[Pup-Associated Conditioned Place Preference and Maternal Behavior in Depressive WAG/Rij Rats]

Elaboration of conditioned place preference (CPP) associated with own and foster pups, and maternal behavior were compared in females of WAG/Rij and Wistar rats. In addition, behavior of females in the open field, elevated plus-maze and forced swimming tests were investigated before pregnancy and after pup delivery. In has been found that females of WAG/Rij rats elaborate worse CPP task associated with both their own (WAG/Rij) and foster (Wistar) pups. Thus, the number of females that increase time spent in initially non-preferred compartment after its association with pups and the number of females that reach criterion of CPP elaboration in WAG/Rij rats were less than in Wistar controls. WAG/Rij females exhibited less maternal care in the place preference test both to their own and foster pups: less number of approaches to pups, pups carrying and the time spent in contact with pups non-associated with feeding. In WAG/Rij females compared with Wistar controls immobility time in the forced swimming test was higher both before pregnancy and after pup delivery indicating a stable depression-like state. Before pregnancy, statistically significant inter-strain differences in the anxiety level have not been revealed. After pup delivery, in WAG/Rij females anxiety level decreased but in Wistar females didn't substantially change. Results suggest that worse elaboration of CPP task and reduced maternal care in depressive WAG/Rij females are not associated with specific features of their own pups but are due to their depression-like state. Put into other words, pups for depressive mothers are less potent reinforcer than for "normal" (non-depressive) mothers.