Neurotoxicology and teratology
-
Neurotoxicol Teratol · Mar 2007
Succimer chelation normalizes reactivity to reward omission and errors in lead-exposed rats.
This study evaluated the efficacy of a 3-week course of succimer treatment to alleviate behavioral deficits in rats exposed to lead (Pb) for the first 4 weeks of life. A 3 x 2 factorial design was used: three levels of lead exposure (No Pb, Moderate, and High Pb) and two levels of chelation (succimer or vehicle). Behavioral testing was conducted following chelation therapy, from 2 to 9 months of age; this report presents the results of two of the administered tasks: (1) a conditional olfactory discrimination task (baseline task), and (2) a conditional olfactory discrimination task with periodic reward omission on some correct trials (RO task). ⋯ Importantly, succimer treatment was effective in normalizing the heightened reactivity of the lead-exposed animals to both errors and reward omission. In addition, non-lead-exposed rats that were treated with succimer tended to be more affected by a prior error than controls in their latency to respond on post-error trials. In sum, these findings provide new evidence that succimer chelation can significantly lessen the lasting neurobehavioral dysfunction produced by early lead exposure, but also suggest that there may be risks of administering the drug to individuals without elevated blood lead levels.
-
Neurotoxicol Teratol · Jul 2005
Comparative StudyConcurrent exposure to aluminum and stress during pregnancy in rats: Effects on postnatal development and behavior of the offspring.
The present study was conducted to assess the potential combined influence of maternal restraint stress and aluminum (Al) exposure on postnatal development and behavior in the offspring of exposed rats. Female rats were concurrently exposed to 0 (control group), 50 or 100 mg/kg/day of Al administered as Al nitrate nonahydrate in drinking water with citric acid (355 or 710 mg/kg/day) for a period of 15 days prior to mating with untreated males. Aluminum exposure was maintained throughout the gestational, lactational and post-weaning periods. ⋯ Learning in a passive avoidance task indicated facilitated performance for Al treated rats at 100 mg/kg/day combined with prenatal restraint as evidenced by longer avoidance latencies, while learning in a water maze task showed a shorter latency to find the platform on acquisition day 2 for Al treated rats. However, no effects of Al on water maze performance were detected during the retention probe trial in which the only effect noted was an increase in the platform quadrant swim time for the prenatal restraint group. In general terms, the results of the present study did not show a notable influence of maternal restraint on the Al-induced postnatal developmental and behavioral effects in the offspring of prenatally Al-exposed rats.
-
Neurotoxicol Teratol · Nov 2004
Beneficial effects of the sigma1 receptor agonists igmesine and dehydroepiandrosterone against learning impairments in rats prenatally exposed to cocaine.
In utero cocaine (IUC) exposure results in offspring rats in complex neurochemical and behavioral alterations, particularly affecting learning and memory processes. We examined here the impact of IUC exposure on memory functions in male and female offspring rats and report that selective sigma(1) (sigma(1)) receptor agonists are effective in reversing the deficits. Dams received a daily cocaine, 20 mg/kg ip, injection between gestational days E17 to E20. ⋯ The sigma(1) antagonist BD1063 (1 mg/kg ip) failed to affect performances alone but blocked the igmesine and DHEA effects, confirming the involvement of the sigma(1) receptor. IUC exposure thus results in marked memory deficits, affecting spatial and nonspatial short- and long-term memories in juvenile male and female offspring rats. The activation of the sigma(1) neuromodulatory receptor allows a complete behavioral recovery of the memory functions in prenatally cocaine-exposed rats.
-
Neurotoxicol Teratol · Mar 2004
Comparative StudyGestational exposure to methylmercury retards choice in transition in aging rats.
Developmental exposure to methylmercury has behavioral effects that extend into adulthood and aging. In this study, methylmercury's prolonged effects on the acquisition of choice and sensitivity to changes in reinforcement rates were studied. Pregnant female rats were exposed to drinking water containing 0, 0.5, or 6.4 ppm Hg as methylmercury, resulting in about 40 and 500 microg/kg/day of mercury intake. ⋯ Moreover, two rate measures, lever-press rates and changeover rates, were not systematically affected by methylmercury. The acquisition of choice appears to be very sensitive to subtle consequences of developmental methylmercury exposure. The specific tactics greatly reduced the time required to study behavior in transition from a month in previous reports to a single session here.
-
Neurotoxicol Teratol · Jan 2004
Comparative StudyPerinatal choline supplementation attenuates behavioral alterations associated with neonatal alcohol exposure in rats.
Children exposed to alcohol prenatally suffer from a variety of behavioral alterations, including hyperactivity and learning deficits. Given that women continue to drink alcohol during pregnancy, it is critical that effective interventions and treatments be identified. Previously, we reported that early postnatal choline supplementation can reduce the severity of learning deficits in rats exposed to alcohol prenatally. ⋯ Exposure to choline significantly reduced the number of ethanol-related errors. Importantly, these behavioral changes were not due to the acute effects of choline, but were related to long-lasting organizational effects of early choline supplementation. These data suggest that early dietary interventions may reduce the severity of fetal alcohol effects.