Differential Roles of Phospholipase D Proteins in FcεRI-Mediated Signaling and Mast Cell Function.

Phospholipase D (PLD) proteins are enzymes that catalyze the hydrolysis of phosphatidylcholine to generate an important signaling lipid, phosphatidic acid. Phosphatidic acid is a putative second messenger implicated in the regulation of vesicular trafficking and cytoskeletal reorganization. Previous studies using inhibitors and overexpression of PLD proteins indicate that PLD1 and PLD2 play positive roles in FcεRI-mediated signaling and mast cell function. We used mice deficient in PLD1, PLD2, or both to study the function of these enzymes in mast cells. In contrast to published studies, we found that PLD1 deficiency impaired FcεRI-mediated mast cell degranulation; however, PLD2 deficiency enhanced it. Biochemical analysis showed that PLD deficiency affected activation of the PI3K pathway and RhoA. Furthermore, our data indicated that, although PLD1 deficiency impaired F-actin disassembly, PLD2 deficiency enhanced microtubule formation. Together, our results suggested that PLD1 and PLD2, two proteins that catalyze the same enzymatic reaction, regulate different steps in mast cell degranulation.

α-Glucosidase inhibition and antihyperglycemic activity of flavonoids from Ampelopsis grossedentata and the flavonoid derivatives.

The dried leaves and stems of Ampelopsis grossedentata have been used as a health tea and herbal medicine for hundreds of years in China. The study was aimed at searching for novel α-glucosidase inhibitors among the richest components of A. grossedentata and their derivatives. Three known major components (1-3) were isolated by recrystallization process and six new derivatives (4-9) were obtained by etherification of the bioactive flavonoid. All compounds were evaluated for their inhibitory activities against α-glucosidase (from Saccharomyces cerevisiae). As a result, compound 9 showed a significant α-glucosidase inhibitory activity with IC50 value of 9.3 µM and acted as a competitive inhibitor with the value of the inhibition constant (Ki) being 10.3 µM. The oral administration of compound 9 at a dose of 50mg/kg significantly reduced the post prandial blood glucose levels of normal and streptozotocin (STZ)-induced diabetic mice. Furthermore, compound 9 significantly decreased the fasting blood glucose levels in STZ-induced diabetic mice.

In vitro selection of proteins with desired characteristics using mRNA-display.

mRNA-display is an amplification-based, iterative rounds of in vitro protein selection technique that circumvents a number of difficulties associated with yeast two-hybrid and phage display. Because of the covalent linkage between the genotype and the phenotype, mRNA-display provides a powerful means for reading and amplifying a peptide or protein sequence after it has been selected from a library with very high diversity. The purpose of this article is to provide a summary of the field and practical framework of mRNA-display-based selections. We summarize the advantages and limitations of selections using mRNA-display as well as the recent applications, namely, the identification of novel affinity reagents, target-binding partners, and enzyme substrates from synthetic peptide or natural proteome libraries. Practically, we provide a detailed procedure for performing mRNA-display-based selections with the aim of identifying protease substrates and binding partners of a target protein. Furthermore, we describe how to confirm the function of the selected protein sequences by biochemical assays and bioinformatic tools.

(R)-[(R)-3-Benzyl-2-oxooxazolidin-4-yl][4-(methyl-sulfon-yl)phen-yl]methyl acetate.

The structure of the title compound, C20H21NO6S, is of inter-est with respect to its anti-bacterial properties. The oxazolidine ring makes dihedral angles of 79.63 (14) and 56.16 (12)° with the phenyl and benzene rings, respectively, while the phenyl and benzene rings make a dihedral angle of 64.37 (13)°. In the crystal, non-classical C-H⋯O hydrogen bonds link adjacent mol-ecules along the c axis.

The Incidences and Related CT Features of Vascular Lake Phenomenon on Angiography Before Chemoembolization.

