Inhibitory Postsynaptic Currents Induced by Activation of Interneurons in Cultured Rat Hippocampal Neurons

• Published in: Neurophysiology (New York) Vol. 37; no. 2; pp. 104 - 110
• Main Authors: Moskalyuk, A. A., Koval', O. M., Fedulova, S. A., Veselovskii, N. S.
• Format: Journal Article
• Language: English
• Published: New York Springer Nature B.V 01.03.2005
• ISSN: 0090-2977; 1573-9007
• DOI: 10.1007/s11062-005-0051-1

Using the patch-clamp technique in the whole-cell configuration, we studied the characteristics of a series of action potentials (APs) induced by a 500-msec-long current pulse applied to a pre-synaptic unit, as well as the kinetic characteristics of post-synaptic currents (PSCs) evoked by the APs in a post-synaptic unit, in synaptically connected pairs of cultured hippocampal neurons. Presynaptic inhibitory units were identified as GABA-ergic interneurons; they were divided into two groups according to the size of the soma and the number of processes. The kinetic characteristics of PSCs, which were induced in the post-synaptic neuron by a series of the APs generated in the pre-synaptic cell, demonstrated a certain dependence on the morphological characteristics of these cells. In interneurons with large-sized somata, the kinetics of the currents were more fast, and the reversal potential was close to the equilibrium Cl potential. In interneurons with small-sized somata, currents were slower, and the reversal potential was shifted. We conclude that under conditions of culturing, a pre-synaptic cell not only directly provokes the development of PSC in a post-synaptic neuron and determines the amplitude of this current but also significantly influences the kinetics of this current.