Document Detail


Age-dependent effects of gradual decreases in cerebral perfusion pressure on the neurochemical response in swine.
MedLine Citation:
PMID:  20232040     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: There is still a lack of knowledge on the age-dependent relation between a reduction in cerebral perfusion pressure (CPP) and compromised brain perfusion leading to excessive transmitter release and brain damage cascades. The hypothesis is that an age-dependent lower threshold of cerebral blood flow (CBF) autoregulation determines the amount and time course of transmitter accumulation. DESIGN AND SETTING: This was a prospective randomized, blinded animal study performed in a university laboratory involving eight newborn and 11 juvenile anesthetized pigs. INTERVENTION: Striatal dopamine, glutamate, glucose, and lactate were monitored by microdialysis. For CPP manipulation, the cisterna magna was infused with artificial cerebrospinal fluid to control intracranial pressure at the maintained arterial blood pressure (stepwise CPP decrease in 15-min stages to 50, 40, 30, and finally 0 mmHg). MEASUREMENTS AND MAIN RESULTS: Juvenile pigs showed a gradual decrease in CBF between 50 mmHg CPP (CPP-50) and 30 mmHg CPP (CPP-30), but a significant CBF reduction did not occur in newborn piglets until CPP-30 (P < 0.05). At CPP-30, brain oxidative metabolism was reduced only in juveniles, concomitantly with elevations in dopamine and glutamate levels (P < 0.05). In contrast, newborn piglets exhibited a delayed and blunted accumulated of transmitters and metabolites (P < 0.05). CONCLUSIONS: The lower limit of CBF autoregulation was associated with modifications in neurochemical parameters that clearly occurred before brain oxidative metabolism was compromised. Early indicators for mild to moderate hypoperfusion are elevated levels of lactate and dopamine, but elevated levels of glutamate appear to be an indicator of brain ischemia. The shift to the left of the lower autoregulatory threshold is mainly responsible for the postponed neurochemical response to decrements in the CPP in the immature brain.
Authors:
Bernd Walter; Kristina Aisenpreis; Harald G Fritz; Jens Soukup; Michael Eiselt; Reinhard Bauer
Publication Detail:
Type:  Journal Article     Date:  2010-03-16
Journal Detail:
Title:  Intensive care medicine     Volume:  36     ISSN:  1432-1238     ISO Abbreviation:  Intensive Care Med     Publication Date:  2010 Jun 
Date Detail:
Created Date:  2010-05-06     Completed Date:  2010-09-08     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7704851     Medline TA:  Intensive Care Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1067-75     Citation Subset:  IM    
Affiliation:
Institute of Molecular Cell Biology, Universitätsklinikum Jena, Friedrich Schiller University, 07745, Jena, Germany.
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MeSH Terms
Descriptor/Qualifier:
Age Factors
Animals
Animals, Newborn
Blood Pressure
Brain Chemistry / physiology*
Cerebrovascular Circulation / physiology*
Corpus Striatum / metabolism
Female
Intracranial Pressure / physiology*
Microdialysis
Prospective Studies
Random Allocation
Receptors, Neurotransmitter / metabolism*
Swine*
Chemical
Reg. No./Substance:
0/Receptors, Neurotransmitter

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


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