Midazolam induces expression of c-Fos and EGR-1 by a non-GABAergic mechanism.
Gene expression changes induced by general anesthetics have not been extensively examined. In this investigation, we treated rat pheochromocytoma PC12 cells with IV anesthetics, and assessed expression of immediate early gene products, c-Fos and EGR-1, by immunoblot analysis. Thiopental, ketamine, propofol, and diazepam did not significantly change the expression level of c-Fos and EGR-1. In contrast, midazolam dose- and time-dependently induced expression of c-Fos and EGR-1, which was not affected by antagonists of the benzodiazepine receptors, flumazenil and PK11195. The midazolam-induced c-Fos and EGR-1 expression was abolished by PD98059, an inhibitor for mitogen- activated protein kinase/extracellular signal-regulated kinase kinase, suggesting the involvement of extracellular signal-regulated kinases (ERKs). Immunoblot analysis demonstrated that midazolam induces phosphorylation and activation of ERKs. These results indicate that midazolam induces the expression of c-Fos and EGR-1, by activation of ERKs through a mechanism independent from gamma-aminobutyric acid(A) receptors, in PC12 cells, and suggest the possibility that midazolam can induce long-term changes of neural functions by changing gene expression.


CONCLUSIONS
Gene expression changes induced by anesthetics in neuronal cells have not been noticed. We demonstrate that a large concentration of midazolam can induce expression of immediate early genes by a non-GABAergic mechanism in PC12 cells, suggesting that the administration of midazolam might lead to long-term changes of neural functions by changing gene expression.
Fukuda
Kazuhiko
K
Department of Anesthesia, Kyoto University Hospital, Kyoto, Japan. kfukuda@kuhp.kyoto-u.ac.jp
Shoda
Takehiro
T
Mima
Hiroyuki
H
Uga
Hisatoshi
H
D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D051766:Early Growth Response Protein 1; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016762:Genes, fos / Q000187:drug effects*; D017874:Immediate-Early Proteins; D015151:Immunoblotting; D008874:Midazolam / Q000494:pharmacology*; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000235:genetics; D016716:PC12 Cells; D010766:Phosphorylation; D051381:Rats; D011963:Receptors, GABA-A / Q000187:drug effects; D013997:Time Factors; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects*; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D018686:Anesthetics, Intravenous; D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D004791:Enzyme Inhibitors; D017874:Immediate-Early Proteins; D011963:Receptors, GABA-A; D014157:Transcription Factors; D005680:gamma-Aminobutyric Acid; D020928:Mitogen-Activated Protein Kinases; D008874:Midazolam