Korean J Physiol Pharmacol.  2003 Apr;7(2):59-64.

Inhibitory and Excitatory Postsynaptic Currents of Medial Vestibular Nucleus Neurons of Rats

• Chun SW
• Choi JH
• Park BR

Abstract

The medial vestibular nucleus (MVN) neurons are controlled by excitatory synaptic transmission from the vestibular afferent and commissural projections, and by inhibitory transmission from interneurons. Spontaneous synaptic currents of MVN neurons were studied using whole cell patch clamp recording in slices prepared from 13- to 17-day-old rats. The spontaneous inhibitory postsynaptic currents (sIPSCs) were significantly reduced by the GABAA antagonist bicuculline (20micrometer), but were not affected by the glycine antagonist strychnine (1micrometer). The frequency, amplitude, and decay time constant of sIPSCs were 4.3 0.9 Hz, 18.1 2.0 pA, and 8.9 0.4 ms, respectively. Spontaneous excitatory postsynaptic currents (sEPSCs) were mediated by non-NMDA and NMDA receptors. The specific AMPA receptor antagonist GYKI-52466 (50micrometer) completely blocked the non-NMDA mediated sEPSCs, indicating that they are mediated by an AMPA-preferring receptor. The AMPA mediated sEPSCs were characterized by low frequency (1.5 0.4 Hz), small amplitude (13.9 1.9 pA), and rapid decay kinetics (2.8 0.2 ms). The majority (15/21) displayed linear I-V relationships, suggesting the presence of GluR2-containing AMPA receptors. Only 35% of recorded MVN neurons showed NMDA mediated currents, which were characterized by small amplitude and low frequency. These results suggest that the MVN neurons receive excitatory inputs mediated by AMPA, but not kainate, and NMDA receptors, and inhibitory transmission mediated by GABAA receptors in neonatal rats.

Keyword

Inhibitory postsynaptic current; Excitatory postsynaptic current; GluR2 AMPA receptor; GABAA receptor; Medial vestibular nucleus

MeSH Terms

alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
Animals
Bicuculline
Excitatory Postsynaptic Potentials*
Glycine
Inhibitory Postsynaptic Potentials
Interneurons
Kainic Acid
Kinetics
N-Methylaspartate
Neurons*
Rats*
Receptors, AMPA
Receptors, N-Methyl-D-Aspartate
Strychnine
Synaptic Transmission
Vestibular Nuclei*
Bicuculline
Glycine
Kainic Acid
N-Methylaspartate
Receptors, AMPA
Receptors, N-Methyl-D-Aspartate
Strychnine
alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid