Abstract
The relative roles of neural and pressure gradient factors, causing a fall or maintenance of bronchial blood flow in exercising sheep, are unknown. These were examined in sheep prepared under thiopentone/isoflurane general anaesthesia with a pulsed Doppler probe mounted on the bronchial artery, and aortic pressure (Pa) catheter in superficial cervical artery. After recovery, Swan-Ganz catheters were inserted under local anaesthesia into the pulmonary artery. Bronchial flow and conductance (Qbr, Cbr), and pressure gradients (Pg; i.e. aortic minus right atrial, Pg_RAP; pulmonary artery, Pg_Ppa; and, left atrial (wedge) Pg_LAP) were derived from continuous records, after switching between downstream sites during and after moderately severe treadmill exercise (3.8km.h-1, for 1.7min, 6min recovery). The protocol was repeated after combined α1,α2-adrenoceptor/ cholinoceptor blockade using phentolamine methanesulfonate and methscopolamine bromide. Bronchial flow fell in both receptor intact (INT) and (BL) blocked state. Pa rose in INT, but downstream pressures rose only 3.7 (RAP), 2.8 (Ppa) and 2.0 (LAP) mmHg (P for each <0.05) in both INT and BL. Pg_RAP and Pg_Ppa did not rise, but Pg_LAP rose 4.0 mmHg (P < 0.05). In BL, Pa fell, as did Pg_RAP (7.0 mmHg, P < 0.05), Pg_Ppa (8.9 mmHg, P < 0.001), but Pg_LAP did not change. Thus, downstream pressures change by small amounts, and pressure gradients to RAP and Ppa sites do not change during moderately severe exercise in normal sheep. The fall in Qbr in INT is due to neural factors, but in BL is due to a fall in Pg. The relative rise in Pg_LAP in both INT and BL favours redistribution within total Qbr to the pulmonary capillary/vein/left atrium site.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 309-313 |
| Number of pages | 5 |
| Journal | Archives of Physiology and Biochemistry |
| Volume | 111 |
| Issue number | 4 |
| DOIs | |
| State | Published - Oct 1 2003 |
| Externally published | Yes |
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Keywords
- Bronchial blood flow
- Exercise
- Pressure gradients
- Sheep
ASJC Scopus subject areas
- Physiology
- Physiology (medical)
Cite this
Analysis of bronchovascular downstream blood pressure changes in exercising sheep. / Quail, A.; Cottee, D.; McLeod, D.; Blake, R.; Bishop, Robert; McIlveen, S.; White, S.
In: Archives of Physiology and Biochemistry, Vol. 111, No. 4, 01.10.2003, p. 309-313.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Analysis of bronchovascular downstream blood pressure changes in exercising sheep
AU - Quail, A.
AU - Cottee, D.
AU - McLeod, D.
AU - Blake, R.
AU - Bishop, Robert
AU - McIlveen, S.
AU - White, S.
PY - 2003/10/1
Y1 - 2003/10/1
N2 - The relative roles of neural and pressure gradient factors, causing a fall or maintenance of bronchial blood flow in exercising sheep, are unknown. These were examined in sheep prepared under thiopentone/isoflurane general anaesthesia with a pulsed Doppler probe mounted on the bronchial artery, and aortic pressure (Pa) catheter in superficial cervical artery. After recovery, Swan-Ganz catheters were inserted under local anaesthesia into the pulmonary artery. Bronchial flow and conductance (Qbr, Cbr), and pressure gradients (Pg; i.e. aortic minus right atrial, Pg_RAP; pulmonary artery, Pg_Ppa; and, left atrial (wedge) Pg_LAP) were derived from continuous records, after switching between downstream sites during and after moderately severe treadmill exercise (3.8km.h-1, for 1.7min, 6min recovery). The protocol was repeated after combined α1,α2-adrenoceptor/ cholinoceptor blockade using phentolamine methanesulfonate and methscopolamine bromide. Bronchial flow fell in both receptor intact (INT) and (BL) blocked state. Pa rose in INT, but downstream pressures rose only 3.7 (RAP), 2.8 (Ppa) and 2.0 (LAP) mmHg (P for each <0.05) in both INT and BL. Pg_RAP and Pg_Ppa did not rise, but Pg_LAP rose 4.0 mmHg (P < 0.05). In BL, Pa fell, as did Pg_RAP (7.0 mmHg, P < 0.05), Pg_Ppa (8.9 mmHg, P < 0.001), but Pg_LAP did not change. Thus, downstream pressures change by small amounts, and pressure gradients to RAP and Ppa sites do not change during moderately severe exercise in normal sheep. The fall in Qbr in INT is due to neural factors, but in BL is due to a fall in Pg. The relative rise in Pg_LAP in both INT and BL favours redistribution within total Qbr to the pulmonary capillary/vein/left atrium site.
AB - The relative roles of neural and pressure gradient factors, causing a fall or maintenance of bronchial blood flow in exercising sheep, are unknown. These were examined in sheep prepared under thiopentone/isoflurane general anaesthesia with a pulsed Doppler probe mounted on the bronchial artery, and aortic pressure (Pa) catheter in superficial cervical artery. After recovery, Swan-Ganz catheters were inserted under local anaesthesia into the pulmonary artery. Bronchial flow and conductance (Qbr, Cbr), and pressure gradients (Pg; i.e. aortic minus right atrial, Pg_RAP; pulmonary artery, Pg_Ppa; and, left atrial (wedge) Pg_LAP) were derived from continuous records, after switching between downstream sites during and after moderately severe treadmill exercise (3.8km.h-1, for 1.7min, 6min recovery). The protocol was repeated after combined α1,α2-adrenoceptor/ cholinoceptor blockade using phentolamine methanesulfonate and methscopolamine bromide. Bronchial flow fell in both receptor intact (INT) and (BL) blocked state. Pa rose in INT, but downstream pressures rose only 3.7 (RAP), 2.8 (Ppa) and 2.0 (LAP) mmHg (P for each <0.05) in both INT and BL. Pg_RAP and Pg_Ppa did not rise, but Pg_LAP rose 4.0 mmHg (P < 0.05). In BL, Pa fell, as did Pg_RAP (7.0 mmHg, P < 0.05), Pg_Ppa (8.9 mmHg, P < 0.001), but Pg_LAP did not change. Thus, downstream pressures change by small amounts, and pressure gradients to RAP and Ppa sites do not change during moderately severe exercise in normal sheep. The fall in Qbr in INT is due to neural factors, but in BL is due to a fall in Pg. The relative rise in Pg_LAP in both INT and BL favours redistribution within total Qbr to the pulmonary capillary/vein/left atrium site.
KW - Bronchial blood flow
KW - Exercise
KW - Pressure gradients
KW - Sheep
UR - http://www.scopus.com/inward/record.url?scp=14344264096&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=14344264096&partnerID=8YFLogxK
U2 - 10.1080/13813450312331337469
DO - 10.1080/13813450312331337469
M3 - Article
C2 - 15764061
AN - SCOPUS:14344264096
VL - 111
SP - 309
EP - 313
JO - Archives of Physiology and Biochemistry
JF - Archives of Physiology and Biochemistry
SN - 1381-3455
IS - 4
ER -