Pertussis toxin reduces the day-night rhythm of nociception and mu and kappa opioid peptide-mediated antinociception in the snail, Cepaea nemoralis.
There is accumulating evidence that pertussis toxin-sensitive G proteins are associated with the transduction of opioid-mediated antinociception in mammals. The present study examined the effects of hemocel injections of pertussis toxin (0.10 microgram) on the day-night rhythm of nociception and mu and kappa opioid-mediated antinociception in a mollusc, the land snail, Cepaea nemoralis. Five days after treatment, pertussis toxin significantly reduced the naloxone-sensitive, opioid-mediated nocturnal peak in the day-night rhythm of nociception [as measured by the latency of response to a thermal (40 degrees C) stimulus] in Cepaea, without affecting the daytime response latency. Pertussis toxin also significantly decreased the antinociceptive effects of the mu agonist, DAMGO, and blocked those of the kappa opioid agonist, U-69,593. These results suggest that G protein substrates of pertussis toxin are associated with the transduction of opioid-mediated nociception and antinociception in the snail, Cepaea.
Yu
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Division of Oral Biology, Faculty of Dentistry, University of Western Ontario, London, Canada.
Kavaliers
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M
D000818:Animals; D044482:Benzeneacetamides; D002940:Circadian Rhythm; D004723:Endorphins / Q000037:antagonists & inhibitors / Q000502:physiology*; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004745:Enkephalins / Q000494:pharmacology; D009619:Nociceptors / Q000187:drug effects* / Q000502:physiology; D037342:Pertussis Toxin; D011759:Pyrrolidines / Q000494:pharmacology; D011957:Receptors, Opioid / Q000187:drug effects / Q000502:physiology; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D012908:Snails / Q000502:physiology*; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D044482:Benzeneacetamides; D004723:Endorphins; D004745:Enkephalins; D011759:Pyrrolidines; D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D010566:Virulence Factors, Bordetella; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D037342:Pertussis Toxin; C045444:U 69593