Methamphetamine exposure from postnatal day 11 to 20 causes impairments in both behavioral strategies and spatial learning in adult rats.
Spatial learning and memory deficits in a water maze have been observed in adult animals exposed to a regimen of 4 daily doses of d-methamphetamine (MA) at 2 h intervals from postnatal day 11 to 20. An interpretational issue for these long-term effects of MA is whether they are truly spatial deficits or are secondary to alterations in sensorimotor systems. In this experiment, we evaluated the effects of a pretraining procedure shown to minimize the influence of drug-induced sensorimotor deficits. Animals within a litter were treated with MA or saline. Animals were either pretrained for nonspatial task requirements in the water maze (i.e., swimming and platform climbing) or were nai;ve to the task. Animals that received the pretraining did better than the nai;ve animals. The nai;ve MA animals performed worse than the nai;ve control animals as previously observed. By contrast, no difference in search time was noted between pretrained MA- and SAL-treated animals during the acquisition phase of testing. When the platform was relocated in a novel position, spatial learning was impaired for MA animals, regardless of pretraining. No increase in the number of platform nonrecognition events (swimovers, deflections, or jump-offs) occurred among pretrained or nai;ve groups compared to controls. These data suggest that sensorimotor deficits do not account for the spatial learning and memory deficits in animals exposed neonatally to MA.
Williams
Michael T
MT
Pharmacology Research Center, Children's Hospital Research Foundation and University of Cincinnati, 3333 Burnet Ave, Cincinnati, OH 45229-3039, USA.
Vorhees
Charles V
CV
Boon
Francis
F
Saber
Andrea J
AJ
Cain
Donald P
DP
D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000502:physiology* / Q000523:psychology; D005260:Female; D007858:Learning / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D013037:Spatial Behavior / Q000187:drug effects* / Q000502:physiology; D013997:Time Factors
D008694:Methamphetamine