1. Anesthetic Sevoflurane Causes Rho-Dependent Filopodial Shortening in Mouse Neurons
- Author
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Fang Fang, Yiying Zhang, Jeffrey H. Zimering, Zhongcong Xie, Lining Huang, and Yuanlin Dong
- Subjects
rho GTP-Binding Proteins ,Pathology ,Dendritic spine ,RHOA ,Physiology ,Pyridines ,Kinase Inhibitors ,Synaptogenesis ,Dendritic spine morphogenesis ,lcsh:Medicine ,Nervous System ,Microtubules ,Biochemistry ,Hippocampus ,0302 clinical medicine ,030202 anesthesiology ,Animal Cells ,Anesthesiology ,Medicine and Health Sciences ,Anesthesia ,Pseudopodia ,Enzyme Inhibitors ,lcsh:Science ,Cytoskeleton ,Neurons ,Multidisciplinary ,Pharmaceutics ,Drugs ,Cell biology ,Electrophysiology ,Female ,Cellular Types ,Anatomy ,Cellular Structures and Organelles ,Filopodia ,Research Article ,Methyl Ethers ,medicine.medical_specialty ,Imaging Techniques ,Cell Survival ,Dendritic Spines ,Neurophysiology ,Biology ,Research and Analysis Methods ,03 medical and health sciences ,Sevoflurane ,Drug Therapy ,Cellular neuroscience ,Fluorescence Imaging ,medicine ,Pain Management ,Animals ,Protein Kinase Inhibitors ,Anesthetics ,Pharmacology ,Neuropeptides ,lcsh:R ,Biology and Life Sciences ,Cell Biology ,Neuronal Dendrites ,Amides ,Actins ,Mice, Inbred C57BL ,Rho kinase inhibitor ,Cellular Neuroscience ,Synapses ,biology.protein ,Enzymology ,lcsh:Q ,030217 neurology & neurosurgery ,Neuroscience - Abstract
Early postnatal anesthesia causes long-lasting learning and memory impairment in rodents, however, evidence for a specific neurotoxic effect on early synaptogenesis has not been demonstrated. Drebrin A is an actin binding protein whose localization in dendritic protrusions serves an important role in dendritic spine morphogenesis, and is a marker for early synaptogenesis. We therefore set out to investigate whether clinically-relevant concentrations of anesthetic sevoflurane, widely- used in infants and children, alters dendritic morphology in cultured fetal day 16 mouse hippocampal neurons. After 7 days in vitro, mouse hippocampal neurons were exposed to four hours of 3% sevoflurane in 95% air/5% CO2 or control condition (95% air/5% CO2). Neurons were fixed in 4% paraformaldehyde and stained with Alexa Fluor555-Phalloidin, and/or rabbit anti-mouse drebrin A/E antibodies which permitted subcellular localization of filamentous (F)-actin and/or drebrin immunoreactivity, respectively. Sevoflurane caused acute significant length-shortening in filopodia and thin dendritic spines in days-in-vitro 7 neurons, an effect which was completely rescued by co-incubating neurons with ten micromolar concentrations of the selective Rho kinase inhibitor Y27632. Filopodia and thin spine recovered in length two days after sevoflurane exposure. Yet cluster-type filopodia (a precursor to synaptic filopodia) were persistently significantly decreased in number on day-in-vitro 9, in part owing to preferential localization of drebrin immunoreactivity to dendritic shafts versus filopodial stalks. These data suggest that sevoflurane induces F-actin depolymerization leading to acute, reversible length-shortening in dendritic protrusions through a mechanism involving (in part) activation of RhoA/Rho kinase signaling and impairs localization of drebrin A to filopodia required for early excitatory synapse formation.
- Published
- 2016