Naringin enhances the migration and osteogenic differentiation of human dental pulp stem cells

Bioactive flavonoids have been shown to improve the biological activity of stem cells derived from different sources in tissue regeneration. The goal of this study was to see how naringin, a natural flavonoid discovered in citrus fruits, affected the biological properties of human dental pulp stem cells (HDPSCs). In this study, we found that naringin increases the migratory ability of HDPSCs. Naringin increased matrix metalloproteinase-2 (MMP-2) and C-X-C chemokine receptor type 4 (CXCR4) mRNA and protein expression in HDPSCs. ARP100, a selective MMP-2 inhibitor, and AMD3100, a CXCR4 antagonist, both inhibited the naringin-induced migration of HDPSCs. Furthermore, naringin increased osteogenic differentiation of HDPSCs and the expression of the osteogenic-related marker, alkaline phosphatase in HDPSCs. Taken together, our findings suggest that naringin may be beneficial on dental tissue or bone regeneration by increasing the biological activities of HDPSCs.

Vinpocetine inhibits the proliferation and induces apoptosis in human colon cancer cells

Vinpocetine induces anti-inflammatory effects in various inflammatory diseases via the inhibition of phosphodiesterase type-1-independent nuclear factor-κB signaling pathway and the release of inflammatory cytokines. In this study, we investigated the effect of vinpocetine on the proliferation of colon cancer cells and its underlying molecular mechanisms. Our data showed that vinpocetine inhibits the viability and proliferation of colon cancer cells. Vinpocetine treatment induced cell death in HCT116 cells, which the percentages of sub-G1 phase were significantly increased, and the apoptosis-related genes were regulated after HCT116 cells were treated with vinpocetine. In sum, our findings indicated that vinpocetine could be a therapeutically useful candidate in the treatment of colon cancer.

Water-soluble coenzyme Q10 provides better protection than lipid-soluble coenzyme Q10 in a rat model of chronic tacrolimus nephropathy

Background/Aims@#Coenzyme Q10 (CoQ10), is a promising antioxidant; however, low bioavailability owing to lipid-solubility is a limiting factor. We developed water-soluble CoQ10 (CoQ10-W) and compared its effects with conventional lipid-soluble CoQ10 (CoQ10-L) in an experimental model of chronic tacrolimus (Tac) nephropathy. @*Methods@#CoQ10-W was developed from a glycyrrhizic-carnitine mixed layer CoQ10 micelle based on acyltransferases. Chronic nephropathy was induced in rats with 28-day Tac treatment; they were concomitantly treated with CoQ10-L or CoQ10-W. CoQ10 level in plasma and kidney were measured using liquid chromatography–mass spectrometry. CoQ10-W and CoQ10-L effects on Tac-induced nephropathy were assessed in terms of renal function, histopathology, oxidative stress, and apoptotic cell death. Their effects on cell viability and reactive oxygen species (ROS) production were assessed in cultured proximal tubular cells, human kidney 2 (HK-2) cells. @*Results@#The plasma CoQ10 level was significantly higher in the CoQ10-W group than in the CoQ10-L group. Tac treatment caused renal dysfunction, typical pathologic lesions, and oxidative stress markers. Serum creatinine was restored in the Tac + CoQ10-L or CoQ10-W groups compared with that in the Tac group. CoQ10-W administration reduced oxidative stress and apoptosis markers. Mitochondrial ultrastructure assessment revealed that the addition of CoQ10-L or CoQ10-W with Tac increased mitochondrial size and number than Tac treatment alone. In vitro investigations revealed that both CoQ10-L and CoQ10-W improved cell viability and reduced ROS production in the Tac-induced HK-2 cell injury. @*Conclusions@#CoQ10-W has a better therapeutic effect in Tac-induced renal injury than conventional CoQ10-L, possibly associated with improved CoQ10 bioavailability

Vinpocetine inhibits the proliferation and induces apoptosis in human colon cancer cells

Vinpocetine induces anti-inflammatory effects in various inflammatory diseases via the inhibition of phosphodiesterase type-1-independent nuclear factor-κB signaling pathway and the release of inflammatory cytokines. In this study, we investigated the effect of vinpocetine on the proliferation of colon cancer cells and its underlying molecular mechanisms. Our data showed that vinpocetine inhibits the viability and proliferation of colon cancer cells. Vinpocetine treatment induced cell death in HCT116 cells, which the percentages of sub-G1 phase were significantly increased, and the apoptosis-related genes were regulated after HCT116 cells were treated with vinpocetine. In sum, our findings indicated that vinpocetine could be a therapeutically useful candidate in the treatment of colon cancer.

