Biomaterial Database

Methylphenidate: rate-dependent drug effects in hyperactive boys. 1985

K Weber

The purpose of this study was to test whether the effects of methylphenidate on rates of operant responding in hyperactive boys differed depending on the predrug baseline rates of responding. On the basis of the rate dependency hypothesis, dose-related decreases from high baseline rates and increases from low baseline rates would be predicted. A multiple FR-DRL (fixed ratio-differential reinforcement of low Rates) schedule was used to generate high and low rates of responding on a simple operant task, using nickels as reinforcers. Three dosage levels were used: placebo, 0.3 mg/kg, and 1.0 mg/kg of methylphenidate. Both experimenter and subject were blind to dosage level. Surprisingly, DRL response rates were not significantly affected by the drug, while FR rates increased linearly with increasing dose. Thus, the predicted between-schedule differences were not found. However, within the FR schedule, changes from baseline to postdrug rates within each active drug condition were consistent with the rate dependency hypothesis; i.e., subjects with lower baselines increased their response rates, while subjects with higher baselines decreased or did not change their rates. The opposite effect occurred following placebo.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008774	Methylphenidate	A central nervous system stimulant used most commonly in the treatment of ATTENTION DEFICIT DISORDER in children and for NARCOLEPSY. Its mechanisms appear to be similar to those of DEXTROAMPHETAMINE. The d-isomer of this drug is referred to as DEXMETHYLPHENIDATE HYDROCHLORIDE.	Centedrin,Concerta,Daytrana,Equasym,Metadate,Methylin,Methylphenidate Hydrochloride,Phenidylate,Ritalin,Ritalin-SR,Ritaline,Tsentedrin,Hydrochloride, Methylphenidate,Ritalin SR
D012055	Reinforcement Schedule	A schedule prescribing when the subject is to be reinforced or rewarded in terms of temporal interval in psychological experiments. The schedule may be continuous or intermittent.	Reinforcement Schedules,Schedule, Reinforcement,Schedules, Reinforcement
D002648	Child	A person 6 to 12 years of age. An individual 2 to 5 years old is CHILD, PRESCHOOL.	Children
D003216	Conditioning, Operant	Learning situations in which the sequence responses of the subject are instrumental in producing reinforcement. When the correct response occurs, which involves the selection from among a repertoire of responses, the subject is immediately reinforced.	Instrumental Learning,Learning, Instrumental,Operant Conditioning,Conditionings, Operant,Instrumental Learnings,Learnings, Instrumental,Operant Conditionings
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001289	Attention Deficit Disorder with Hyperactivity	A behavior disorder originating in childhood in which the essential features are signs of developmentally inappropriate inattention, impulsivity, and hyperactivity. Although most individuals have symptoms of both inattention and hyperactivity-impulsivity, one or the other pattern may be predominant. The disorder is more frequent in males than females. Onset is in childhood. Symptoms often attenuate during late adolescence although a minority experience the full complement of symptoms into mid-adulthood. (From DSM-V)	ADHD,Attention Deficit Disorder,Attention Deficit Hyperactivity Disorder,Brain Dysfunction, Minimal,Hyperkinetic Syndrome,Minimal Brain Dysfunction,ADDH,Attention Deficit Disorders with Hyperactivity,Attention Deficit Hyperactivity Disorders,Attention Deficit-Hyperactivity Disorder,Attention Deficit Disorders,Attention Deficit-Hyperactivity Disorders,Deficit Disorder, Attention,Deficit Disorders, Attention,Deficit-Hyperactivity Disorder, Attention,Deficit-Hyperactivity Disorders, Attention,Disorder, Attention Deficit,Disorder, Attention Deficit-Hyperactivity,Disorders, Attention Deficit,Disorders, Attention Deficit-Hyperactivity,Dysfunction, Minimal Brain,Syndromes, Hyperkinetic