1. Prolonged methamphetamine exposure during a critical period in neonatal Sprague Dawley rats does not exacerbate egocentric and allocentric learning deficits but increases reference memory impairments.
- Author
-
Williams MT, Amos-Kroohs RM, and Vorhees CV
- Subjects
- Animals, Animals, Newborn, Critical Period, Psychological, Female, Male, Rats, Rats, Sprague-Dawley, Central Nervous System Stimulants pharmacology, Maze Learning drug effects, Memory drug effects, Methamphetamine pharmacology, Spatial Navigation drug effects
- Abstract
Children exposed to methamphetamine (MA) in utero have cognitive deficits. MA administration in rats for 5-10 days between postnatal days (P)6 and 20 produces cognitive deficits. The purpose of this study was to determine if extending MA administration by 5 days within P6-20 would exacerbate allocentric (Morris water maze) and egocentric (Cincinnati water maze) learning deficits. Sprague Dawley female and male offspring (split-litter design) were administered saline (SAL) or MA (10 mg/kg) four times daily from P6 to 20 to create four groups: (a) SAL from P6 to 20, (b) MA from P6 to 20 (MA6-20), (c) MA from P6 to 15 (MA6-15), or (d) MA from P11 to 20 (MA11-20); the latter groups received saline on days they did not receive MA. Egocentric, allocentric, and conditioned freezing tests began on P60. The MA6-15 and MA6-20 groups showed egocentric deficits, all MA groups had allocentric deficits but no differences in conditioned freezing compared with SAL controls. The MA6-15 and MA6-20 groups had similar deficits in learning and memory that were larger than in the MA11-20 group. Learning in both mazes was sex dependent, but no interactions with MA were found. The data demonstrate that extending the exposure period of MA beyond the sensitive periods (P6-15 and P11-20) did not exacerbate the cognitive deficits., (© 2020 International Society for Developmental Neuroscience.)
- Published
- 2020
- Full Text
- View/download PDF