PURPOSE: To elucidate incidence rates of vascular lake phenomenon (VLP) in hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (ICC), hepatic metastasis (HMT) on transarterial angiography before chemoembolization, and to identity CT features predictive for it. MATERIALS AND METHODS: A comprehensive evaluation involved 665 subjects for incidence analysis, comprising 527 of HCC, 33 of ICC and 105 of HMT. VLP was characterized as intratumoral contrast material pool persisting late into venous phase. Incidences were cataloged on both super-selective and common hepatic artery angiography. For CT features analysis, a subset of 182 cases were analyzed. Enhancement ratio served as an index for comparative analysis of nodule enhancement degrees. RESULTS: In HCC, incidence of VLP ascertained via super-selective angiography was 13.5%, whereas it as 7.8% on common hepatic artery angiography. Remarkably, no incidences of VLP were recorded in either ICC or HMT cases. On pre-interventional CT, the prevalence of pseudocapsule was statistically greater in VLP group than Non-VLP group (66.6% vs. 37.6%, P = 0.015). The Houndsfield units (HU) of tumors in plain scan (P = 0.007), arterial phase (P = 0.001), venous phase (P = 0.041), arterial phase enhancement ratio (P < 0.001) were statistically higher in VLP group compared to Non-VLP group. Arterial phase enhancement ratio (P = 0.025), presence of pseudocapsule (P = 0.001), HU of tumor in plain scan (P = 0.035) serve as independent risk factors for VLP manifestation. CONCLUSION: VLP is a distinct angiography phenomenon uniquely associated with HCC. High arterial phase enhancement ratio, presence of pseudocapsule, high HU of tumor in plain scan are independent risk factors for VLP.

Role of Arg228 in the phosphorylation of galactokinase: the mechanism of GHMP kinases by quantum mechanics/molecular mechanics studies.

GHMP kinases are a group of structurally related small molecule kinases. They have been found in all kingdoms of life and are mostly responsible for catalyzing the ATP-dependent phosphorylation of intermediary metabolites. Although the GHMP kinases are of clinical, pharmaceutical, and biotechnological importance, the mechanism of GHMP kinases is controversial. A catalytic base mechanism was suggested for mevalonate kinase that has a structural feature of the γ-phosphate of ATP close to an aspartate residue; however, for one GHMP family member, homoserine kinase, where the residue acting as general base is absent, a direct phosphorylation mechanism was suggested. Furthermore, it was proposed by some authors that all the GHMP kinases function by a similar mechanism. This controversy in mechanism has limited our ability to exploit these enzymes as drug targets and in biotechnology. Here the phosphorylation reaction mechanism of the human galactokinase, a member of the GHMP kinase family, was investigated using molecular dynamics simulations and density functional theory-based quantum mechanics/molecular mechanics calculations (B3LYP-D/AMBER99). The reaction coordinates were localized by potential energy scan using an adiabatic mapping method. Our results indicate that a highly conserved Glu174 captures Arg105 in the proximity of the α-phosphate of ATP, forming a H-bond network; therefore, the mobility of ATP in the large oxyanion hole is restricted. Arg228 functions to stabilize the negative charge developed at the ß,γ-bridging oxygen of the ATP during bond cleavage. The reaction occurs via a direct phosphorylation mechanism, and the Asp186 in the proximity of ATP does not directly participate in the reaction pathway. Because Arg228 is not conserved among GHMP kinases, reagents which form interactions with Arg228, and therefore can interrupt its function in phosphorylation, may be developed into potential selective inhibitors for galactokinase.

[Curative effects on standardized management of community patients with coronary heart disease complicated with chronic heart failure].

OBJECTIVE: To explore the effects on the standardized management of patients with coronary atherosclerotic heart disease complicated with chronic heart failure. METHODS: A total of 823 patients discharged from our department were randomly enrolled. Among 734 patients with follow-up consents, they were divided into management and control groups (n = 440, 294). The management group received standardized out-of-hospital management, regular health education and follow-ups of telephone and outpatient visits. RESULTS: Compared with the control group, the management group had lower rates of all-cause mortality, cardiac death and readmission due to cardiovascular events (CVE) declining by 26.5%, 32.2% and 57.0% respectively. Over a 4-year period, the annular survival rate of management group was 92%, 85%, 83% and 82% while that of control group 95%, 89%, 82% and 75% respectively. Patient compliance of digoxin and diuretics in the control group was inferior to that in the management group. CONCLUSION: Through standardized out-of-hospital management, the patients with coronary atherosclerotic heart disease plus chronic heart failure may achieve significant benefits through reducing the rates of all-cause mortality, cardiac death and readmission due to CVE and improving survival rate.

Transcriptome-Wide Study Revealed That N6-Methyladenosine Participates in Regulation Meat Production in Goats.

