title: Evidence for opioid and non-opioid forms of stress-induced analgesia in the snail, Cepaea nemoralis.
abstract: Exposure to either cold or warm stress increased the thermal nociceptive thresholds of the terrestrial snail, Cepaea nemoralis. The warm stress-induced 'analgesia' was blocked by the prototypic opiate antagonist, naloxone, and the delta-opiate antagonist, ICI 154,129, and was suppressed by a 24-h pretreatment with the irreversible opiate antagonist, beta-funaltrexamine (B-FNA). In contrast, cold stress-induced analgesia was unaffected by either naloxone, ICI 154,129 or B-FNA. These results indicate that this mollusc displays both opioid and non-opioid forms of stress-induced analgesia in a manner analogous to that reported for mammals. These findings suggest an early evolutionary development and phylogenetic continuity of opioid and non-opioid mediated stress responses to aversive environmental stimuli.
mesh_terms: D000818:Animals; D003080:Cold Temperature / Q000009:adverse effects; D004723:Endorphins / Q000502:physiology*; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives; D006358:Hot Temperature / Q000009:adverse effects; D009270:Naloxone; D009271:Naltrexone / Q000031:analogs & derivatives; D010146:Pain / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D012908:Snails / Q000502:physiology*; D013312:Stress, Physiological / Q000503:physiopathology*
chemical_list: D004723:Endorphins; D009270:Naloxone; D004743:Enkephalin, Leucine; D009271:Naltrexone; C024524:beta-funaltrexamine; C036405:ICI 154129