RT Journal Article
SR Electronic
T1 Phorbol 12-Myristate 13-Acetate Potentiation of <em>N</em>-Methyl-<span class="sc">d</span>-aspartate-Induced Currents in Primary Cultured Cerebellar Granule Cells Is Mediated by Protein Kinase Cα
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 641
OP 649
DO 10.1124/jpet.109.153163
VO 330
IS 2
A1 Jason C. Reneau
A1 Mary E. Reyland
A1 Jonathan Phillips
A1 Carissa Kindy
A1 R. Lisa Popp
YR 2009
UL http://jpet.aspetjournals.org/content/330/2/641.abstract
AB We have previously reported that activation of protein kinase C (PKC) by phorbol 12-myristate 13-acetate (PMA) results in potentiation of N-methyl-d-aspartate-induced currents (INMDA)of receptors contained in primary cultured cerebellar granule cells (CGCs). The purpose of this study was to identify which PKC isoform(s) was responsible for this effect by using the whole-cell patch-clamp technique. Experiments were conducted on CGCs that expressed both the NR2A and NR2B NMDA receptor subunits as well as the PMA-sensitive PKC isoforms α, βI, βII, δ, ϵ, γ, and θ. As observed previously, N-methyl-d-aspartate-induced peak currents (IPk) were enhanced by a 12.5-min, 100 nM PMA exposure at 37°C under normal recording conditions. Potentiation of receptor function was not observed when extracellular Ca2+ was removed and 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid was present inside the cell. PMA-induced potentiation of IPk did not occur when PKCα-specific antibody was introduced into the cell via the recording electrode. However, in similar experiments with antibodies specific for PKCβII, δ, ϵ, γ, and θ, PMA potentiation of IPk was observed. Down-regulation of PMA-sensitive PKC isoforms by an overnight exposure of 100 nM PMA resulted in lack of potentiation by PMA that was rescued when catalytically active PKCα was introduced into the cell via the patch electrode. PMA potentiation of IPk was not recovered when catalytically active PKCβI, PKCβII, or PKCγ was introduced into the cell via the patch electrode. Collectively, our data provide strong evidence that PMA-enhanced function of native NMDA receptors expressed in primary cultured CGCs is mediated by activation of PKCα. The American Society for Pharmacology and Experimental Therapeutics