ATP-sensitive potassium channel opener iptakalim protects against MPP-induced astrocytic apoptosis via mitochondria and mitogen-activated protein kinase signal pathways

J Neurochem. 2007 Oct;103(2):569-79. doi: 10.1111/j.1471-4159.2007.04775.x. Epub 2007 Jul 17.

Abstract

Inhibition of astrocytic apoptosis has been regarded as a novel prospective strategy for treating neurodegenerative disorders such as Parkinson's disease. In the present study, we demonstrated that iptakalim (IPT), an ATP-sensitive potassium channel (K(ATP) channel) opener, exerted protective effect on MPP(+)-induced astrocytic apoptosis, which was reversed by selective mitochondrial K(ATP) channel blocker 5-hydroxydecanoate. Further study revealed that IPT inhibited glutathione (GSH) depletion, mitochondrial membrane potential loss and subsequent release of pro-apoptotic factors (cytochrome c and apoptosis-inducing factor (AIF), and c-Jun NH(2)-terminal kinase/mitogen-activated protein kinases (MAPK) phosphorylation induced by MPP(+). Meanwhile, extracellular signal-regulated kinase (ERK) 1/2 inhibitor PD98059 inhibited the protective effect of IPT on MPP(+)-induced astrocytic apoptosis. Furthermore, IPT could also activate ERK/MAPK and maintain increased phospho-ERK1/2 level after MPP(+) exposure. Taken together, these findings reveal for the first time that IPT protects against MPP(+)-induced astrocytic apoptosis via inhibition of mitochondria apoptotic pathway and regulating the MAPK signal transduction pathways by opening mitochondrial ATP-sensitive potassium (mitoK(ATP)) channels in astrocytes. And targeting K(ATP) channels expressed in astrocytes may provide a novel therapeutic strategy for neurodegenerative disorders.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects*
  • Astrocytes / drug effects*
  • Astrocytes / ultrastructure
  • Blotting, Western
  • Cells, Cultured
  • Cytochromes c / metabolism
  • Flow Cytometry
  • Glutathione / metabolism
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Membrane Potentials / drug effects
  • Mitochondria / drug effects
  • Mitochondria / physiology*
  • Mitogen-Activated Protein Kinases / drug effects
  • Mitogen-Activated Protein Kinases / physiology*
  • Nerve Tissue Proteins / metabolism
  • Phosphorylation
  • Propylamines / pharmacology*
  • Pyridinium Compounds / pharmacology*
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction / drug effects*

Substances

  • N-(1-methylethyl)-1,1,2-trimethylpropylamine
  • Nerve Tissue Proteins
  • Propylamines
  • Pyridinium Compounds
  • 1-(4-methoxyphenyl)pyridinium
  • Cytochromes c
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinases
  • Glutathione