Ingestion of moderate and high amounts of alcohol (ETOH) results in ETOH-induced hypertension (EIH) and exacerbation of existing hypertension. The mechanisms remain undefined. However, ETOH produces imbalances in the vascular production of the potent vasodilator nitric oxide (NO) and the vasoconstrictors superoxide (SO) and angiotensin II (AII) that may be causal to the dose-dependent hemodynamic sequelae produced by ETOH. Chronic ingestion of ETOH decreases antioxidants (e.g. NO, SO dismutase [SOD], glutathione peroxidase [GP]) and up regulates SO and hydrogen peroxide (H202). Up regulation of tyrosine kinases (TYR-K) and selective isozymes of protein kinase C (PKC) may be involved. In vitro TYR-K up regulates NADPH oxidase and angiotensin II (AII) converting enzyme (ACE), whereas PKC isozymes and ETOH down regulate NO at the level of transcription and translation and facilitate the transcription of ACE which generates the potent vasoconstrictor AII. This promotes a positive feedback cycle which can culminate in EIH, since NO decreases and SO increases intracellular calcium (Ca2+) and sodium (Na+) ions and blood pressure. We postulate that EIH results from ETOH-induced parallel increases of free radials and the TYR-K/PKC cascade which increase SO via increased AII and increased NADPH oxidase activity and decreased DOS and GP activity and uncoupling of NOS. This increases the SO/NO balance in the VSM. AII, via formation of SO, in turn, increases Ca2+ and Na+ in smooth muscle producing hypertension. The questions we will test are: (a) Does ETOH increase the SO/NO balance in blood vessels? Using on-line chemical, electrophysiologic and molecular biologic techniques we will measure the changes in production of SO, NO, and H202 by the perfused mesenteric and renal vasculature and their relationship to changes in vascular Ca2+ and Na+ in cohorts of male and female fed a chronic alcoholic (AR) or isocaloric diet (NAI) during the progression of EIH. (b) Test the concept that ETOH activates phospholipase D to increase TYR-K which up regulates oxygen free radicals and PKC isozymes which up regulates ACE and down regulates NOS and the anti-oxidant enzymes to cause the long-term changes in SO/NO ratio and ACE. Planned experiments will define the site at which ETOH up regulates phosphorylation of these enzymes, the specific isozymes of TYR-K and PKC involved and the mechanism by which ETOH prevents their down regulation and their temporal relationship to the increased free radical/NO ratio and to EIH. (c) Test the concept that EIH is mediated by the SO-PKC/TYR-K - AII cascade. NAI and AR rats will be chronically treated with an ACE inhibitor, PEG-SOD, glutathione monoethylester, a selective TTYR-K and PKC isozyme inhibitor, an irreversible NOS inhibitor and l-arginine. The exacerbation or prevention of EIH will be related to drug effects on the cell-signaling pathway. This research can define the cell-signaling pathway in EIH and provide new and novel approaches to treating EIH.

Agency
National Institute of Health (NIH)
Institute
National Institute on Alcohol Abuse and Alcoholism (NIAAA)
Type
Research Project (R01)
Project #
1R01AA011224-01A1
Application #
2411388
Study Section
Special Emphasis Panel (ZRG4-ALTX-3 (04))
Project Start
1997-09-01
Project End
2002-08-31
Budget Start
1997-09-01
Budget End
1998-08-31
Support Year
1
Fiscal Year
1997
Total Cost
Indirect Cost
Name
Louisiana State University Hsc New Orleans
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
782627814
City
New Orleans
State
LA
Country
United States
Zip Code
70112
Giles, Thomas D; Given, Michael B; Greenberg, Stan S et al. (2002) Myocardial effects of ethanol consumption in the rat with streptozotocin-induced diabetes. Alcohol Clin Exp Res 26:1128-33
Giles, T D; Ouyang, J; Kerut, E K et al. (1998) Changes in protein kinase C in early cardiomyopathy and in gracilis muscle in the BB/Wor diabetic rat. Am J Physiol 274:H295-307
Given, M B; Jie, O; Zhao, X et al. (1998) Protein kinase C isozymes in skeletal muscles during the early stage of genetic and streptozocin diabetes. Proc Soc Exp Biol Med 218:382-9