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Using the tight-seal voltage-clamp method, the ionic currents in the enzymatically dispersed single smooth muscle cells of the guinea pig taenia coli have been studied. In a physiological medium containing 3 mM Ca 2 § the cells are gently tapering spindles, averaging 201 (length) x 8 #m (largest diameter in center of cell), with a volume of 5 pl. The average cell capacitance is 50 pF, and the specific membrane capacitance 1.15 #F/cm ~. The input impedance of the resting cell is 1-2 Gfl. Spatially uniform voltage-control prevails after the first 400 #s. There is much overlap of the inward and outward currents, but the inward current can be isolated by applying Cs § internally to block all potassium currents. The inward current is carried by Ca 2 § Activation begins at ~-30 mV, maximum/ca occurs at +10-+20 mV, and the reversal potential is ~+75 inV. The Ca ~+ channel is permeable to Sr 2+ and Ba 2+, and to Cs + moving outwards, but not to Na + moving inwards. Activation and deactivation are very rapid at ~33"C, with timeconstants of < 1 ms. Inactivation has a complex time course, resolvable into three exponential components, with average time constants (at 0 mV) of 7, 45, and 400 ms, which are affected differently by voltage. Steady-state inactivation is half-maximal at -30 mV for all components combined, but -36 mV for the fast component and -26 and -23 mV for the other two components. The presence of multiple forms of Ca 2 § channel is inferred from the inactivation characteristics, not from activation properties. Recovery of the fast channel occurs with a time-constant of 72 ms (at + 10 mV). Ca 2 § influx during an action potential can transfer ~9 pC of charge, which could elevate intracellular Ca 2+ concentration adequately for various physiological functions.

Background The novel coronavirus disease (2019-nCoV) has been affecting global health since the end of 2019 and there is no sign that the epidemic is abating . The major issue for controlling the infectious is lacking efficient prevention and therapeutic approaches. Chloroquine (CQ) and Hydroxychloroquine (HCQ) have been reported to treat the disease, but the underlying mechanism remains controversial. Purpose The objective of this study is to investigate whether CQ and HCQ could be ACE2 blockers and used to inhibit 2019-nCoV virus infection. Methods In our study, we used CCK-8 staining, flow cytometry and immunofluorescent staining to evaluate the toxicity and autophagy of CQ and HCQ, respectively, on ACE2 high-expressing HEK293T cells (ACE2 h cells). We further analyzed the binding character of CQ and HCQ to ACE2 by molecular docking and surface plasmon resonance (SPR) assays, 2019-nCoV spike pseudotyped virus was also used to observe the viropexis effect of CQ and HCQ in ACE2 h cells. Results Results showed that HCQ is slightly more toxic to ACE2 h cells than CQ. Both CQ and HCQ could bind to ACE2 with K D = (7.31 ± 0.62) e −7 M and (4.82 ± 0.87) e −7 M, respectively. They exhibit equivalent suppression effect for the entrance of 2019-nCoV spike pseudotyped virus into ACE2 h cells. Conclusions CQ and HCQ both inhibit the entrance 2019-nCoV into cells by blocking the binding of the virus with ACE2. Our findings provide novel insights into the molecular mechanism of CQ and HCQ treatment effect on virus infection.

The SARS-CoV-2 outbreak, began in late 2019, has caused a worldwide pandemic and shows no signs of slowing. Glucocorticoids (GCs), including dexamethasone (DEX), have been widely used as effective anti-inflammatory and immunosuppressant drugs. In this study, seven GCs had no obvious effect on cell viability of angiotensin converting enzyme 2 (ACE2) high expressed HEK293T cells when concentrations were under 10 μM. Molecular docking results revealed that DEX occupied with active binding site of ACE2 of SARS-CoV-2 spike protein. Surface plasmon resonance (SPR) results showed that K D value between DEX and ACE2 was (9.03 ± 0.78) e−6 M. Cell membrane chromatography (CMC) results uncovered that DEX had a chromatographic retention. DEX was found out to inhibiting the viropexis into ACE2 h cells using SARS-CoV-2 spike pseudotyped virus. Therefore, DEX inhibits the entrance of SARS-CoV-2 spike pseudotyped virus into cell by binding to ACE2.

