Document Detail

Age-related changes in response of brain stem vessels to opening of ATP-sensitive potassium channels.
MedLine Citation:
PMID:  8996507     Owner:  NLM     Status:  MEDLINE    
BACKGROUND AND PURPOSE: This study was designed to determine regional differences and age-related changes in the contribution of ATP-sensitive potassium (KATP) channels to vasodilator responses in the brain stem circulation in vivo. METHODS: Changes in diameter of the basilar artery (baseline diameter, 270 +/- 5 microns [mean +/- SEM]), its large branch (112 +/- 5 microns), and its small branch (49 +/- 2 microns) in response to KATP channel openers levcromakalim and Y-26763 were measured through a cranial window in anesthetized adult (4 to 6 months) and aged (24 to 26 months) Sprague-Dawley rats. RESULTS: Topical application of levcromakalim and Y-26763 produced concentration-dependent vasodilation that was similar among the three vessel groups in adult rats. In aged rats, dilator responses of the branches, but not of the basilar artery, to the KATP channel openers were smaller than those in adult rats (P < .05). Glibenclamide, a selective KATP channel blocker, almost abolished this vasodilation in both groups of rats. Vasodilator responses to sodium nitroprusside were preserved in aged rats. CONCLUSIONS: In adult rats, there is no regional heterogeneity in vasodilator response to KATP channel openers in the brain stem circulation in vivo. In aged rats, although KATP channels are also functional in the brain stem circulation, dilator response of the microvessels but not of the large arteries to direct activation of KATP channels is impaired.
K Toyoda; K Fujii; Y Takata; S Ibayashi; T Kitazono; T Nagao; M Fujikawa; M Fujishima
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Stroke; a journal of cerebral circulation     Volume:  28     ISSN:  0039-2499     ISO Abbreviation:  Stroke     Publication Date:  1997 Jan 
Date Detail:
Created Date:  1997-02-07     Completed Date:  1997-02-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0235266     Medline TA:  Stroke     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  171-5     Citation Subset:  IM    
Department of Internal Medicine, Kyushu Dental College, Kitakyushu, Japan.
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MeSH Terms
Aging / physiology*
Analysis of Variance
Antihypertensive Agents
Basilar Artery / growth & development,  physiology*
Benzopyrans / pharmacology
Brain Stem / blood supply*,  growth & development
Ion Channel Gating
Muscle Development
Muscle, Smooth, Vascular / growth & development,  physiology
Nitroprusside / pharmacology
Potassium Channels / drug effects,  physiology*
Pyrroles / pharmacology
Rats, Sprague-Dawley
Vasodilation / drug effects
Vasodilator Agents / pharmacology
Reg. No./Substance:
0/Antihypertensive Agents; 0/Benzopyrans; 0/Potassium Channels; 0/Pyrroles; 0/Vasodilator Agents; 127408-31-5/Y 26763; 15078-28-1/Nitroprusside; 94470-67-4/Cromakalim

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