Water-soluble coenzyme Q10 provides better protection than lipid-soluble coenzyme Q10 in a rat model of chronic tacrolimus nephropathy

Background/Aims@#Coenzyme Q10 (CoQ10), is a promising antioxidant; however, low bioavailability owing to lipid-solubility is a limiting factor. We developed water-soluble CoQ10 (CoQ10-W) and compared its effects with conventional lipid-soluble CoQ10 (CoQ10-L) in an experimental model of chronic tacrolimus (Tac) nephropathy. @*Methods@#CoQ10-W was developed from a glycyrrhizic-carnitine mixed layer CoQ10 micelle based on acyltransferases. Chronic nephropathy was induced in rats with 28-day Tac treatment; they were concomitantly treated with CoQ10-L or CoQ10-W. CoQ10 level in plasma and kidney were measured using liquid chromatography–mass spectrometry. CoQ10-W and CoQ10-L effects on Tac-induced nephropathy were assessed in terms of renal function, histopathology, oxidative stress, and apoptotic cell death. Their effects on cell viability and reactive oxygen species (ROS) production were assessed in cultured proximal tubular cells, human kidney 2 (HK-2) cells. @*Results@#The plasma CoQ10 level was significantly higher in the CoQ10-W group than in the CoQ10-L group. Tac treatment caused renal dysfunction, typical pathologic lesions, and oxidative stress markers. Serum creatinine was restored in the Tac + CoQ10-L or CoQ10-W groups compared with that in the Tac group. CoQ10-W administration reduced oxidative stress and apoptosis markers. Mitochondrial ultrastructure assessment revealed that the addition of CoQ10-L or CoQ10-W with Tac increased mitochondrial size and number than Tac treatment alone. In vitro investigations revealed that both CoQ10-L and CoQ10-W improved cell viability and reduced ROS production in the Tac-induced HK-2 cell injury. @*Conclusions@#CoQ10-W has a better therapeutic effect in Tac-induced renal injury than conventional CoQ10-L, possibly associated with improved CoQ10 bioavailability

The therapeutic efficacy of water-soluble coenzyme Q10 in an experimental model of tacrolimus-induced diabetes mellitus

Background/Aims@#Coenzyme Q10 (CoQ10) has antioxidant effects and is commercially available and marketed extensively. However, due to its low bioavailability, its effects are still controversial. We developed a water-soluble CoQ10-based micelle formulation (CoQ10-W) and tested it in an experimental model of tacrolimus (TAC)-induced diabetes mellitus (DM). @*Methods@#We developed CoQ10-W from a glycyrrhizic-carnitine mixed layer CoQ10 micelle preparation based on acyltransferases. TAC-induced DM rats were treated with either lipid-soluble CoQ10 (CoQ10-L) or CoQ10-W for 4 weeks. Their plasma and pancreatic CoQ10 concentrations were measured using liquid chromatography- tandem mass spectrometry. The therapeutic efficacies of CoQ10-W and CoQ10-L on TAC-induced DM were compared using functional and morphological parameters and their effects on cell viability and reactive oxygen species (ROS) production were also evaluated in cultured rat insulinoma cells. @*Results@#The plasma CoQ10 level was significantly increased in the CoQ10-W group compared to that in the CoQ10-L group. Intraperitoneal glucose tolerance tests and glucose-stimulated insulin secretion revealed that CoQ10-W controlled hyperglycemia and restored insulin secretion significantly better than CoQ10-L. The TAC-mediated decrease in pancreatic islet size was significantly attenuated by CoQ10-W but not by CoQ10-L. TAC-induced oxidative stress and apoptosis were significantly more reduced by CoQ10-W than CoQ10-L. Electron microscopy revealed that CoQ10-W restored TAC-induced attenuation in the number of insulin granules and the average mitochondrial area, unlike CoQ10-L. In vitro studies showed that CoQ10-L and CoQ10-W both improved cell viability and reduced ROS production in TAC-treated islet cells to a similar extent. @*Conclusions@#CoQ10-W has better therapeutic efficacy than CoQ10-L in TAC-induced DM.

Resveratrol inhibits cell growth via targeting the Bmi-1 pathway in YD-10B human oral squamous cell carcinoma cells

Resveratrol has been reported to exert anticancer activity via modulation of multiple pathways and genes. In this study, we examined the effect of resveratrol on YD-10B human oral squamous cell carcinoma cells and its molecular mechanisms of action. We found that resveratrol inhibited the proliferation of YD-10B cells in a dose- and timedependent manner. The suppressive effect of resveratrol was accompanied by a reduction in Bmi-1 gene expression.We observed that silencing the Bmi-1 gene by small interfering RNA effectively downregulated the levels of GLUT1 mRNA and protein, which were also repressed by resveratrol. Bmi-1 silencing increased the number of YD-10B cells in S-phase arrest by approximately 2.3-fold compared with the control. In conclusion, the results of the present study demonstrate, for the first time, that resveratrol suppresses Bmi-1-mediated GLUT1 expression in human oral squamous cell carcinoma cells and suggest that the specific molecular targeting of Bmi-1 and/or GLUT1 expression can be combined with a chemotherapeutic strategy to improve the response of oral cancer cells to resveratrol.