In mammals, skeletal muscle development is a complex biological process regulated by many factors. N6-methyladenosine (m6A) RNA modification plays an important role in many biological processes. However, the regulation of m6A on skeletal muscle growth and development in adult goats remains unclear. In this study, Duan goats (DA) and Nubia goats (NBY), both female and 12 months old, were selected as the research objects, and m6A-Seq and RNA-Seq were mainly used to detect the difference of m6A modification and gene expression during the development of the longissimus dorsi (LD) muscle in the two breeds. The results showed that compared with DA, the meat production performance of NBY was better than that of DA, and the modification level of m6A was higher than that of DA in LD. The m6A-Seq of LD indicated m6A peaks were mainly enriched in the coding sequence (CDS) and stop codon. A total of 161 differentially methylated genes (DMGs) and 1294 differentially expressed genes (DEGs) were identified in two breeds. GO and KEGG analysis showed that DMGs were closely related to cellular metabolism, and most of DMGs were enriched in pathways related to energy metabolism, muscle growth and development, mainly MAPK signaling pathway, Wnt signaling pathway and CGMP-PKG signaling pathway. The DEGs were significantly enriched in actin binding, calcium ion binding, angiogenesis, and other biological processes, and most of them were enriched in PI3K-Akt and CGMP-PKG signaling pathways. Combined analysis of m6A-Seq and RNA-Seq data revealed a negative correlation between differentially methylated m6A levels and mRNA abundance, and mRNA expression of the gene with m6A peak near 3'UTR will decrease. In addition, 11 DMGs regulating cell differentiation, muscle growth and development were identified. This study displayed the m6A profiles and distribution patterns in the goat transcriptome, determined the potential role of m6A modification in muscle growth and provided a new reference for the further study of goat skeletal muscle development.

Effect of EGCG Extracted from Green Tea against Largemouth Bass Virus Infection.

(1) Background: Largemouth bass virus (LMBV) is a major viral pathogen in largemouth bass (Micropterus salmoides) aquaculture that often causes high mortality and heavy economic losses, thus developing treatments to combat this pathogen is of great commercial importance. Green tea is a well-known medicinal plant that contains active ingredients with antiviral, antibacterial, and other biological activities. The goals of this study were to explore the effect and mechanism of green tea source compounds on LMBV and provide data to serve as the basis for the screening of targeted drugs in the future. In this study, we evaluated the effects of the main component of green tea, epigallocatechin-3-gallate (EGCG), against LMBV infection. (2) Methods: The safe working concentration of EGCG was identified by cell viability detection and light microscopy. The antiviral activity and mechanism of action of EGCG against LMBV infection were evaluated with light microscopy, an aptamer 6-carboxy-fluorescein-based fluorescent molecular probe, and reverse transcription quantitative PCR. (3) Results: The safe working concentration of EGCG was ≤10 µg/mL. EGCG showed significant anti-LMBV infection activity in a concentration-dependent manner, and it also destroyed the structure of virus particles. EGCG impacted the binding of virus particles to cell receptors and virus invasion into the host cells. Inhibitory effects of EGCG on LMBV particles, LMBV binding to the host-cell membrane, and LMBV invasion were 84.89%, 98.99%, and 95.23%, respectively. Meanwhile, the effects of EGCG subsequently were verified in vivo. The fatality rate of the LMBV + EGCG group was significantly lower than that of the LMBV group. (4) Conclusions: Our results suggest that EGCG has effective antiviral properties against LMBV and may be a candidate for the effective treatment and control of LMBV infections in largemouth bass aquaculture.

Gas-to-ionic liquid partition: QSPR modeling and mechanistic interpretation.

The present work was devoted to explore the quantitative structure-property relationships for gas-to-ionic liquid partition coefficients (log KILA ). A series of linear models were first established for the representative dataset (IL01). The optimal model was a four-parameter equation (1Ed) consisting of two electrostatic potential-based descriptors ( Σ V s , i n d - ${{\rm { \Sigma }}{V}_{s,ind}^{-}}$ and Vs,max ), one 2D matrix-based descriptor (J_D/Dt) and dipole moment (µ). All of the four descriptors introduced in the model can find the corresponding parameters, directly or indirectly, from Abraham's linear solvation energy relationship (LSER) or its theoretical alternatives, which endows the model good interpretability. Gaussian process was utilized to build the nonlinear model. Systematical validations, including 5-fold cross-validation for the training set, the validation for test set, as well as a more rigorous Monte Carlo cross-validation were performed to verify the reliability of the constructed models. Applicability domain of the model was evaluated, and the Williams plot revealed that the model can be used to predict the log KILA values of structurally diverse solutes. The other 13 datasets were also processed in the same way, and all of the linear models with expressions similar to equation 1Ed were obtained. These models, whether linear of nonlinear, represent satisfactory statistical results, which confirms the universality of the method adopted in this study in QSPR modeling of gas-to-IL partition.

