CORRELATION BETWEEN ANALGESIA AND DECREASE OF ACETYLCHOLINE TURNOVER RATE IN CORTEX AND HIPPOCAMPUS ELICITED BY MORPHINE, MEPERIDINE, VIMINOL-R2 AND AZIDOMORPHINE

  • 1 January 1976
    • journal article
    • research article
    • Vol. 199  (3) , 662-668
Abstract
An ED50 for analgesia of morphine, meperidine, viminol R2 or azidomorphine decreases the turnover rate of acetylcholine (TRACh) in rat cortex and hippocampus. The 4 analgesics failed to change the TRACh in striatum which contains a high density of opiate receptors and intrinsic cholinergic neurons when given in a dose range from ED30 for analgesia up to a cataleptic dose. Viminol S2, non-analgesic stereoisomer of viminol R2, failed to decrease the TRACh in cortex and hippocampus. Naltrexone, an opiate antagonist failed to change the cortical and hippocampal TRACh but antagonized the decrease in cortical and hippocampal TRACh elicited by the 4 analgesics. Opiate receptors probably are not exclusively involved in the regulation of TRACh. Results suggest that certain cholinergic pathways participate in the mediation of analgesia.