One of the major signal transduction systems in brain is the receptor coupled adenylated cyclase (AC) system. Work in our own laboratories, and the laboratories of others, has demonstrated that chronic ethanol ingestion reduces the ability of a number of neurotransmitters and hormones to stimulate brain adenylate cyclase activity. There is good evidence that the uncoupling of adenylate cyclase from stimulatory receptors contributes to certain aspects of alcohol tolerance and the alcohol withdrawal syndrome. Although attempts have been made using model systems of cells in culture to determine the mechanism of the ethanol-induced uncoupling of the adenylate cyclase system, the results of these studies do not seem to provide an appropriate picture of events taking place in the mammalian brain. Our studies are, therefore, focused on elucidating the mechanisms of brain-region specific changes in receptor-AC coupling after chronic ethanol administration to mice. Our mouse model system has been previously determined to reflect changes taking place in brains of human alcoholic subjects. The primary focus of our work will be on the quantitative and qualitative changes that may occur in the guanine nucleotide-binding, coupling (G) proteins, that are interposed between the receptors and the adenylate cyclase catalytic unit. We will use immunoblot (Western blot) analysis to quantitate alpha and beta subunits of Ga, Gi and Go. We will use in situ hybridization and Northern blot analysis to study the effects of ethanol on the transcripts for the various G proteins. We will also examine the functional status of G proteins from ethanol-treated and control mice be use of reconstitution assays with Gsalpha deficient cyc- cell membranes. All of these studies will be correlated in time with the development of tolerance and physical dependence on ethanol and will also be related to the obtained evidence of receptor-AC uncoupling. The studies should provide important information on how the brain adapts to the chronic presence of ethanol and how ethanol may damage brain function.

Agency
National Institute of Health (NIH)
Institute
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Type
Research Project (R01)
Project #
5R01AA009014-02
Application #
2045050
Study Section
Biochemistry, Physiology and Medicine Subcommittee (ALCB)
Project Start
1991-08-01
Project End
1996-07-31
Budget Start
1992-08-01
Budget End
1993-07-31
Support Year
2
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Colorado Denver
Department
Pharmacology
Type
Schools of Medicine
DUNS #
065391526
City
Aurora
State
CO
Country
United States
Zip Code
80045
Bhave, Sanjiv V; Hoffman, Paula L (2004) Phosphatidylinositol 3'-OH kinase and protein kinase A pathways mediate the anti-apoptotic effect of pituitary adenylyl cyclase-activating polypeptide in cultured cerebellar granule neurons: modulation by ethanol. J Neurochem 88:359-69
Nelson, Eric J; Hellevuo, Kaisa; Yoshimura, Masami et al. (2003) Ethanol-induced phosphorylation and potentiation of the activity of type 7 adenylyl cyclase. Involvement of protein kinase C delta. J Biol Chem 278:4552-60
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Kirstein, S L; Tabakoff, B (2001) Genetic correlations between initial sensitivity to Ethanol and brain cAMP signaling in inbred and selectively bred mice. Alcohol Clin Exp Res 25:791-9
Tabakoff, B; Nelson, E; Yoshimura, M et al. (2001) Phosphorylation cascades control the actions of ethanol on cell cAMP signalling. J Biomed Sci 8:44-51
Yoshimura, M; Wu, P H; Hoffman, P L et al. (2000) Overexpression of type 7 adenylyl cyclase in the mouse brain enhances acute and chronic actions of morphine. Mol Pharmacol 58:1011-6
Bhave, S V; Snell, L D; Tabakoff, B et al. (1999) Ethanol sensitivity of NMDA receptor function in developing cerebellar granule neurons. Eur J Pharmacol 369:247-59
Yoshimura, M; Tabakoff, B (1999) Ethanol's actions on cAMP-mediated signaling in cells transfected with type VII adenylyl cyclase. Alcohol Clin Exp Res 23:1457-61
Rabbani, M; Nelson, E J; Hoffman, P L et al. (1999) Role of protein kinase C in ethanol-induced activation of adenylyl cyclase. Alcohol Clin Exp Res 23:77-86

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