Fig. 7.

Strong KAR activation depresses the fiber volley.A, a, The fiber volley was recorded in the presence of 100 μm GYKI 53655 and 100 μmCdCl₂. b, After application of 20 μm DA, the fiber volley was substantially depressed.c, The fiber volley recovered fully after washout.B, A summary of the experiments in A is shown. C₁, The depression of the fiber volley cannot be explained by K⁺ efflux. DA (20 μm) caused an increase in K⁺levels of ∼4 mm, as measured by K⁺-sensitive microelectrodes.C₂, Application of 4 mm KCl under these conditions has no effect on the fEPSP.