Synthesis and characterisation of NS13558: a new important tool for addressing KCa1.1 channel function ex vivo.

Abstract

Pharmacological activation of the large-conductance Ca(2+)-activated K(+) channel (KCa1.1) in the cardiac inner mitochondrial membrane has been found to protect the heart against ischemia reperfusion injuries. However, there are concerns about the selectivity of the pharmacological tools used to modulate the channel. Here, we address this issue by synthesising a methylated analogue of the tool KCa1.1 channel activator NS11021. The compound (NS13558) is designed as a structurally closely related and biologically inactive analogue of NS11021. NS13558 did not elicit any significant opening of cloned human KCa1.1 channels, but maintained comparable biological activity towards other cardiac ion channels as compared to NS11021. In isolated perfused rat hearts subjected to ischemia-reperfusion, infarct size was reduced from 29% in control to 7% in NS11021 treated hearts. In comparison, the inactive derivate of NS11021, i.e., NS13558, did not confer any cardioprotection, demonstrated by an infarct size identical to control hearts. This suggests that NS11021 exerts its primary effect through KCa1.1 channels, which indicates an important role of these channels in protection against ischemia-reperfusion injuries. Furthermore, the study demonstrates a novel way of combining an activator of the KCa1.1 channel (NS11021) and its structurally closely related inactive analogue NS13558 to address the functional role of KCa1.1 channels, and we believe these novel tools may constitute a valuable addition to understanding the functional role of KCa1.1 channels under physiological and pathophysiological conditions.

• Authors: Bo Hjorth Bentzen, Rune Wederkinck Andersen, Søren-Peter Olesen, Morten Grunnet, Antonio Nardi
• Journal: Naunyn-Schmiedeberg's archives of pharmacology (Naunyn Schmiedebergs Arch Pharmacol) Vol. 381 Issue 3 Pg. 271-83 (Mar 2010) ISSN: 1432-1912 [Electronic] Germany
• PMID: 19798481 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 1-(3,5-bis(trifluoromethyl)phenyl)-3-(4-bromo-2-(1H-tetrazol-5-yl)phenyl)thiourea
• Cardiotonic Agents
• KCNMA1 protein, human
• Large-Conductance Calcium-Activated Potassium Channel alpha Subunits
• NS13558
• Tetrazoles
• Thiourea

Topics

• Action Potentials (drug effects)
• Animals
• Cardiotonic Agents (chemical synthesis, pharmacology, therapeutic use)
• Cell Line
• Humans
• In Vitro Techniques
• Large-Conductance Calcium-Activated Potassium Channel alpha Subunits (agonists, biosynthesis)
• Male
• Molecular Structure
• Myocardial Infarction (etiology, metabolism, prevention & control)
• Myocardial Reperfusion Injury (complications, drug therapy, metabolism)
• Oocytes (metabolism)
• Patch-Clamp Techniques
• Perfusion
• Rats
• Rats, Sprague-Dawley
• Tetrazoles (chemical synthesis, chemistry, pharmacology, therapeutic use)
• Thiourea (analogs & derivatives, chemistry, pharmacology, therapeutic use)
• Transfection
• Xenopus laevis