Effect of double mutations K214/A-E215/Q of FRATide on GSK3ß: insights from molecular dynamics simulation and normal mode analysis.

Glycogen synthase kinase 3ß (GSK3ß) is a multifunctional serine/threonine protein kinase that is involved in several biological processes including insulin and Wnt signaling pathways. The Wnt signaling via FRAT-mediated displacement of axin inhibits GSK3ß activity toward non-primed substrates without affecting its activity toward primed substrates. Herein, molecular dynamics simulation, molecular mechanics generalized Born/surface area (MM_GBSA) calculation, and normal mode analysis are performed to explore the structural influence of the double mutations K214/A-E215/Q of FRATide on the GSK3ß-FRATide complex. The results reveal that the priming phosphate-binding site, the primed substrate-binding site, the alignment of the critical active site residues in the ATP-binding site, as well as the periodic open-closed conformational change of the ATP-binding site, which are critical for the catalytic activity of GSK3ß, are negligibly influenced in the mutated system compared with the wild-type (WT) system. This indicates that FRATide does not inhibit the GSK3ß activity toward primed substrates. Additionally, MM_GBSA calculation indicates that the less energy-favorable GSK3ß-FRATide complex is observed in the mutant than in the WT complex.

A quantitative structure-property relationship analysis of soot-water partition coefficients for persistent organic pollutants.

Geometrical optimization and electrostatic potential calculations have been performed at the HF/6-31G level of theory for investigated persistent organic pollutants (POPs). A number of statistically based parameters have been obtained. Relationship between soot-water partition coefficients (logK(SC)) of POPs and the structural descriptors has been established by the multiple linear regression method. The result shows that the quantities derived from electrostatic potential V(s)(-)¯ and V(s,max), together with molecular surface area (A(S)) and the energy of the highest occupied molecular orbital (E(HOMO)) can be well used to express the quantitative relationship between structure and logK(SC) (QSPR) of POPs. Predictive capability of the model has been demonstrated by leave-one-out cross-validation with the cross-validated correlation coefficient of 0.9797. Furthermore, the predictive power of this model was further examined for the external test set with the correlation coefficient of 0.9811 between observed and predicted logK(SC), validating the robustness and good predictive ability of our model. Furthermore, in order to further investigate the applicability of these parameters derived from electrostatic potential in prediction of soot-water partition coefficient for organic pollutants, eleven polycyclic aromatic hydrocarbons (PAHs), eleven polychlorinated biphenyls (PCBs) and nine phenyl urea herbicides (PUHs) from other source have also been studied. The QSPR models established may provide a new powerful method for predicting soot-water partition coefficients (logK(SC)) of organic pollutants.

QSPR study on Hydrophobicity of Pt(II) complexes with surface electrostatic potential-based descriptors.

Pt(II) complexes play an important role in bioinorganic chemistry due to their antitumor activities. In the present study, we focused on building predictive models for the hydrophobicity of Pt(II) complexes. A five-parameter model, integrating frontier orbital energies (EHOMO, ELUMO) and descriptors derived from electrostatic potentials on molecular surface, was firstly constructed by using multiple linear regression (MLR) method. Mechanistic interpretations of the introduced descriptors were elucidated in terms of intermolecular interactions in the n-octanol/water partition system. Then, four up-to-date modeling methods, including support vector machine (SVM), least-squares support vector machine (LSSVM), random forest (RF) and Gaussian process (GP), were utilized to build the nonlinear models. Systematical validations including leave-one-out cross-validation, the validation for test set, as well as a very rigorous Monte Carlo cross-validation (MCCV) were performed to verify the reliability of the constructed models. The peak, median and integralRext2 values of the best GP model are 0.88, 0.86 and 0.84, respectively. The root mean squared errors for the test set (RMSEP) of the MLR, SVM, LSSVM and GP models fall in the range of 0.62-0.71. Although they are not superior to prior models built with the use of a number of descriptors, the results are satisfactory. Applicability domain of the model was evaluated.

