9.

KARs modulate inhibitory transmission in the OB. Reciprocal inhibition was induced by self-stimulation (using a brief depolarizing voltage pulse) of mitral cells in OB slices to examine reciprocal inhibition from granule cells. With use of a CsCl electrode, this self-stimulation protocol evoked a flurry of inhibitory postsynaptic currents (IPSCs). These data were quantified by determining the area under the curve (AUC) of the flurry of IPSCs, which represents the charge transfer during the first second after stimulation. Kainate (KA) had biphasic concentration-dependent effects. A) Compared with control, a low concentration of kainate (300 nM) had a potentiating effect on reciprocal IPSCs, with significant recovery of the IPSCs following a wash. B) Histogram showing the effect of 300 nM KA and recovery following a wash expressed as a percentage of the control IPSC AUC (N=5; * P≤ 0.01 compared to control; #P ≤ 0.01 compared to 300 nM KA). C) A higher kainate concentration (5 μM) had an inhibitory effect on reciprocal IPSCs, with only limited recovery of the IPSCs following a wash. D) Histogram showing the effect of 5 μM KA and limited recovery following a wash expressed as a percentage of the control IPSC AUC (N=5; *P ≤ 0.05 compared to control; #P ≥ 0.05 compared to 5 μM KA). Values are the mean ± SEM.