Prostaglandins play a role in memory consolidation in the chick.
Previous studies showed that inhibitors of cyclooxygenases have amnesic effects in chicks in a passive avoidance task. The onset of amnesia has a delay of 2 h post-training. To investigate if this effect is due to the inhibition of induction of the enzyme during learning, the release of cyclooxygenase products into the extracellular fluid was measured at 1, 2 and 3 h post-training. A cyclooxygenase inhibitor, ibuprofen, inhibited the training-dependent increase of cyclooxygenase products only 2 h and 3 h after learning when injected pre-training, as did dexamethasone which prevents cyclooxygenase induction, and SC58125 (1,2-diarylcyclopentene), an inhibitor of inducible cyclooxygenase. Injections 30 min post-training showed the same effect with the exception of dexamethasone. Injecting SC58125, ibuprofen, indomethacin, or dexamethasone i.c. before training showed amnesic effects for training on a one-trial passive avoidance task at 2 h but not 1 h after training. Injections 30 min post-training produced the same effects with the exception of dexamethasone. I conclude that cyclooxygenases are induced during training and that cyclooxygenase products are of importance in memory formation of the chick.
Hölscher
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Biology Department, Open University, Milton Keynes, Bucks, UK.
D000647:Amnesia / Q000139:chemically induced / Q000523:psychology; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D001362:Avoidance Learning / Q000187:drug effects; D001923:Brain Chemistry / Q000187:drug effects / Q000502:physiology; D002645:Chickens / Q000502:physiology*; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D007858:Learning / Q000187:drug effects / Q000502:physiology; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D011453:Prostaglandins / Q000502:physiology*
D000893:Anti-Inflammatory Agents; D000894:Anti-Inflammatory Agents, Non-Steroidal; D016861:Cyclooxygenase Inhibitors; D011453:Prostaglandins; D003907:Dexamethasone