Water-soluble bright NIR AIEgens with hybrid ROS for wash-free mitochondrial "off-on" imaging and photodynamic therapy.

Several aggregation-induced emission luminogens (AIEgens) with excellent water-solubility and near-infrared emission were designed and synthesized for wash-free "off-on" mitochondrial imaging and photodynamic therapy of HeLa cells. The AIEgen TEPP exhibits both bright near-infrared emission (φF = 17.8%) and high hybrid ROS productivity (including OH˙ and 1O2).

Molecularly engineered AIEgens with enhanced quantum and singlet-oxygen yield for mitochondria-targeted imaging and photodynamic therapy.

Luminogens characteristic of aggregation-induced emission (AIEgens) have been extensively exploited for the development of imaging-guided photodynamic therapeutic (PDT) agents. However, intramolecular rotation of donor-acceptor (D-A) type AIEgens favors non-radiative decay of photonic energy which results in unsatisfactory fluorescence quantum and singlet oxygen yields. To address this issue, we developed several molecularly engineered AIEgens with partially "locked" molecular structures enhancing both fluorescence emission and the production of triplet excitons. A triphenylphosphine group was introduced to form a D-A conjugate, improving water solubility and the capacity for mitochondrial localization of the resulting probes. Experimental and theoretical analyses suggest that the much higher quantum and singlet oxygen yield of a structurally "significantly-locked" probe (LOCK-2) than its "partially locked" (LOCK-1) and "unlocked" equivalent (LOCK-0) is a result of suppressed AIE and twisted intramolecular charge transfer. LOCK-2 was also used for the mitochondrial-targeting, fluorescence image-guided PDT of liver cancer cells.

Role of bridging water molecules in GSK3ß-inhibitor complexes: insights from QM/MM, MD, and molecular docking studies.

The role of water molecules is increasingly gaining interest in drug design, and several studies have highlighted their paramount contributions to the specificity and the affinity of ligand binding. In this study, we employ the two-layer ONIOM-based quantum mechanics/molecular mechanics (QM/MM) calculations, molecular dynamics (MD) simulations, and molecular docking studies to investigate the effect of bridging water molecules at the GSK3ß-inhibitors interfaces. The results obtained from the ONIOM geometry optimization and AIM analysis corroborated the presence of bridging water molecules that form hydrogen bonds with protein side chain of Thr138 and/or backbone of Gln185, and mediate interactions with inhibitors in the 10 selected GSK3ß-inhibitor complexes. Subsequently, MD simulations carried out on a representative system of 1R0E demonstrated that the bridging water molecule is stable at the GSK3ß-inhibitor interface and appears to contribute to the stability of the protein-inhibitor interactions. Furthermore, molecular docking studies of GSK3ß-inhibitor complexes indicated that the inhibitors can increase binding affinities and the better docked conformation of inhibitors can be obtained by inclusion of the bridging water molecules, especially for the flexible inhibitors, in docking experiments into individual protein conformations. Our results elucidate the importance of bridging water molecules at the GSK3ß-inhibitor interfaces and suggest that they might prove useful in rational drug design.

The importance of Src homology 2 domain-containing leukocyte phosphoprotein of 76 kilodaltons sterile-alpha motif domain in thymic selection and T-cell activation.

The Src homology 2 domain-containing leukocyte phosphoprotein of 76 kilodaltons (SLP-76) is a cytosolic adaptor protein essential for thymocyte development and T-cell activation. It contains a sterile-alpha motif (SAM) domain, 3 phosphotyrosine motifs, a proline-rich region, and a Src homology 2 domain. Whereas the other domains have been extensively studied, the role of the SAM domain in SLP-76 function is not known. To understand the function of this domain, we generated SLP-76 knockin mice with the SAM domain deleted. Analysis of these mice showed that thymocyte development was partially blocked at the double-positive to single-positive transition. Positive and negative thymic selection was also impaired. In addition, we analyzed T-cell receptor (TCR)-mediated signaling in T cells from these mutant mice. TCR-mediated inositol 1,4,5-triphosphate production, calcium flux, and extracellular signal-regulated kinase activation were decreased, leading to defective interleukin-2 production and proliferation. Moreover, despite normal association between Gads and SLP-76, TCR-mediated formation of SLP-76 microclusters was impaired by the deletion of the SAM domain. Altogether, our data demonstrated that the SAM domain is indispensable for optimal SLP-76 signaling.

