Abstract |
In the larger airways, the blood circulation forms a subepithelial (mucosal) and outer (peribronchial) microvascular network. This raises the possibility that blood flow in these two networks is regulated independently. We used hypoxemia as a stimulus to induce changes in tracheal mucosal blood flow normalized for systemic arterial pressure (Qtr n) measured with an inert soluble gas technique and total bronchial blood flow ( Qbr) and normalized Qbr (Qbrn) measured with an electromagnetic flow probe in anesthetized sheep. Fifteen minutes of hypoxemia [PO2 40 +/- 7 (SD) Torr] decreased mean Qtr n from 1.1 +/- 0.4 to 0.8 +/- 0.4 ml.min-1.mmHg-1.10(2) (-27%; P less than 0.05; n = 7) and increased mean Qbr n from 12.1 +/- 3.2 to 17.1 +/- 5.4 ml.min-1.mmHg-1.10(2) (+41%; P less than 0.05; n = 6). The rise in Qbr correlated with cardiac output (r = 0.68; P less than 0.05). Phentolamine pretreatment (0.1 mg/kg iv) blunted the hypoxemia-related decrease of mean Qtr n (-8%; P = NS). Tyramine (2.5 mg) applied locally to the trachea decreased mean Qtr n significantly after 30 and 45 min by 31 and 19%, respectively (P less than 0.05). 6-Hydroxydopamine (0.2 mg 4 times for 1 h locally applied) prevented the hypoxemia-induced as well as local tyramine-induced decrease in mean Qtr n (0 and 0%).(ABSTRACT TRUNCATED AT 250 WORDS)
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Authors | S Elsasser, W M Long, H J Baier, A D Chediak, A Wanner |
Journal | Journal of applied physiology (Bethesda, Md. : 1985)
(J Appl Physiol (1985))
Vol. 71
Issue 1
Pg. 223-8
(Jul 1991)
ISSN: 8750-7587 [Print] United States |
PMID | 1917746
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.)
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Chemical References |
- Oxidopamine
- Tyramine
- Phentolamine
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Topics |
- Animals
- Blood Pressure
(drug effects)
- Bronchi
(blood supply)
- Female
- Heart Rate
(drug effects)
- Hypoxia
(physiopathology)
- Mucous Membrane
(blood supply)
- Oxidopamine
(pharmacology)
- Phentolamine
(pharmacology)
- Pulmonary Gas Exchange
- Regional Blood Flow
(physiology)
- Respiratory System
(blood supply)
- Sheep
- Trachea
(blood supply)
- Tyramine
(pharmacology)
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