Modulation of pain in fibromyalgia (fibrositis syndrome): cerebrospinal fluid (CSF) investigation of pain related neuropeptides with special reference to calcitonin gene related peptide (CGRP).

The cerebrospinal fluid (CSF) levels of calcitonin gene related peptide (CGRP) were 0.94 +/- 0.06 fmol/ml (mean +/- SEM), of substance P, 35.1 +/- 3.2 fmol/ml and of substance P (1-7), 10.8 +/- 1.2 fmol/ml, as measured by radioimmunoassay in 26 female patients with fibromyalgia. No correlation was found between the levels of CGRP and the substance P and substance P (1-7) levels (r = 0.316, p = 0.14). Our results show that the anatomical coexistence of pain related neuropeptides in neurons is not necessarily reflected by the levels of these peptides measured in the CSF. The presence of CGRP in the CSF could be important since it can enhance the nociceptive activity of tachykinins. This may be of importance in the pathogenesis of pain in fibromyalgia.