Document Detail

Vasopressin contributes to dynorphin modulation of hypoxic cerebrovasodilation.
MedLine Citation:
PMID:  9843806     Owner:  NLM     Status:  MEDLINE    
Because pial artery dilation during a 20- or 40-min hypoxic exposure was less than that observed during a 5- or 10-min exposure, stimulus duration determines the vascular response to hypoxia. Dynorphin (Dyn) modulates hypoxic pial dilation and contributes to decremented dilation during longer hypoxic exposures. This study was designed to determine whether vasopressin (VP) contributes to Dyn modulation of hypoxic pial dilation in newborn pigs equipped with a closed cranial window. Moderate (M) and severe (S) hypoxia (arterial PO2 approximately 35 and 25 mmHg, respectively) had no effect on cerebrospinal fluid VP during a 5-min exposure but increased its concentration during longer exposure periods. The VP antagonist [beta-mercapto-beta,beta-cyclopentamethylenepropionyl1,O-Me-Tyr2, Arg8]vasopressin (MEAVP) had no influence on pial dilation during the 5-min exposure but potentiated the 20- and 40-min M and S hypoxic exposure dilations: 21 +/- 2 vs. 29 +/- 3% and 23 +/- 2 vs. 33 +/- 2% for 20- and 40-min S hypoxic dilation before and after MEAVP. Topical VP during 5 min of hypoxia elicited dilation that was reversed to vasoconstriction during 20 min of S and 40 min of M and S hypoxia. Similarly, during 5 min of hypoxia, Dyn elicited dilation that was reversed to vasoconstriction during longer hypoxic periods. MEAVP blunted this Dyn-induced vasoconstriction. These data show that VP modulates hypoxic pial dilation in a stimulus duration-dependent manner and that VP contributes to the reversal of Dyn from a dilator to a constrictor during prolonged hypoxia. Finally, these data suggest that VP contributes to Dyn modulation of hypoxic cerebrovasodilation.
A Venteicher; W M Armstead
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  275     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1998 Dec 
Date Detail:
Created Date:  1999-02-01     Completed Date:  1999-02-01     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H2072-9     Citation Subset:  IM    
Departments of Anesthesia and Pharmacology, University of Pennsylvania and The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.
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MeSH Terms
Anoxia / physiopathology*
Arginine Vasopressin / analogs & derivatives,  pharmacology
Arteries / drug effects,  physiopathology
Blood Pressure / physiology
Cerebrovascular Circulation / drug effects*,  physiology
Drug Synergism
Dynorphins / pharmacology*
Gases / blood
Hormone Antagonists / pharmacology
Hydrogen-Ion Concentration
Pia Mater / blood supply
Time Factors
Vasodilation / drug effects*,  physiology
Vasopressins / antagonists & inhibitors,  physiology*
Reg. No./Substance:
0/Gases; 0/Hormone Antagonists; 0/vasopressin, 1-(2-mercapto-2,2-(cyclopentamethylene)propionic acid)-2-(O-methyl)Tyr-8-Arg-; 11000-17-2/Vasopressins; 113-79-1/Arginine Vasopressin; 74913-18-1/Dynorphins

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

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