Figure 4

C fiber evoked responses in GRP positive neurons are blocked by glutamate antagonists. (A) The experimental procedure to identify the transmitter between C fibers and GRP positive neurons in rats. (B) In a GRP sensitive neuron (a), a monosynaptic C fiber-evoked EPSCs (b) was totally blocked by a bath application of CNQX (25 μM), a AMPA/KA receptor antagonist (c-e, n = 4).