Serotonergic markers and lowered plasma branched-chain-amino acid concentrations in fibromyalgia.
The aims of the present study were to examine serotonergic markers, i.e. [3H]paroxetine binding characteristics and the availability of plasma tryptophan, the precursor of serotonin (5-HT), and the plasma concentrations of the branched chain amino acids (BCAAs), valine, leucine and isoleucine, in fibromyalgia. The [3H]paroxetine binding characteristics, B(max) and K(d) values, and tryptophan and the competing amino acids (CAA), known to compete for the same cerebral uptake mechanism (i.e. valine, leucine, isoleucine, phenylalanine and tyrosine), were determined in fibromyalgia patients and normal controls. There were no significant differences in the [3H]paroxetine binding characteristics (B(max) and K(d)) between fibromyalgia and control subjects. There were no significant differences in plasma tryptophan or the tryptophan/CAA ratio between fibromyalgia patients and normal controls. In the fibromyalgia patients, there were no significant correlations between [3H]paroxetine binding characteristics or the availability of tryptophan and myalgic or depressive symptoms. Patients with fibromyalgia had significantly lower plasma concentrations of the three BCAAs (valine, leucine and isoleucine) and phenylalanine than normal controls. It is hypothesized that the relative deficiency in the BCAAs may play a role in the pathophysiology of fibromyalgia, since the BCAAs supply energy to the muscle and regulate protein synthesis in the muscles. A supplemental trial with BCAAs in fibromyalgia appears to be justified.
Maes
M
M
Department of Psychiatry & Neuropsychology, University Hospital of Maastricht, Postbus 5800, 6202 AZ, Maastricht, The Netherlands. crc-mh@online.be
Verkerk
R
R
Delmeire
L
L
Van Gastel
A
A
van Hunsel
F
F
Scharpé
S
S
D000328:Adult; D000597:Amino Acids, Branched-Chain / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D005356:Fibromyalgia / Q000097:blood* / Q000175:diagnosis / Q000188:drug therapy; D006801:Humans; D007532:Isoleucine / Q000097:blood; D007930:Leucine / Q000097:blood; D008297:Male; D008875:Middle Aged; D017374:Paroxetine / Q000008:administration & dosage / Q000378:metabolism*; D010649:Phenylalanine / Q000097:blood; D017367:Selective Serotonin Reuptake Inhibitors / Q000008:administration & dosage / Q000378:metabolism*; D014364:Tryptophan / Q000097:blood*; D014633:Valine / Q000097:blood
D000597:Amino Acids, Branched-Chain; D015415:Biomarkers; D007532:Isoleucine; D007930:Leucine; D017374:Paroxetine; D010649:Phenylalanine; D017367:Selective Serotonin Reuptake Inhibitors; D014364:Tryptophan; D014633:Valine