Document Detail

Role of splanchnic constriction in governing the hemodynamic responses to gravitational stress in conscious dogs.
MedLine Citation:
PMID:  21512154     Owner:  NLM     Status:  MEDLINE    
Octreotide is a somatostatin analog that constricts the splanchnic circulation, thereby improving orthostatic tolerance. We tested the hypotheses that octreotide improves orthostatic tolerance by 1)increasing cardiac filling (right atrial) pressure via reductions in vascular capacity; 2) by causing an upward (i.e., cranial) shift of the hydrostatic indifferent point; and 3) by increasing arterial pressure via a reduction in total vascular conductance. Studies were carried out in acepromazine-sedated, hexamethonium-treated atrioventricular-blocked conscious dogs lightly restrained in lateral recumbency. Beat-by-beat cardiac output was held constant via computer-controlled ventricular pacing at rest and during 30 s of 30° head-up tilt. Octreotide (1.5 μg/kg iv) raised right atrial pressure by 0.5 mmHg and raised mean arterial pressure by 11 mmHg by reducing total vascular conductance (all P < 0.05). Right atrial pressure fell by a similar amount in response to tilting before and after octreotide, thus there was no difference in location of the hydrostatic indifferent point. These data indicate that octreotide improves orthostatic tolerance by decreasing total vascular conductance and by increasing cardiac filling pressure via a reduction in unstressed vascular volume and not by eliciting a cranial shift of the location of the hydrostatic indifferent point.
Brett J Wong; Don D Sheriff
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural     Date:  2011-04-21
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  111     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2011 Jul 
Date Detail:
Created Date:  2011-07-12     Completed Date:  2013-07-08     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  40-7     Citation Subset:  IM    
Department of Kinesiology, Kansas State University, Manhattan, Kansas, USA.
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MeSH Terms
Atrial Function, Right
Atrioventricular Block / physiopathology
Blood Pressure
Cardiac Output
Cardiac Pacing, Artificial
Conscious Sedation*
Hydrostatic Pressure
Octreotide / pharmacology
Orthostatic Intolerance / drug therapy,  etiology,  physiopathology*
Splanchnic Circulation* / drug effects
Stress, Physiological*
Tilt-Table Test
Time Factors
Vasoconstriction* / drug effects
Vasoconstrictor Agents / pharmacology
Grant Support
Reg. No./Substance:
0/Vasoconstrictor Agents; 83150-76-9/Octreotide

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

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