Figure 1. Effects of intrathecal injection of nociceptin (17 nM), (+)-5-methyl-10,11-dihydro-5H-dibenzo(a,d)cyclohepten-5,-10-imine hydrogen maleate (MK-801; 30 nM), DL-2-amino-5-phosphonovaleric acid (AP-5; 51 nM), and saline on the thermal nociceptive threshold. Ordinate: paw withdrawal latency (measured in seconds). The abscissa shows time (measured in minutes) after drug injection. Each line represents the mean +/- SD determination made in five or six rats. Injured paw = sciatic nerve injured paw (right paw); uninjured paw = sciatic nerve uninjured paw (left paw).