Document Detail


Effect of portal hypertension on splenic blood flow, intrasplenic extravasation and systemic blood pressure.
MedLine Citation:
PMID:  12736184     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We have previously shown that intrasplenic fluid extravasation is important in controlling blood volume. We proposed that, because the splenic vein flows in the portal vein, portal hypertension would increase splenic venous pressure and thus increase intrasplenic microvascular pressure and fluid extravasation. Given that the rat spleen has no capacity to store/release blood, intrasplenic fluid extravasation can be estimated by measuring the difference between splenic arterial inflow and venous outflow. In anesthetized rats, partial ligation of the portal vein rostral to the junction with the splenic vein caused portal venous pressure to rise from 4.5 +/- 0.5 to 12.0 +/- 0.9 mmHg (n = 6); there was no change in portal venous pressure downstream of the ligation, although blood flow in the liver fell. Splenic arterial flow did not change, but the arteriovenous flow differential increased from 0.8 +/- 0.3 to 1.2 +/- 0.1 ml/min (n = 6), and splenic venous hematocrit rose. Mean arterial pressure fell (101 +/- 5.5 to 95 +/- 4 mmHg). Splenic afferent nerve activity increased (5.6 +/- 0.9 to 16.2 +/- 0.7 spikes/s, n = 5). Contrary to our hypothesis, partial ligation of the portal vein caudal to the junction with the splenic vein (same increase in portal venous pressure but no increase in splenic venous pressure) also caused the splenic arteriovenous flow differential to increase (0.6 +/- 0.1 to 1.0 +/- 0.2 ml/min; n = 8). The increase in intrasplenic fluid efflux and the fall in mean arterial pressure after rostral portal vein ligation were abolished by splenic denervation. We propose there to be an intestinal/hepatic/splenic reflex pathway, through which is mediated the changes in intrasplenic extravasation and systemic blood pressure observed during portal hypertension.
Authors:
Susan Kaufman; Jody Levasseur
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  284     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2003 Jun 
Date Detail:
Created Date:  2003-05-08     Completed Date:  2003-06-17     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R1580-5     Citation Subset:  IM    
Affiliation:
Department of Physiology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2. Susan.jacobs@ualberta.ca
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MeSH Terms
Descriptor/Qualifier:
Afferent Pathways / physiology
Animals
Blood Pressure / physiology*
Hypertension, Portal / physiopathology*
Ligation
Liver / blood supply
Male
Portal Vein / physiology
Rats
Rats, Long-Evans
Regional Blood Flow / physiology*
Spleen / blood supply*,  innervation
Splenic Artery / physiology

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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