Effects of chronic and acute cocaine treatment on the onset of maternal behavior and aggression in Sprague-Dawley rats.

Abstract

Pregnant rats were treated either throughout gestation (GD 1-20) with 30 mg/kg per day (chronic cocaine) or with one 15-mg/kg dose immediately following parturition (acute cocaine). Chronic and acute cocaine treatment delayed or diminished the postpartum onset of some components of maternal behavior, and chronically treated dams were significantly more aggressive toward a male intruder than acute cocaine-treated or saline-treated dams. Cocaine increased the latency to crouch over pups and decreased crouch duration during a 30-min observation period that immediately followed parturition. Latencies to nest build were also longer in more chronic cocaine-treated dams than in saline controls. On Day 6 postpartum, 83% of chronic cocaine-treated dams pinned and attacked an intruder male 8 or more times during a 10-min observation period, whereas only 4% of acute cocaine-treated and none of the saline-treated dams exhibited this much aggression.

Cocaine treatment and prenatal environment interact to disrupt intergenerational maternal behavior in rats.

“…Their offspring are born blind, unable to thermoregulate, defecate, urinate, or protect themselves from attack (Numan, 1994), thus needing considerable maternal care to survive (Stern, 1997). Behaviorally and neurologically, maternal behavior in the rat has also been relatively well characterized (Numan, 1994;Pedersen, Ascher, Monroe, & Prange, 1982;Pedersen, Caldwell, Walker, Ayers, & Mason, 1994) so that any insult to normal maternal behavior can be easily determined.Maternal separation studies also support a rat intergenerational model of behavior showing that cross-fostering results in behavior of offspring similar to behavior of rearing dams, suggesting a nongenetic transmission of behavior (Francis, Diorio, Liu, & Meaney, 1999;Liu, Caldji, Sharma, Plotsky, & Meaney, 2000), which among other data led us to investigate the presence of intergenerational effects of cocaine use.As far as the literature to date, there is general agreement that acute cocaine treatment in rat dams disrupts both early onset and established pup-directed maternal behavior, while increasing locomotor behavior and stereotypies (Johns, Nelson, et al, 1998;Johns, Noonan, Zimmerman, Li, & Pedersen, 1994;Kinsley et al, 1994; Zimmerberg & Gray, 1992). Significant disruptions in maternal behavior following chronic gestational cocaine treatment during pregnancy were reported for the onset or very early post-partum period, and these dams did not display the hyperactivity often seen in acutely treated dams (Heyser, Molina, & Spear, 1992;Kinsley et al, 1994;Peeke, Dark, Salamy, Salfi, & Shah, 1994; Vernotica, Lisciotto, Rosenblatt, & Morrell, 1996).…”

Cocaine disrupts pup-induced maternal behavior in juvenile and adult rats

“…Various rodent studies have reported numerous effects of prenatal exposure to cocaine on subsequent adolescent and adult play, social, and aggressive behaviors [23,38,52,53]. To our knowledge, no prior study has examined the differential effects of prenatal cocaine exposure and rearing condition on next generation offspring pup-induced maternal behavior, although we have recently reported differences in postpartum maternal behavior following prenatal cocaine exposure and altered rearing conditions [17].…”

“…The intermittent schedule was modeled after a previous study examining behavioral effects of prenatal cocaine exposure on offspring [19] and is designed to model intermittent usage patterns in humans. The IC treatment regimen was employed in addition to the CC treatment as previous research indicated differences in maternal behavior following either acute or intermittent cocaine treatment in dams [20,23,25,50,55] accompanied by differences in oxytocin (OT) system dynamics following the different treatment regimens [7,22]. UN dams were weighed and handled daily, but received no drug treatment.…”

“…It is probable that drug-induced maternal neglect has detrimental effects on the future social and parental behavior of adult children, especially given that many of these children are also prenatally exposed to cocaine. Previous reports using animal models found that gestational and postpartum cocaine treatment cause significant delays and disruptions in various aspects of early maternal behavior in the treated rat dam [16,17,20,23,25,39,50,55] and that rearing condition as well as prenatal cocaine exposure has detrimental effects on the onset of maternal behavior in next generation female offspring [17].…”

“…Though the intact medial preoptic area (MPOA) is essential for postpartum and pup-induced maternal behavior in adult rats [13,41,43], large lesions of the MPOA in adolescents impair retrieval and nest-building behaviors only, rather than all elements of maternal behavior and gender does not seem to play as important a role [24]. Whereas adult females typically exhibit pup-induced maternal behavior faster than adult males, the reverse is true in juveniles, with males typically taking fewer days to exhibit pup-induced maternal behavior compared to females and juveniles of both sexes generally perform it several days faster than adults [2][3][4]14,23,30,45,54].…”