Role of potassium channels in the relaxant effect of levosimendan in guinea pig tracheal preparations

eksert B., USTA C.

PHARMACOLOGICAL REPORTS, vol.61, no.2, pp.275-280, 2009 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 61 Issue: 2
  • Publication Date: 2009
  • Doi Number: 10.1016/s1734-1140(09)70032-5
  • Journal Name: PHARMACOLOGICAL REPORTS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.275-280
  • Keywords: levosimendan, potassium channel, guinea pig trachea, BRONCHIAL SMOOTH-MUSCLE, CALCIUM SENSITIZER, K+ CHANNEL, INODILATOR, CROMAKALIM, ARTERIES, DRUGS, CELLS, HEART
  • Akdeniz University Affiliated: Yes

Abstract

We investigated both the effect of levosimendan and the role of various potassium channels in carbachol-precontracted tracheal preparations samples obtained from guinea pig. The tracheas were cut into 0.5 cm wide rings and suspended in a 20 ml organ bath. Isometric tension was continuously measured with an isometric force transducer connected to a computer-based data acquisition system. Levosimendan or cromakalim produced concentration-dependent relaxation responses in guinea pig tracheal rings precontracted by carbachol. Incubation of guinea pig tracheal rings with the ATP-dependent potassium channel (K-ATP) blocker glibenclamide for 30 min significantly inhibited the relaxant responses to both levosimendan and cromakalim. The large conductance Ca2+-activated potassium channel (BKCa) blocker iberiotoxin also caused a significant inhibition on relaxant responses to levosimendan. However, incubation of the tracheal rings with the voltage-dependent potassium channel blocker 4-aminopyridine for 10 min did not cause significant alterations on relaxant responses to levosimendan. The present findings suggested that the relaxant effect induced by levosimendan might be partially due to K-ATP and BKCa in isolated guinea pig tracheal rings.

We investigated both the effect of levosimendan and the role of various potassium channels in carbachol-precontracted tracheal preparations samples obtained from guinea pig. The tracheas were cut into 0.5 cm wide rings and suspended in a 20 ml organ bath. Isometric tension was continuously measured with an isometric force transducer connected to a computer-based data acquisition system. Levosimendan or cromakalim produced concentration-dependent relaxation responses in guinea pig tracheal rings precontracted by carbachol. Incubation of guinea pig tracheal rings with the ATP-dependent potassium channel (K-ATP) blocker glibenclamide for 30 min significantly inhibited the relaxant responses to both levosimendan and cromakalim. The large conductance Ca2+-activated potassium channel (BKCa) blocker iberiotoxin also caused a significant inhibition on relaxant responses to levosimendan. However, incubation of the tracheal rings with the voltage-dependent potassium channel blocker 4-aminopyridine for 10 min did not cause significant alterations on relaxant responses to levosimendan. The present findings suggested that the relaxant effect induced by levosimendan might be partially due to K-ATP and BKCa in isolated guinea pig tracheal rings.