Gadolinium and mechanotransduction of rat aortic baroreceptors

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

The cellular mechanisms enabling baroreceptors to transduce wall distortion into axonal discharge are unknown but might involve stretch- activated ion channels. Gadolinium (Gd3+, 10 μM) blocks stretch-activated channels in several preparations. Here we tested Gd3+ effects on discharge responses of 15 single-fiber baroreceptors in vitro. We simultaneously measured discharge, pressure, and aortic diameter at Gd3+ concentrations from 0.001 to 400 μM. High levels of Gd3+ added to a bicarbonate-buffered perfusate (Krebs) slightly shifted the pressure-discharge relation (<4 mmHg, n = 3, P = 0.01) without affecting slope or discharge frequency at threshold. Gd3+ in Krebs variably altered the pressure-diameter relation. Because 500 μM Gd3+ produced visible precipitate in Krebs, we tested Gd3+ in a simpler perfusate using N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES). Gd3+ in HEPES (n = 10) induced minor, but statistically significant, average increases in threshold (less than +5-7%) and no changes in gain. However, prolonged HEPES exposure alone (n = 2) produced similar shifts. Electron microscopy verified that Gd3+ diffused from the lumen to reach extracellular locations near baroreceptor endings. We conclude that 1) HEPES perfusate alone reversibly depresses baroreceptor discharge and 2) Gd3+ has no direct effects on baroreceptors. Thus it appears that aortic baroreceptor mechanotransduction must utilize a different class of stretch- activated ion channels.

Original languageEnglish (US)
Pages (from-to)H1415-H1421
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume262
Issue number5 31-5
DOIs
StatePublished - 1992

Keywords

  • N-2- hydroxyethylpiperazine-N'-2-ethanesulfonic acid
  • lanthanides
  • mechanoreceptors
  • pressoreceptors
  • sensory transduction
  • stretch-activated channels

ASJC Scopus subject areas

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

Fingerprint Dive into the research topics of 'Gadolinium and mechanotransduction of rat aortic baroreceptors'. Together they form a unique fingerprint.

  • Cite this