The Effects of Mild Maternal Stress During Pregnancy on the Behavior of Rat Pups

Abstract

Mild maternal stress in the form of chronic daily subcutaneous injections of saline or the vehicle for diazepam to pregnant rats was shown to result in some long term, subtle but reliable, changes in the behavior of the offspring. The same vehicle given for the same period of time in the dam's drinking water, without injection had no effect on the development of later behavior of rat pups. Chronic prenatal injections of saline or vehicle for diazepam, used in many experiments as controls for the evaluation of drug effects were shown to have some long lasting behavioral effects in the offspring of the treated dams. The series of experiments reported here compared the offspring of saline or vehicle injected dams to those of uninjected dams on a variety of developmental measurements, an open field behaviour and on learning performance in a complex brightness discrimination maze.

Endocrine activation mimics the adverse effects of prenatal stress on the neuromotor development of the infant primate

“…During the next 4 decades, numerous studies documented a wide range of prenatal stress-induced effects on the developing fetus and infant (Field, Sandberg, Quetel, Garcia, & Rosario, 1985;Nuckolls, Cassel, & Kaplan, 1972;Ottinger & Simmons, 1964;Stott, 1959;Ward, 1972;Williamson, LeFevre, & Hector, 1989). In studies with rodents, stress during pregnancy was reported to result in low birth weight and early motor retardation (Fride & Weinstock, 1984), deficits in discrimination learning (Grimm & Frieder, 1987), feminization of the male fetus (Ward, 1972), and increased anxiety under conditions of novelty (Fride, Dan, Gavish, & Weinstock, 1985). These reports concurred with studies on humans linking stressful life events during pregnancy to reductions in infant birth weight and early motor delays (Field et al 1985), increased anxiety (Meijer, 1985), neurological dysfunction, developmental retardation, and behavior disturbances (Stott, 1973).…”

Prenatal Restraint Stress and Long-Term Affective Consequences

“…In addition, PS rats were less willing to leave their cage in the home cage emergence test. Data from both anxietyrelated tests used support the general idea that PS may lead to more anxious offspring [Thompson, 1957;Archer and Blackman, 1971;Grimm and Frieder, 1987;Wakshlak and Weinstock, 1990;Weinstock et al, 1992;Poltyrev et al, 1996;Vallee et al, 1997].…”

Effects of pre‐ and postnatal stimulation on developmental, emotional, and cognitive aspects in rodents: A review

“…In conditioned avoidance tests, the prenatally stressed rats showed shorter latencies and more avoidance responses than the controls (Joffe, 1965a(Joffe, , 1965b. When tested for brightness discrimination learning in a maze, the prenatally stressed rats learned more slowly than the controls (Grimm & Frieder, 1987). In general, it seems that prenatal stress impairs learning capabilities, but may facilitate learning in fearful situations.…”

“…Indeed, different types of stressful procedures applied to pregnant rodents are well documented and have been shown to produce numerous biological and behavioral dysfunctions in both dams (Becker & Kowall, 1977;Power & Moore, 1986) and pups (Barlow, Henry, Kabbaj, Simon, Le Moal, & Maccari, 1994;Knight, & Sullivan, 1978;Maccari et al, 1995;Peters, 1988;Politch & Herrenkohl, 1984;Weinstock, 1997). In these different studies, pregnant animals were subjected to cutaneous injections of saline (Grimm & Frieder, 1987), ACTH (Fameli, Kitraki, & Stylianopoulou, 1995), toluene or alcohol inhalation exposure Ogilvie & Rivier, 1997), conditioned avoidance training (Thompson, 1957), immobilization (Rojo, Marin, & MenendezPatterson, 1985), heat and restraint (Politch & Herrenkohl, 1984), sleep deprivation (Suchecki & Palermo Neto, 1991;Velazquez-Moctezuma, Salazar, & Rueda, 1993), hyperthemia (Shiota & Kayamura, 1989), immersion in cold water (Guo et al, 1993), food restriction (Wright, Crawford, & Anderson, 1988) or repeated electric tail shocks (Takahashi & Kalin, 1991). Of these different models, the one employed by Ward (1972) and Ward & Weisz (1984) involving physical constraint in a plastic cylinder under strong light illumination remains the most commonly used (Maccari et al, 1995;Vallée, Mayo, Maccari, Le Moal, & Simon, 1996;Vallée, Mayo, Dellu, Le Moal, Simon, & Maccari, 1997).…”