Inhibition of glutamate transporters enhances immediate and prolonged burst firing of PNs in response to a short high frequency burst of parallel fibre activity. A , example cell-attached recording from a PN reveals how action potential firing changes during the application of 50 μM TBOA and 50 μM TBOA in the presence of the mGluR antagonist 0.2 mM MCPG. Horizontal bar represents 200 Hz high frequency stimulation to PFs. B, shows a raster plot for the cell shown in A, each sweep (horizontal dots represent each action potential in the sweep) occurred at an interval of 30 seconds during the application of TBOA and TBOA and MCPG (left, vertical bars). Note the enhanced firing after the burst in the presence of TBOA and the inability of MCPG to reduce this. Arrows represent the raster plot for the traces shown above. C, bars show mean values (error bars are sem) of action potential firing frequency obtained from a 500 ms epoch just before stimulation, compared with action potential firing frequency at the peak of the TBOA-induced 200 Hz EPSC (during the 100 ms after the end of the stimulation) and later during the 400 ms after the stimulation when the slower, mGluR1 and EAAT4 dependent phase of the 200 Hz EPSC is active. **** represents P < 0.0001, two way ANOVA, ns is not significant.