Characterization of Ca2+ channels involved in endothelin-1-induced contraction of rabbit basilar artery

J Cardiovasc Pharmacol. 2002 Sep;40(3):438-47. doi: 10.1097/00005344-200209000-00013.

Abstract

This study attempted to characterize Ca2+ channels involved in endothelin-1-induced contraction of rabbit basilar artery using whole-cell patch-clamp and measurement of intracellular free Ca2+ concentration. Endothelin-1 activates two types of Ca2+-permeable nonselective cation channels (NSCC-1 and NSCC-2) and a store-operated Ca2+ channel (SOCC) in addition to the voltage-operated Ca2+ channel (VOCC). These channels can be discriminated using Ca2+ channel blockers, SK&F 96365 and LOE 908. Tension study was conducted to clarify the Ca2+ channels involved in endothelin-1-induced contraction of basilar artery. Endothelin-1-induced basilar artery contraction is fully dependent on extracellular Ca2+ influx. Based on sensitivity to nifedipine, an L-type VOCC blocker, VOCCs have a minor role in endothelin-1-induced contraction. Both LOE 908 and SK&F 96365 inhibit endothelin-1-induced contraction in a concentration-dependent manner, and their combination abolished it. The median inhibitory concentrations of these blockers for endothelin-1-induced contraction correlated well with those of the endothelin-1-induced [Ca2+]i responses. Thus, the inhibitory action of these blockers on endothelin-1-induced contraction may be mediated by blockade of NSCC-1, NSCC-2, and the SOCC. Extracellular Ca2+ influx through NSCC-1, NSCC-2, and SOCC may be essential for endothelin-1-induced basilar artery contraction.

MeSH terms

  • Animals
  • Basilar Artery / drug effects*
  • Basilar Artery / physiology
  • Calcium Channel Blockers / pharmacology
  • Calcium Channels / physiology*
  • Dose-Response Relationship, Drug
  • Endothelin-1 / pharmacology*
  • In Vitro Techniques
  • Male
  • Muscle, Smooth, Vascular / cytology
  • Muscle, Smooth, Vascular / drug effects*
  • Muscle, Smooth, Vascular / physiology
  • Nifedipine / pharmacology
  • Patch-Clamp Techniques
  • Rabbits
  • Vasoconstriction / drug effects*
  • Vasoconstriction / physiology

Substances

  • Calcium Channel Blockers
  • Calcium Channels
  • Endothelin-1
  • Nifedipine