Baseline concentrations of
beta-endorphin (beta-EP) and monoamine metabolites (
MHPG: 3-methoxy-4-hydroxy-phenylglycol, HVA:
homovanillic acid, 5-HIAA: 5-
hydroxyindoleacetic acid) in lumbar CSF (LCSF) and ventricular CSF (VCSF) were measured in 18 patients with
intractable pain; 10 with deafferented
pain and 8 with peripheral
pain. Control values were obtained from 37 individuals of various ages. Changes in the concentrations of these substances were determined before and after giving stimulations (2-5 V, 0.2-0.5 msec, 40-50 Hz, 20-sec duration) to 6 patients through
electrodes implanted in deep brain structures (DBS; posterior limb of the internal capsule in 5 patients and rostral mesencephalic lemniscus medialis in one patient), and to 2 other patients through
electrodes implanted in the spinal dorsal column (DCS). The control value of beta-EP in LCSF was 57.6 +/- 24.7 pg/ml, which was not significantly different from that of VCSF. Great variation in the individual control LCSF beta-EP concentrations was found, but it was not related to differences in age. The mean baseline LCSF beta-EP concentration was significantly higher (p less than 0.05) than the control in the patients with deaffernted
pain before stimulation. One of the monoamine-metabolites,
MHPG, showed higher level in the patients with peripheral
pain (p less than 0.01). The LCSF beta-EP concentration was not affected by
deep brain stimulation, but was increased by dorsal column stimulation. In one patient with excellent
pain relief by stimulation of the posterior limb of the internal capsule, the LCSF HVA and
5-HIAA concentrations were conspicuously increased.(ABSTRACT TRUNCATED AT 250 WORDS)