Posted by Anonymoose on November 13, 2007, at 16:50:54
In reply to Does l-phenylalnine inhibit natural dopamine prod?, posted by 3 Beer Effect on March 23, 2002, at 23:00:07
Hi all, new poster here, having recently gone through many of the old archives. To comment on 3BE's question about B6 (pyridoxine) and l-dopa:
This morning I experienced the nullifying effects of a B6 supplement (50mg B6 and other B/C vitamins) on l-dopa taken in conjunction (obtained from ~100g cooked fava beans).
Apparently B6 is a cofactor for the decarboxylation of l-dopa; vitamin B6 enhances peripheral conversion of l-dopa to dopamine, making less readily available for use in the CNS (across the BBB). Link to a handout from a Howard pharmacology class:
http://www.med.howard.edu/pharmacology/handouts/parkinsons.htm
I definitely had a more pronounced response to the fava beans the night before, taken without anything else in conjunction. Whereas the initial response to the l-dopa was noticeably beneficial (both activating and calming, re: BarbaraCat's experience with Mucuna Pruriens), the l-dopa taken with B Complex was not nearly as helpful. If anything, it made me both drowsy and jumpy at the same time. Perhaps the vitamin C along with the B complex helped convert the peripheral dopamine too quickly into NE and epinephrine running free inside/outside my CNS. The effect was that random noises outside my window would cause me to startle very easily, and feel a sharp adrenaline-like spike. Hopefully future intake of l-dopa without the B-complex vitamin will continue to have positive effects.
A little about me: 27yo male, with a 9-year unipolar depressive spiral. Includes some anxiety and agitation, but most prominently apathetic and anhedoic in nature.
What I feel is the most striking feature, and I think most important to understanding the cause and treatment, is the increasing loss of "feeling" over time, into increasingly anhedonic states. I can trace the disease's progression in terms of increasing loss of sensitivity to "pleasure-states/stimuli", if you will.
Over the last 9 years or so I've slowly lost the ability to "feel" certain things (loss of dopamine receptor sensitivity, perhaps?) The ability to "feel" music, to be able to "crush" on a love interest. Then went the ability to get a buzz off a cigarette (social smoker). Then I slowly lost buzz-response to caffeine, alcohol, and finally P-stims ritalin and adderall.
Along the way my SE and NE pathways have probably gotten all out of whack as well, probably in large part in response to the DA troubles. Zoloft was the first AD tried (7 yrs ago) and had a wonderful (euphoric, almost) initial effect, but pooped out after a month. Since then I've tried other SSRIs, Effexor, and Wellbutrin with little benefit. Have always had to augment those with ritalin or adderall, but now both of those Pstims have pooped out completely as well.
I've been getting more and more desperate for relief and more and more convinced that the DA pathways are the key to my problem, so I'm waiting for selegeline (l-deprenyl) to arrive from a euro pharmacy.
Anybody else here have a similar experience? Feel free to email me if you'd like (babblemail or through board posts).
Deperately wanting to feel again...
> A few months ago I read on Pubmed about a study that said that l-phenylalnine supplementation inhibits either tyrosine hydroxylase (the thing that turns l-tyrosine into l-dopa) or the thing that turns l-dopa into dopamine (aromatic hydroxylase or something like that. Not sure which one it inhibits? Does anyone know about l-phenylalanine inhibiting dopamine production?
>
> L-phenylalanine seemed like a good thing to take since unlike most amino acids it actually crosses the blood brain barrier & seemed to have some slight amphetamine like effect after 2 weeks of 1500 mg/morning on an empty stomach (Twinlab w/o vitamin B6 was the only brand that worked for me, country life w/ B6 had no effect). But I stopped taking it after reading the dopamine inhibition article & now I can't find the article I read (in Pubmed).
>
> Also, why do many l-phenylalanine supplements contain vitamin B6 (pyridoxine) when vitamin B6 completely nulls the dopamine enhancing effects of levodopa?
>
> I used to take l-tyrosine but stopped since it doesn't cross the blood brain barrier & can only be transported to the brain by a carrier that is already saturated by a normal diet. I also noticed no effects & it seemed a waste of time/money.
>
> But I wonder if tyrosine or phenylalanine supplementation would be a good idea if you were taking Dexedrine or Adderall everyday & thus constantly depleting your dopamine stores or perhaps like many supplements found at the health food store it is a waste of money?
poster:Anonymoose
thread:99751
URL: http://www.dr-bob.org/babble/20071104/msgs/794893.html