EFFECTS OF MEDIAL SEPTAL LESION ON HIPPOCAMPAL EXTRACELLULAR GLUTAMATE AND GABA LEVELS DURING SPATIAL ALTERNATION...

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neurobiology

Background:

• Spatial working memory is crucial for cognitive function.
• The medial septum (MS) plays a role in hippocampal function and memory.
• Neurotransmitter release in the hippocampus is implicated in memory processes.

Purpose of the Study:

• To investigate the impact of medial septal (MS) lesions on spatial working memory (SA task).
• To examine hippocampal glutamate and GABA release during and after SA testing in lesioned and control rats.
• To assess the effect of MS lesions on KCl-stimulated glutamate and GABA release in the hippocampus.

Main Methods:

• Electrolytic medial septal (MS) lesions in rats.
• Spontaneous alternation (SA) task for spatial working memory assessment.
• In vivo microdialysis to measure hippocampal glutamate and GABA release.
• KCl stimulation to assess neurotransmitter release capacity.

Main Results:

• MS lesions significantly impaired SA performance.
• Hippocampal glutamate efflux during SA was blunted in MS-lesioned rats compared to controls.
• MS lesions significantly reduced KCl-stimulated glutamate release in the hippocampus.
• GABA levels and release showed no significant changes during SA testing or KCl stimulation.

Conclusions:

• Decreased hippocampal glutamate release, particularly upon stimulation, may underlie the spatial working memory deficits observed in MS-lesioned rats.
• SA testing combined with in vivo microdialysis is a valuable method for studying the neurochemical basis of hippocampal-dependent memory.
• This approach can aid in understanding cognitive decline in various neurological disorders and neurodegenerative diseases.