title: Dose-related effects of MK-801 on acute and chronic methylphenidate administration.
abstract: The non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist MK-801 has been shown to modulate both the effects of stimulants, such as amphetamine and cocaine, in producing locomotion and the chronic effects of stimulants in producing sensitization. In this study, we examine the interactions between MK-801 and the stimulant methylphenidate. Three different doses of MK-801 were administered 60 min prior to methylphenidate injection (2.5 mg/kg) and the acute response to MK-801 alone and the coadministration with methylphenidate were characterized. MK-801 alone was found to produce dose-dependent locomotor activation. The 0.15 mg/kg dose of MK-801 had no effect on the response to methylphenidate, while the 0. 3 and 0.6 mg/kg doses augmented the methylphenidate response. The effect of pretreatment with MK-801 on subsequent repeated methylphenidate administration was assessed. For all three doses tested, MK-801 pretreatment blocked the progressive locomotor sensitization expected during repeated methylphenidate administration. These findings suggest that MK-801 may exert a long-lasting effect on learning and memory process that result in a blocking of the development of sensitization.
authors.affiliation: Department of Neurobiology and Anatomy, The University of Texas Medical School at Houston, P.O. Box 20708, Houston, TX 77225, USA.
authors.forename: S
authors.initials: S
authors.lastname: Sripada
authors.forename: O
authors.initials: O
authors.lastname: Gaytan
authors.forename: S
authors.initials: S
authors.lastname: Al-rahim
authors.forename: A
authors.initials: A
authors.lastname: Swann
authors.forename: N
authors.initials: N
authors.lastname: Dafny
mesh_terms: D000818:Animals; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D008297:Male; D008774:Methylphenidate / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D000697:Central Nervous System Stimulants; D018691:Excitatory Amino Acid Antagonists; D008774:Methylphenidate; D016291:Dizocilpine Maleate