Document Detail

Episcleral venous pressure responses to topical nitroprusside and N-Nitro-L-arginine methyl ester.
MedLine Citation:
PMID:  19875657     Owner:  NLM     Status:  MEDLINE    
PURPOSE: To determine the episcleral venous pressure (EVP) responses to nitroprusside (NP) and L-NAME.
METHODS: In anesthetized rabbits (n = 36), arterial pressure and IOP were measured by direct cannulation, and carotid blood flow and heart rate were measured with an ultrasound flowmeter and cardiotachometer. EVP was measured in two groups with a servonull system. Group 1 (n = 13) was given NP (50 microL, 10 mg/mL). Group 2 (n = 10) was given L-NAME (100 microL, 10 mg/mL) followed by NP (50 microL, 10 mg/mL). In group 3 (n = 13), fluorophotometric aqueous flow was measured before and after NP (100 microL, 10 mg/mL).
RESULTS: Systemic parameters were unaffected by treatment in all groups. In group 1, NP increased EVP from 9.1 +/- 0.6 to 11.6 +/- 0.8 mm Hg (P < 0.01) and IOP from 18.7 +/- 1.4 to 23.9 +/- 1.6 mm Hg (P < 0.01). In group 2, L-NAME lowered EVP from 11.5 +/- 1.2 to 8.8 +/- 1.0 mm Hg (P < 0.01) and subsequent NP increased EVP to 13.9 +/- 1.7 mm Hg (P < 0.01 versus L-NAME and baseline). L-NAME decreased IOP from 20.8 +/- 1.7 to 16.7 +/- 1.8 mm Hg (P < 0.01), and then it increased to 20.7 +/- 1.3 mm Hg after NP (P < 0.01 versus L-NAME and P > 0.05 versus baseline). In group 3, NP increased IOP from 16.6 +/- 0.7 to 20.0 +/- 0.9 mm Hg (P < 0.01) but did not alter aqueous flow (2.65 +/- 0.3 vs. 3.0 +/- 0.3 microL/min, P > 0.05).
CONCLUSIONS: Because a topical NO donor raises EVP and a topical NO synthase inhibitor lowers EVP, the authors conclude that EVP is modulated by NO.
David O Zamora; Jeffrey W Kiel
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2009-10-29
Journal Detail:
Title:  Investigative ophthalmology & visual science     Volume:  51     ISSN:  1552-5783     ISO Abbreviation:  Invest. Ophthalmol. Vis. Sci.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-02-26     Completed Date:  2010-03-26     Revised Date:  2013-05-31    
Medline Journal Info:
Nlm Unique ID:  7703701     Medline TA:  Invest Ophthalmol Vis Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1614-20     Citation Subset:  IM    
Department of Ophthalmology, University of Texas Health Science Center, San Antonio, Texas 78229, USA.
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MeSH Terms
Administration, Topical
Aqueous Humor / secretion
Blood Flow Velocity
Enzyme Inhibitors / administration & dosage*
Heart Rate / physiology
Intraocular Pressure / physiology
NG-Nitroarginine Methyl Ester / administration & dosage*
Nitroprusside / administration & dosage*
Sclera / blood supply*
Vasodilator Agents / administration & dosage*
Venous Pressure / drug effects,  physiology*
Grant Support
Reg. No./Substance:
0/Enzyme Inhibitors; 0/Vasodilator Agents; 15078-28-1/Nitroprusside; 50903-99-6/NG-Nitroarginine Methyl Ester

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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