Faculty Collaboration Database

Inhibition of nitric oxide synthesis augments centrally induced sympathetic coronary vasoconstriction in cats. Am J Physiol 1994 Oct;267(4 Pt 2):H1272-8

Date

10/01/1994

Pubmed ID

7943371

DOI

10.1152/ajpheart.1994.267.4.H1272

Scopus ID

2-s2.0-0028152810 (requires institutional sign-in at Scopus site)   32 Citations

Abstract

The principal effect of sympathetic activation on the coronary circulation is an alpha-adrenergic coronary vasoconstriction in the presence of beta-receptor blockade. Secondary effects include vasodilation due to beta-adrenoceptor stimulation and alpha 2-mediated release of endothelium-derived relaxing factor (EDRF) from the coronary vascular endothelium. We hypothesized that blockade of nitric oxide synthesis (nitro-L-arginine methyl ester, L-NAME) would augment coronary vasoconstriction to sympathetic stimulation as a result of a decrease in alpha 2-mediated EDRF release. In chloralose-anesthetized cats, hypothalamic stimulation produced increases in coronary vascular resistance [maximum 26 +/- 9% (SE)] and arterial pressure (41 +/- 7%) and a decrease in coronary blood flow velocity (15 +/- 6%). L-NAME (3 mg/kg iv) increased baseline arterial pressure from 69 +/- to 92 +/- 7 mmHg (P < 0.05). After L-NAME, a greater increase in coronary vascular resistance (55 +/- 20%, P < 0.05), a decrease in coronary blood flow velocity (24 +/- 7%, P < 0.05), and a similar pressor response (34 +/- 7%) were observed in response to hypothalamic stimulation. L-Arginine reversed the effect of L-NAME on coronary vasoconstriction to hypothalamic stimulation. Similar increases in arterial pressure (from 73 +/- 3 to 91 +/- 5 mmHg, P < 0.05) with vasopressin (0.01-0.05 U/min) failed to enhance coronary vasoconstriction to activation in anterior hypothalamus. We conclude that inhibition of EDRF synthesis augments centrally induced sympathetic coronary vasoconstriction in the cat.

Author List

Goodson AR, Leibold JM, Gutterman DD

MESH terms used to index this publication - Major topics in bold

Animals
Arginine
Blood Flow Velocity
Blood Pressure
Cats
Coronary Vessels
Electric Stimulation
Female
Hypothalamus
Male
Muscle, Smooth, Vascular
NG-Nitroarginine Methyl Ester
Nitric Oxide
Sympathetic Nervous System
Time Factors
Vascular Resistance
Vasoconstriction
Vasodilation
Vasopressins
Vena Cava, Inferior