Pharmacological correction of the sequelae of acute alcohol-induced myocardial damage with new derivatives of neuroactive amino acids coupled with the blockade of the neuronal NO synthase isoform

Introduction: Acute alcohol intoxication (AAI) induces a number of myocardial disorders, which result in mitochondrial dysfunction in cardiomyocytes, oxidative stress, and decreased cardiac contractility. Nitric oxide produced by the nNOS is one of the major modulators of cardiac activity. New derivatives of GABA (RSPU-260 compound) and glutamate (glufimet) can be potentially regarded as such agents as the interaction between the NO system and the GABA and glutamatergic systems has been proved. Materials and methods: All the studies were performed on female white Wistar rats, aged 10 months, whose weight was 280–320g AAI intoxication was modeled of 32% ethanol (gavage, 4g/kg). Results and discussion: Glufimet and the RSPU-260 compound caused a significant improvement in myocardial contractility, increased oxygen consumption in the V3 state according to Chance, raised the respiratory control ratio and decreased the intensity of LPO intensity. Their effectiveness exceeded that of mildronate, their comparator. nNOS inhibition resulted in a pronounced aggravation of oxidative stress implicated in MDA accumulation in cardiac mitochondria and decreased activity of SOD; myocardial contractility and mitochondrial function indicators did not show a significant difference from the control group. The compounds under study coupled with nNOS inhibition had a cardioprotective effect. Conclusion: Glufimet and the RSPU-260 compound, derivatives of neuroactive amino acids, have a pronounced cardioprotective effect, restrict LPO processes, enhance SOD activity, improve the mitochondrial respiratory function after acute alcohol intoxication when coupled with neuronal NO-synthase inhibition, the expression of which persists after AAI. Graphical abstract

Chronic Nicotine Modifies Skeletal Muscle Na,K-ATPase Activity through Its Interaction with the Nicotinic Acetylcholine Receptor and Phospholemman

Our previous finding that the muscle nicotinic acetylcholine receptor (nAChR) and the Na,K-ATPase interact as a regulatory complex to modulate Na,K-ATPase activity suggested that chronic, circulating nicotine may alter this interaction, with long-term changes in the membrane potential. To test this hypothesis, we chronically exposed rats to nicotine delivered orally for 21–31 days. Chronic nicotine produced a steady membrane depolarization of ∼3 mV in the diaphragm muscle, which resulted from a net change in electrogenic transport by the Na,K-ATPase α2 and α1 isoforms. Electrogenic transport by the α2 isoform increased (+1.8 mV) while the activity of the α1 isoform decreased (−4.4 mV). Protein expression of Na,K-ATPase α1 or α2 isoforms and the nAChR did not change; however, the content of α2 subunit in the plasma membrane decreased by 25%, indicating that its stimulated electrogenic transport is due to an increase in specific activity. The physical association between the nAChR, the Na,K-ATPase α1 or α2 subunits, and the regulatory subunit of the Na,K-ATPase, phospholemman (PLM), measured by co-immuno precipitation, was stable and unchanged. Chronic nicotine treatment activated PKCα/β2 and PKCδ and was accompanied by parallel increases in PLM phosphorylation at Ser63 and Ser68. Collectively, these results demonstrate that nicotine at chronic doses, acting through the nAChR-Na,K-ATPase complex, is able to modulate Na,K-ATPase activity in an isoform-specific manner and that the regulatory range includes both stimulation and inhibition of enzyme activity. Cholinergic modulation of Na,K-ATPase activity is achieved, in part, through activation of PKC and phosphorylation of PLM

Efficiency of Finding Muon Track Trigger Primitives in CMS Cathode Strip Chambers

In the CMS Experiment, muon detection in the forward direction is accomplished by cathode strip chambers~(CSC). These detectors identify muons, provide a fast muon trigger, and give a precise measurement of the muon trajectory. There are 468 six-plane CSCs in the system. The efficiency of finding muon trigger primitives (muon track segments) was studied using~36 CMS CSCs and cosmic ray muons during the Magnet Test and Cosmic Challenge~(MTCC) exercise conducted by the~CMS experiment in~2006. In contrast to earlier studies that used muon beams to illuminate a very small chamber area ($< \! 0.01$~m$^2$), results presented in this paper were obtained by many installed CSCs operating {\em in situ} over an area of $\approx \! 23$~m$^2$ as a part of the~CMS experiment. The efficiency of finding 2-dimensional trigger primitives within 6-layer chambers was found to be~$99.93 \pm 0.03\%$. These segments, found by the CSC electronics within $800$~ns after the passing of a muon through the chambers, are the input information for the Level-1 muon trigger and, also, are a necessary condition for chambers to be read out by the Data Acquisition System

Carbon Nanoscrolls Produced from Acceptor-Type Graphite Intercalation Compounds

A low-temperature wet chemistry technique for producing carbon nanoscrolls is described. The technique is based on the use of readily available acceptor-type graphite intercalation compounds. The initial graphite intercalation compound is first exfoliated to produce a suspension of graphene monolayers in ethanol which is subsequently sonicated yielding a suspension of carbon nanoscrolls. The technique does not require heating and the use of inert atmosphere thus providing an improvement compared to the previously reported methods

Changes in the respiratory function of the heart and brain mitochondria of animals after chronic alcohol intoxication affected by a new GABA derivative

