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Experiments suggesting a role for nitric oxide in the hippocampus in memory processes
C Fin1, C da Cunha, E Bromberg
1Departamento de Bioquímica, Instituto de Biociencias, UFRGS (Centro), Porto Alegre, Brazil.
Neurobiology of Learning and Memory
|March 1, 1995
Summary
Nitric oxide (NO) plays a crucial role in memory formation. Inhibiting NO synthase impaired memory, while supplementing NO donors improved it, suggesting NO-sensitive processes are vital for hippocampal memory storage.
Area of Science:
- Neuroscience
- Molecular Biology
- Behavioral Science
Background:
- Nitric oxide (NO) is implicated in synaptic plasticity, including long-term potentiation (LTP).
- NO can induce long-term synaptic enhancement when combined with tetanic stimulation.
- N-Nitroarginine (NO-Arg), an inhibitor of NO-synthase, blocks LTP in hippocampal slices.
Purpose of the Study:
- To investigate the role of nitric oxide (NO) in memory storage.
- To examine the effects of NO synthase inhibition and NO donation on memory consolidation in rats.
Main Methods:
- Infusion of N-Nitroarginine (NO-Arg) or S-nitroso-N-acetylpenicillamine (SNAP) into the dorsal hippocampus of male Wistar rats.
- Training rats in a step-down inhibitory avoidance task with a footshock.
- Testing memory retention 24 hours after training.
Main Results:
- Pre- or post-training infusion of NO-Arg (2.0 microgram) impaired retention performance when administered immediately before or after training.
- NO-Arg administration 30 or 60 minutes post-training did not affect retention.
- Post-training infusion of SNAP (5.0 microgram) enhanced retention performance when given at 0, 60, or 150 minutes post-training, but not at 300 minutes.
Conclusions:
- Memory storage is dependent on NO-sensitive processes within the hippocampus.
- These findings support the hypothesis that NO-mediated LTP at the time of training is critical for memory formation.