Percutaneous vertebroplasty as a treatment for painful osteoblastic metastatic spinal lesions.

Percutaneous vertebroplasty (PVP) has been used widely to treat pain caused by osteolytic spinal lesions, whereas vertebroplasty for osteoblastic spinal lesions is less known. The purpose of this study is to describe PVP as a highly effective miniinvasive procedure to treat painful osteoblastic metastatic spinal lesions. Four patients with painful osteoblastic metastatic spinal lesions were treated by PVP in the authors' department, and immediately relief of pain was achieved in all of them. The findings from this study may encourage more studies of PVP in palliative treatment of patients with osteoblastic lesions.

Molecular modeling and molecular dynamics simulation studies of the GSK3ß/ATP/substrate complex: understanding the unique P+4 primed phosphorylation specificity for GSK3ß substrates.

Substrate specificity of protein kinases is of fundamental importance for the integrity and fidelity of signaling pathways. Glycogen synthase kinase 3ß (GSK3ß) has a unique substrate specificity that prefers phosphorylation of its substrates at the P+4 serine before it can further phosphorylate the substrate at the P0 serine in the canonical motif SXXXS(p), where S(p) is the primed phosphorylation site. The detailed phosphorylation mechanism, however, is not clearly understood. In this study, a three-dimensional (3D) model of the ternary complex of GSK3ß, ATP, and the phosphorylated glycogen synthase (pGS), termed GSK3ß/ATP/pGS, is constructed using a hierarchical approach and by integrating molecular modeling and molecular dynamics (MD) simulations. Based on the 3D model, the substrate primed phosphorylation mechanism is investigated via two 12 ns comparative MD simulations of the GSK3ß/ATP/pGS and GSK3ß/ATP/GS systems, which differ in the phosphate group bound to the P+4 serine of GS. In agreement with structural analysis, computed binding free energies reveal that the binding of pGS to GSK3ß is favored in the prephosphorylated state compared with the GS native state. More importantly, comparison with the system simulated without primed phosphorylation in the GSK3ß/ATP/GS complex shows that for an optimal phosphorylation reaction to occur, the pGS priming phosphate in the GSK3ß/ATP/pGS system optimizes the proper orientation of the GSK3ß N- and C-terminal domains and clamps the P0 serine of pGS in the appropriate configuration for interaction with the ATP γ-phosphate within the catalytic groove.

Drug metabolism-based design, synthesis, and bioactivities of 1-(2,6-dimethylphenoxy)-2-(3,4-dimethoxyphenylethylamino)propane hydrochloride (DDPH) analogs as α1-adrenoceptors antagonists.

1-(2,6-dimethylphenoxy)-2-(3,4-dimethoxyphenylethylamino)propane hydrochloride (DDPH) is a potent α1-adrenoceptor antagonist that is currently under Phase II clinic trials. However, the fast metabolism has restricted its further use. In this paper, 11 DDPH analogs were designed according to the probable metabolism pathways of DDPH, and featured the structures of halogen, methyl, and cyano groups at the 3-, or 4-position of aromatic ring A to block the hydroxylation, and one hydroxyl group at the 3-, or 4-position of aromatic ring B to extend the duration time. These compounds were synthesized in moderate to good yields from the reductive amination of substituted phenoxyacetones with substituted phenylethylamines, and fully characterized with ¹H NMR, IR, and HRMS. Biological evaluation indicated that most of the compounds exhibited strong blocking and moderate to good antihypertensive activities. It is clear that the compounds having 4-OH/3-OMe on group B exhibited higher blocking activities and longer duration time than their corresponding analogs having 4-OMe/3-OMe (and also 3-OH/4-OMe). Among them, compound 13 having bromo group at the 4-position of ring A and 4-OH/3-OMe on group B, exhibited the highest blocking activity, whereas compound 17 that had a methyl group at the 4-position of ring A and a hydroxyl group at the 4-position of ring B, was more active than potent DDPH in terms of both blocking and antihypertensive activities. In addition, the possible correlations between the blocking and antihypertensive activities are also briefly discussed.