The cellular effects of many neurotransmitters involve the activation of adenylate cyclase with a subsequent increase in intracellular cyclic AMP content. Because of the importance of cyclic AMP in neuronal function, the present proposal will investigate the direct effects of chronic ethanol exposure on adenylate cyclase activity and cyclic AMP content. Since the direct actions of chronic ethanol exposure can be most readily determined with cells in culture, the present studies will use both clonal cells (PC 12) and cerebellar neurons in culture. It has been observed that chronic ethanol exposure results in a decrease in the stimulation of adenylate cyclase activity by neurotransmitters (i.e. desensitization) and a selective increase in the activation of adenylate cyclase by in vitro ethanol in some brain cells. The specific objectives of the present proposal are; 1. to characterize the ethanol induced alterations in adenylate cyclase activity in cerebellar neurons in culture; and 2. to determine the molecular mechanism responsible for the ethanol-induced desensitization. The beta-adrenergic and adenosine- sensitive adenylate cyclase systems in cerebellar neuronal cultures will be used to determine: 1. the time course for the onset of ethanol-induced changes in adenylate cyclase activity: 2. the effects of withdrawal on enzyme activity (i.e., time course for recovery); and 3. the concentration dependency for the ethanol-induced alterations in enzyme activity. The molecular basis for ethanol-induced desensitization will be determined in PC 12 cells because a homogeneous population of cells will facilitate interpretation of the data. Since adenylate cyclase consists of three subunits, experiments will be carried out to determine whether chronic ethanol exposure alters; 1. the amount of each of the subunits; 2. the properties of the subunits; or 3. the interactions of the subunits. Since PC 12 cells are a transformed cell line, these results will be corroborated the direct effects of chronic ethanol exposure on neuronal adenylate cyclase activity, and permit the determination of the molecular mechanism responsible for ethanol induced desensitization. Results from this project are a necessary first step in understanding the response of adenylate cyclase to chronic ethanol administration in vivo.

Agency
National Institute of Health (NIH)
Institute
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Type
Research Project (R01)
Project #
5R01AA006207-05
Application #
3109404
Study Section
Biochemistry, Physiology and Medicine Subcommittee (ALCB)
Project Start
1984-01-01
Project End
1991-11-30
Budget Start
1989-12-01
Budget End
1990-11-30
Support Year
5
Fiscal Year
1990
Total Cost
Indirect Cost
Name
State University of New York at Buffalo
Department
Type
Schools of Dentistry
DUNS #
038633251
City
Buffalo
State
NY
Country
United States
Zip Code
14260
Oberdoerster, J; Rabin, R A (1999) Enhanced caspase activity during ethanol-induced apoptosis in rat cerebellar granule cells. Eur J Pharmacol 385:273-82
Oberdoerster, J; Rabin, R A (1999) NGF-differentiated and undifferentiated PC12 cells vary in induction of apoptosis by ethanol. Life Sci 64:PL 267-72
Rabin, R A (1996) Regulation of the stress-like protein adenotin in PC 12 cells by ethanol exposure. Biochem Pharmacol 51:183-6
Rabin, R A; Winter, J C (1996) Effects of ibogaine and noribogaine on phosphoinositide hydrolysis. Brain Res 731:226-9
Rabin, R A; Winter, J C (1996) Ibogaine and noribogaine potentiate the inhibition of adenylyl cyclase activity by opioid and 5-HT receptors. Eur J Pharmacol 316:343-8
Zou, J Y; Cohan, C; Rabin, R A et al. (1995) Continuous exposure of cultured rat cerebellar macroneurons to ethanol-depressed NMDA and KCl-stimulated elevations of intracellular calcium. Alcohol Clin Exp Res 19:840-5
Kim, W K; Rabin, R A (1994) Characterization of the purinergic P2 receptors in PC12 cells. Evidence for a novel subtype. J Biol Chem 269:6471-7
Kim, W K; Johnson, R G; Izu, L T et al. (1994) Chronic ethanol exposure inhibits ATP-stimulated but not KCl-stimulated dopamine release in PC 12 cells. J Pharmacol Exp Ther 270:336-41
Rabin, R A (1993) Ethanol-induced desensitization of adenylate cyclase: role of the adenosine receptor and GTP-binding proteins. J Pharmacol Exp Ther 264:977-83
Rabin, R A; Acara, M A (1993) Regulation of Na+, K(+)-ATPase by chronic ethanol exposure of PC 12 cells. Biochem Pharmacol 45:1653-8

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