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The NMDA receptor participates in respiration-related mitral cell synchrony
B D Philpot1, E M Lyders, P C Brunjes
1Department of Psychology, University of Virginia, Charlottesville 22903, USA.
Abstract:
The N-methyl-D-aspartate (NMDA)-type glutamate receptor participates in the excitation of olfactory bulb mitral cells and is important in granule-cell-mediated feedback-inhibition. In the present study, extracellular unit recordings were made in vivo to demonstrate that the firing rates of mitral cells are not affected by peripheral administration of the non-competitive NMDA receptor antagonist MK-801. However, while over 50% of odor-driven mitral cell activity is normally correlated with the respiratory cycle, only about 10% of mitral cell activity is correlated with the respiratory cycle 30 min after MK-801 administration. Thus, the NMDA receptor is a participant in normal respiration-related mitral cell activity and may have an important role in the formation of bulb oscillations that encode olfactory information. Furthermore, the NMDA receptor is in a position to mediate activity-dependent changes in the bulb that rely on synchronous activity.
Insights
The N-methyl-D-aspartate (NMDA) receptor influences olfactory bulb activity related to breathing. Blocking NMDA receptors disrupts odor-driven mitral cell activity and respiratory cycle correlation in the olfactory bulb.
Area of Science:
- Neuroscience
- Olfactory System Research
Background:
- The N-methyl-D-aspartate (NMDA)-type glutamate receptor is crucial for olfactory bulb mitral cell excitation.
- It plays a role in granule-cell-mediated feedback inhibition within the olfactory bulb.
Purpose of the Study:
- To investigate the role of the NMDA receptor in olfactory bulb mitral cell activity.
- To determine the effect of NMDA receptor antagonism on respiration-related mitral cell activity and olfactory information processing.
Main Methods:
- Extracellular unit recordings were performed in vivo.
- The non-competitive NMDA receptor antagonist MK-801 was administered peripherally.
Main Results:
- MK-801 administration did not alter the basal firing rates of mitral cells.
- The correlation between odor-driven mitral cell activity and the respiratory cycle decreased significantly after MK-801 administration (from >50% to ~10%).
Conclusions:
- The NMDA receptor is essential for normal respiration-related activity in the olfactory bulb.
- NMDA receptors may be involved in generating bulb oscillations that encode olfactory information.
- NMDA receptors can mediate activity-dependent changes reliant on synchronous activity in the olfactory bulb.