title: Interactive effects of MK-801 and morphine on EEG, EEG power spectra and behavior in rats: II. Morphine dependence.
abstract: A potential interaction between MK-801 and the cortical electroencephalographic (EEG) and behavioral expressions of morphine dependence in female Sprague-Dawley rats was assessed. Rats were treated chronically (7 days) with either morphine alone, morphine and MK-801, MK-801 alone or saline vehicle alone. On day 8 all rats received morphine alone followed by naloxone. An additional group received chronic (7 days) morphine alone, followed by MK-801 on day 8 prior to morphine and naloxone. Naloxone-induced EEG complexity in morphine-dependent rats was significantly lower than in chronic saline-treated rats. Total power, mobility, mean frequency, complexity and edge frequency in response to naloxone-induced withdrawal in morphine-dependent rats were significantly altered from those in chronically MK-801 alone-treated rats. No differences were found in the EEG and behavioral responses to naloxone between rats that received chronic MK-801 and those that didn't during chronic morphine treatment. Acute MK-801 prior to naloxone in morphine-dependent rats attenuated the behavioral, but not the EEG response to naloxone-induced withdrawal.
authors.affiliation: Department of Pharmacology and Toxicology, University of Maryland School of Pharmacy, Baltimore 21201.
authors.forename: K A
authors.initials: KA
authors.lastname: Haberny
authors.forename: G A
authors.initials: GA
authors.lastname: Young
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D004347:Drug Interactions; D004569:Electroencephalography / Q000187:drug effects*; D005260:Female; D009020:Morphine / Q000494:pharmacology*; D009021:Morphine Dependence / Q000503:physiopathology / Q000523:psychology; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D009270:Naloxone; D016291:Dizocilpine Maleate; D009020:Morphine