These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


PUBMED FOR HANDHELDS

Search MEDLINE/PubMed


  • Title: Reverberation of chloride-dependent synaptic potentials in the rat entorhinal cortex in vitro.
    Author: Lopantsev V, Avoli M.
    Journal: Neurosci Lett; 1996 May 24; 210(1):5-8. PubMed ID: 8762178.
    Abstract:
    The spontaneous activity generated by rat entorhinal neurons during application of 4-aminopyridine (4AP; 50 microM) was studied with intracellular and extracellular field-potential recordings in an vitro slice preparation. Long-lasting depolarizations (LLDs) with amplitudes of 15 +/- 7.6 mV (mean +/- SD; n = 14) and durations of 1.65 +/- 0.77 s (n = 14) occurred at 0.036 +/- 0.01/s (n = 14). Each LLD was followed by a rhythmic sequence of depolarizing potentials (up to 22 events) with amplitudes of 4-30 mV, durations of 40-500 ms and frequency of 0.9 +/- 0.2/s (n = 14). These intracellular potentials were mirrored by negative-going field potentials, suggesting that they represented synchronous events. Membrane input resistance decreased by 79-86% during both LLDs and subsequent rhythmic depolarizations. Intracellular injection of steady depolarizing or hyperpolarizing current modified the amplitude of these potentials in a similar manner: the reversal potential of the LLDs and of the rhythmic depolarizations was -66.4 +/- 4 mV and -67.9 +/- 3.2 mV, respectively (n = 7). Intracellular injection of Cl- increased the amplitude of both types of potentials. Spontaneous LLDs continued to occur during application of the non-N-methyl-D-aspartate (NMDA) receptor antagonist 6-cyano-7-nitro-quinoxaline-2,3-dione (10 microM), a procedure that abolished the subsequent rhythmic depolarizations (n = 3). LLDs were blocked by further addition of the gamma-aminobutyric acid (GABA)A receptor antagonist bicuculline methiodide (10 microM, n = 3). Our findings demonstrate that during 4AP application entorhinal neurons generate glutamatergic-independent LLDs as well as synchronous, Cl(-)-dependent depolarizations that reverberate through non-NMDA-mediated excitatory circuits.
    [Abstract] [Full Text] [Related] [New Search]