Isolated human and rat cerebral arteries constrict to increases in flow: Role of 20-HETE and TP receptors

Peter Toth, Bernadett Rozsa, Zsolt Springo, Tamas Doczi, Akos Koller

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Abstract

Elevation of intraluminal pressure increases vasomotor tone, which thought to have a substantial role in regulation of cerebral blood flow (CBF). Interestingly, responses of cerebral vessels to increases in flow varied and have not been studied in human cerebral arteries. We hypothesized that increases in flow elicit constrictions of isolated human and rat cerebral arteries and aimed to elucidate the underlying mechanisms. Human cerebral arteries and rat middle cerebral arteries constricted to increases in flow (P<0.05). Simultaneous increase in intraluminal flowpressure further reduced the diameter compared with pressure-induced changes (P<0.05), leading to constant estimated CBF. Flow-induced constrictions were abolished by HET0016 (inhibitor of synthesis of 20-hydroxyeicosatetraenoic acid (20-HETE) or inhibition of COXs or blocking TP (thromboxane A 2/prostaglandin H 2, receptors and attenuated by scavenging reactive oxygen species (ROS). Flow-enhanced ROS formation was significantly reduced by HET0016. In conclusion, in human and rat cerebral arteries (1) increases in flow elicit constrictions, (2) signaling mechanism of flow-induced constriction of cerebral arteries involves enhanced production of ROS, COX activity, and mediated by 20-HETE via TP receptors, and (3) we propose that simultaneous operation of pressure-and flow-induced constrictions is necessary to provide an effective autoregulation of CBF.

Original languageEnglish
Pages (from-to)2096-2105
Number of pages10
JournalJournal of Cerebral Blood Flow and Metabolism
Volume31
Issue number10
DOIs
Publication statusPublished - Oct 1 2011

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Keywords

  • COX
  • ROS
  • TP receptors
  • autoregulation
  • cytochrome P450 4A

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology
  • Cardiology and Cardiovascular Medicine

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