No evidence for endorphin deficiency in fibromyalgia following investigation of cerebrospinal fluid (CSF) dynorphin A and Met-enkephalin-Arg6-Phe7.
The CSF levels of Met-enkephalin-Arg6-Phe7 and dynorphin A were measured in patients with fibromyalgia. The mean CSF Met-enkephalin-Arg6-Phe7 level was 35.1 +/- 2.4 fmol/ml (mean +/- S.E.M.). The mean CSF level of dynorphin A was 14.3 +/- 0.9 fmol/ml. Regression analysis showed a statistically significant correlation between Met-enkephalin-Arg6-Phe7 and dynorphin A (r = 0.5369, P = 0.001). When correlated to the previously measured CSF levels of beta-endorphin, a statistically significant correlation was found with Met-enkephalin-Arg6-Phe7 (r = 0.5055, P = 0.03) but not with dynorphin A (P greater than 0.05). The Met-enkephalin-Arg6-Phe7 and dynorphin A levels are elevated compared to the levels available for comparison groups. Therefore, a lack of endorphin secretion does not seem to be the basis for the hyperalgesia observed in these patients.
Department of Biological and Medical Psychology, University of Bergen, BergenNorway Department of Pharmaceutical Pharmacology, University of Uppsala, UppsalaSweden Department of Experimental Drug Dependence Research, Karolinska Institute, StockholmSweden.
Henning
H
Vaerøy
Fred
F
Nyberg
Lars
L
Terenius
D000328:Adult; D015415:Biomarkers; D004399:Dynorphins / Q000134:cerebrospinal fluid*; D004723:Endorphins / Q000172:deficiency*; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000134:cerebrospinal fluid; D005260:Female; D005356:Fibromyalgia / Q000134:cerebrospinal fluid*; D006801:Humans; D011863:Radioimmunoassay; D012044:Regression Analysis
D015415:Biomarkers; D004723:Endorphins; D004744:Enkephalin, Methionine; C027511:enkephalin-Met, Arg(6)-Phe(7)-; D004399:Dynorphins