Expression of dn-PKG1 in radial glia lowers mEPSC frequency in adjacent neurons. A, Whole-cell patch-clamp recordings were performed on tectal neurons surrounded by radial glia expressing either EGFPf (left lobe on schematic) or dn-PKG1 (right lobe on schematic). B, Example traces of AMPA mEPSC recordings from tectal neurons surrounded by EGFPf-transfected (control) or dn-PKG1-transfected radial glia. C, D, Neurons surrounded by dn-PKG1-expressing glia exhibit normal mEPSC amplitudes (C) but significantly reduced frequencies (D). *p < 0.05, Student's t test.