Suppression of inhibitory synaptic potentiation by presynaptic activity through postsynaptic GABA(B) receptors in a Purkinje neuron.
At inhibitory synapses on a cerebellar Purkinje neuron, the depolarization caused by heterosynaptic climbing fiber activation induces long-lasting potentiation accompanied by an increase in GABA(A) receptor responsiveness. Here we show that activation of a presynaptic inhibitory interneuron during the conditioning postsynaptic depolarization suppresses the potentiation. The suppression is due to postsynaptic GABA(B) receptor activation by GABA released from presynaptic terminals. The results suggest that GABA(B) receptor activation decreases the activity of cAMP-dependent protein kinase through the G(i)/G(o) proteins. The presynaptic activity-dependent suppression of synaptic plasticity is a novel regulatory mechanism of synaptic efficacy at individual synapses and may contribute to the learning and computational ability of the cerebellar cortex.
Kawaguchi
S
S
Department of Biophysics, Graduate School of Science, Kyoto University, Japan.
Hirano
T
T
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003712:Dendrites / Q000187:drug effects / Q000378:metabolism; D004558:Electric Stimulation; D018755:GABA Agonists / Q000494:pharmacology; D058786:GABA-B Receptor Agonists; D058788:GABA-B Receptor Antagonists; D019204:GTP-Binding Proteins / Q000378:metabolism; D007395:Interneurons / Q000166:cytology / Q000378:metabolism; D007478:Iontophoresis; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D018408:Patch-Clamp Techniques; D017729:Presynaptic Terminals / Q000378:metabolism; D011689:Purkinje Cells / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000378:metabolism; D018080:Receptors, GABA-B / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism / Q000494:pharmacology
D018755:GABA Agonists; D058786:GABA-B Receptor Agonists; D058788:GABA-B Receptor Antagonists; D011963:Receptors, GABA-A; D018080:Receptors, GABA-B; D005680:gamma-Aminobutyric Acid; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D019204:GTP-Binding Proteins; D002118:Calcium