OBJECTIVETo assess the binding activity of polypeptide containing human Na+, K+-ATPase alpha1 subunit M1-M2 extracellular segment (HES1 derivative).

METHODSHES1 derivative was synthesized by Fmoc method and purified by high-performance liquid chromatography-mass spectrometry, and its binding activity was identified by radioligand binding assay.

RESULTS3H-ouabain and synthetic HES1 derivative showed some binding activity with the equilibrium dissociation constant (KD) of 24.58 nmol/L, with the the receptor density of 492.43 fmol x mg(-1) pro. and IC50 of 3.078 x 10(-7) mol/L.

CONCLUSIONHES1 derivative can bind to ouabain and has the potential of becoming an effective therapeutic agent.

Binding Sites ; drug effects ; Extracellular Space ; metabolism ; Humans ; Ouabain ; chemistry ; pharmacology ; Peptides ; chemistry ; Protein Binding ; Sodium-Potassium-Exchanging ATPase ; chemistry ; genetics ; metabolism

OBJECTIVETo investigate the vasodilative effect of paeonol in rat mesenteric artery and the mechanisms responsible for it.

METHODSRats were anaesthetized and sacrificed. The superior mesenteric artery was removed, dissected free of adherent tissue and cut into 2.0 mm long cylindrical segments. Isometric tension of artery rings was recorded by a myograph system in vitro. Concentration-relaxation curves of paeonol (17.8 μ mol/L to 3.16 mmol/L) were recorded on artery rings precontracted by potassium chloride (KCl) and concentration-contraction curves of KCl, 5-hydroxytryptamine (5-HT), noradrenaline (NA) or calcium chloride (CaCl2) were recorded in the presence of paeonol (10(-4.5), 10(-3.8), 10(-3.5) mol/L) respectively. And also, concentration-relaxation curves of paeonol were recorded in the presence of different potassium channel inhibitors and propranolol on rings precontracted with KCl respectively. To investigate the role of intracellular Ca(2+) release from Ca(2+) store, the contraction induced by NA (100 μ mol/L) and CaCl2 (2 mmol/L) in Ca(2+) free medium was observed in the presence of paeonol respectively.

RESULTSPaeonol relaxed artery rings precontracted by KCl in a concentration-dependent manner and the vasodilatation effect was not affected by endothelium denudation. Paeonol significant decreased the maximum contractions (Emax) induced by KCl, CaCl2, NA and 5-HT, as well as Emax induced by NA and CaCl2 in Ca(2+) -free medium, suggesting that paeonol dilated the artery via inhibiting the extracellular Ca(2+) influx mediated by voltage-dependent calcium channel, and receptor-mediated Ca(2+)-influx and release. Moreover, none of glibenclamide, tetraethylammonium, barium chlorded and propranolol affected the paeonol-induced vasodilatation, indicating that the vasodilatation was not contributed to ATP sensitive potassium channel, calcium-activated potassium channel, inwardly rectifying potassium channel, and β-adrenoceptor.

CONCLUSIONPaeonol induces non-endothelium dependent-vasodilatation in rat mesenteric artery via inhibiting voltage-dependent calcium channel-mediated extracellular Ca(2+) influx and receptor-mediated Ca(2+) influx and release.

Acetophenones ; pharmacology ; Adrenergic beta-Antagonists ; pharmacology ; Animals ; Calcium ; metabolism ; Calcium Chloride ; pharmacology ; Endothelium, Vascular ; drug effects ; physiology ; Extracellular Space ; drug effects ; metabolism ; Female ; In Vitro Techniques ; Intracellular Space ; drug effects ; metabolism ; Male ; Mesenteric Arteries ; drug effects ; physiology ; Norepinephrine ; pharmacology ; Potassium Channel Blockers ; pharmacology ; Potassium Chloride ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Serotonin ; pharmacology ; Vasoconstriction ; drug effects ; Vasodilation ; drug effects

