General anesthetics cause mitochondrial dysfunction and reduction of intracellular ATP levels

<div><p>General anesthetics are indispensable for effective clinical care. Although, the mechanism of action of general anesthetics remains controversial, lipid bilayers and proteins have been discussed as their targets. In this study, we focused on the relationship between cellular ATP levels and general anesthetics. The ATP levels of nematodes and cultured mammalian cells were decreased by exposure to three general anesthetics: isoflurane, pentobarbital, and 1-phenoxy-2-propanol. Furthermore, these general anesthetics abolished mitochondrial membrane potential, resulting in the inhibition of mitochondrial ATP synthesis. These results suggest that the observed decrease of cellular ATP level is a common phenomenon of general anesthetics.</p></div

ATP level changes in Neuro2A cells by general anesthetics.

<p>ATP levels in Neuro2A cells were measured after each anesthetic treatment (<i>n</i> = 3). The values were normalized by protein concentration. The cells were treated with IF under saturated vapor pressure conditions. C, control treated without anesthetics for 30 min. Other anesthetics were added into the culture medium (0.3% 1PP, or 0.2% PBNa). The numbers under the graphs indicate the treatment time. Error bars indicate S.D. *<i>P</i> < 0.05, ANOVA with Bonferroni test vs control.</p

<i>In vivo</i> ATP imaging of pharyngeal muscle cells in nematodes.

<p><i>In vivo</i> ATP imaging after treatment with each anesthetic. A, The panel shows typical YFP/CFP ratio images of nematodes after anesthetic treatment. The YFP/CFP ratio on the pharyngeal cells is pseudo-colored. B, The panel shows the averages of YFP/CFP ratios of ATeam after anesthetic treatment. Nematodes were exposed under the same conditions as used in for assessment of ATP levels. Error bars indicate S.D. *<i>P</i> < 0.05, ANOVA with Bonferroni test vs control.</p

ATP imaging of Neuro2a cells during anesthetics treatments.

<p>(A) Live cell imaging after treatment with the indicated anesthetics. The YFP/CFP ratios in the cells are pseudo-colored. The number in each panel indicates the treatment time (min). The cells were treated in sealed boxes in the cases of IF (left top and bottom panels). In other cases, anesthetics added into the culture medium. (B) Time courses of the average YFP/CFP ratios of the Neuro2a cells expressing ATeam. The black and red lines indicate control (<i>n</i> = 31) and IF (saturated vapor pressure, <i>n</i> = 24) conditions, respectively. IF treatment was initiated at time 0 (min). (C) Black, blue, and green lines show control (<i>n</i> = 26), 1PP (0.2%, <i>n</i> = 9), and PBNa (0.2%, <i>n</i> = 32) treatment, respectively. Anesthetics were added at time 5 (min). Error bars indicate S.D.</p

Anesthetic treatment reduced ATP levels in nematodes.

<p>The level of ATP in each animal was measured after treatment with anesthetics for the indicated times (n = 24 for each measurement). Nematodes were exposed to IF under saturated vapor pressure in a sealed box. For the other anesthetics, nematodes were soaked in each anesthetic solution at concentrations of 0.2% PBNa, or 0.3% 1PP. The numbers under the graphs indicate the treatment time. Error bars indicate S.D. *<i>P</i> < 0.05, ANOVA with Bonferroni test vs control.</p

Construction of Plastid Reference Proteomes for Maize and <i>Arabidopsis</i> and Evaluation of Their Orthologous Relationships; The Concept of Orthoproteomics

Plastids are essential organelles because they contribute to primary and secondary metabolism and plant signaling networks. A high-quality inventory of the plastid proteome is therefore a critical tool in plant research. We present reference plastid proteomes for maize (<i>Zea mays</i>) and <i>Arabidopsis</i> (<i>Arabidopsis thaliana</i>) with, respectively, 1564 and 1559 proteins. This was based on manual curation of published experimental information, including >150 proteomics studies regarding different (sub)­cellular fractions, and new quantitative proteomics experiments on plastid subfractions specifically designed to fill gaps in current knowledge. These plastid proteomes represent an estimated 40 (maize) to 50% (<i>Arabidopsis</i>) of all plastid proteins and can serve as a “gold standard” because of their low false-positive rate. To facilitate direct comparison of these plastid proteomes, identify “missing” proteins, and evaluate species-specific differences, we determined their orthologous relationships. The multistep strategy to best define these orthologous relationships is explained. Putative plastid locations for orthologs without known subcellular locations were inferred based on the robustness of orthology and weighing of experimental evidence, increasing both plastid proteome sizes. Examples that highlight differences and similarities between maize and <i>Arabidopsis</i> and underscore the quality of the orthology assignments are discussed

Construction of Plastid Reference Proteomes for Maize and <i>Arabidopsis</i> and Evaluation of Their Orthologous Relationships; The Concept of Orthoproteomics

Plastids are essential organelles because they contribute to primary and secondary metabolism and plant signaling networks. A high-quality inventory of the plastid proteome is therefore a critical tool in plant research. We present reference plastid proteomes for maize (<i>Zea mays</i>) and <i>Arabidopsis</i> (<i>Arabidopsis thaliana</i>) with, respectively, 1564 and 1559 proteins. This was based on manual curation of published experimental information, including >150 proteomics studies regarding different (sub)­cellular fractions, and new quantitative proteomics experiments on plastid subfractions specifically designed to fill gaps in current knowledge. These plastid proteomes represent an estimated 40 (maize) to 50% (<i>Arabidopsis</i>) of all plastid proteins and can serve as a “gold standard” because of their low false-positive rate. To facilitate direct comparison of these plastid proteomes, identify “missing” proteins, and evaluate species-specific differences, we determined their orthologous relationships. The multistep strategy to best define these orthologous relationships is explained. Putative plastid locations for orthologs without known subcellular locations were inferred based on the robustness of orthology and weighing of experimental evidence, increasing both plastid proteome sizes. Examples that highlight differences and similarities between maize and <i>Arabidopsis</i> and underscore the quality of the orthology assignments are discussed