THE NMDA RECEPTOR PARTICIPATES IN RESPIRATION-RELATED MITRAL CELL SYNCHRONY

The N-methyl-D-aspartate (NMDA)-type glutamate receptor participates i n the excitation of olfactory bulb mitral cells and is important in gr anule-cell-mediated feedback-inhibition In the present study, extracel lular unit recordings were made in vivo to demonstrate that the firing rates of mitral cells are not affected by peripheral administration o f the non-competitive NMDA receptor antagonist MK-801. However, while over 50% of odor-driven mitral cell activity is normally correlated wi th the respiratory cycle, only about 10% of mitral cell activity is co rrelated with the respiratory cycle 30 min after MK-801 administration . Thus, the NMDA receptor is a participant in normal respiration-relat ed mitral cell activity and may have an important role in the formatio n of bulb oscillations that encode olfactory information. Furthermore, the NMDA receptor is in a position to mediate activity-dependent chan ges in the bulb that rely on synchronous activity.