Figure 10.

The effects of intra-VL PAG microinjections of vehicle (0.05% DMSO in ACSF), L335677 (10 pg), PGE2 (1 pg) alone, or PGE2 (1 pg) in combination with L355677 (0.1 pg) on the ON cell tail flick-evoked burst of firing (A) and onset of the burst (C), or OFF cell tail flick-evoked pause (B) and onset of the pause (D). Each histogram represents the mean ± S.E.M of 6-7 neurons of different treated groups of rats. * indicates significant differences vs vehicle and° versus PGE2 (1 pg). P values < 0.05 were considered statistically significant.