The neuroplastic index p-FADD/FADD and phosphoprotein PEA-15, interacting at GABAA receptor, are upregulated in brain cortex during midazolam-induced hypnosis in mice.
Fas-associated death domain (FADD) adaptor is involved in the signaling of metabotropic G protein-coupled receptors, whose agonists stimulate its phosphoryaltion (p) increasing p-FADD/FADD ratio in brain. Whether FADD might also participate in the activation of dissimilar receptors such as the ligand-gated ion channels is not known. This study investigated the role of FADD and phosphoprotein-enriched in astrocytes of 15 kDa (PEA-15, a FADD partner) in the activation of γ-aminobutyric acid-A (GABAA) receptor, which mediates the hypnotic effect of midazolam. The main findings revealed that during the time course of midazolam (60 mg/kg)-induced hypnosis in mice (about 2 h) p-FADD (and p-FADD/FADD ratio) as well as p-PEA (and its phosphorylating Akt1 kinase) were markedly increased (36-80%) in brain cortex, and these effects were partially (only p-FADD) or fully prevented by flumazenil (a neutral allosteric ligand) and FG 7142 (a partial negative allosteric ligand) acting at GABAA receptors. The upregulation of cortical p-FADD/FADD was exclusively observed in the nucleus (up to 2.8-fold), where the transciption factor NF-κB was also increased (up to 46%), and that of p-PEA/p-Akt1 only in the cytosol (up to 53%), suggesting that p-FADD/p-PEA/p-Akt1 are involved in sleep-induced neuroplasticity. Repeated treatment with midazolam (60 mg/kg, 4 days) induced behavioral (prolonged sleep latency and reduced sleeping time) and neurochemical (reduced p-FADD/p-PEA contents) tolerance. These findings indicated that p-FADD/p-PEA are novel molecules in GABAA receptor signaling and that cortical p-PEA and p-FADD, working in tandem, are involved in the complex molecular processes leading to the hypnotic effect of midazolam in mice.
Laboratorio de Neurofarmacología, IUNICS-IdISPa, Universitat de les Illes Balears, Palma de Mallorca Spain; Redes Temáticas de Investigación Cooperativa en Salud-Red de Trastornos Adictivos (RETICS-RTA), ISCIII, Madrid, Spain.
María
M
Álvaro-Bartolomé
Laboratorio de Neurofarmacología, IUNICS-IdISPa, Universitat de les Illes Balears, Palma de Mallorca Spain; Redes Temáticas de Investigación Cooperativa en Salud-Red de Trastornos Adictivos (RETICS-RTA), ISCIII, Madrid, Spain. Electronic address: jesus.garcia-sevilla@uib.es.
Jesús A
JA
García-Sevilla
D000818:Animals; D051017:Apoptosis Regulatory Proteins; D001933:Brain Stem / Q000187:drug effects / Q000378:metabolism; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism*; D053200:Fas-Associated Death Domain Protein / Q000378:metabolism*; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008874:Midazolam / Q000494:pharmacology*; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011897:Random Allocation; D011963:Receptors, GABA-A / Q000378:metabolism; D013788:Thalamus / Q000187:drug effects / Q000378:metabolism; D015854:Up-Regulation
D051017:Apoptosis Regulatory Proteins; C505534:Fadd protein, mouse; D053200:Fas-Associated Death Domain Protein; D006993:Hypnotics and Sedatives; C490444:Pea15 protein, mouse; D010750:Phosphoproteins; D011963:Receptors, GABA-A; D051057:Proto-Oncogene Proteins c-akt; D008874:Midazolam
Akt1; FADD; Hypnosis; Midazolam; Mouse brain; PEA-15