FIG. 2.
PPG neurons have postsynaptic ionotropic glutamate receptors. A: Voltage-clamp recording at a holding potential of −70 mV demonstrating spontaneous excitatory postsynaptic current (EPSC) activity and its inhibition by the glutamate receptor antagonist kynurenic acid (Kyn; 1 mmol/l). B: Mean data from recordings as shown in A and from experiments with the non-NMDA receptor antagonist DNQX (10 μmol/l). Mean EPSC frequency was determined over 3 min under each condition. **P < 0.01 against control. C: Bath application of 0.1 mmol/l glutamate during a perforated patch clamp recording caused a reversible depolarization by ∼40 mV in this PPG neuron. D: Mean effects of glutamate and glutamate plus DNQX (20 μmol/l) on the input resistance (RM) and membrane potential (EM) of PPG neurons. Note that DNQX almost completely abolishes the glutamate effect. **P < 0.01 against control; ##P < 0.01 against glutamate. Numbers of cells tested (n) are given above the bars.