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Titolo:
SYMPATHOVAGAL INTERPLAY IN THE CONTROL OF OVERALL BLOOD-PRESSURE VARIABILITY IN UNANESTHETIZED RATS
Autore:
FERRARI AU; FRANZELLI C; DAFFONCHIO A; PERLINI S; DIRIENZO M;
Indirizzi:
UNIV MILAN,CTR FISIOL CLIN & IPERTENS,CATTEDRA FISIOPATOL APPLICATA I-20122 MILAN ITALY OSPED MAGGIORE I-20122 MILAN ITALY CNR I-20122 MILAN ITALY POLITECN MILAN,CTR BIOINGN,LAB RIC CARDIOVASC I-20038 SEREGNO ITALY USSL 30,OSPED SEREGNO AZ,DIV CARDIORIBILITAZ I-20038 SEREGNO ITALY
Titolo Testata:
American journal of physiology. Heart and circulatory physiology
fascicolo: 6, volume: 39, anno: 1996,
pagine: 2143 - 2148
SICI:
0363-6135(1996)39:6<2143:SIITCO>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
HEART-RATE VARIABILITIES; CONSCIOUS RATS; ARTERIAL-PRESSURE; SYMPATHECTOMY;
Keywords:
HEART RATE VARIABILITY; HYPERTENSION; SPONTANEOUSLY HYPERTENSIVE RATS; SYMPATHECTOMY; CHOLINERGIC BLOCKADE; 6-HYDROXYDOPAMINE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
23
Recensione:
Indirizzi per estratti:
Citazione:
A.U. Ferrari et al., "SYMPATHOVAGAL INTERPLAY IN THE CONTROL OF OVERALL BLOOD-PRESSURE VARIABILITY IN UNANESTHETIZED RATS", American journal of physiology. Heart and circulatory physiology, 39(6), 1996, pp. 2143-2148

Abstract

The role of sympathetic and parasympathetic influences in the controlof overall blood pressure variability was studied in chronically instrumented, freely behaving Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) subjected to sympathectomy by 6-hydroxydopamine (100 mu g/kg ip) twice in 1 wk (effectiveness verified by abolition ofpresser and tachycardic response to tyramine, 150 mg/kg iv) and/or tocholinergic blockade by atropine (0.7 mg/kg iv). Overall heart rate and blood pressure variabilities were measured as variation coefficients computed beat to beat on 90-min blood pressure recordings. As compared with the vehicle-treated controls, sympathectomized rats had much larger blood pressure variability (WKY, +61%, SHR, +86%, both P < 0.01). Cholinergic blockade superimposed to sympathectomy caused heart ratevariability to markedly fall and the already augmented blood pressurevariability to further rise 47% in WKY and 28% in SHR (both P < 0.01). Prolonged observation of the animals revealed the systematic occurrence of rapid blood pressure falls occurring at the onset of locomotor activity, accounting for a substantial fraction of the sympathectomy-related increase in blood pressure variability. It is concluded that 1)under undisturbed daily life conditions, sympathetic influences oppose blood pressure variations, presumably by adjusting their vasoconstrictor influences to compensate for the metabolic vasodilation occurringin functionally active tissues; 2) when sympathetic vascular control is lost, vagally mediated heart rate variations oppose the rise in blood pressure variability, possibly via rapid changes in cardiac output that partly offset the fluctuations in total peripheral resistance; and 3) chronic hypertension fails to alter these cardiovascular regulatory mechanisms.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/11/20 alle ore 09:54:26