Venular constriction of submucosal arterioles induced by dextran sodium sulfate.
BACKGROUND
Leukocyte and platelet adherence in postcapillary venules has been speculated to induce constriction of closely paired arterioles. This mechanism was investigated in the current study, in a model of intestinal inflammation induced by dextran sodium sulfate (DSS; 5,000 molecular weight).


METHODS
Closely paired, parallel arterioles and venules in the submucosa of the mouse intestine were observed using fluorescent intravital microscopy. Arterioles in control mice were compared to arterioles in mice given 5% DSS in drinking water for 11 days.


RESULTS
DSS induced an inflammatory response in which fluorescently labeled leukocytes and platelets were observed adhering to venules. Arterioles constricted and flow decreased significantly when the arterioles were paired with venules having adherent leukocytes and platelets, although the decreases in flow and diameter appeared to be more dependent on platelet than leukocyte adherence. No significant constriction was observed in arterioles paired with venules having minimal platelet adherence. Inhibition of thromboxane with 100 mg/kg ozagrel induced a significant dilation of arterioles in DSS mice that was absent in control mice.


CONCLUSIONS
The results are consistent with a proposed mechanism in which thromboxane constricts submucosal arterioles when the arterioles are closely paired with platelet-bearing venules in DSS-induced inflammation.
Harris
Norman R
NR
Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, Louisiana, USA. nharr6@lsuhsc.edu
Whatley
Joseph R
JR
Carter
Patsy R
PR
Specian
Robert D
RD
D000818:Animals; D001160:Arterioles; D001792:Blood Platelets / Q000502:physiology*; D002448:Cell Adhesion; D016264:Dextran Sulfate / Q000494:pharmacology; D007249:Inflammation / Q000503:physiopathology; D007410:Intestinal Diseases / Q000276:immunology / Q000503:physiopathology*; D007413:Intestinal Mucosa / Q000098:blood supply*; D007962:Leukocytes / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D013931:Thromboxanes / Q000037:antagonists & inhibitors / Q000502:physiology; D014661:Vasoconstriction; D014699:Venules
D013931:Thromboxanes; D016264:Dextran Sulfate