title: Effects of Etomidate on GABAergic and Glutamatergic Transmission in Rat Thalamocortical Slices.
abstract: Although accumulative evidence indicates that the thalamocortical system is an important target for general anesthetics, the underlying mechanisms of anesthetic action on thalamocortical neurotransmission are not fully understood. The aim of the study is to explore the action of etomidate on glutamatergic and GABAergic transmission in rat thalamocortical slices by using whole cell patch-clamp recording. We found that etomidate mainly prolonged the decay time of spontaneous GABAergic inhibitory postsynaptic currents (sIPSCs), without changing the frequency. Furthermore, etomidate not only prolonged the decay time of miniature inhibitory postsynaptic currents (mIPSCs) but also increased the amplitude. On the other hand, etomidate significantly decreased the frequency of spontaneous glutamatergic excitatory postsynaptic currents (sEPSCs), without altering the amplitude or decay time in the absence of bicuculline. When GABAAreceptors were blocked using bicuculline, the effects of etomidate on sEPSCs were mostly eliminated. These results suggest that etomidate enhances GABAergic transmission mainly through postsynaptic mechanism in thalamocortical neuronal network. Etomidate attenuates glutamatergic transmission predominantly through presynaptic action and requires presynaptic GABAAreceptors involvement.
authors: Department of Critical Care Medicine, Affiliated Hospital of Zunyi Medical College, Zunyi, Guizhou, China.
authors: Bao
authors: B
authors: Fu
authors: Department of Anesthesiology, Affiliated Hospital of Zunyi Medical College, Zunyi, Guizhou, China.
authors: Yuan
authors: Y
authors: Wang
authors: Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical College, Dalian road 149, Zunyi, 563000, Guizhou, China.
authors: Hao
authors: H
authors: Yang
authors: Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical College, Dalian road 149, Zunyi, 563000, Guizhou, China. gztianyu0607@sina.com.
authors: Tian
authors: T
authors: Yu
mesh_terms: D018681:Anesthetics, General / Q000494:pharmacology*; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002540:Cerebral Cortex / Q000187:drug effects* / Q000502:physiology; D005045:Etomidate / Q000494:pharmacology*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000502:physiology*; D066298:In Vitro Techniques; D053444:Inhibitory Postsynaptic Potentials / Q000187:drug effects; D055369:Miniature Postsynaptic Potentials / Q000187:drug effects; D017207:Rats, Sprague-Dawley; D011963:Receptors, GABA-A / Q000502:physiology; D017661:Receptors, Presynaptic / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects; D013788:Thalamus / Q000187:drug effects* / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
chemical_list: D018681:Anesthetics, General; D058787:GABA-A Receptor Antagonists; D011963:Receptors, GABA-A; D017661:Receptors, Presynaptic; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D001640:Bicuculline; D005045:Etomidate
keywords: Etomidate; GABA; Glutamate; Synaptic transmission; Thalamocortical