Cross‐fostering effect on postnatal development of rat pups exposed to methamphetamine during gestation and preweaning periods

Abstract

There are studies showing that drug abuse during pregnancy may have a long-term effect on progeny of drug-abusing mothers. Our previous work demonstrated that prenatal and/or postnatal methamphetamine injections impair maternal behavior. The purpose of the present study was to assess the effect of prenatal methamphetamine or stress exposure and postnatal breeding on postnatal development of rat pups. Female rats were injected with methamphetamine (5 mg/kg daily) or physiological saline prior, during and after gestation. Absolute controls did not receive any injections. On postnatal day 1, pups were cross-fostered so that each mother received some of her own and some of the pups from the mothers with the other two treatments. Pups were weighted daily for the entire lactation period. Postural motor reaction development was examined daily by righting reflex between postnatal day 1 and 12. On postnatal day 15 homing test examining pups' nest-seeking behavior was performed. On postnatal day 23 rotarod and bar-holding tests were used to investigate sensorimotor coordination of pups. We demonstrated that prenatal methamphetamine exposure impairs performance of sensorimotor tests (righting reflex on surface and rotarod test). Moreover, the effect of methamphetamine as well as the effect of prenatal stress induced by saline injections was affected by postnatal breeding conditions in sensorimotor tests as well as in the test of homing. Our results support the hypothesis that the variation in rat maternal care could serve as a mechanism for a nongenomic behavioral mode of transmission of traits.

Developmental and behavioral consequences of prenatal methamphetamine exposure: A review of the Infant Development, Environment, and Lifestyle (IDEAL) study

“…These epigenetic changes may account for the adverse effects observed in the future generations of offspring exposed to methamphetamine during development(Šlamberová et al 2007). Of critical importance, improvements in sensorimotor testing have been demonstrated by cross fostering exposed offspring to unexposed mothers, suggesting the postnatal environment is a critical factor for attenuating methamphetamine-induced changes in neural function(Pometlová et al 2009) .…”

Antagonism of orexin 1 receptors eliminates motor hyperactivity and improves homing response acquisition in juvenile rats exposed to alcohol during early postnatal period

“…In addition, AE resulted in a significant increase in the shortest HR latency and in the number of trials necessary to reach HR with the shortest latency. The HR test quantifies the nest-seeking behavior of pre-weaning rats, which may depend on the sensory and motor functions, motivation and learning abilities [28]. The test does not allow one to clearly differentiate among these impairments.…”

“…However, a contribution of sensory or motor deficits is unlikely, because an earlier study did not reveal abnormalities in sensory development or locomotion in pre-weaning rats following even more severe AE [6]. HR test is also considered to reflect olfactory orientation of pups and functioning of the working memory [27,28]. Results from a previous study utilizing the same model of AE show that pre-weaning AE rats exhibit unaltered sensory component of the orienting response to olfactory stimuli but may fail to form a working memory of the olfactory stimulus [30].…”

Fostering itself increases nicotine self-administration in young adult male rats

“…Rats with prenatal methamphetamine exposure (5mg/kg/day) show improvement in maturation tests when fostered to drug-naïve dams (Pometlova et al 2009). Similarly, while non-fostered rat offspring with in utero saline or morphine exposure (5mg/kg injection GD11-13, 10mg/kg GD14-18) did not exhibit higher operant response rates for cocaine (0.5mg/kg/inj) compared to controls, fostering itself increased responding for cocaine regardless of prenatal treatment group (Vathy et al 2007).…”