Impaired learning in adulthood following neonatal delta9-THC exposure. 2005

M O'Shea, and P E Mallet
School of Psychology, University of New England, Armidale, New South Wales, Australia.

Cannabis is one of the most commonly used illicit drugs during pregnancy, but little is known about the lasting effects of early-life exposure to this drug. In this study, male Wistar rat pups were treated daily with (-)-delta9-tetrahydrocannabinol (THC; 5 mg/kg, s.c.) or its vehicle between postnatal days (PND) 4 and 14. Drug administration during this early postnatal period in rats is analogous to the third trimester of gestation in humans, which is a major period of synaptogenesis. Rats were subsequently tested drug-free during young adulthood (PND 56) using a two-component food-motivated double Y-maze test. Each trial included distinct spatial discrimination and delayed alternation components, which permitted the simultaneous assessment of reference memory and working memory. Rats were tested for 30 trials/day, 5 days/week for 5 weeks. Results revealed no significant differences between THC- and vehicle-treated rats in the spatial discrimination task. However, compared to vehicle-treated rats, THC-treated rats committed significantly more errors, and required significantly longer to obtain 80% correct over two consecutive days in the delayed alternation task. Results suggest that neonatal THC exposure leads to a specific and lasting deficit in learning in adulthood, which is likely due to impaired working memory function.

UI MeSH Term Description Entries
D007859 Learning Disabilities Conditions characterized by a significant discrepancy between an individual's perceived level of intellect and their ability to acquire new language and other cognitive skills. These may result from organic or psychological conditions. Relatively common subtypes include DYSLEXIA, DYSCALCULIA, and DYSGRAPHIA. Adolescent Learning Disabilities,Adult Learning Disabilities,Child Learning Disabilities,Developmental Academic Disability,Developmental Academic Disorder,Developmental Disabilities of Scholastic Skills,Learning Disabilities, Adolescent,Learning Disabilities, Child,Learning Disorders,Academic Disorder, Developmental,Adult Learning Disorders,Developmental Disorders of Scholastic Skills,Learning Disorders, Adult,Learning Disturbance,Scholastic Skills Development Disorders,Academic Disabilities, Developmental,Academic Disability, Developmental,Academic Disorders, Developmental,Adolescent Learning Disability,Adult Learning Disability,Adult Learning Disorder,Child Learning Disability,Developmental Academic Disabilities,Developmental Academic Disorders,Disabilities, Adolescent Learning,Disabilities, Adult Learning,Disabilities, Child Learning,Disabilities, Developmental Academic,Disabilities, Learning,Disability, Adolescent Learning,Disability, Adult Learning,Disability, Child Learning,Disability, Developmental Academic,Disability, Learning,Disorder, Learning,Disorders, Adult Learning,Disorders, Learning,Disturbance, Learning,Disturbances, Learning,Learning Disabilities, Adult,Learning Disability,Learning Disability, Adolescent,Learning Disability, Adult,Learning Disability, Child,Learning Disorder,Learning Disorder, Adult,Learning Disturbances
D008297 Male Males
D008568 Memory Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory.
D011897 Random Allocation A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects. Randomization,Allocation, Random
D001835 Body Weight The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms. Body Weights,Weight, Body,Weights, Body
D005260 Female Females
D000704 Analysis of Variance A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable. ANOVA,Analysis, Variance,Variance Analysis,Analyses, Variance,Variance Analyses
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D000831 Animals, Newborn Refers to animals in the period of time just after birth. Animals, Neonatal,Animal, Neonatal,Animal, Newborn,Neonatal Animal,Neonatal Animals,Newborn Animal,Newborn Animals
D013759 Dronabinol A psychoactive compound extracted from the resin of Cannabis sativa (marihuana, hashish). The isomer delta-9-tetrahydrocannabinol (THC) is considered the most active form, producing characteristic mood and perceptual changes associated with this compound. THC,Tetrahydrocannabinol,delta(9)-THC,9-ene-Tetrahydrocannabinol,Marinol,Tetrahydrocannabinol, (6a-trans)-Isomer,Tetrahydrocannabinol, (6aR-cis)-Isomer,Tetrahydrocannabinol, (6aS-cis)-Isomer,Tetrahydrocannabinol, Trans-(+-)-Isomer,Tetrahydrocannabinol, Trans-Isomer,delta(1)-THC,delta(1)-Tetrahydrocannabinol,delta(9)-Tetrahydrocannabinol,9 ene Tetrahydrocannabinol,Tetrahydrocannabinol, Trans Isomer

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