EVALUATION OF BETA-ENDORPHIN SECRETION IN PATIENTS SUFFERING FROM EPISODIC CLUSTER HEADACHE

In order to obtain data regarding peripheral levels of beta-endorphin in head pain syndromes, we evaluated the plasma beta-endorphin secreto ry pattern in 12 adult male patients suffering from cluster headache. Blood samples were drawn every 2 hours for a 24-hour period, and in ad dition at 30-minute intervals for 120 minutes during cluster attacks. The same sampling was repeated during an asymptomatic period. Cluster headache patients showed no significant beta-endorphin circadian rhyth m and a delayed acrophase during cluster periods compared with that re corded in the remission period and in normal subjects. Eighteen cluste r headache attacks were recorded during the study day, 13 (72%) of whi ch were followed by a significant increase in beta-endorphin levels. N o correlation was found between beta-endorphin maximum net increase an d intensity and/or duration of pain. These data suggest the hypothesis of a temporary alteration of beta-endorphin circadian secretion, prob ably related to involvement of neural structures controlling biorhythm pacemakers.