Figure 8.

NPY (1 μm) reduced and BIIE0246 (300-500 nm) increased the magnitude of mossy fiber-evoked granule cell epileptiform activity. A-E, Traces from representative experiments. The top response in each pair was recorded after superfusion for 65.5-70 min with medium that contained 30 μm bicuculline and 6 mm K⁺. The lower response was recorded 20-24.5 min after the addition of the test compound(s) to the superfusion medium. The asterisk indicates the stimulus artifact. A, NPY reduced the magnitude of evoked short-latency epileptiform activity and the amplitude of the underlying negative wave. It also abolished the delayed burst. B, BIIE0246 increased the magnitude of evoked short-latency epileptiform activity and the amplitude of the underlying negative wave. C, The addition of BIIE0246 to the superfusion medium not only reversed the effect of previously applied NPY but also enhanced evoked short-latency epileptiform activity compared with pretreatment recordings and caused the appearance of delayed bursts. D, BIIE0246 increased the magnitude of evoked short-latency epileptiform activity despite coapplication of NPY. E, Simply continuing superfusion with bicuculline/6 K⁺ medium for 20-24.5 min did not consistently change either the evoked short-latency epileptiform activity or the number and amplitude of any delayed bursts. F, Grouped data from seven (control and NPY), five [BIIE0246 (BIIE)], or eight (NPY plus BIIE0246 applied simultaneously) hippocampal slices. Control, Continued superfusion without the addition of test compound. Values are means ± SEM; ^*p < 0.05; ^**p < 0.025 by paired t test with respect to recordings made just before exposure to the test compound(s).