Endothelial dysfunction impairs vascular neurotransmission in tail arteries

• Tipo: Artigo em Revista Científica Internacional
• Data: 2015

Autores

Joana B Sousa (Autor) Outra; Paula Fresco (Autor) FFUP; Carmen Diniz (Autor) FFUP

Revista

Título: Neurochemistry International

Vol. 80

Páginas: 7-13

ISSN: 0197-0186

Editora: Elsevier

Indexação

ISI Web of Knowledge - 5 Citações

Scopus - 7 Citações

Classificação Científica

FOS: Ciências médicas e da saúde > Medicina básica

Outras Informações

ID Authenticus: P-00A-1YC

DOI: 10.1016/j.neuint.2014.11.001

Abstract (EN): The present study intends to clarify if endothelium dysfunction impairs vascular sympathetic neurotransmission. Electrically-evoked tritium overflow (100 pulses/5 Hz) was evaluated in arteries (intact and denuded) or exhibiting some degree of endothelium dysfunction (spontaneously hypertensive arteries), pre-incubated with [H-3]-noradrenaline in the presence of enzymes (nitric oxide synthase (NOS); nicotinamide adenine dinucleotide phosphate (NADPH) oxidase: xanthine oxidase; cyclooxygenase; adenosine kinase) inhibitors and a nucleoside transporter inhibitor. Inhibition of endothelial nitric oxide synthase with L-NIO dihydrochloride reduced tritium overflow in intact arteries whereas inhibition of neuronal nitric oxide synthase with N omega-Propyl-L-arginine hydrochloride was devoid of effect showing that only endothelial nitric oxide synthase is involved in vascular sympathetic neuromodulation. Inhibition of enzymes involved in reactive oxygen species or prostaglandins production with apocynin and allopurinol or indomethacin. respectively, failed to alter tritium overflow. A facilitation or reduction of tritium overflow was observed in the presence of 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) or of 5-iodotubericidin, respectively, but only in intact arteries. These effects can be ascribed to a tonic inhibitory effect mediated by A(1) receptors. In denuded and hypertensive arteries, 7-(2-phenylethyl)-5-amino2-(2-furyl)-pyrazolo-(4,3-el-1,2,4-triazolo[1,5-c] pyrimidine (SCH 58261) reduced tritium overflow, suggesting the occurrence of a tonic activation of A2A receptors. When endogenous adenosine bioavailability was increased by the nucleoside transporter inhibitor, S-(4-Nitrobenzyl)-6-thioinosine, tritium overflow increased in intact, denuded and hypertensive arteries. Among the endothelium-derived substances studied that could alter vascular sympathetic transmission only adenosine/adenosine receptor mediated mechanisms were clearly impaired by endothelium injury/dysfunction.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 7