Two classes of spontaneous GABA-mediated miniature synaptic currents in cultured rat hippocampal neurons.
Amplitude and time course of spontaneous gamma-aminobutyric acid (GABA)-mediated miniature postsynaptic currents (MPSCs), recorded in cultured embryonic hippocampal neurons in presence of either tetrodotoxin (TTX) or increased external [Mg2+/Ca2+] ratio, revealed that they form two classes. The distribution of the most commonly recorded MPSCs was skewed both in terms of peak amplitude and rise-time (skew-MPSCs, mode: 70-120 pS). Another, less frequent class (mode: 1-3 nS) formed bell-shaped (bell-MPSCs) amplitude and rise-time distributions. MPSC initial slope did not correlate with rise time, indicating that smaller MPSCs were not electrotonically attenuated. Bell-MPSCs did not result from the integration of skew-MPSCs and both classes appeared to be composed of subunits.
Vautrin
J
J
Laboratory of Neurophysiology, National Institute of Neurological and Communicative Disorders and Stroke, National Institute of Health, Bethesda, MD 20892.
Schaffner
A E
AE
Baker
J L
JL
D000818:Animals; D002122:Calcium Chloride / Q000494:pharmacology; D002478:Cells, Cultured; D004622:Embryo, Mammalian; D005071:Evoked Potentials / Q000187:drug effects; D006624:Hippocampus / Q000502:physiology*; D015636:Magnesium Chloride / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D015636:Magnesium Chloride; D013779:Tetrodotoxin; D005680:gamma-Aminobutyric Acid; D002122:Calcium Chloride