Appearance of beta-endorphin-like immunoreactivity in human ventricular cerebrospinal fluid upon analgesic electrical stimulation.

Overview

beta-Endorphin-like immunoreactivity in human ventricular cerebrospinal fluid was measured with a specific radioimmunoassay. The subjects were undergoing a surgical procedure for relief of chronic intractable pain. This procedure involved the focal stimulation of a medial thalamic site adjacent to the wall of the third ventricle. Samples were collected before and during the analgesic stimulation. No beta-endorphin-like immunoreactivity could be detected prior to stimulation, suggesting that baseline levels are below 25 fmol/ml of cerebrospinal fluid. Electrical stimulation led to substantial increases (13- to 20-fold) in immunoreactive material in every subject. These results suggest that beta-endorphin-like material can be released into the ventricular system and may contribute to the pain blockade that results from periventricular stimulation.

Proceedings of the National Academy of Sciences of the United States of America Journal