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The role of adenosine in the vascular adaptation of neonatal cerebral blood flow during hypotension.
Laudignon, N; Beharry, K; Farri, E; Aranda, J V.
  • Laudignon N; Developmental Pharmacology and Perinatal Research Unit, McGill University, Montreal, Canada.
J Cereb Blood Flow Metab ; 11(3): 424-31, 1991 May.
Article en En | MEDLINE | ID: mdl-2016349
ABSTRACT
This study investigated the potential role of adenosine in cerebral blood flow (CBF) regulation in the neonate during moderate and severe hypotension. Experiments were done in anesthetized, 1- to 3-day-old piglets. Regional CBF (determined by radiolabeled microsphere technique) and cerebral metabolic rate for O2 (CMRO2) were measured (a) during normotension and (b) during a 3-min period of moderate (58 +/- 9 mm Hg) or severe (36 +/- 7 mm Hg) hypotension produced by the inflation of a balloon catheter placed in the aortic root. Measurements of CBF and CMRO2 were performed successively after intracerebroventricular (i.c.v.) injections of vehicle (n = 17), the adenosine receptor blocker 8-phenyltheophylline (8-PT, 10 micrograms, n = 14), and the A2-receptor agonist 5'-N-(ethylcarboxamide)adenosine (NECA, 2 ng, n = 8). After i.c.v. administration of vehicle, none of the parameters studied was significantly altered by moderate hypotension, but severe hypotension decreased the total CBF (mean +/- SD) from 86 +/- 24 to 40 +/- 15 ml min-1 100 g-1 and CMRO2 from 3.2 +/- 0.8 to 1.8 +/- 1.0 ml min-1 100 g-1 (p less than 0.05). Administration of 8-PT did not alter these parameters during normotension, but significantly decreased CBF during moderate hypotension compared to postvehicle values (53 +/- 11 versus 81 +/- 12 ml min-1 100 g-1, p less than 0.05). This loss of autoregulation was completely reversed by NECA. During severe hypotension, 8-PT altered the CBF redistribution towards the brainstem.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
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Banco de datos: MEDLINE Asunto principal: Adenosina / Circulación Cerebrovascular / Hipotensión / Animales Recién Nacidos Límite: Animals Idioma: En Año: 1991 Tipo del documento: Article
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Banco de datos: MEDLINE Asunto principal: Adenosina / Circulación Cerebrovascular / Hipotensión / Animales Recién Nacidos Límite: Animals Idioma: En Año: 1991 Tipo del documento: Article