Corticotrophin-releasing factor (CRF) plays a major role in coordinating stress responses. We aimed to test whether blocking endogenous CRF activity can prevent the stress-induced dilation of intercellular spaces in esophageal mucosa. Eighteen adult male rats were divided into 3 groups: 1) a non-stressed group (the non-stressed group), 2) a saline-pretreated stressed group (the stressed group), 3) and an astressin-pretreated stressed group (the astressin group). Immediately after completing the experiments according to the protocol, distal esophageal segments were obtained. Intercellular space diameters of esophageal mucosa were measured by transmission electron microscopy. Blood was sampled for the measurement of plasma cortisol levels. Mucosal intercellular spaces were significantly greater in the stressed group than in the non-stressed group. Mucosal intercellular spaces of the astressin group were significantly smaller than those of the stressed group. Plasma cortisol levels in the stressed group were significantly higher than in the non-stressed group. Pretreatment with astressin tended to decrease plasma cortisol levels. Acute stress in rats enlarges esophageal intercellular spaces, and this stress-induced alteration appears to be mediated by CRF. Our results suggest that CRF may play a role in the pathophysiology of reflux-induced symptoms or mucosal damage.
Animals ; Corticotropin-Releasing Hormone/*antagonists & inhibitors/metabolism/pharmacology ; Esophagus/anatomy & histology/*drug effects ; Extracellular Space/*drug effects ; Hydrocortisone/blood ; Male ; Mucous Membrane/anatomy & histology/*drug effects ; Neuroprotective Agents/pharmacology ; Peptide Fragments/*pharmacology ; Rats ; Rats, Wistar ; *Stress, Psychological/blood/physiopathology

OBJECTIVETo investigate the changes of pharmacokinetic parameters of amikacin in the subeschar tissue fluid (STF) in the early stage of severe burns.

METHODSAmikacin concentration in the STF of 10 severely burned patients were determined by fluorescence polarization immunoassay (FPIA) at different time points after intravenous amikacin infusion of the initial dose of 400 mg given within 60 min. The pharmacokinetic parameters of amikacin were measured using 3P97 program and statistically analyzed with SPSS10.0 software.

RESULTS AND CONCLUSIONAfter the initial dose of 400 mg of amikacin, the STF concentration-time curves of amikacin were fitted in two compartment model. The pharmacokinetic parameters of amikacin in the STF were: t(1/2alpha)=(4.35-/+1.66) h, t(1/2beta)= (80.04-/+9.52) h, Vc= (13.17-/+1.32) L, AUC= (1802.49-/+285.68) microg. h.ml(-1), and CLs= (0.2272-/+0.0383) L. h(-1), demonstrating significantly lower clearance and longer elimination half life of amikacin in the STF following amikacin administration in early stage of severe burns. Elimination half-life of amikacin in the STF in severely burned patients was 28.20-44.78 times longer than that in the serum of normal volunteers, and the effective inhibitory concentration of amikacin could maintain for at least 24 h, suggesting antibiotic retention in the third space after early and short-term use of potent antibiotics and formation of antibiotic barrier in the STF, which may help prevent bacterial infection of the wound.

Adult ; Amikacin ; administration & dosage ; pharmacokinetics ; therapeutic use ; Anti-Bacterial Agents ; administration & dosage ; pharmacokinetics ; therapeutic use ; Burns ; drug therapy ; metabolism ; Extracellular Space ; metabolism ; Exudates and Transudates ; metabolism ; Female ; Humans ; Infusions, Intravenous ; Male ; Skin ; drug effects ; metabolism ; pathology

