Document Detail

Atrial natriuretic factor increases splenic microvascular pressure and fluid extravasation in the rat.
MedLine Citation:
PMID:  11351034     Owner:  NLM     Status:  MEDLINE    
The spleen is an important site of atrial natriuretic factor (ANF)-induced fluid extravasation into the systemic lymphatic system. The mechanism underlying this process was studied in a blood-perfused (1 ml min(-1)) rat spleen using the double occlusion technique. To ensure that our observations were spleen specific, a similar protocol was repeated in the hindquarters. Rat ANF(1-28), infused into the splenic artery of anaesthetized male rats, caused a dose-dependent (0.3-59 pmol min(-1)) increase in microvascular pressure from 11.3 +/- 0.7 to 14.9 +/- 0.5 mmHg and in post-capillary resistance from 7.2 +/- 0.6 to 10.1 +/- 1.1 mmHg ml(-1). ANF elicited no change in splenic pre-capillary resistance or in hindquarter haemodynamics. Intrasplenic ANF (6.5 pmol min(-1)) caused a sustained increase in intrasplenic fluid efflux from 0.1 +/- 0.1 to 0.3 +/- 0.1 ml min(-1), and in capillary filtration coefficient (Kf) from 1.2 +/- 0.5 to 2.4 +/- 0.6 ml mmHg-1 min-1 (100 g tissue)-1. Mechanical elevation of splenic intravascular pressure (from 11.3 +/- 0.7 to 22.4 +/- 0.2 mmHg) significantly increased intrasplenic fluid extravasation (from 0.4 +/- 0.3 to 1.4 +/- 0.3 ml min(-1)). The natriuretic peptide receptor-C (NPRC)-specific agonist C-ANF(4-23) (12.5 and 125 pmol min(-1)) did not alter splenic intravascular pressure or pre-/post-capillary resistance. The ANF antagonist A71915 (8.3 and 83 pmol min-1), which blocks ANF-stimulated cGMP production via natriuretic peptide receptor-A (NPRA), inhibited the ANF-induced changes in splenic microvascular pressure and post-capillary resistance. It is concluded that ANF enhances the extravasation of isoncotic fluid from the splenic vasculature both by raising intrasplenic microvascular pressure (increased post-capillary resistance) and by increasing filtration area. The constrictive activity of ANF on the splenic vasculature is mediated through NPRA.
R Sultanian; Y Deng; S Kaufman
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of physiology     Volume:  533     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2001 May 
Date Detail:
Created Date:  2001-05-14     Completed Date:  2001-08-02     Revised Date:  2013-06-11    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  273-80     Citation Subset:  IM    
Department of Physiology, University of Alberta, Edmonton, Alberta, Canada T6G 2S2.
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MeSH Terms
Atrial Natriuretic Factor / pharmacology*
Blood Pressure / drug effects,  physiology
Body Fluids / physiology*
Dose-Response Relationship, Drug
Hindlimb / blood supply
Hypertension, Portal / physiopathology
Microcirculation / drug effects
Portal Vein / physiology
Rats, Long-Evans
Spleen / blood supply*
Splenic Artery / physiology
Vascular Resistance / drug effects
Water-Electrolyte Balance / drug effects*,  physiology
Reg. No./Substance:
0/atrial natriuretic peptide, rat; 85637-73-6/Atrial Natriuretic Factor

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