Myocardial contractile effects of L-arginine in the human allograft.
J Am Coll Cardiol
; 29(6): 1332-8, 1997 May.
Article
em En
| MEDLINE
| ID: mdl-9137232
ABSTRACT
OBJECTIVES:
In the present study, we investigated, in transplant recipients, whether L-arginine (L-arg) potentiates the myocardial contractile effects of receptor-mediated coronary endothelial stimulation. Moreover, because inducible nitric oxide synthase (iNOS) is frequently expressed in transplanted myocardium, we also performed intracoronary infusion of L-arg in the absence of receptor-mediated coronary endothelial stimulation to investigate whether similar left ventricular (LV) contractile effects could be induced by providing more substrate for iNOS.BACKGROUND:
Nitric oxide (NO), released from coronary endothelium after receptor-mediated stimulation by substance P (SP), affects vascular smooth muscle tone and modulates LV contractile performance. L-arg augments receptor-mediated endothelium-dependent coronary vasodilation in transplant recipients by increasing substrate availability for endothelial NO production.METHODS:
Sixteen transplant recipients were studied at the time of annual coronary angiography. In eight transplant recipients, microtip LV pressures were recorded before and during intracoronary (IC) SP (20 pmol/min) and after the addition of IC L-arg (160 mumol/min) to IC SP. In eight transplant recipients, microtip LV pressures were recorded before and during IC L-arg (160 mumol/min) alone, and in six of these patients, endomyocardial biopsy samples were obtained to detect the expression of iNOS gene by reverse transcription-polymerase chain reaction.RESULTS:
Addition of IC L-arg to IC SP induced a fall (mean +/- SEM) in LV peak systolic pressure (-16 +/- 4 mm Hg), which was larger (p < 0.01) than that observed during IC SP (-7 +/- 2 mm Hg). During IC L-arg alone, there was no change in LV peak systolic pressure despite the presence of iNOS mRNA in five of the six biopsy samples.CONCLUSIONS:
In transplant recipients, L-arg potentiates the paracrine myocardial contractile effects of receptor-mediated coronary endothelial stimulation, probably by providing more substrate for endothelial NO production. Despite the myocardial expression of iNOS gene, L-arg alone fails to elicit similar contractile effects.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Arginina
/
Endotélio Vascular
/
Transplante de Coração
/
Óxido Nítrico Sintase
/
Contração Miocárdica
/
Óxido Nítrico
Limite:
Female
/
Humans
/
Male
/
Middle aged
Idioma:
En
Revista:
J Am Coll Cardiol
Ano de publicação:
1997
Tipo de documento:
Article
País de afiliação:
Bélgica