A role for heterocellular coupling and EETs in dilation of rat cremaster arteries

Iain N. McSherry, Shaun L. Sandow, William B. Campbell, J R Falck, Michael A. Hill, Kim A. Dora

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

Objective: The authors probed endothelium-dependent dilation and endothelial cell Ca2+ handling in myogenically active resistance arteries. Methods: First-order arteries were removed from rat cremaster muscles, cannulated, and pressurized (75 mmHg). Vessel diameter and endothelial cell Ca2+ were monitored using confocal microscopy, and arterial ultrastructure was determined using electron microscopy. Results: Acetylcholine (ACh) stimulated elevations and oscillations in endothelial cell Ca2+, and concentration-dependently dilated arteries with myogenic tone. NO-independent dilation was blocked by 35 mM K+. Combined IK Ca (1 μM TRAM-34) and SKCa (100 nM apamin) blockade partially inhibited NO-independent relaxations, with residual relaxations sensitive to BK Ca or cytochrome P-450 inhibition (100 nM iberiotoxin, and 20 μM 17-ODYA or 10 μM MS-PPOH). 11,12-EET stimulated iberiotoxin-sensitive dilation, but did not affect endothelial cell Ca2+. 15 mM K+ evoked dilation sensitive to inhibition of KIR (30 μM Ba2+) and Na+/K+ -ATPase (10 μM ouabain), whereas these blockers did not affect ACh-mediated dilations. Homo- and heterocellular gap junctions were identified in radial sections through arteries. Conclusion:These data suggest that rises in endothelial cell Ca2+ stimulate SKCa and IKCa channels, leading to hyperpolarization and dilation, likely due to electrical coupling. In addition, a component was unmasked following SKCa and IKCa blockade, attributable to activation of BKCa channels by cytochrome P-450 metabolites.

Original languageEnglish (US)
Pages (from-to)119-130
Number of pages12
JournalMicrocirculation
Volume13
Issue number2
DOIs
StatePublished - Mar 2006

Keywords

  • Ca -activated K channel
  • Calcium
  • EDHF
  • Endothelial cell

ASJC Scopus subject areas

  • Physiology
  • Molecular Biology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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