Post-training cyclooxygenase-2 (COX-2) inhibition impairs memory consolidation

Area of Science:

• Neuroscience
• Molecular Biology
• Pharmacology

Background:

• Prostanoids, including prostaglandins, regulate neural plasticity, a key mechanism for learning and memory.
• Cyclooxygenase (COX) enzymes, specifically COX-1 and COX-2, are involved in prostanoid synthesis.
• The precise role of COX isoforms in memory consolidation remains to be fully elucidated.

Purpose of the Study:

• To investigate the involvement of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) in post-training memory processes.
• To determine if inhibiting COX isoforms affects hippocampus-dependent or dorsal striatal-dependent memory tasks.

Main Methods:

• Adult male Long-Evans rats were trained on hippocampus-dependent (hidden platform) and dorsal striatal-dependent (visible platform) water maze tasks.
• Following training, rats received intraperitoneal injections of COX inhibitors (indomethacin, piroxicam, NS-398) or vehicle/saline.
• Memory retention was assessed 24 hours later by measuring escape platform latencies.

Main Results:

• Inhibition of COX-2 using NS-398 significantly impaired retention of the hippocampus-dependent task.
• Nonselective COX inhibition with indomethacin also impaired hippocampus-dependent memory retention.
• Neither COX-1 inhibition with piroxicam nor delayed administration of indomethacin or NS-398 affected memory retention in either task.

Conclusions:

• Cyclooxygenase-2 (COX-2) is essential for the consolidation of hippocampus-dependent memory.
• COX-1 does not appear to play a significant role in the memory consolidation processes investigated.
• These findings highlight COX-2 as a critical molecular component in learning and memory.