These studies propose to isolate differences in the metabolism of a major drug of abuse, cocaine, using two distinct but genetically related rat strains, the spontaneously hypertensive rat (SHR) and it normotensive control, the Wistar-Kyoto rat (WKY). Relationships between conversion of cocaine to norcocaine and differences between SHR and WKY in pharmacodynamic and toxic responses to administrations of cocaine and norcocaine will be determined. Experimental observations will focus on the relative effects of cocaine and norcocaine on neurological and cardiovascular responses that are mediated by dopaminergic neurons. This emphasis is prompted by evidence that pharmacological sequelae to cocaine ingestion involve actions on dopaminergic neurons. In addition, major differences between SHR and WKY in dopaminergic function are known. Neurological, cardiovascular and toxic effects of acute and subacute administration of cocaine and norcocaine will be observed and correlated with the degree of bioconversion of cocaine to norcocaine in the two strains, by determination of brain and liver N-demethylase activities and levels of cocaine and norcocaine. Concentrations of dopamine (DA) and DA-metabolites, activities of tyrosine hydroxylase and monoamine oxidase and the characteristics of DA and cocaine receptors from isolated membrane preparations will be determined in specified brain regions. Finally, intracerebroventricular injections of DA or DA receptor antagonists will be used to assess, in vivo, specific contributions of dopaminergic neuronal systems to the behavior, cardiovascular and toxic actions of cocaine and norcocaine. The results will significantly extend knowledge of mechanisms underlying individual differences in the mechanism of action of and toxic responses to cocaine.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
1R01DA004264-01
Application #
3209648
Study Section
(SRCD)
Project Start
1987-01-01
Project End
1991-12-31
Budget Start
1987-01-01
Budget End
1987-12-31
Support Year
1
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Mississippi Medical Center
Department
Type
Schools of Medicine
DUNS #
928824473
City
Jackson
State
MS
Country
United States
Zip Code
39216
Rockhold, R W; Byrne, M; Sprabery, S et al. (1994) Urethane anesthesia reverses the protective effect of noncompetitive NMDA receptor antagonists against cocaine intoxication. Life Sci 54:321-30
Yu, Z J; Jin, C; Rockhold, R W et al. (1993) Site and mechanism of behavioral tolerance to cocaine: a study of dopamine release in Wistar-Kyoto and spontaneously hypertensive rats. Neurochem Res 18:1203-9
Inada, T; Polk, K; Jin, C et al. (1992) Cocaine elevates striatal dopamine efflux in spontaneously hypertensive and Wistar-Kyoto rats. Brain Res Bull 28:227-31
Rockhold, R W; Surrett, R S; Oden, G et al. (1992) Inhibition of cocaine intoxication by excitatory amino acid receptor antagonists. Ann N Y Acad Sci 648:335-7
Qian, X B; Andy, O J; Dearman, C et al. (1992) Cocaine-induced brainstem seizures and behavior. Integr Physiol Behav Sci 27:117-29
Inada, T; Polk, K; Purser, C et al. (1992) Behavioral and neurochemical effects of continuous infusion of cocaine in rats. Neuropharmacology 31:701-8
Rockhold, R W (1991) Excitatory amino acid receptor antagonists: potential implications for cardiovascular therapy and cocaine intoxication. Med Hypotheses 35:342-8
Rockhold, R W; Oden, G; Ho, I K et al. (1991) Glutamate receptor antagonists block cocaine-induced convulsions and death. Brain Res Bull 27:721-3
Rockhold, R W; Carver, E S; Ishizuka, Y et al. (1991) Dopamine receptors mediate cocaine-induced temperature responses in spontaneously hypertensive and Wistar-Kyoto rats. Pharmacol Biochem Behav 40:157-62
Jin, C; Rockhold, R W; Hoskins, B et al. (1991) Comparisons of cocaine receptors in brain regions from WKY and SHR. Brain Res Bull 27:853-6

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