Si. Myers et al., AUTOREGULATION OF RENAL AND SPLANCHNIC BLOOD-FLOW FOLLOWING INFRARENAL AORTIC CLAMPING IS MEDIATED BY NITRIC-OXIDE AND VASODILATOR PROSTANOIDS, Journal of Cardiovascular Surgery, 37(2), 1996, pp. 97-103
Objective. This study examines the hypothesis that nitric oxide and va
sodilator prostanoids contribute to the autoregulation of renal artery
and superior mesenteric artery (SMA) blood flow following infra-renal
aortic clamping. Experimental design. Renal and SMA artery blood flow
were measured in anesthetized rats, The rats received bolus injection
of saline carrier, L-NAME (25 mg/kg) or indomethacin (15 mg/kg) prior
to sham or infra-renal aortic occlusion. In vivo blood flow was measu
red 1, 30 and 60 minutes during aortic occlusion and 1, 30, and 60 min
utes following release of the aortic cross clamp. Results. Aortic occl
usion transiently increased SMA blood flow but did not alter renal art
ery blood flow, Aortic clamp release resulted in a 40% decrease in bot
h SMA and renal artery blood flow. L-NAME or indomethacin pretreatment
decreased both SMA. and renal artery blood now at 60 minutes followin
g infra-renal aortic occlusion, Indomethacin decreased SMA blood flow
at 1 minute following unclamping of the aorta and L-NAME decreased SMA
blood flow at 30 and 60 minutes following aortic clamp release. Both
L-NAME and indomethacin markedly decreased renal artery blood flow at
all time periods following aortic clamp release. Conclusions. These da
ta suggest that renal and splanchnic vascular beds utilize endogenous
vasodilator eicosanoids and nitric oxide to maintain blood flow during
cross clamping and unclamping of the infra-renal aorta.