Presence of arteriovenous shunting in transplanted but not in native single kidney in the rat.
OBJECTIVE
We previously reported the presence of renal arteriovenous (A-V) shunting in rats subjected to renal transplant rejection, hydronephrosis and severe hypotension caused by bleeding. The question as to whether blood partially by-passes the renal cortex under certain conditions is still controversial and an alternative explanation for the findings has been vasodilatation. The aim of this investigation was to determine whether A-V shunting is part of the haemodynamic changes taking place after unilateral nephrectomy and if the sympathetic nervous system is involved.


METHODS
Unilateral nephrectomy was performed and radioactive microspheres (15.5 microm) were injected into the right remaining renal artery 30 min (n = 10), 24 h (n = 13) and 3 weeks (n = 14) later. The proportion of radioactivity in the lungs was considered to reflect A-V shunting in the kidney. Sham-operated animals (n = 30) and animals (n = 10) without previous sham operation, all with two kidneys, were used as controls. Isogenic renal transplantation (n = 10) was performed after bilateral nephrectomy to represent a denervated single kidney status.


RESULTS
Renal A-V shunting was significantly (p < 0.001) reduced 30 min and 3 weeks after unilateral nephrectomy compared with controls. In isogenically transplanted rats, A-V shunting was not reduced compared with sham-operated animals, and significantly (p < 0.001) greater compared with the reduced levels of shunting at all times after unilateral nephrectomy.


CONCLUSIONS
Reduced renal shunting of microspheres was observed after uninephrectomy and seems to require an intact renal innervation. It is likely that vasodilatation after unilateral nephrectomy and A-V shunting are two separate phenomena.
Nilsson
L
L
Department of Experimental Research and Department of Vascular and Renal Diseases, Lund University, University Hospital, Malmö, Sweden.
Sterner
G
G
Ekberg
H
H
D000818:Animals; D001164:Arteriovenous Fistula / Q000209:etiology*; D006084:Graft Rejection; D007668:Kidney / Q000098:blood supply* / Q000294:innervation; D016030:Kidney Transplantation; D008297:Male; D009392:Nephrectomy; D051381:Rats; D011920:Rats, Inbred WF; D012077:Renal Artery; D012079:Renal Circulation / Q000502:physiology; D012082:Renal Veins; D014664:Vasodilation / Q000502:physiology