Introduction: Chronic ethanol consumption leads to significant functional and structural changes in the mitochondria of the heart and brain, increasing generation of reactive oxygen species. Therefore, the search for substances, which improve the functional state of the mitochondria and, meantime, reduce the oxidative stress, is relevant. Materials and methods: 10-months-old Wistar female rats were used in the experiments. Chronic alcohol intoxication (CAI) was modelled by replacing drinking water with a 10% ethanol solution containing sucrose (50 g/L) for 24 weeks. Four groups were formed: 1 – intact animals; 2 – animals after chronic alcohol consumption; 3 – rats after CAI which were administered RSPU-260 (25 mg/kg); 4 – rats after CAI which were administered the reference drug Mildronate (50 mg/kg). The intensity of lipid peroxidation (LPO) and the rate of oxygen consumption in various metabolic states were determined. Results and discussion: Administration of the compound RSPU-260 to the animals exposed to alcohol over a long period of time resulted in an increase in both the rate of oxygen consumption (state 3) and the respiratory control ratio (RCR) of the mitochondria of heart and brain cells. The use of a GABA derivative promoted a decrease in malonic dialdehyde in the mitochondria of the heart and brain. Total SOD activity in the mitochondria of heart cells was significantly increased in the groups of rats treated with RSPU-260. In terms of efficiency, the compound RSPU-260 was comparable to the reference drug Mildronate. Conclusions: The compound RSPU-260, and the reference drug Mildronate improve mitochondrial oxidative phosphorylation in heart and brain cells, the functioning of antioxidant enzymes in animals after CAI, and can be used to correct alcoholic damage to these organs

Distribution histogram of resting membrane potentials in the diaphragm of control (solid bars) and nicotine-treated rats (striped bars).

<p>Treated animals received nicotine orally in the drinking water for 21–31 days prior to tissue removal. RMPs were recorded from 622 fibers from 9 muscles (nicotine) and 676 fibers from 10 control muscles (vehicle). The solid and dashed curves are Gaussian fits to the RMP distribution for each group. The distribution of RMPs in each group was consistent with a normal distribution based on the Kolmogorov-Smirnov normality test (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033719#s2" target="_blank">Methods</a>). The classes on the histograms are grouped (using ORIGIN 6.1) with Bin size 4.1 mV for 12 bins, in the range from −50 mV to −97.5 mV. For ease of visualization, the gap between bars was chosen = 0, overlap is 60%.</p

Na,K-ATPase α1 and α2 and nAChR content in diaphragm muscles of control and nicotine-treated rats.

<p><b>A</b>, <b>B</b>, <b>C</b> – whole homogenate; <b>D</b>, <b>E</b> – plasma membrane fraction. Upper panels show representative immunoblots; lower panels show mean densities ± SE from 9–10 blots prepared using different muscle samples. * p<0.05. Nicotine was administered orally for 21–31 days as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033719#s2" target="_blank">Methods</a>. Assays were made using diaphragm tissue from the same muscles used for RMP and activity measurements (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033719#pone-0033719-g001" target="_blank">Fig. 1</a> & <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033719#pone-0033719-g002" target="_blank">2C</a>, oral nicotine).</p

Contributions to the resting membrane potential (mV) from electrogenic active transport by the α1 and α2 Na, K-ATPase isozymes in the diaphragm muscle of control and chronic nicotine-exposed rats.

<p><b>A</b>) RMP of muscle fibers versus ouabain concentration. Each data point represents the mean ± SEM of 130–170 measurements from 4–6 muscles. The solid line is a nonlinear regression fit to a two-site binding model: RMP = RMP₀+A₁/(1+[I]/K₁)+A₂/(1+[I]/K₂), where RMP₀ is the RMP when both ouabain-binding sites are inhibited; K₁ and K₂ are the half maximal ouabain concentrations for ouabain binding to α1 and α2 isoforms, respectively; A₁ and A₂ (mV) are their respective contributions to the RMP and [I] is the inhibitor (ouabain) concentration. The left vertical bar indicates the electrogenic potentials contributed by the α1 (black) and α2 (grey) isoforms obtained from the fitted data. Horizontal dashed lines show the predicted RMP levels for three cases: when both α isoforms are inactive (∼−61 mV, E_Nernst alone), when only α1 is active (∼−74 mV), and when both α1 and α2 are active (∼−78 mV). Muscles were incubated with the indicated concentration of ouabain for one hour before the start of recording. <b>B</b>) Concentration-dependence and K values for inhibition of the α2 and α1 isozymes, computed from the data in panel A. <b>C</b>) Changes in RMP elicited by 1 µM and 500 µM ouabain in the diaphragm of control (filled circles) and nicotine-treated (open circles) rats. Rats received nicotine orally for 21–31 days, as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033719#s2" target="_blank">Methods</a>. Measurements are from the same muscles as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033719#pone-0033719-g001" target="_blank">Fig. 1</a> (oral nicotine). Arrows indicate when ouabain was added and the horizontal bar indicates when ouabain was present in the solution. RMPs were measured 15, 30 and 45 minutes and stabilized to a new level within 30 min of each solution change. Left vertical bars denote the electrogenic potentials contributed by the α1 (black) and α2 (grey) isozymes. Measurements are from 10 (control) and 9 (nicotine-treated) animals.</p

Mean RMPs in the diaphragm muscle of control and chronic nicotine-treated rats, and the electrogenic potentials generated by α1 and α2 Na,K-ATPase basal transport.

<p>RMPs were computed from measurements in muscles perfused sequentially with no ouabain (control solution), 1 µM ouabain, or 500 µM ouabain, as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033719#pone-0033719-g002" target="_blank">Fig. 2C</a>.</p>**<p>p<0.01 and</p>***<p>p<0.001, compared to control. Treated rats received nicotine orally for 21–31 days prior to tissue removal. RMPs were measured 30–45 min after each solution change. n = number of fibers. Mean RMPs were obtained from a fit of the RMPs in each group to a Gaussian function, after confirming that the RMPs distributed normally (Kolmogorov-Smirnov test, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033719#s2" target="_blank">Methods</a>).</p