GABAB Receptor‐ and Metabotropic Glutamate Receptor‐Dependent Cooperative Long‐Term Potentiation of Rat Hippocampal GABAA Synaptic Transmission

• DOI: 10.1113/jphysiol.2003.049015
• Publication Date: 2003-09-09T02:32:18Z
• Authors: Christian Patenaude; C. Andrew Chapman; Sandrine Bertrand; Patrice Congar; Jean‐Claude Lacaille
• Keywords: LTP induction; Schaffer collateral; GABAB receptor

Repetitive stimulation of Schaffer collaterals induces activity-dependent changes in the strength polysynaptic inhibitory postsynaptic potentials (IPSPs) hippocampal CA1 pyramidal neurons that are dependent on parameters. In present study, we investigated effects two patterns, theta-burst (TBS) and 100 Hz tetani, pharmacologically isolated monosynaptic GABAergic responses adult cells. Tetanization with trains transiently depressed both early late IPSPs, whereas TBS induced long-term potentiation (LTP) IPSPs lasted at least 30 min. Mechanisms mediating this TBS-induced were examined using whole-cell recordings. The paired-pulse ratio currents (IPSCs) was not affected during LTP, suggesting presynaptic GABA release involved potentiation. Bath application GABAB receptor antagonist CGP55845 or group I/II metabotropic glutamate E4-CPG inhibited IPSC Preventing G-protein activation Ca2+ rise by injection GDP-beta-S BAPTA, respectively, abolished indicating a G-protein- Ca2+-dependent induction LTP. Finally paired-recordings, individual interneurons intracellular elicited solely short-term increases average unitary IPSCs These results indicate paradigm mimicking endogenous theta rhythm activates cooperative mechanisms GABABR, mGluR, G-proteins Ca2+, which lead to sustained GABAA synaptic transmission synapses may therefore contribute functional plasticity hippocampus.