Central role of connexin40 in the propagation of electrically activated vasodilation in mouse cremasteric arterioles in vivo

Xavier F. Figueroa, David L. Paul, Alexander M. Simon, Daniel A. Goodenough, Kathy H. Day, David N. Damon, Brian R. Duling

Research output: Contribution to journalArticlepeer-review

134 Scopus citations

Abstract

When a short segment of arteriole is stimulated, vasomotor responses spread bidirectionally along the vessel axis purportedly via gap junctions. We used connexin40 knockout (Cx40-/-) mice to study vasomotor responses induced by 10-second trains of electrical stimulation (30 Hz, 1 ms, 30 to 50 V) in 2nd or 3rd order arterioles of the cremaster muscle. Measurements were made at the stimulation site (local) and at conducted sites (500, 1000, and 2000 μm upstream). In wild-type (Cx40+/+) animals, electrical stimulation evoked a local vasoconstriction and a conducted vasodilation that spread very rapidly along the vessel length without detectable decay. In Cx40-/- mice, the conducted dilation was converted into either vasoconstriction or a slowly developing vasodilation that decayed along the vessel length. Tetrodotoxin (TTX, 1 μmol/L) had no effect on the local vasoconstriction in either Cx40+/+ or Cx40-/- mice, but enhanced the conducted vasodilation in Cx40+/+ animals. In Cx40-/- mice, TTX abolished the conducted vasoconstriction when present and revealed a small vasodilation that decayed with distance. In the group of Cx40-/- mice in which electrical stimulation elicited a conducted vasodilation, TTX had no effect. Immunocytochemistry revealed Cx40 only in the endothelial layer of arterioles from Cx40+/+ mice and complete elimination of this connexin in the Cx40-/- animals. These results indicate that focal current stimulation causes vasoconstriction by a combination of perivascular nerve stimulation and smooth muscle activation. Moreover, electrical stimulation activates a nonneuronal, Cx40-dependent vasodilator response that spreads along the vessel length without decay.

Original languageEnglish (US)
Pages (from-to)793-800
Number of pages8
JournalCirculation research
Volume92
Issue number7
DOIs
StatePublished - Apr 18 2003

Keywords

  • Conducted response
  • Connexin40
  • Cremaster microcirculation
  • Electrical stimulation
  • Vasodilation

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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