Functional switching of GABAergic synapses by ryanodine receptor activation.
The role of the ryanodine receptor (RyR) in modifiability of synapses made by the basket interneurons onto the hippocampal CA1 pyramidal cells was examined in rats. Associating single-cell RyR activation with postsynaptic depolarization increased intracellular free Ca(2+) concentrations and reversed the basket interneuron-CA1 inhibitory postsynaptic potential into an excitatory postsynaptic potential. This synaptic transformation was accompanied by a shift of the reversal potential from that of chloride toward that of bicarbonate. This inhibitory postsynaptic potential-excitatory postsynaptic potential transformation was prevented by blocking RyR or carbonic anhydrase. Associated postsynaptic depolarization and RyR activation, therefore, changes GABAergic synapses from excitation filters to amplifier and, thereby, shapes information flow through the hippocampal network.
Sun
M K
MK
Laboratory of Adaptive Systems, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA. mksun@codon.nih.gov
Nelson
T J
TJ
Alkon
D L
DL
D000818:Animals; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D007736:Kynurenic Acid / Q000494:pharmacology; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D019837:Ryanodine Receptor Calcium Release Channel / Q000187:drug effects* / Q000502:physiology; D013569:Synapses / Q000187:drug effects* / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D018691:Excitatory Amino Acid Antagonists; D019837:Ryanodine Receptor Calcium Release Channel; D005680:gamma-Aminobutyric Acid; D007736:Kynurenic Acid