FIG. 5.
CCK stimulation of spontaneous EPSCs is sensitive to yohimbine. A: Overlay of 15 consecutive 500 ms traces from a recording like that shown in Fig. 2B in the presence of CCK (top) and CCK after preincubation with yohimbine (second from top). CCK-8s, bath-applied at 100 nmol/L, led to an increase in sEPSC frequency. This effect could be blocked by 10 μmol/L yohimbine. Bottom two traces show overlays from a recording where CCK was first applied alone (top trace) and then in the presence of the β-adrenoreceptor antagonist ICI118,551 hydrochloride (10 μmol/L; bottom trace). The CCK effect was not reduced by the β-adrenoreceptor antagonist. B: Mean normalized effects of CCK in the presence or absence of various drugs on sEPSC frequency from recordings as depicted in A. The mean sEPSC frequency in presence of the drug (freqD) as a fraction of the frequency in the absence of any drug (freqC) is plotted. The effect of CCK is blocked by yohimbine (10 μmol/L) but not ICI118,551. *P < 0.05 compared with control; ##P < 0.01 compared with CCK. Numbers of cells tested are given above the bars.