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.
Vaerøy
Henning
H
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.
Nyberg
Fred
F
Terenius
Lars
L
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