Kainate-induced K+ efflux and plasma membrane depolarization in cultured cerebellar granule cells.
It is becoming increasingly evident that activation of ionotropic glutamate receptors leads to significant changes in cytosolic [K+] ([K+]c), a major determinant of the plasma membrane (PM) potential, Em. Since Em affects fluxes of key cations, such as Ca2+, it is important to precisely quantify [K+]c and Em in neurons exposed to glutamate receptor agonists. Here we studied the relationships between [K+]c and Em in primary cultures of cerebellar granule cells, and found that kainate elicits a rapid drop in [K+]c below 10 mM. Using patch electrodes containing 10 or 150 mM K+, we determined that kainate depolarizes the PM to -2 or -28 mV, respectively. Therefore, the actual PM depolarization elicited by kainate is much larger than that routinely measured with K+-rich electrodes.
Kiedrowski
L
L
The Psychiatric Institute, Department of Psychiatry, College of Medicine, The University of Illinois at Chicago, 60612, USA.
Mienville
J M
JM
D000818:Animals; D000831:Animals, Newborn; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D007608:Kainic Acid / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D011188:Potassium / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D018690:Excitatory Amino Acid Agonists; D011188:Potassium; D007608:Kainic Acid