The accumulation of abnormal protein aggregates is a major characteristic of many neurodegenerative disorders, including Parkinson's disease (PD). The intracytoplasmic deposition of alpha-synuclein aggregates and Lewy bodies, often found in PD and other alpha-synucleinopathies, is thought to be linked to inefficient cellular clearance mechanisms, such as the proteasome and autophagy/lysosome pathways. The accumulation of alpha-synuclein aggregates in neuronal cytoplasm causes numerous autonomous changes in neurons. However, it can also affect the neighboring cells through transcellular transmission of the aggregates. Indeed, a progressive spreading of Lewy pathology among brain regions has been hypothesized from autopsy studies. We tested whether inhibition of the autophagy/lysosome pathway in alpha-synuclein-expressing cells would increase the secretion of alpha-synuclein, subsequently affecting the alpha-synuclein deposition in and viability of neighboring cells. Our results demonstrated that autophagic inhibition, via both pharmacological and genetic methods, led to increased exocytosis of alpha-synuclein. In a mixed culture of alpha-synuclein-expressing donor cells with recipient cells, autophagic inhibition resulted in elevated transcellular alpha-synuclein transmission. This increase in protein transmission coincided with elevated apoptotic cell death in the recipient cells. These results suggest that the inefficient clearance of alpha-synuclein aggregates, which can be caused by reduced autophagic activity, leads to elevated alpha-synuclein exocytosis, thereby promoting alpha-synuclein deposition and cell death in neighboring neurons. This finding provides a potential link between autophagic dysfunction and the progressive spread of Lewy pathology.
Adenine/analogs & derivatives/pharmacology ; Animals ; *Autophagy/drug effects ; Cell Line ; *Exocytosis/drug effects ; Extracellular Space/*metabolism ; Humans ; Mice ; Mice, Knockout ; Microtubule-Associated Proteins/deficiency/metabolism ; Phagosomes/drug effects/metabolism ; Protein Structure, Quaternary ; Protein Transport/drug effects ; alpha-Synuclein/chemistry/*metabolism/secretion/toxicity

Aminolevulinic acid (ALA) is biosynthesized by the enzyme ALA synthase (ALAS). The ALA production has been studied using the overproducing ALAS from several bacteria in Escherchia coil, respectively. However, ALAS from eucaryote expressed in E. coli for producing ALA in the culture is not known. The extracellular ALA production and cell growth were investageted respectively using the recombinant E. coli overproducing Saccharomyces cerevisiae ALAS in shake-flask fermentations. The ALAS activity from the cell extract was assayed. The extracellular ALA was purified by the national-made large-dimension resins and confirmed by the capillary electrophoresis measurements. At 12h after induction at 37 degrees C, the extracellular ALA production was up to 162mg per liter LB culture at initial pH 6.5 with exogenous levulinate, succinate and and glycine at the concentration of 20 mmol/L respectively. The purity of ALA after purification is up to 90%.
5-Aminolevulinate Synthetase ; genetics ; metabolism ; Aminolevulinic Acid ; isolation & purification ; metabolism ; Cell Division ; drug effects ; Dose-Response Relationship, Drug ; Electrophoresis, Capillary ; Escherichia coli ; genetics ; growth & development ; metabolism ; Extracellular Space ; drug effects ; metabolism ; Glycine ; pharmacology ; Hydrogen-Ion Concentration ; Levulinic Acids ; pharmacology ; Recombinant Proteins ; metabolism ; Saccharomyces cerevisiae ; enzymology ; genetics ; Saccharomyces cerevisiae Proteins ; genetics ; metabolism ; Succinic Acid ; pharmacology

OBJECTIVETo investigate the effect of 2,3,4',5-tetrahydroxystilbene-2-O-β-D-glucoside (TSG), an active component extracted from the root of Polygonum multiflorum, on angiotensin II (Ang II)-induced proliferation of cultured rat vascular smooth muscle cells (VSMCs) and to identify the potential mechanism.

METHODSCell proliferation and cell cycle were determined by cell counting, 5-bromo-2'-deoxyuridine incorporation assay, proliferating cell nuclear antigen protein expression and flow cytometry. Levels of phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2), mitogenic extracellular kinase 1/2 (MEK1/2) and Src in VSMCs were measured by Western blot. The expression of c-fos, c-jun and c-myc mRNA were measured by reverse transcription polymerase chain reaction (RT-PCR). Intracellular reactive oxygen species (ROS) was measured by fluorescence assay.

