Fig. 5.

The Arg activator DPH prevents CORT-induced behavioral abnormalities. (a) Experimental timeline indicating CORT and DPH administration periods and timing of behavioral testing. (b) We utilized a spatial reversal learning task in which mice are initially trained to nose poke on one aperture, then the location of the active operand is reversed to a nose poke recess in a different location in the chamber. (c) Male mice acquired the food-reinforced response and responded minimally on the inactive aperture, however (d) CORT increased errors in the reversal phase, and DPH corrected this deficiency. (e) DPH also increased the percentage of responses that were reinforced. (f) In female mice, CORT induced anhedonic-like sucrose neglect, a depression-like behavior, and this was fully corrected by DPH, an antidepressant-like response. (g) Sucrose consumption patterns could not be accounted for by estrous phase at the time of testing. (h) Further, CORT and CORT + DPH groups locomoted a similar amount (although the DPH-alone group was more active). Bars and symbols = means + SEMs. *p < 0.05 vs. control or as indicated. n = 6–8/group.