Intracellular control of GABAA-receptor responses in hippocampal neurons: role of phosphorylation.
Recent studies show that GABAA-receptors mediated responses in the hippocampal cells are suppressed upon increases in intracellular Ca2+ [Ca2+]i. A series of experiments were carried out to evaluate the physiological significance of this modulatory action of [Ca2+]i. We show that GABAA-responses are suppressed by a preceding NMDA application in hippocampal cells. Furthermore the suppressive effect is mediated via an increase in [Ca2+]i. Additional data reveal that NMDA application suppressed the GABAA response by initiating an Ca2+ dependent dephosphorylation process and the suppression is prevented by intracellular ATP-gamma-S or okadaic acid. Our study suggest that there interactions between the excitatory synaptic responses and the inhibitory synaptic responses may be effected with intracellular Ca2+ serving as a second messenger.
Chen
Q X
QX
Department of Pharmacology, State University of New York, Brooklyn 11203, USA.
Wong
R K
RK
D000818:Animals; D002118:Calcium / Q000378:metabolism; D006624:Hippocampus / Q000502:physiology*; D016202:N-Methylaspartate / Q000494:pharmacology; D010766:Phosphorylation; D011963:Receptors, GABA-A / Q000502:physiology*; D014357:Trypsin / Q000494:pharmacology
D011963:Receptors, GABA-A; D016202:N-Methylaspartate; D014357:Trypsin; D002118:Calcium