Effects of bremazocine on passive avoidance behaviour in mice

Area of Science:

• Neuroscience
• Pharmacology
• Behavioral Science

Background:

• Memory processes are crucial cognitive functions influenced by various neurochemical systems.
• Opioid receptors, particularly kappa-opioid receptors, play a role in modulating learning and memory.
• Bremazocine, a kappa-opioid receptor agonist, has potential effects on memory consolidation.

Purpose of the Study:

• To investigate the impact of bremazocine on memory processes in DBA/2 mice.
• To explore the involvement of kappa-opioid receptors in bremazocine's effects on memory.
• To examine the influence of stress and familiarization on bremazocine-induced memory changes.

Main Methods:

• DBA/2 mice were tested in a passive avoidance apparatus to assess memory.
• Bremazocine and the kappa-opioid-receptor antagonist MR-1452 were administered post-training.
• Experiments included varying drug dosages, administration timings, immobilization stress, and apparatus familiarization.

Main Results:

• Bremazocine administration immediately post-training impaired memory; MR-1452 improved memory.
• These effects were not observed when drugs were administered 120 minutes post-training.
• Bremazocine's effects were antagonized by MR-1452, and enhanced by immobilization stress, but reduced by familiarization.

Conclusions:

• Bremazocine impairs memory consolidation in mice, mediated by kappa-opioid receptors.
• The timing of drug administration is critical for observing effects on memory.
• Emotionality, modulated by stress and context, influences bremazocine's impact on memory.