Korean Circ J.  2005 Dec;35(12):891-896. 10.4070/kcj.2005.35.12.891.

Effects of Nitric Oxide Synthesis Inhibition on the Depressor Response of Atrial Natriuretic Peptide in Rats

• Kim H
• Jeong SA
• Yoo IJ
• Kim JS
• Choi S
• Jun JY
• Yoon PJ
• Kim MY
• Hong SP
• Yeum CH

• KMID: 2227130
• DOI: http://doi.org/10.4070/kcj.2005.35.12.891

Abstract

BACKGROUND AND OBJECTIVES
It has been suggested that nitric oxide (NO) and atrial natriuretic peptide (ANP) share a final common pathway for vascular smooth muscle relaxation. The aim of the present study was to determine the role of NO on the hypotensive and vasorelaxant effects of ANP.
MATERIALS AND METHODS
Sprague-Dawley rats weighing 250-300 g each were anesthetized with thiopental (50 mg/kg IP). The femoral artery was cannulated and the arterial blood pressure and heart rate were continuously monitored in the anesthetized rats (n=19). ANP was administered into the jugular vein after L-NAME treatment. In vitro experiments were performed on intact and endothelium-denuded isolated thoracic aortic rings (n=51) in the presence of either L-NAME or methylene blue.
RESULTS
Intravenous administration of ANP (5 ug/kg bolus and 0.2 ug/kg/min infusion) caused a decrease in the mean arterial pressure. L-NAME-pretreatment (1 mg/kg) suppressed the depressor response of ANP. In vitro, the ANP caused a dose-dependent relaxation, and the relaxation response to ANP was attenuated by L-NAME (10-4 M). Endothelium removal or methylene blue (10-5 M) also inhibited the ANP-induced vascular relaxation.
CONCLUSION
These results suggest that the hypotensive and the vasorelaxant effect of ANP are, at least in part, NO-dependent.

Keyword

Atrial natriuretic peptides; Nitric oxide

MeSH Terms

Administration, Intravenous
Animals
Arterial Pressure
Atrial Natriuretic Factor
Endothelium
Femoral Artery
Heart Rate
Jugular Veins
Methylene Blue
Muscle, Smooth, Vascular
NG-Nitroarginine Methyl Ester
Nitric Oxide*
Rats*
Rats, Sprague-Dawley
Relaxation
Thiopental
Atrial Natriuretic Factor
Methylene Blue
NG-Nitroarginine Methyl Ester
Nitric Oxide
Thiopental