Fig. 5. Actions of selective δ-receptor agonists and antagonists. (A ) The δ-receptor–selective antagonist naltrindole reversed the depressant action of DADLE on the amplitude of stimulus-evoked NMDA–EPSCs. (B ) The δ-receptor–selective agonist DPDPE induced a concentration-dependent reduction in the amplitudes of evoked NMDA–EPSCs. Each trace represents the average of five consecutive single recordings performed at an interval of 30 s.