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Olfactory system modulation of hippocampal cell death.
Kenneth Pope1, Donald A Wilson
1Department of Zoology, University of Oklahoma, Norman, OK 73019, USA.
Neuroscience Letters
|June 29, 2007
Summary
Olfactory bulb ablation in rats transiently increased cell death in the piriform cortex and dentate gyrus. This suggests olfactory input loss impacts hippocampal neuron survival via trans-synaptic regulation.
Area of Science:
- Neuroscience
- Cell Biology
Background:
- The hippocampal dentate gyrus receives significant olfactory input from the piriform cortex and olfactory bulb.
- Neuronal activity is crucial for the survival of dentate gyrus granule cells.
Purpose of the Study:
- To investigate the immediate impact of olfactory input deprivation on apoptosis in the hippocampus and piriform cortex.
- To understand the role of olfactory input in regulating neuronal survival.
Main Methods:
- Adult rats underwent unilateral or bilateral olfactory bulb ablations (OBX).
- Apoptosis was assessed using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) in the piriform cortex and dentate gyrus 24-72 hours post-surgery.
Main Results:
- Olfactory bulb ablation (OBX) caused a transient increase in TUNEL-positive cells (apoptotic cells) in the ipsilateral piriform cortex and dentate gyrus.
- This increase in cell death was observed within 24 hours and was more pronounced and longer-lasting in the piriform cortex compared to the dentate gyrus.
Conclusions:
- The findings suggest that loss of olfactory input triggers apoptosis in the piriform cortex and dentate gyrus.
- This indicates a trans-synaptic regulation of neuronal survival, potentially involving at least two synapses in the olfactory-hippocampal pathway.
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