard this too. Sometimes cholinergic drugs such as lecethin and aricept can have antimanic and mood stabalizing effects. I would think in part, psychostimulants calm by activating the prefrontal cortex. But I do know that ritalin has fair affinity for the serotonin transporter, and this was purportedly the mechanism that produced the calming effect of it.
I personnally find psychostimulants very depressing.
Linkadge
Posted by zeugma on August 24, 2004, at 18:13:10
In reply to Paradoxical Stimulant Response Abstract, posted by KaraS on August 24, 2004, at 16:29:07
I think it was shown that one difference between cocaine and methylphenidate was that methylphenidate had little affinity for the serotonin transporter. Stimulants calm me down, personally, because I'm a lot less nervous that I'm going to lose track of where I am, who I'm talking to, etc.
Posted by KaraS on August 24, 2004, at 21:15:36
In reply to Re: Paradoxical Stimulant Response Abstract, posted by SLS on August 24, 2004, at 16:35:26
> Did you know that amphetamine can sometimes have an anti-manic effect.
>
> Pretty cool, huh?
>
>
> - Scott
No, I didn't. Way cool! I learn something new everyday here at PB.- Kara
Posted by KaraS on August 24, 2004, at 21:19:54
In reply to Re: Paradoxical Stimulant Response Abstract, posted by linkadge on August 24, 2004, at 17:05:23
> I heard this too. Sometimes cholinergic drugs such as lecethin and aricept can have antimanic and mood stabalizing effects. I would think in part, psychostimulants calm by activating the prefrontal cortex. But I do know that ritalin has fair affinity for the serotonin transporter, and this was purportedly the mechanism that produced the calming effect of it.
>
> I personnally find psychostimulants very depressing.
>
>
> Linkadge
>Thanks. I find them very confusing at this point.
Kara
Posted by KaraS on August 24, 2004, at 21:24:51
In reply to Re: Paradoxical Stimulant Response Abstract, posted by zeugma on August 24, 2004, at 18:13:10
> I think it was shown that one difference between cocaine and methylphenidate was that methylphenidate had little affinity for the serotonin transporter. Stimulants calm me down, personally, because I'm a lot less nervous that I'm going to lose track of where I am, who I'm talking to, etc.
z,
Isn't that the opposite of what they're saying here, about stimulants for those with ADHD:"This paradoxical calming effect of psychostimulants depended on serotonergic neurotransmission..."
Posted by paulbwell on August 24, 2004, at 22:38:47
In reply to Re: Paradoxical Stimulant Response Abstract » zeugma, posted by KaraS on August 24, 2004, at 21:24:51
Does anyone notice when shortly after taking IR Methylphenidate,(Ritalin) they feel a chill? cold feeling?
Cheers
Posted by zeugma on August 25, 2004, at 4:43:31
In reply to Re: Paradoxical Stimulant Response Abstract » zeugma, posted by KaraS on August 24, 2004, at 21:24:51
Isn't that the opposite of what they're saying here, about stimulants for those with ADHD:
"This paradoxical calming effect of psychostimulants depended on serotonergic neurotransmission..."
Hi Kara,
The abstract is wrong, at least as far as Ritalin goes:
: Eur J Pharmacol. 1999 Jun 4;373(2-3):187-93. Related Articles, Links
Chronic methylphenidate alters locomotor activity and dopamine transporters differently from cocaine.Izenwasser S, Coy AE, Ladenheim B, Loeloff RJ, Cadet JL, French D.
Psychobiology Section, National Institute on Drug Abuse, Division of Intramural Research, Baltimore, MD 21224, USA. sizenwas@newssun.med.miami.edu
Continuous infusion of cocaine produces partial behavioral tolerance to its locomotor activating effects, while daily injections produce sensitization. Methylphenidate binds with a similar affinity to cocaine at the dopamine transporter, but has a much lower affinity for the serotonin transporter than does cocaine. This study was done to compare the effects of chronic methylphenidate with chronic cocaine. The pattern of locomotor activity over a 7 day treatment period was significantly different from cocaine. Methylphenidate elevated activity on each day, compared to saline, yet neither tolerance to a continuous infusion of the drug, nor sensitization to repeated daily injections was produced. We have previously shown that neither of these treatments with cocaine produces significant alterations in dopamine transporter density 1 day after the end of treatment. In contrast, methylphenidate injections significantly decreased dopamine transporters in rostral caudate putamen, with no change in nucleus accumbens. Continuous infusion of methylphenidate had no effect on dopamine transporters in either brain region. These findings provide further evidence that different classes of dopamine uptake inhibitors may interact with the dopamine transporter in qualitatively different manners. Furthermore, it is possible that the inhibition of serotonin uptake by cocaine may contribute to the adaptations in behavioral activity that are seen during chronic treatment.
PMID: 10414438 [PubMed - indexed for MEDLINE]
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http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=10414438
all the info I have seen indicates that Ritalin is weak as an inhibitor of the serotonin transporter.-z
Posted by Sidamo on August 25, 2004, at 16:22:21
In reply to RE:Methylphenidate-make anyone feel cold?, posted by paulbwell on August 24, 2004, at 22:38:47
> Does anyone notice when shortly after taking IR Methylphenidate,(Ritalin) they feel a chill? cold feeling?
>
> CheersAbsolutely. In fact, detecting the "chill" feeling is one of the ways I discern whether the meds are in effect or not.
I notice this effect both when taking methylphenidate and Adderall, so I suppose it is common to most stimulants.
I also find it kind of pleasant--maybe because it reminds me that I'm in "all systems go!" mode.
Posted by KaraS on August 25, 2004, at 16:28:47
In reply to Re: Paradoxical Stimulant Response Abstract » KaraS, posted by zeugma on August 25, 2004, at 4:43:31
Posted by paulbwell on August 25, 2004, at 23:54:23
In reply to RE:Methylphenidate-make anyone feel cold?, posted by Sidamo on August 25, 2004, at 16:22:21
> > Does anyone notice when shortly after taking IR Methylphenidate,(Ritalin) they feel a chill? cold feeling?
> >
> > Cheers
>
> Absolutely. In fact, detecting the "chill" feeling is one of the ways I discern whether the meds are in effect or not.
>
> I notice this effect both when taking methylphenidate and Adderall, so I suppose it is common to most stimulants.
>
> I also find it kind of pleasant--maybe because it reminds me that I'm in "all systems go!" mode.
>Do you feel much colder. Like your body temperature drops and you just want to sit in the sun, or in front of a heater?
I was taking 20mgs TID, before my Doc took me off it. while it did produce that pleasant tingle down my spine,as you describe, it also made me feel colder and somewhat lazier.
I even had extensive blood work done,Thyroid, liver, Iron count, everything, and it all came back normal. So now i'm at a crossroads. Do I ask for it back (which I'm thinking of doing),or ask to trial Dex. The Methylphenidate did produce a nice mood improvement, without all the S/E of the AD's I have taken, and made me feel somewhat more peacefull, so we'll see tomorrow when he talks to the Psy.
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