title: Oxygen sensing and conducted vasomotor responses in mouse cremaster arterioles in situ.
abstract: 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 (DeltaD = 16.0 +/- 4.9 microm) when changing from high (PO(2) = 242.5 +/- 13.3 mm Hg) to low (PO(2) = 22.5 +/- 4.8 mm Hg) oxygen tension as seen in the intact cremaster circulation (DeltaD = 18.7 +/- 1.0 microm). 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 (PO(2) = 23.3 +/- 5.7 mmHg) or high (PO(2) = 300.0 +/- 25.7 mm Hg) oxygen tension caused vasodilatation or -constriction locally and at a site 1,000 microm upstream (distantly). Glibenclamide blocker of ATP-sensitive K(+) channels inhibited vasodilatation and -constriction to low (PO(2) = 16.0 +/- 6.4 mm Hg) and high (PO(2) = 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.
authors.affiliation: Division of Renal & Vascular Research, Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200, Copenhagen, Denmark. anhngo@sund.ku.dk
authors.forename: Anh Thuc
authors.initials: AT
authors.lastname: Ngo
authors.forename: Lars Jørn
authors.initials: LJ
authors.lastname: Jensen
authors.forename: Mads
authors.initials: M
authors.lastname: Riemann
authors.forename: Niels-Henrik
authors.initials: NH
authors.lastname: Holstein-Rathlou
authors.forename: Christian
authors.initials: C
authors.lastname: Torp-Pedersen
mesh_terms: D000241:Adenosine / Q000378:metabolism; D058916:Adenosine A1 Receptor Antagonists; D058917:Adenosine A2 Receptor Antagonists; D000818:Animals; D001160:Arterioles / Q000293:injuries / Q000378:metabolism; D015687:Cell Hypoxia; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004912:Erythrocytes / Q000378:metabolism; D054086:KATP Channels / Q000037:antagonists & inhibitors / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008833:Microcirculation; D018715:Microscopy, Video; D009132:Muscles / Q000098:blood supply*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D010100:Oxygen / Q000097:blood / Q000378:metabolism*; D010477:Perfusion; D026902:Potassium Channel Blockers / Q000494:pharmacology; D043682:Receptor, Adenosine A1 / Q000378:metabolism; D043683:Receptors, Adenosine A2 / Q000378:metabolism; D012039:Regional Blood Flow; D014661:Vasoconstriction / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
chemical_list: D058916:Adenosine A1 Receptor Antagonists; D058917:Adenosine A2 Receptor Antagonists; D004791:Enzyme Inhibitors; D054086:KATP Channels; D026902:Potassium Channel Blockers; D043682:Receptor, Adenosine A1; D043683:Receptors, Adenosine A2; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D000241:Adenosine; D010100:Oxygen
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