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Endothelium-derived nitric oxide reduces baseline venous tone in awake instrumented rats.
- Source :
-
The American journal of physiology [Am J Physiol] 1993 Jul; Vol. 265 (1 Pt 2), pp. H47-51. - Publication Year :
- 1993
-
Abstract
- To determine whether nitric oxide, which is likely endothelium-derived relaxing factor (EDRF), modulates baseline venous tone, the effects of intravenous NG-monomethyl-L-arginine (L-NMMA) (3-25 mg/kg), an EDRF inhibitor, on mean circulatory filling pressure (MCFP) were determined in 10 awake instrumented rats. MCFP, the equilibrated systemic pressure occurring when the circulation is arrested by transient inflation of a balloon in the right atrium, is a measure of total venous capacitance. L-NMMA caused a dose-dependent increase in mean arterial pressure and a dose-dependent decrease in heart rate. MCFP rose from 6.6 +/- 0.2 to 7.6 +/- 0.2 mmHg at the highest L-NMMA dose. The effects of L-NMMA on MCFP were reversed with L-arginine. In an additional four rats, in which hexamethonium was administered to induce ganglionic blockade, L-NMMA (25 mg/kg) caused a similar increase in MCFP (4.1 +/- 0.6 to 5.0 +/- 0.7 mmHg, P = 0.22) during the ganglionic blocked state as during the control unblocked state. These findings suggest that nitric oxide, which is likely EDRF, reduces baseline venous tone.
- Subjects :
- Animals
Arginine analogs & derivatives
Arginine pharmacology
Blood Pressure drug effects
Coronary Circulation
Dose-Response Relationship, Drug
Ganglionic Blockers pharmacology
Hexamethonium
Hexamethonium Compounds pharmacology
Injections, Intravenous
Male
Rats
Rats, Sprague-Dawley
omega-N-Methylarginine
Endothelium, Vascular metabolism
Nitric Oxide metabolism
Vascular Resistance physiology
Veins physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0002-9513
- Volume :
- 265
- Issue :
- 1 Pt 2
- Database :
- MEDLINE
- Journal :
- The American journal of physiology
- Publication Type :
- Academic Journal
- Accession number :
- 8102035
- Full Text :
- https://doi.org/10.1152/ajpheart.1993.265.1.H47