ELEVATED SUBSTANCE P LEVEL IN CEREBROSPINAL FLUID FROM PATIENTS WITH FIBROMYALGIA IS CONTRASTED BY A DECREASE IN MET-ENKEPHALIN-ARG-PHE

Abstract

The levels of substance P and Met-enkephalin-Arg-Phe were measured by radioimmunoassay in cerebrospinal fluid from 26 patients with fibromyalgia and compared to those of 15 matched controls. The result indicated a significant elevation in substance P-like immunoraeactivity in the fibromyalgia patients, whereas the level of Met-enkephalin-Arg-Phe was significantly reduced. The identity between the detected immunoreactive peptide material and the authentic peptides were confirmed by HPLC analyses. It thus appears that the observed elevation of substance P occurs at the expense of the enkephalin heptapeptide. As substance P is believed to facilitate the nociceptive impulses in sensory afferents and the opioid peptides postulated to primary function in pain inhibition or pain modulation it is likely that the observed increase in substance P results from a deficiency in the enkephalin secretion leading to a decreased pain treshold in fibromyalgia.