ABSTRACT
This study investigated whether exposure to cocaine during critical periods of brain development alters the motor stimulating effects of amphetamine given in adulthood. Female rats received 50 mg/kg/day cocaine HCl SC or vehicle during either postnatal days 1-10 or 11-20. At 60-65 days of age, activity counts were collected over a 15-min baseline period. Subjects then received one of 3 doses (0, 0.1, 0.25 mg/kg) of d-amphetamine sulfate SC followed by a 90-min period of activity monitoring. Adult activity in 1-10-day cocaine-treated rats was different from vehicle-treated rats in response to 0.1 mg/kg amphetamine only. Adult activity in 11-20-day cocaine-treated rats was different from vehicle-treated rats in response to 0.25 mg/kg only. The observed differences represented an increase and decrease in activity, respectively. These alterations in amphetamine response may be related to the observed alterations in D-1 receptor concentrations as well as the altered rates of brain glucose metabolism we have observed in adult rats neonatally exposed to cocaine.
Subject(s)
Cocaine/pharmacology , Dextroamphetamine/pharmacology , Motor Activity/drug effects , Analysis of Variance , Animals , Animals, Newborn , Body Weight/drug effects , Dose-Response Relationship, Drug , Female , Rats , Rats, Inbred Strains , Reference ValuesABSTRACT
Pregnant guinea pigs were administered aspartame (500 mg/kg) in sesame oil by gavage or sesame oil alone between the day of conception and parturition. A nontreated control group was also maintained. There were no statistically significant effects of the treatment on maternal weight gain, litter size, or birth weight of the pups. Newborn pups were weighed daily and on day 15 were injected with either LiCl or saline and placed in a cage with vanilla odor for 30 min. Twenty-four hr later the pups were permitted to choose between vanilla and lemon odors in a preference test. While both the vehicle-treated control and nontreated control groups injected with LiCl showed a conditioned aversion to vanilla, the aspartame-treated pups injected with LiCl did not. These data indicate that aspartame exposure at 500 mg/kg throughout gestation disrupts odor-associative learning in 15-day-old guinea pigs.
Subject(s)
Aspartame/toxicity , Avoidance Learning/drug effects , Dipeptides/toxicity , Odorants , Animals , Body Weight/drug effects , Female , Guinea Pigs , Humans , Pregnancy , Prenatal Exposure Delayed EffectsABSTRACT
Garter snakes reliably spend more time and tongue flick more frequently at a dish containing surface washings of earthworm (EW) than at a control dish containing water or sodium chloride. In a series of experiments EW was examined to further characterize and purify the snake-attracting component(s). Earthworm wash boiled for up to two hours did not lose its snake-attracting activity, but EW boiled for four hours was not discriminated from a control substance. The active components of EW were completely precipitated by 90 and 100% saturated ammonium sulfate solutions. The molecular weight of the active components, as determined by dialysis, is larger than 67,000 daltons. Earthworm wash was separated into two peaks on either G-75 or AcA 44. The larger peak (F2) contains snake-attracting material of molecular weight greater than 67K. The smaller peak material (F4) is inactive as a snake-attractant and contains material of approximate molecular weight of 3K. Biological activity of EW covaried with Lowry (protein) assay and Dubois (carbohydrate) assay values and 280 nm absorbance. The response eliciting components of EW are not extractable from earthworms at temperatures below 60 degrees C, but can be extracted at 60 degrees C (for one minute) from the worms or the soil that forms the bedding for the earthworms.
