Analgesic action of intrathecal and intracerebral beta-endorphin in rats: comparison with morphine.
beta-Endorphin and morphine were given into the nucleus reticularis gigantocellularis (NRGC), spinal subarachnoid space and third ventricle of rats, and the antinociceptive effects were assessed by the tail-pinch method. The NRGC was 4-5 times as sensitive to beta-endorphin as was the spinal subarachnoid space and third ventricle, while the NRGC was 13-19 times as sensitive to morphine as were the other regions. Thus, it would appear that beta-endorphin has more sites of action for the production of analgesia than does morphine.
D000700:Analgesics; D000818:Animals; D001921:Brain; D004723:Endorphins / Q000008:administration & dosage / Q000494:pharmacology*; D007267:Injections; D007278:Injections, Spinal; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D001615:beta-Endorphin
D000700:Analgesics; D004723:Endorphins; D001615:beta-Endorphin; D009020:Morphine