The long-term objective of this project is to better understand the neurobiological and metabolic consequences of phencyclidine (PCP) abuse. Acute use of PCP has been shown to produce violent, self-destructive and psychotic behavior, and in some chronic users a long-term schizophrenia.
The specific aims of this project are designed to test the hypothesis that PCP metabolites can lead to long term, detrimental effects through irreversibly binding to critical macromolecules in the central nervous system and at peripheral sites. For these studies, an animal model is being developed to provide a source of tissues for in vitro studies of the mechanism(s) underlying vulnerability to PCP metabolite covalent binding. These in vitro experiments will permit studies of specific isoenzyme pathways and other potential targets of covalent binding in normal animals and in animals which are genetically deficient in the isoenzyme pathway responsible for generating the electrophillic metabolites. Covalent binding to specific isoenzymes and other proteins will be assessed using a series of complimentary biochemical, immunochemical and physical/chemical methodologies. Together, these techniques will allow characterization of metabolite covalent binding in tissue sections, isolated proteins, and peptide fragments. In other studies, the consequences of irreversible PCP metabolite binding will be studied by measuring the changes in function of specific metabolic pathways in normal animals, PCP chronically dosed animals and genetically deficient animals. Finally, the neurobiological consequences of PCP metabolite covalent binding will be assessed through immunohistochemical localization of the covalent binding sites in the central nervous system and a series of ligand binding studies using brain homogenates and partially purified receptors from normal and PCP chronically dosed animals. Together, these data should allow us to better predict the consequences of PCP metabolite covalent binding of PCP metabolites could lead to a better understanding of the long-term neurobiological consequences of PCP abuse and elucidate mechanisms through which certain individuals might be particularly susceptible.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
2R01DA004136-07
Application #
3209339
Study Section
Special Emphasis Panel (SRCD (11))
Project Start
1986-04-01
Project End
1996-03-31
Budget Start
1992-04-01
Budget End
1993-03-31
Support Year
7
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Arkansas for Medical Sciences
Department
Type
Schools of Medicine
DUNS #
City
Little Rock
State
AR
Country
United States
Zip Code
72205
Shelnutt, S R; Gunnell, M; Owens, S M (1999) Sexual dimorphism in phencyclidine in vitro metabolism and pharmacokinetics in rats. J Pharmacol Exp Ther 290:1292-8
Sharma, U; Roberts, E S; Kent, U M et al. (1997) Metabolic inactivation of cytochrome P4502B1 by phencyclidine: immunochemical and radiochemical analyses of the protective effects of glutathione. Drug Metab Dispos 25:243-50
Owens, S M (1997) Antibodies as pharmacokinetic and metabolic modifiers of neurotoxicity. NIDA Res Monogr 173:259-72
Shelnutt, S R; Cornett, L E; Owens, S M (1997) Phencyclidine continuous dosing produces a treatment time-dependent regulation of rat CYP2C11 function, protein expression and mRNA levels. J Pharmacol Exp Ther 281:574-81
Laurenzana, E M; Owens, S M (1997) Brain microsomal metabolism of phencyclidine in male and female rats. Brain Res 756:256-65
Laurenzana, E M; Owens, S M (1997) Metabolism of phencyclidine by human liver microsomes. Drug Metab Dispos 25:557-63
Shelnutt, S R; Badger, T M; Owens, S M (1996) Phencyclidine metabolite irreversible binding in the rat: gonadal steroid regulation and CYP2C11. J Pharmacol Exp Ther 277:292-8
Laurenzana, E M; Sorrels, S L; Owens, S M (1995) Antipeptide antibodies targeted against specific regions of rat CYP2D1 and human CYP2D6. Drug Metab Dispos 23:271-8
Owens, S M; Gunnell, M; Laurenzana, E M et al. (1993) Dose- and time-dependent changes in phencyclidine metabolite covalent binding in rats and the possible role of CYP2D1. J Pharmacol Exp Ther 265:1261-6
Wessinger, W D; Owens, S M (1991) Chronic administration of phencyclidine: pharmacokinetic comparison of intravenous and subcutaneous infusions in Sprague-Dawley rats. Drug Metab Dispos 19:719-21

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