cyclic-gmp and Pain--Intractable

Effects of dorsal root entry zone lesions (DREZLs) on cerebrospinal fluid (CSF) and plasma concentrations of neuropeptides, catecholamines, and cyclic nucleotides were studied in 9 patients with intractable chronic pain. Contents of beta-endorphin-like-material in CSF decreased in all patients 12-17 days following DREZLs during which complete to good pain relief was achieved. Contents of beta-endorphin-like-material in CSF increased again about one month after DREZLs in two and remained unchanged in one of three patients tested, who complained of partial reappearance of pain. Contents of beta-endorphin-like-materials in plasma showed no significant changes after DREZLs. Substance P, noradrenaline, adrenaline, and cyclic nucleotide levels in both CSF and plasma were variable among the subjects and did not change significantly following the operations. Thus, the results suggest that production of beta-endorphin-like-material in the central nervous system is decreased by DREZL, though the increase in its turn-over might not be neglected. The mechanisms of the decrease in contents of beta-endorphin-like-material in CSF after DREZLs were discussed in terms of our current knowledge of pain and pain inhibitory systems.

Topics: Adult; beta-Endorphin; Blood-Brain Barrier; Catecholamines; Cyclic AMP; Cyclic GMP; Female; Ganglia, Spinal; Humans; Male; Middle Aged; Neuralgia; Neuropeptides; Pain Measurement; Pain, Intractable; Substance P

Pain-alleviating effects of epidural spinal cord stimulation (ESCS) were assessed in patients with chronic intractable pain including cancer pain, and some aspects concerning its mechanisms were discussed. The temporary ESCS with percutaneously inserted electrodes was employed in 105 patients, and the implantable systems for long-term use in 19 patients. The ESCS had satisfactory effects especially in patients suffering from cancer pain, causalgia, facial and nape pain. The conditioning stimuli applied to the cervical dorsal cord exhibited interactions with the segmentally evoked spinal cord potential (SCP). The N1 wave of the SCP was inhibited up to 120 ms, while the P2 wave was facilitated for more than 100 ms, suggesting that the presynaptic inhibitory action at the dorsal horn is responsible for mechanism of the ESCS. CSF concentration of norepinephrine was significantly decreased by the ESCS therapy, indicating the existence of the relationship between norepinephrinergic descending inhibitory system and the ESCS in pain-alleviating mechanism.

Topics: Adult; Aged; Cerebral Palsy; Cyclic GMP; Electric Stimulation Therapy; Electrodes, Implanted; Female; Humans; Male; Middle Aged; Neoplasms; Neuralgia; Norepinephrine; Pain, Intractable; Pain, Postoperative; Spinal Cord; Spinal Cord Diseases; Spinal Cord Injuries