Oxygen sensing and conducted vasomotor responses in mouse cremaster arterioles in situ

TY - JOUR

T1 - Oxygen sensing and conducted vasomotor responses in mouse cremaster arterioles in situ

AU - Ngo, Thuc Anh

AU - Jensen, Lars Jørn

AU - Riemann, Mads Achen

AU - von Holstein-Rathlou, Niels-Henrik

AU - Torp-Pedersen, Christian Tobias

PY - 2010/6

Y1 - 2010/6

N2 - This study examines mechanisms by which changes in tissue oxygen tension elicit vasomotor responses and whether localized changes in oxygen tension initiates conducted vasomotor responses in mouse cremaster arterioles. Intravital microscopy was used to visualize the mouse cremaster microcirculation. The cremaster was superfused with Krebs' solution with different oxygen tensions, and a gas exchange chamber was used to induce localized changes in oxygen tension. In arterioles where red blood cells were removed by buffer perfusion, arterioles responded with same magnitudes of vasodilatation (ΔD=16.0±4.9 μm) when changing from high (PO 2=242.5±13.3 mm Hg) to low (PO2=22.5±4.8 mm Hg) oxygen tension as seen in the intact cremaster circulation (ΔD=18.7±1.0 μm). Blockade of NO synthases by L-NAME and adenosine receptors by DPCPX had no effects on vasomotor responses to low or high oxygen. Induction of localized low (PO2=23.3±5.7 mmHg) or high (PO2=300.0±25.7 mm Hg) oxygen tension caused vasodilatation or -constriction locally and at a site 1,000 μm upstream (distantly). Glibenclamide blocker of ATP-sensitive K+ channels inhibited vasodilatation and -constriction to low (PO2=16.0±6. 4 mm Hg) and high (PO2=337.4±12.8 mm Hg) oxygen tension. 1) ATP-sensitive K+ channels seem to mediate, at least in part, vasodilatation and vasoconstriction to low and high oxygen tension; 2) Red blood cells are not necessary for inducing vasodilatation and vasoconstriction to low or high oxygen tension; 3) localized changes in the oxygen tension cause vasomotor responses, which are conducted upstream along arterioles in mouse cremaster microcirculation.

AB - This study examines mechanisms by which changes in tissue oxygen tension elicit vasomotor responses and whether localized changes in oxygen tension initiates conducted vasomotor responses in mouse cremaster arterioles. Intravital microscopy was used to visualize the mouse cremaster microcirculation. The cremaster was superfused with Krebs' solution with different oxygen tensions, and a gas exchange chamber was used to induce localized changes in oxygen tension. In arterioles where red blood cells were removed by buffer perfusion, arterioles responded with same magnitudes of vasodilatation (ΔD=16.0±4.9 μm) when changing from high (PO 2=242.5±13.3 mm Hg) to low (PO2=22.5±4.8 mm Hg) oxygen tension as seen in the intact cremaster circulation (ΔD=18.7±1.0 μm). Blockade of NO synthases by L-NAME and adenosine receptors by DPCPX had no effects on vasomotor responses to low or high oxygen. Induction of localized low (PO2=23.3±5.7 mmHg) or high (PO2=300.0±25.7 mm Hg) oxygen tension caused vasodilatation or -constriction locally and at a site 1,000 μm upstream (distantly). Glibenclamide blocker of ATP-sensitive K+ channels inhibited vasodilatation and -constriction to low (PO2=16.0±6. 4 mm Hg) and high (PO2=337.4±12.8 mm Hg) oxygen tension. 1) ATP-sensitive K+ channels seem to mediate, at least in part, vasodilatation and vasoconstriction to low and high oxygen tension; 2) Red blood cells are not necessary for inducing vasodilatation and vasoconstriction to low or high oxygen tension; 3) localized changes in the oxygen tension cause vasomotor responses, which are conducted upstream along arterioles in mouse cremaster microcirculation.

U2 - 10.1007/s00424-010-0837-x

DO - 10.1007/s00424-010-0837-x

M3 - Journal article

C2 - 20383716

SN - 0031-6768

VL - 460

SP - 41

EP - 53

JO - Pflügers Archiv: European Journal of Physiology

JF - Pflügers Archiv: European Journal of Physiology

IS - 1

ER -