Document Detail

Endothelial dysfunction augments myogenic arteriolar constriction in hypertension.
MedLine Citation:
PMID:  8244524     Owner:  NLM     Status:  MEDLINE    
To elucidate the underlying reason or reasons for the increased peripheral resistance in hypertension, we investigated the pressure-diameter relation--the myogenic response--of isolated, cannulated arterioles (approximately 50 microns) of cremaster muscle of 12-week-old Wistar-Kyoto (WKY) rats, spontaneously hypertensive rats (SHR), and normal Wistar (NW) rats. All arterioles constricted in response to step increases in perfusion pressure from 20 to 160 mm Hg. This constriction was, however, significantly enhanced from 60 to 160 mm Hg in arterioles of SHR compared with NW or WKY rats. For example, at 80 and 140 mm Hg, respectively, the normalized diameter (expressed as a percentage of the corresponding passive diameter of arterioles of SHR) was 11.8% and 27.6% (P < .05) less compared with those of WKY rats. Endothelium removal eliminated the enhanced pressure-induced tone in SHR. Similarly, indomethacin (10(-5) mol/L, sufficient to block prostaglandin synthesis) or SQ 29,548 (10(-6) mol/L), a thromboxane A2-prostaglandin H2 receptor blocker that inhibited vasoconstriction to the thromboxane agonist U46619, attenuated the enhanced pressure-diameter curve and reversed the blunted dilation to arachidonic acid in SHR. In contrast, the thromboxane A2 synthesis inhibitor CGS 13,080 (5 x 10(-6) mol/L) did not affect the increased pressure-induced tone or the reduced dilation to arachidonic acid in SHR. Thus, the present findings suggest that in early hypertension pressure-induced arteriolar constriction is increased. This seems to be due to an enhanced production of endothelium-derived constrictor factors, primarily prostaglandin H2.
A Huang; D Sun; A Koller
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Hypertension     Volume:  22     ISSN:  0194-911X     ISO Abbreviation:  Hypertension     Publication Date:  1993 Dec 
Date Detail:
Created Date:  1994-01-06     Completed Date:  1994-01-06     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  913-21     Citation Subset:  IM    
Department of Physiology, New York Medical College, Valhalla 10595.
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MeSH Terms
15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid
Acetylcholine / pharmacology
Arachidonic Acid / pharmacology
Arterioles / drug effects,  physiopathology*
Blood Pressure / physiology
Endothelium, Vascular / physiopathology*
Hydrazines / pharmacology
Hypertension / physiopathology*
Imidazoles / pharmacology
Indomethacin / pharmacology
Muscles / blood supply
Nitroprusside / pharmacology
Prostaglandin Endoperoxides, Synthetic / pharmacology
Prostaglandin H2
Prostaglandins / physiology
Prostaglandins H / physiology
Pyridines / pharmacology
Rats, Inbred SHR
Rats, Inbred WKY
Rats, Wistar
Receptors, Thromboxane / antagonists & inhibitors
Thromboxane A2 / antagonists & inhibitors
Thromboxane-A Synthase / antagonists & inhibitors
Vasoconstriction* / drug effects
Vasoconstrictor Agents / pharmacology
Grant Support
Reg. No./Substance:
0/Hydrazines; 0/Imidazoles; 0/Prostaglandin Endoperoxides, Synthetic; 0/Prostaglandins; 0/Prostaglandins H; 0/Pyridines; 0/Receptors, Thromboxane; 0/Vasoconstrictor Agents; 15078-28-1/Nitroprusside; 42935-17-1/Prostaglandin H2; 506-32-1/Arachidonic Acid; 51-84-3/Acetylcholine; 53-86-1/Indomethacin; 57576-52-0/Thromboxane A2; 76898-47-0/15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; 85691-74-3/pirmagrel; 98299-61-7/SQ 29548; EC Synthase

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