BETA-ENDORPHIN LEVELS ARE REDUCED IN PERIPHERAL-BLOOD MONONUCLEAR-CELLS OF CLUSTER HEADACHE PATIENTS

Opioid system hypofunction has been postulated in cluster headache (CH ) on the basis of reduced opioid levels found in the cerebrospinal flu id (CSF). In this study beta-endorphin levels were monitored in the pe ripheral blood mononuclear cells of 65 episodic CH patients (32 in rem ission and 33 in cluster period) and 50 healthy controls. Beta-endorph in levels were significantly lower than controls in CH patients experi encing both phases of the illness (ANOVA, p < 0.0001). The persistence of this abnormality during pain-free remission suggests a primary alt eration in the regulation of beta-endorphin in peripheral blood mononu clear cells. We speculate that these findings reflect reduced CNS leve ls of beta-endorphin in CH.