Activation of endogenous protein kinase C enhances currents through alpha 1 and alpha 2 glycine receptor channels.
The effects of Ca2+ /phospholipid dependent (PKC) phosphorylation on the current amplitudes of alpha 1 and alpha 2 glycine receptors expressed in Xenopus oocytes were examined by whole cell voltage clamp recording. In studies using phorbol esters, PKC phosphorylation has been shown to reduce glycine-induced currents. Endogenous PKC activation by pretreatment with serum, however, enhanced the currents to around 140% in both alpha 1 and alpha 2 glycine receptors. This effect was completely blocked by a specific PKC inhibitor, GF109203X. Instead, treatment with a potent PKC activator, 12-O-tetradecanoylphorbol-13-acetate (TPA) revealed a decrease in glycine-gated channel currents. Thus, the present results demonstrate that glycine receptor phosphorylation mediated by endogenous pathway of PKC activation potentiates glycine-induced currents and phorbol esters may have a direct action on glycine receptor channels independent of PKC activation.
Nishizaki
T
T
Department of Physiology, Kobe university School of Medicine, Japan.
Ikeuchi
Y
Y
D000818:Animals; D004789:Enzyme Activation / Q000502:physiology; D005998:Glycine / Q000494:pharmacology; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D011493:Protein Kinase C / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D018009:Receptors, Glycine / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014981:Xenopus
D007473:Ion Channels; D012333:RNA, Messenger; D018009:Receptors, Glycine; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D005998:Glycine