Ba2+- and bupivacaine-sensitive background K+ conductances mediate rapid EPSP attenuation in oligodendrocyte precursor cells.
Glutamatergic transmission onto oligodendrocyte precursor cells (OPCs) may regulate OPC proliferation, migration and differentiation. Dendritic integration of excitatory postsynaptic potentials (EPSPs) is critical for neuronal functions, and mechanisms regulating dendritic propagation and summation of EPSPs are well understood. However, little is known about EPSP attenuation and integration in OPCs. We developed realistic OPC models for synaptic integration, based on passive membrane responses of OPCs obtained by simultaneous dual whole-cell patch-pipette recordings. Compared with neurons, OPCs have a very low value of membrane resistivity, which is largely mediated by Ba(2+)- and bupivacaine-sensitive background K(+) conductances. The very low membrane resistivity not only leads to rapid EPSP attenuation along OPC processes but also sharpens EPSPs and narrows the temporal window for EPSP summation. Thus, background K(+) conductances regulate synaptic responses and integration in OPCs, thereby affecting activity-dependent neuronal control of OPC development and function.
C.-C. Lien: Institute of Neuroscience, National Yang-Ming University, 155, Section 2, Li-Nong Street, Taipei 11221, Taiwan. cclien@ym.edu.tw.
Chu-Fang
CF
Chan
Tzu-Wei
TW
Kuo
Ju-Yun
JY
Weng
Yen-Chu
YC
Lin
Ting-Yu
TY
Chen
Jen-Kun
JK
Cheng
Cheng-Chang
CC
Lien
D000818:Animals; D001464:Barium / Q000494:pharmacology*; D002045:Bupivacaine / Q000494:pharmacology*; D019706:Excitatory Postsynaptic Potentials; D008297:Male; D058953:Neural Stem Cells / Q000378:metabolism / Q000502:physiology*; D009474:Neurons / Q000378:metabolism / Q000502:physiology; D009836:Oligodendroglia / Q000378:metabolism / Q000502:physiology*; D011188:Potassium / Q000378:metabolism*; D024661:Potassium Channels, Inwardly Rectifying / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000378:metabolism / Q000502:physiology
D024661:Potassium Channels, Inwardly Rectifying; D001464:Barium; D011188:Potassium; D002045:Bupivacaine