Fig. 1. Effects of DAMGO (1 μm) on monosynaptic excitatory postsynaptic currents (EPSCs) evoked by stimulating Aδ fiber ( A ) and C fiber ( B ) or both Aδ and C fibers ( C ). ( A –C ) Averaged traces of five consecutive evoked EPSCs before ( left ), during ( middle ; where control EPSC on the left is superimposed for comparison), and after ( right ) the action of DAMGO. The EPSCs were evoked at 0.1 Hz. The intensities of the stimuli used in A –C were 73, 480, and 380 μA, respectively. An illustration ( C , left ) showed how the amplitude of C-EPSC was measured.