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Titolo:
Adrenergic vasoconstrictor activity in the cerebral circulation after inhibition of nitric oxide synthesis in conscious goats
Autore:
Fernandez, N; Martinez, MA; Monge, L; Garcia-Villalon, AL; Dieguez, G;
Indirizzi:
Univ Autonoma Madrid, Fac Med, Dept Fisiol, Madrid 28029, Spain Univ Autonoma Madrid Madrid Spain 28029 Dept Fisiol, Madrid 28029, Spain
Titolo Testata:
AUTONOMIC NEUROSCIENCE-BASIC & CLINICAL
fascicolo: 1-2, volume: 89, anno: 2001,
pagine: 16 - 23
SICI:
1566-0702(20010620)89:1-2<16:AVAITC>2.0.ZU;2-Y
Fonte:
ISI
Lingua:
ENG
Soggetto:
ARGININE METHYL-ESTER; BLOOD-FLOW; AWAKE GOATS; CONTRACTILE RESPONSES; SYNTHASE INHIBITION; RETE MIRABILE; IN-VIVO; ENDOTHELIUM; REACTIVITY; ARTERY;
Keywords:
cerebral blood flow; cerebrovascular resistance; cerebral vasoconstriction;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
42
Recensione:
Indirizzi per estratti:
Indirizzo: Dieguez, G Univ Autonoma Madrid, Fac Med, Dept Fisiol, Arzobispo Morcillo 2, Madrid 28029, Spain Univ Autonoma Madrid Arzobispo Morcillo 2 Madrid Spain 28029 n
Citazione:
N. Fernandez et al., "Adrenergic vasoconstrictor activity in the cerebral circulation after inhibition of nitric oxide synthesis in conscious goats", AUTON NEURO, 89(1-2), 2001, pp. 16-23

Abstract

The interaction between nitric oxide (NO) and adrenergic activity in the cerebral circulation was studied using conscious goats, where blood flow to one brain hemisphere (cerebral blood flow) was electromagnetically measured, and the effects of phentolamine and hexamethonium on cerebrovascular resistance were evaluated before (control) and after inhibition of NO synthesiswith N-W-nitro-L-arginine methyl ester (L-NAME). L-NAME (12 goats, 40 mg kg(-1) administered i.v.) reduced cerebral blood flow from 62 +/- 3 to 44 +/- 2 ml min(-1), increased mean systemic arterial pressure from 100 +/- 3 to126 +/- 4 mm Hg, decreased heart rate from 79 +/- 5 to 50 +/- 4 beats min(-1). and increased cerebrovascular resistance from 1.63 +/- 0.08 to 2.91 +/- 0.016 mm Hg ml(-1) min(-1) (an P < 0.01). These hemodynamic variables normalized 48-72 h after L-NAME administration. Phentolamine (six goats, 1 mg), injected into the cerebral circulation, increased cerebral blood flow without changing systemic arterial pressure, but its cerebrovascular effects were augmented for about 24 h after L-NAME. The decrements in cerebrovascular resistance induced by phentolamine, in mm Hg ml(-1) min(-1), were: under control, 0.42 +/- 0.05; immediately after L-NAME, 1.38 +/- 0.09 (P < 0.01 compared with control): by about 24 h after L-NAME, 0.71 +/- 0.09 (P < 0.05 compared with control); and by about 48 h after L-NAME, 0.40 +/- 0.07 (P > 0.05 compared with control). Hexamethonium (six goats, 0.5-1 mg kg(-1) lin-L i.v.) decreased mean systemic arterial pressure to about 75 mm Kg and caused tachycardia similarly before and after L-NAME, but the decrements in cerebrovascular resistance were augmented for about 24 h sfter L-NAME. The decrements in cerebrovascular resistance induced by hexamethonium. in mm Hg ml(-1) min(-1), were: under control, 0.61 +/- 0.09, immediately after L-NAME, 1.33 +/- 0.16 (P < 0.01 compared with control); by about 24 h after L-NAME, 1.18 +/- 0.10 (P < 0.01 compared with control); and by about 48 h after L-NAME, 0.99 +/- 0.10 (P > 0.05 compared with control). Therefore, these results suggest that adrenergic vasoconstrictor tone in cerebral vasculature may be augmented after inhibition of NO synthesis, and that this increment may contribute to the reduction of cerebral blood flow after inhibition of NO formation. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 31/03/20 alle ore 05:10:43