RESULTSTSG significantly inhibited Ang II-induced VSMCs proliferation and arrested cells in the G /S checkpoint (P<0.05 or P<0.01). TSG decreased the levels of phosphorylated ERK1/2, MEK1/2 and Src in VSMCs (P<0.05 or P<0.01). TSG also suppressed c-fos, c-jun and c-myc mRNA expression <0.05 or P<0.01). In addition, the intracellular ROS was reduced by TSG (P<0.01).

CONCLUSIONSTSG inhibited Ang II-induced VSMCs proliferation. Its antiproliferative effect might be associated with down-regulation of intracellular ROS, followed by the suppression of the Src-MEK1/2-ERK1/2 signal pathway, and hence, blocking cell cycle progression.

Angiotensin II ; pharmacology ; Animals ; Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Glucosides ; pharmacology ; Intracellular Space ; metabolism ; Male ; Mitogen-Activated Protein Kinase Kinases ; metabolism ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; cytology ; drug effects ; Phosphorylation ; drug effects ; Proliferating Cell Nuclear Antigen ; metabolism ; Proto-Oncogene Proteins ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats, Sprague-Dawley ; Reactive Oxygen Species ; metabolism ; Stilbenes ; pharmacology ; Superoxide Dismutase ; metabolism

Previously we demonstrated that ATP released from LPS-activated microglia induced IL-10 expression in a process involving P2 receptors, in an autocrine fashion. Therefore, in the present study we sought to determine which subtype of P2 receptor was responsible for the modulation of IL-10 expression in ATP-stimulated microglia. We found that the patterns of IL-10 production were dose-dependent (1, 10, 100, 1,000 micrometer) and bell-shaped. The concentrations of ATP, ATP-gammaS, ADP, and ADP-beta S that showed maximal IL-10 release were 100, 10, 100, and 100 micrometer respectively. The rank order of agonist potency for IL-10 production was 2'-3'-O-(4-benzoyl)-benzoyl ATP (BzATP) = dATP > 2-methylthio-ADP (2-meSADP). On the other hand, 2-methylthio-ATP (2-meSATP), alpha,beta-methylene ATP (alpha,beta-meATP), UTP, and UDP did not induce the release of IL-10 from microglia. Further, we obtained evidence of crosstalk between P2 receptors, in a situation where intracellular Ca2+ release and/or cAMP-activated PKA were the main contributors to extracellular ATP-(or ADP)-mediated IL-10 expression, and IL-10 production was down- regulated by either MRS2179 (a P2Y1 antagonist) or 5'-AMPS (a P2Y11 antagonist), indicating that both the P2Y1 and P2Y11 receptors are major receptors involved in IL-10 expression. In addition, we found that inhibition of IL-10 production by high concentrations of ATP-gammaS (100 micrometer) was restored by TNP-ATP (an antagonist of the P2X1, P2X3, and P2X4 receptors), and that IL-10 production by 2-meSADP was restored by 2meSAMP (a P2Y12 receptor antagonist) or pertusis toxin (PTX; a Gi protein inhibitor), indicating that the P2X1, P2X3, P2X4 receptor group, or the P2Y12 receptor, negatively modulate the P2Y11 receptor or the P2Y1 receptor, respectively.
Adenosine Diphosphate/analogs & derivatives/pharmacology ; Adenosine Triphosphate/analogs & derivatives/*pharmacology ; Adenylate Cyclase/antagonists & inhibitors ; Animals ; Calcium/metabolism ; Chelating Agents/pharmacology ; Cyclic AMP-Dependent Protein Kinases/antagonists & inhibitors ; Enzyme Inhibitors/pharmacology ; Extracellular Space/drug effects/*metabolism ; Gene Expression Regulation/drug effects ; Interleukin-10/*biosynthesis ; Microglia/*drug effects/enzymology/*metabolism ; RNA, Messenger/genetics/metabolism ; Rats ; Rats, Sprague-Dawley ; Receptor Cross-Talk/*drug effects ; Receptors, Purinergic P2/agonists/antagonists & inhibitors/genetics/*metabolism ; Thionucleotides/pharmacology