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 > 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.
∗Correspondence to: Dr. Henning Vaerøy, M.D., Department of Biological and Medical Psychology, University of Bergen, Aarstadveien 21, N-5000 Bergen, Norway.
Submitted October 31, 1990; revised January 16, 1991; accepted January 18, 1991.
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