Presence of depolarization-induced suppression of inhibition in a fraction of GABAergic synaptic connections in rat neocortical cultures.
Brief depolarization of postsynaptic neurons in hippocampus and cerebellum results in a transient depression of GABAergic inhibitory input, called "depolarization-induced suppression of inhibition" (DSI). We studied whether a similar phenomenon occurs in the rat neocortical neurons. Using patch-clamp technique in neocortical cell cultures, we examined the effects of a 5-second depolarization of postsynaptic neurons on evoked GABAergic inhibitory post-synaptic currents (IPSCs). We found that the depolarization evoked a suppression of IPSC amplitude in 6 out of 26 neuronal pairs tested. The suppression of IPSC amplitude lasted for approximately 70 seconds and was accompanied by changes of paired-pulse ratio and IPSC coefficient of variation (CV), which is suggestive of a presynaptic mechanism. These results are in agreement with previous observations in hippocampal cell cultures and suggest that neocortical neurons express DSI.
Storozhuk
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MV
A. A.Bogomoletz Institute of Physiology, Kiev, Ukraine. maksim@biph.kiev.ua
Ivanova
S Y
SY
Piomelli
D
D
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002478:Cells, Cultured; D004558:Electric Stimulation; D019579:Neocortex / Q000166:cytology / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D018408:Patch-Clamp Techniques; D051381:Rats; D018079:Receptors, GABA / Q000502:physiology*; D013569:Synapses / Q000502:physiology*
D018079:Receptors, GABA