title: The involvement of opioid peptides in stress-induced analgesia in the slug Arion ater.
abstract: Application of tail-pinch stress to the terrestrial slug, Arion ater, produced a significant increase in the response time when tested on the hot-plate for foot-lifting response. The analgesia was completely reversed by injections of the opiate antagonists, naltrexone and ICI 174864, in a dose-dependent manner. Analgesia could also be elicited by the injection into the foot of beta-endorphin and the enkephalin analogues, DAGO and DADLE. No effect was seen with dynorphin A (1-8) or dynorphin A (1-17). The stress-induced analgesia disappeared after 30 minutes but could be maintained for 100 min following the injection of a mixture of bestatin and the enkephalinase inhibitor, N-carboxymethyl-L-phenylalanyl-L-leucine. This work suggests that in the slug, a physical stressor produces an analgesia which may be due to the release of endogenous opiates.
authors.affiliation: Anglo-European College of Chiropractic, Bournemouth, Dorset, U.K.
authors.forename: L M
authors.initials: LM
authors.lastname: Dalton
authors.forename: P S
authors.initials: PS
authors.lastname: Widdowson
mesh_terms: D000698:Analgesia; D000818:Animals; D004399:Dynorphins / Q000494:pharmacology; D004723:Endorphins / Q000494:pharmacology*; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D016308:Enkephalin, Leucine-2-Alanine; D004745:Enkephalins / Q000494:pharmacology; D008974:Mollusca / Q000187:drug effects / Q000502:physiology*; D009271:Naltrexone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D012016:Reference Values; D013312:Stress, Physiological; D001615:beta-Endorphin / Q000494:pharmacology
chemical_list: D004723:Endorphins; D004745:Enkephalins; D009292:Narcotic Antagonists; D011480:Protease Inhibitors; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004743:Enkephalin, Leucine; D009271:Naltrexone; D001615:beta-Endorphin; D016308:Enkephalin, Leucine-2-Alanine; D004399:Dynorphins; C040643:N,N-diallyl-tyrosyl-alpha-aminoisobutyric acid-phenylalanyl-leucine