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Titolo:
Brain stem Po-2 and pH of the working heart-brain stem preparation during vascular perfusion with aqueous medium
Autore:
Wilson, RJA; Remmers, JE; Paton, JFR;
Indirizzi:
Univ Calgary, Dept Physiol & Med Biophys, Calgary, AB T2N 4N1, Canada UnivCalgary Calgary AB Canada T2N 4N1 ophys, Calgary, AB T2N 4N1, Canada Univ Bristol, Dept Physiol, Bristol BS8 1TD, Avon, England Univ Bristol Bristol Avon England BS8 1TD Bristol BS8 1TD, Avon, England
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY
fascicolo: 2, volume: 281, anno: 2001,
pagine: R528 - R538
SICI:
0363-6119(200108)281:2<R528:BSPAPO>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
RESPIRATORY RHYTHM GENERATION; PRE-BOTZINGER COMPLEX; CEREBRAL BLOOD-FLOW; GUINEA-PIG BRAIN; SPINAL-CORD; NEONATAL RATS; IN-VITRO; SYNAPTIC INHIBITION; PACEMAKER NEURONS; DEPTH PROFILES;
Keywords:
cardiovascular; respiration; breathing; eupnea;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
46
Recensione:
Indirizzi per estratti:
Indirizzo: Wilson, RJA Univ Calgary, Dept Med Physiol, 3330 Hosp Dr NW, Calgary, AB T2N 4N1, Canada Univ Calgary 3330 Hosp Dr NW Calgary AB Canada T2N 4N1 Canada
Citazione:
R.J.A. Wilson et al., "Brain stem Po-2 and pH of the working heart-brain stem preparation during vascular perfusion with aqueous medium", AM J P-REG, 281(2), 2001, pp. R528-R538

Abstract

The rat working heart-brain stem preparation (WHBP) is an in situ preparation having many of the advantages associated with in vitro preparations while retaining cardiovascular response functionality and an eupnoeic respiratory motor pattern. The preparation is perfused arterially with an aqueous medium having a much lower oxygen-carrying capacity than blood. To evaluate the efficacy of the artificial perfusion in providing adequate gas exchangewithin the brain stem, we used polarographic PO2 and pH microelectrodes todetermine the tissue PO2 and pH of the medulla oblongata at various depths. When the perfusate was equilibrated with 5% CO2 and 95% O-2, average tissue PO2 was 294 Torr and no hypoxic areas were encountered. Tissue pH was remarkably uniform throughout the tissue, and on average was only 0.04 +/- 0.02 pH units more acidic than that of the perfusate. Increasing the PCO2 of the perfusate increased tissue PO2 and decreased arterial resistance. Decreasing perfusate PCO2 (while keeping pH constant) decreased tissue PO2 and reduced the respiratory activity. These results suggest that arterial PCO2, independent of arterial pH, is an essential variable in determining both respiratory drive and cerebrovascular perfusion. We conclude that the medullaof the WHBP is oxygenated and within a physiological pH, which accounts for the eupneic pattern of respiratory motor activity it generates. Furthermore, this preparation may be a useful model for exploring mechanisms of central chemoreception as well as the dynamics of the cerebral vasculature responses following changes in blood gases.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/04/20 alle ore 12:30:50