Halothane modulates NMDA and non-NMDA excitatory synaptic transmission in rat cortical neurons.
OBJECTIVE
Although general anesthetics may decrease neuronal excitation, their detailed effects on spontaneous excitatory postsynaptic currents (EPSCs) remain controversial. We investigated and compared the effects of halothane on N-methyl-D-asparate (NMDA) and non-NMDA receptor-mediated postsynaptic currents.


METHODS
Spontaneous synaptic currents were recorded by the patch clamp technique in cultured rat cortical neurons. They were isolated by specific pharmacological blocking agents and their electrophysiologic properties were examined.


RESULTS
The frequency of NMDA EPSCs was preferentially decreased as compared with that of non-NMDA EPSCs at halothane 1.2 mM. The total net charge of EPSCs mediated by NMDA and non-NMDA receptors was depressed to 56% +/- 6% (mean +/- SD) and 71% +/- 7% of control by halothane 0.6 mM, and to 11% +/- 9% and 59% +/- 11% of control by halothane 1.2 mM, respectively.


CONCLUSIONS
These results show that halothane causes decrease of excitatory synaptic activity, with NMDA EPSCs being more sensitive than non-NMDA EPSCs.
Kitamura
Akira
A
Department of Anesthesiology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, 113-9603, Japan.
Satoh
Ryoichi
R
Nagano
Tomoo
T
Matsuda
Hiroyuki
H
Shimizu
Toru
T
Sakamoto
Atsuhiro
A
Ogawa
Ryo
R
D000465:Algorithms; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D002540:Cerebral Cortex / Q000166:cytology* / Q000187:drug effects; D004594:Electrophysiology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects*; D005971:Glutamates / Q000502:physiology; D006221:Halothane / Q000494:pharmacology*; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects*; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*; D005680:gamma-Aminobutyric Acid / Q000502:physiology
D018685:Anesthetics, Inhalation; D005971:Glutamates; D016194:Receptors, N-Methyl-D-Aspartate; D005680:gamma-Aminobutyric Acid; D006221:Halothane