Fig. 5.

Effect of an EP1-selective agonist on behaviors. (A) Effect of ONO-DI-004 on electric-shock-induced fighting. Age-matched pairs of wild-type male mice were exposed to electric shock 30 min after i.c.v. injection of ONO-DI-004 (2 or 10 nmol per animal, n = 9 pairs per dose) or vehicle (n = 10 pairs). The amplitude and duration of the electric shock and the size of the arena were adjusted to increase the rate of fighting in wild-type animals. The latency to the first fighting episode and the total number and duration of fighting episodes during 5 min were measured. **, P < 0.01. (B) Effect of ONO-DI-004 on the open-field test. Wild-type male mice were put into a round open field 10 min after i.c.v. injection of ONO-DI-004 (2 or 10 nmol per animal, n = 12 and 13 pairs, green triangles and blue squares, respectively) or vehicle (n = 12 pairs, filled circles). Ambulation, rearing, grooming, defecation, and urination were scored during three separate 5-min intervals during 10–15, 20–25, and 30–35 min after the injection. #, P < 0.05 for the comparison between the group injected with 2 nmol of ONO-DI-004 vs. the one injected with vehicle. *, P < 0.05 and **, P < 0.01 for the comparison between the group injected with 10 nmol of ONO-DI-004 vs. the one injected with vehicle.