The role of ERK activation in the neuronal excitability in the chronically compressed dorsal root ganglia.
We examined the roles of phosphorylation of extracellular signal-regulated protein kinases (pERK) in regulating the excitability of neurons in the dorsal root ganglion (DRG) after chronic compression. A chronic compression of DRG (CCD) induced a significant increase in pERK in intact L4/L5 DRGs of rats as assessed by Western blot analysis. The treatment of U0126, the mitogen-activated protein kinase (MAPK) kinase 1/2 inhibitor, suppressed excitability in CCD-injured DRG neurons but not in naïve DRG neurons. Furthermore, the inhibition of ERK signaling increased A-type fast inactivating potassium current. Taken together, the excitation of CCD neurons might be attributed to the CCD-induced activation of ERK, which suppressed the A-type fast inactivating potassium conductance in CCD neurons.
Zhang
Yili
Y
Department of Physiology, Second Military Medical University, Shanghai 200433, PR China.
Cai
Guojun
G
Ni
Xin
X
Sun
Jihu
J
D000818:Animals; D002908:Chronic Disease; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005260:Female; D005727:Ganglia, Spinal / Q000201:enzymology* / Q000503:physiopathology; D008026:Ligation; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009475:Neurons, Afferent / Q000201:enzymology*; D010523:Peripheral Nervous System Diseases / Q000201:enzymology* / Q000503:physiopathology; D010766:Phosphorylation; D015221:Potassium Channels / Q000378:metabolism; D011843:Radiculopathy / Q000201:enzymology / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015854:Up-Regulation / Q000502:physiology
D004791:Enzyme Inhibitors; D015221:Potassium Channels; D048049:Extracellular Signal-Regulated MAP Kinases