Spinal antinociceptive action of three representative opioid peptides in frogs.
Spinal administration of low doses of dynorphin, beta-endorphin or Met-enkephalin produces a potent, dose-dependent increase in the nociceptive threshold in the unanesthetized frog, Rana pipiens. Nociceptive thresholds were determined by using the acetic acid test, previously shown to be a sensitive indicator of antinociception in this amphibian species. Of particular interest, spinally administered dynorphin produces a potent antinociception in frogs without any signs of motor dysfunction seen after spinally administered dynorphin in mammalian species.
D000700:Analgesics; D000818:Animals; D004399:Dynorphins / Q000494:pharmacology; D004723:Endorphins / Q000494:pharmacology*; D004744:Enkephalin, Methionine / Q000494:pharmacology; D010146:Pain / Q000188:drug therapy / Q000503:physiopathology*; D011894:Rana pipiens; D012684:Sensory Thresholds / Q000187:drug effects; D013116:Spinal Cord / Q000187:drug effects*; D001615:beta-Endorphin
D000700:Analgesics; D004723:Endorphins; D004744:Enkephalin, Methionine; D001615:beta-Endorphin; D004399:Dynorphins