Alteration of aortic function from streptozotocin-diabetic rats with Kilham's virus is associated with inducible nitric oxide synthase.
Kilham's rat virus (KRV) is a parvovirus commonly known to affect laboratory rats. Qualitative immunohistochemical analysis revealed that aorta isolated from KRV-infected streptozotocin (STZ)-induced diabetic adult rats expressed markedly greater levels of inducible nitric oxide synthase (iNOS) than aorta from KRV-infected controls. In contrast with the prevailing literature, nitric oxide-mediated endothelium-dependent relaxation to acetylcholine was not blunted by STZ-diabetes, but was comparable to relaxations of aorta from controls. However, with increasing ex vivo duration, a decreased response to acetylcholine was observed in the STZ-diabetic aorta. In addition, whereas contraction responses to phenylephrine were not significantly altered over time in control tissue, aorta from STZ-diabetic rats developed increased tensions. The data suggest that increased iNOS-derived nitric oxide masks expected acetylcholine-mediated relaxation deficits as a result of KRV-infection, and that the deficit is unmasked by iNOS turnover ex vivo.
Nangle
Matthew R
MR
Pain Management Research Institute, University of Sydney, Royal North Shore Hospital, St Leonards, NSW, Australia. stish@med.usyd.edu.au
Cotter
Mary A
MA
Cameron
Norman E
NE
D000818:Animals; D001013:Aorta, Thoracic / Q000201:enzymology / Q000276:immunology / Q000503:physiopathology*; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology / Q000276:immunology / Q000503:physiopathology* / Q000821:virology; D004730:Endothelium, Vascular / Q000201:enzymology / Q000276:immunology / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000502:physiology; D052247:Nitric Oxide Synthase Type II / Q000502:physiology*; D010322:Parvoviridae Infections / Q000201:enzymology / Q000276:immunology / Q000503:physiopathology*; D017992:Parvovirus / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D052247:Nitric Oxide Synthase Type II