Kavaliers M, Tepperman FS. Exposure to novel odors induces opioid-mediated analgesia in the land snail, Cepaea nemoralis.
BEHAVIORAL AND NEURAL BIOLOGY 1988;
50:285-99. [PMID:
2849409 DOI:
10.1016/s0163-1047(88)90970-3]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Land snails, Cepaea nemoralis, that were exposed for 1-30 min to a novel odor of either peppermint extract or vegetable juice concentrate displayed an increase in the latency of their nociceptive response to an aversive thermal stimulus (40 degrees C, hot-plate). This "analgesic" response, which entailed the elevation of the fully extended foot in hydrated snails, was evident directly after exposure to the novel chemostimuli and lasted for 15-30 min. This novelty-induced analgesia was blocked by the exogenous opiate antagonist naloxone. Analgesia was not observed in snails that were exposed to the same olfactory cue 4 or 24 h later, but was evident when the alternate novel odor (peppermint or vegetable juice) was presented. However, a significant analgesia was displayed by snails that were reexposed to their initial olfactory stimulus after 48-72 h. These findings indicate that exposure to a novel olfactory stimulus can activate endogenous opioid systems and induce an analgesic response in mollusks.
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