Fig. 2

Glutamatergic transmission is diminished in Gpt2-null CA1 hippocampus pyramidal neurons. A Schematic of the hippocampal slice preparation and a CA1 pyramidal neuron (red) and recording pipette. The representative whole-cell recordings of wild-type (left, black) and Gpt2-null (right, red) CA1 pyramidal neurons in current clamp mode at postnatal day 18 (P18). Current steps of 20 pA were used to depolarize or hyperpolarize the neuron. B Resting membrane potentials of Gpt2-null CA1 pyramidal neurons are slightly depolarized. The resting membrane potential of CA1 neurons from wild-type (black) and Gpt2-null (red) mice at P18 was obtained immediately after breaking into the cell in current clamp mode. n = 4–5 mice/4–5 slices/8–12 cells. *P = 0.02. C Gpt2-null CA1 pyramidal neurons have greater membrane input resistance. Each dot represents a different cell recording from wild-type (black) and Gpt2-null (red) mice at P18. n = 4–5 mice/4–5 slices/8–12 cells. *P = 0.01. D Gpt2-null CA1 pyramidal neurons have lower capacitance. Each dot represents a different cell recording from wild-type (black) and Gpt2-null (red) mice at P18. **P = 0.002. E Representative traces of miniature excitatory synaptic currents (mEPSC) from whole-cell recordings in CA1 pyramidal neurons of wild-type (top, black) and Gpt2-null (bottom, red) mice at P18. Averaged mEPSCs from one representative cell from wild-type (black) and Gpt2-null (red) cells at P18 are shown on the right. F mEPSC frequency is not changed in Gpt2-null CA1 pyramidal neurons. Each dot represents a different cell recording from wild-type (black) and Gpt2-null (red) mice at P18. n = 4–6 mice/4–6 slices/8–9 cells. P = 0.52. G mEPSC peak amplitude is reduced in Gpt2-null CA1 pyramidal neurons. Each dot represents a different cell recording from wild-type (black) and Gpt2-null (red) mice at P18. n = 4–5 mice/4–5 slices/8–12 cells. **P = 0.004. H Cumulative probability histogram of mEPSC peak amplitudes from representative wild-type (black) and Gpt2-null (red) CA1 pyramidal neurons at P18. Kolmogorov–Smirnov test was conducted, 4 neurons from each genotype were used to construct the curves; total mEPSC events, wild-type: 799 and Gpt2-null: 793. ***P < 0.0001; d = 0.24. I Representative traces of miniature inhibitory synaptic currents (mIPSC) from whole-cell recordings in CA1 pyramidal neurons of wild-type (top, black) and Gpt2-null (bottom, red) mice at P18. Averaged mIPSCs from one representative cell from wild-type (black) and Gpt2-null (red) CA1 pyramidal neurons at P18 are shown on the right. J mIPSC frequency is not changed in Gpt2-null CA1 pyramidal neurons. Each dot represents a different cell recording from wild-type (black) and Gpt2-null (red) mice at P18. n = 4–6 mice/4–6 slices/8–9 cells. P = 0.56. K mIPSC peak amplitude is not changed in Gpt2-null CA1 pyramidal neurons. Each dot represents a different cell recording from wild-type (black) and Gpt2-null (red) mice at P18. n = 4–6 mice/4–6 slices/8–9 cells. P = 0.5. L Cumulative probability histogram of mIPSC peak amplitudes from representative wild-type (black) and Gpt2-null (red) CA1 pyramidal neurons at P18. Kolmogorov–Smirnov test was conducted, 4 neurons from each genotype were used to construct the curves; total mEPSC events, wild-type: 800 and Gpt2-null: 800. P = 0.1960; D = 0.054. M Paired pulse ratios were unchanged as recorded in Gpt2-null CA1 pyramidal neurons at P18. Each dot represents a different cell recording from wild-type (black) and Gpt2-null (red) mice at P18. n = 7–9 mice/17 slices/17 cells. P = 0.16