Comparison of midazolam effects on inhibitory postsynaptic currents in hippocampal CA3 with those in CA1.
We compared the effects of midazolam, one of the popular benzodiazepines, on inhibitory postsynaptic currents in CA3 pyramidal cells with those in CA1 pyramidal cells in rat hippocampal slices. With all of the midazolam concentrations tested, the conductance of the evoked inhibitory postsynaptic current of the CA3 and CA1 pyramidal cells was significantly larger than the control, and increased in a dose-dependent manner. The normalized conductance of the inhibitory postsynaptic currents of the CA3 and CA1 pyramidal cells was not significantly different. However, we found that midazolam significantly prolonged the decay time of inhibitory postsynaptic currents of CA3 pyramidal cells. The results suggest that the differential effect of midazolam on the inhibitory postsynaptic currents could be due to the different decay kinetics, which depend on the gamma-aminobutyric acid type A receptor subunit compositions of the CA3 and CA1 pyramidal cells.
Kobayashi
Suguru
S
Department of Physiology, Sapporo Medical University School of Medicine, South 1, West 17, Chuo-ku, Sapporo 060-8556, Japan. suguruk@sapmed.ac.jp
Fujito
Yutaka
Y
Matsuyama
Kiyoji
K
Aoki
Mamoru
M
D000818:Animals; D000831:Animals, Newborn; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D018757:GABA Modulators / Q000494:pharmacology*; D006624:Hippocampus / Q000166:cytology* / Q000187:drug effects; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D008874:Midazolam / Q000494:pharmacology*; D009433:Neural Inhibition / Q000187:drug effects*; D018408:Patch-Clamp Techniques / Q000379:methods; D017966:Pyramidal Cells / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology
D018757:GABA Modulators; D008874:Midazolam