Figure 4

Inhibition of glutamate transporters enhances paired pulse facilitation at the PF-PN synapse and prolongs the decay of the excitatory post synaptic current, EPSC. A, shows an example recording from a PN showing EPSCs evoked with a pair of closely timed single stimulations to the PFs (downward arrows). Note the enhancement of the amplitude of the second EPSC upon application of 50 μM TBOA and the concomitant increase in duration of the second EPSC, in the absence of any change in the amplitude of the first EPSC (in 7/11 cells shown in A(i) where bars are mean ± SEM, ns is not significant in Student’s paired t-test). Dashed lines in A represent single exponential fits to estimate the time constant of recovery of the second EPSC; mean values (error bars are SEM) shown in A(ii) ** represents P < 0.01 Student’s paired t-test. Inset traces indicate no change in series resistance or input resistance by TBOA, see text, scale bar is 100 pA and 10 ms. B shows the change in mean absolute values of PPF in Control and after 50 μM TBOA, bars are mean ± SEM, ** represents P < 0.01 Student’s paired t-test. Left panel shows PPF change normalised to control for the 7/11 cells, bold colour, with remaining cells where the first EPSC increased, and PPF also increased, after TBOA, shown in a transparent shade.