Document Detail

Involvement of constitutive nitric oxide synthase in the portal-systemic collaterals of portal hypertensive rats.
MedLine Citation:
PMID:  15984816     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Recent studies have shown that endothelial nitric oxide (NO) is involved in modulating the vascular response to vasoconstrictors in portal-systemic collaterals of portal hypertensive rats. This study investigated which isoform of NO synthase is involved in the collateral circulation of portal hypertensive rats. METHODS: The relaxation response to acetylcholine (10(-8) M, 10(-7) M and 10(-6) M) in norepinephrine (NE)-preconstricted portal-systemic collaterals was investigated after incubation with vehicle (Krebs solution), a preferential inducible NO synthase inhibitor (aminoguanidine [AG]), or a non-selective NO synthase inhibitor (Nomega-nitro-L-arginine [NNA]), in rats with partial portal vein ligation. Mean arterial pressure was measured before the perfusion experiments. RESULTS: Bodyweight and mean arterial pressure before the perfusion studies were similar in the vehicle, AG and NNA groups. Preincubation with NNA, but not AG, produced a significant increase in baseline perfusion pressure compared with the vehicle group (p < 0.05). The increase in perfusion pressure in response to NE was enhanced in the presence of NNA (p < 0.05), but not AG. In addition, preincubation with NNA, but not AG, significantly suppressed acetylcholine-induced relaxation in the portal-systemic collaterals (p < 0.05). CONCLUSION: These results suggest that constitutive, rather than inducible, NO synthase is involved in the vascular response to vasoconstrictors in the portal-systemic collaterals of portal hypertensive rats.
Ching-Chih Chang; Hui-Chun Huang; Sun-Sang Wang; Fa-Yauh Lee; Full-Young Chang; Han-Chieh Lin; Ming-Chieh Hou; Shou-Dong Lee
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of the Chinese Medical Association : JCMA     Volume:  68     ISSN:  1726-4901     ISO Abbreviation:  J Chin Med Assoc     Publication Date:  2005 Jun 
Date Detail:
Created Date:  2005-06-29     Completed Date:  2005-07-14     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  101174817     Medline TA:  J Chin Med Assoc     Country:  China (Republic : 1949- )    
Other Details:
Languages:  eng     Pagination:  245-9     Citation Subset:  IM    
Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, R.O.C.
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MeSH Terms
Acetylcholine / pharmacology
Collateral Circulation / physiology*
Hypertension, Portal / physiopathology*
Nitric Oxide / physiology
Nitric Oxide Synthase / physiology*
Nitroarginine / pharmacology
Portal System / physiopathology*
Rats, Sprague-Dawley
Vasodilation / drug effects
Reg. No./Substance:
10102-43-9/Nitric Oxide; 2149-70-4/Nitroarginine; 51-84-3/Acetylcholine; EC Oxide Synthase

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