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Titolo:
Origins of heart rate variability: Autonomic blockade of large magnitude, transient bradycardia in conscious rabbits
Autore:
Roach, D; Thakore, E; Sheldon, R;
Indirizzi:
Univ Calgary, Fac Med, Hlth Sci Ctr, Cardiovasc Res Grp, Calgary, AB T2N 4N1, Canada Univ Calgary Calgary AB Canada T2N 4N1 s Grp, Calgary, AB T2N 4N1, Canada
Titolo Testata:
CANADIAN JOURNAL OF CARDIOLOGY
fascicolo: 2, volume: 17, anno: 2001,
pagine: 185 - 191
SICI:
0828-282X(200102)17:2<185:OOHRVA>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACOUSTIC STARTLE REFLEX; DYNAMICS;
Keywords:
autonomic nervous system; bradycardia; electrocardiography; heart rate; hemodynamics;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Citazioni:
28
Recensione:
Indirizzi per estratti:
Indirizzo: Sheldon, R Univ Calgary, Fac Med, Hlth Sci Ctr, Cardiovasc Res Grp, 3330 Hosp Dr NW, Calgary, AB T2N 4N1, Canada Univ Calgary 3330 Hosp Dr NW CalgaryAB Canada T2N 4N1 , Canada
Citazione:
D. Roach et al., "Origins of heart rate variability: Autonomic blockade of large magnitude, transient bradycardia in conscious rabbits", CAN J CARD, 17(2), 2001, pp. 185-191

Abstract

BACKGROUND: Heart period sequences are composed of recurrent, similarly shaped, physiologically meaningful, transient heart period structures. One such structure is a large magnitude transient bradycardia (LMTB), which resembles published reports of responses to alerting stimuli. Alerting responsesare sensitive to alpha(1)-adrenoceptor and cholinergic receptor blockade. OBJECTIVES: To determine whether LMTBs are related to alerting responses by assessing the response of rabbit LMTBs to autonomic inhibitors. ANIMALS AND METHODS: Using a Latin square, crossover design, six conscious, unsedated rabbits received placebo, intramuscular glycopyrrolate 0.05 mg/kg and intravenous prazosin 0.15 mg/kg, and six rabbits: received placebo, intravenous metoprolol 0.15 mg/kg and intravenous ICI-118,551 0.1 mg/kg. Heart period and blood pressure were continuously recorded, digitized and analyzed off-line. RESULTS: LMTBs were suppressed by 93% and 95% by alpha(1)-adrenergic and muscarinic blockade, respectively, but not by beta(1)-adrenergic or beta(2)-adrenergic blockade. The drugs altered none of the morphological parametersof shape, magnitude or duration, or any of the hypotensive features. CONCLUSIONS: LMTBs are similar to alerting responses; they are both expressed as transient hypotensive and bradycardic events that are markedly reduced by muscarinic and alpha I adrenoceptor blockade hut not by beta-adrenoceptor block ade. The presence of LMTBs may indicate ongoing, subtle changes in the laboratory environment.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/01/20 alle ore 17:43:08