Impairment of single-trial memory formation by oral methylphenidate in the rat.
High synaptic concentrations of dopamine and/or norepinephrine can impair the working memory function of the prefrontal cortex and impede attention and learning. Methylphenidate, a dopamine and norepinephrine transporter blocker known to facilitate these cognitive processes at low doses, was hypothesized to interfere with memory storage at doses that may raise concentrations of these neurotransmitters to systemically disruptive levels. In the present experiments, a dose of 10.0mg/kg of this drug was administered to female and male Long-Evans rats using a novel oral administration procedure designed to model the normal mode of delivery to humans. It was found to interfere with single-trial memory acquisition in a delayed object recognition test, a spontaneous learning task that involves no appetitive or aversive motivator. The time that the rats spent in overt exploration of the to-be-remembered objects during the acquisition trial was not affected, suggesting that the drug may have impaired processes of memory formation independently of interference with attention.
Chuhan
Yadvinder S
YS
Florence M. Christie Laboratory for Life Sciences, Department of Psychology, University of New Brunswick, 100 Tucker Park Road, Saint John, New Brunswick, Canada E2L 4L5.
Taukulis
Harald K
HK
D000284:Administration, Oral; D000818:Animals; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism; D005106:Exploratory Behavior / Q000187:drug effects; D005260:Female; D008297:Male; D008568:Memory / Q000187:drug effects*; D011939:Mental Recall / Q000187:drug effects; D008774:Methylphenidate / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism; D010364:Pattern Recognition, Visual / Q000187:drug effects; D051381:Rats; D020318:Rats, Long-Evans; D012737:Sex Factors
D000697:Central Nervous System Stimulants; D008774:Methylphenidate; D004298:Dopamine; D009638:Norepinephrine