Nitric oxide/soluble guanylyl cyclase signaling mediates depolarization-induced protection of rat mesencephalic dopaminergic neurons from MPP⁺ cytotoxicity

Neuroscience. 2013 Feb 12;231:206-15. doi: 10.1016/j.neuroscience.2012.11.044. Epub 2012 Dec 10.

Abstract

Neuronal electrical activity has been known to affect the viability of neurons in the central nervous system. Here we show that long-lasting membrane depolarization induced by elevated extracellular K(+) recruits nitric oxide (NO)/soluble guanylyl cyclase/protein kinase G signaling pathway, induces 8-nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP)-mediated protein S-guanylation, and confers dopaminergic neuroprotection. Treatment of primary mesencephalic cell cultures with 1-methyl-4-phenylpyridinium (MPP(+)) for 72 h decreased the number of dopaminergic neurons, whereas the cell loss was markedly inhibited by elevated extracellular concentration of K(+) (+40 mM). The neuroprotective effect of elevated extracellular K(+) was significantly attenuated by tetrodotoxin (a Na(+) channel blocker), amlodipine (a voltage-dependent Ca(2+) channel blocker), N(ω)-nitro-l-arginine methyl ester (l-NAME) (a nitric oxide synthase inhibitor), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) (a soluble guanylyl cyclase inhibitor), and KT5823 or Rp-8-bromo-β-phenyl-1,N(2)-ethenoguanosine 3',5'-cyclic monophosphorothioate (Rp-8-Br-PET-cGMPS) (protein kinase G inhibitors). Elevated extracellular K(+) increased 8-nitro-cGMP production resulting in the induction of protein S-guanylation in cells in mesencephalic cultures including dopaminergic neurons. In addition, exogenous application of 8-nitro-cGMP protected dopaminergic neurons from MPP(+) cytotoxicity, which was prevented by zinc protoporphyrin IX, an inhibitor of heme oxygenase-1 (HO-1). Zinc protoporphyrin IX also inhibited the neuroprotective effect of elevated extracellular K(+). On the other hand, KT5823 or Rp-8-Br-PET-cGMPS did not inhibit the induction of HO-1 protein expression by 8-nitro-cGMP, although these protein kinase G inhibitors abrogated the neuroprotective effect of 8-nitro-cGMP. These results suggest that protein S-guanylation (leading to HO-1 induction) as well as canonical protein kinase G signaling pathway plays an important role in NO-mediated, activity-dependent dopaminergic neuroprotection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 1-Methyl-4-phenylpyridinium / pharmacology
  • Animals
  • Cyclic GMP / analogs & derivatives
  • Cyclic GMP / pharmacology
  • Dopaminergic Neurons / drug effects
  • Dopaminergic Neurons / metabolism*
  • Enzyme Inhibitors / pharmacology
  • Guanylate Cyclase / metabolism*
  • Mesencephalon / metabolism*
  • NG-Nitroarginine Methyl Ester / pharmacology
  • Nitric Oxide / metabolism*
  • Nitric Oxide Donors / pharmacology
  • Rats
  • Receptors, Cytoplasmic and Nuclear / metabolism*
  • Signal Transduction / drug effects
  • Signal Transduction / physiology*
  • Soluble Guanylyl Cyclase
  • Thionucleotides / pharmacology

Substances

  • 8-nitroguanosine 3',5'-cyclic monophosphate
  • Enzyme Inhibitors
  • Nitric Oxide Donors
  • Receptors, Cytoplasmic and Nuclear
  • Thionucleotides
  • 8-bromoguanosino-3',5'-cyclic monophosphorothioate
  • 8-bromo-beta-phenyl-1,N(2)-ethenoguanosine 3',5'-cyclic monophosphorothioate
  • Nitric Oxide
  • Guanylate Cyclase
  • Soluble Guanylyl Cyclase
  • Cyclic GMP
  • 1-Methyl-4-phenylpyridinium
  • NG-Nitroarginine Methyl Ester