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In single myocytes of the guinea pig taenia coli, dispersed by enzymatic digestion, the late outward current is carried by K +. It has both a Ca 2+-activated component and a voltage-dependent component which is resistant to external Co 2+. The reversal potential is -84 mV, and the channel(s) for it are highly selective to K +. At 33~ the activation follows n ~ kinetics, with a voltagedependent time constant of 10.6 ms at 0 mV, which shortens to 1.7 ms at +70 mV. Deactivation follows a single-exponential time course, with a voltage-dependent time constant of 11 ms at -50 mV, which lengthens to 33 ms at -20 mV. During a 4.5-s maintained depolarization, IK inactivates, most of it into two exponential components, but there is a small noninactivating residue. It is surmised that during an action potential under physiological conditions, there is sufficient IK tO cause repolarization.

Since December 2019, the new coronavirus (also known as severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2, 2019-nCoV])-induced disease, COVID-19, has spread rapidly worldwide. Studies have reported that the traditional Chinese medicine Salvia miltiorrhiza possesses remarkable antiviral properties; however, the anti-coronaviral activity of its main components, salvianolic acid A (SAA), salvianolic acid B (SAB), and salvianolic acid C (SAC) is still debated. In this study, we used Cell Counting Kit-8 staining and flow cytometry to evaluate the toxicity of SAA, SAB, and SAC on ACE2 (angiotensin-converting enzyme 2) high-expressing HEK293T cells (ACE2 h cells). We found that SAA, SAB, and SAC had a minor effect on the viability of ACE2 h cells at concentrations below 100 μM. We further evaluated the binding capacity of SAA, SAB, and SAC to ACE2 and the spike protein of 2019-nCoV using molecular docking and surface plasmon resonance. They could bind to the receptorbinding domain (RBD) of the 2019-nCoV with a binding constant (K D ) of (3.82 ± 0.43) e−6 M, (5.15 ± 0.64)e−7 M, and (2.19 ± 0.14)e-6 M; and bind to ACE2 with K D (4.08 ± 0.61)e−7 M, (2.95 ± 0.78)e−7 M, and (7.32 ± 0.42)e−7 M, respectively. As a result, SAA, SAB, and SAC were determined to inhibit the entry of 2019-nCoV Spike pseudovirus with an EC 50 of 11.31, 6.22, and 10.14 μM on ACE2 h cells, respectively. In conclusion, our study revealed that three Salvianolic acids can inhibit the entry of 2019-nCoV spike pseudovirus into ACE2 h cells by binding to the RBD of the 2019-nCoV spike protein and ACE2 protein.

PurposeTo conduct a systematic review of included studies assessing the association of GP210 and SP100 with the risk of primary biliary cirrhosis (PBC) using meta-analysis.MethodsFive databases, the Cochrane Library, MEDLINE, VIP, CNKI, WANFANG were used to detect the role of GP210 and SP100 in diagnosis of PBC. Approximately 13,000 participants from several countries were included in this analysis. Meta-DiSc statistical software was used for analysis.Results25 studies on GP210 and 21 studies on SP100 were included in the meta-analysis. The DOR, sensitivity, specificity of GP210 in diagnosis of PBC were 24.854 (11.957–51.660), 0.272 (0.257–0.288), 0.985 (0.982–0.988), respectively, and they were 9.133 (4.739–17.600), 0.231 (0.213–0.249), 0.977 (0.973–0.981) for SP100.ConclusionOur meta-analysis indicated both GP210 and SP100 had high specificity but low sensitivity in diagnosis of PBC.