Porphyromonas gingivalis lipopolysaccharide stimulates vascular smooth muscle cell migration through signal transducer and activator of transcription 3-mediated matrix metalloproteinase-9 expression

Periodontal diseases have been associated with the development of cardiovascular diseases. Accumulating evidences have indicated that Porphyromonas gingivalis, a major periodontopathic pathogen, plays a critical role in the pathogenesis of atherosclerosis. In the present study, we demonstrated that P. gingivalis lipopolysaccharide (LPS) increases the mRNA and protein expression of matrix metalloproteinase-9 (MMP-9) in rat vascular smooth muscle cells. We showed that the MMP-9 expression induced by P. gingivalis LPS is mediated by the activation of signal transducer and activator of transcription 3 (STAT3) in vascular smooth muscle cells. Furthermore, the inhibition of STAT3 activity reduced P. gingivalis LPS-induced migration of vascular smooth muscle cells. Overall, our findings indicate that P. gingivalis LPS stimulates the migration of vascular smooth muscle cells via STAT3-mediated MMP-9 expression.

Simultaneous quantification of ticagrelor and its active metabolite, AR-C124910XX, in human plasma by liquid chromatography-tandem mass spectrometry: Applications in steady-state pharmacokinetics in patients

A sensitive and simple liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous quantification of ticagrelor and its active metabolite, AR-C124910XX from 50 µL human plasma using tolbutamide as an internal standard as per regulatory guidelines. Analytes in plasma were extracted by simple protein precipitation using acetonitrile, followed by chromatographic separation with an Acclaim™ RSLC 120 C₁₈ column (2.2 µm, 2.1 × 100 mm) and a gradient acetonitrile-water mobile phase containing 0.1% formic acid within 8 min. Mass spectrometric detection and quantitation were conducted by selected reaction-monitoring on a negative electrospray ionization mode with the following transitions: m/z 521.11 → 361.10, 477.03 → 361.10, and 269.00 → 169.60 for ticagrelor, AR-C124910XX, and tolbutamide, respectively. The lower limit of quantifications was 0.2 ng/mL with linear ranges of 0.2–2,500 ng/mL (r² ≥ 0.9949) for both analytes. All validation data, including selectivity, cross-talk, precision, accuracy, matrix effect, recovery, dilution integrity, stability, and incurred sample reanalysis, were well within acceptable limits. This assay method was validated using K₂-EDTA as the specific anticoagulant. Also, the anticoagulant effect was tested by lithium heparin, sodium heparin, and K₃-EDTA. No relevant anticoagulant effect was observed. This validated method was effectively used in the determination of ticagrelor and its active metabolite, AR-C124910XX, in plasma samples from patients with myocardial infarction.

Theracurmin Ameliorates Cognitive Dysfunctions in 5XFAD Mice by Improving Synaptic Function and Mitigating Oxidative Stress

As the elderly population is increasing, Alzheimer's disease (AD) has become a global issue and many clinical trials have been conducted to evaluate treatments for AD. As these clinical trials have been conducted and have failed, the development of new theraphies for AD with fewer adverse effects remains a challenge. In this study, we examined the effects of Theracurmin on cognitive decline using 5XFAD mice, an AD mouse model. Theracurmin is more bioavailable form of curcumin, generated with submicron colloidal dispersion. Mice were treated with Theracurmin (100, 300 and 1,000 mg/kg) for 12 weeks and were subjected to the novel object recognition test and the Barnes maze test. Theracurmin-treated mice showed significant amelioration in recognition and spatial memories compared those of the vehicle-treated controls. In addition, the antioxidant activities of Theracurmin were investigated by measuring the superoxide dismutase (SOD) activity, malondialdehyde (MDA) and glutathione (GSH) levels. The increased MDA level and decreased SOD and GSH levels in the vehicle-treated 5XFAD mice were significantly reversed by the administration of Theracurmin. Moreover, we observed that Theracurmin administration elevated the expression levels of synaptic components, including synaptophysin and post synaptic density protein 95, and decreased the expression levels of ionized calcium-binding adapter molecule 1 (Iba-1), a marker of activated microglia. These results suggest that Theracurmin ameliorates cognitive function by increasing the expression of synaptic components and by preventing neuronal cell damage from oxidative stress or from the activation of microglia. Thus, Theracurmin would be useful for treating the cognitive dysfunctions observed in AD.

Melatonin Rescues Human Dental Pulp Cells from Premature Senescence Induced by H₂O₂

Although anti-aging activities of melatonin, a hormone secreted by the pineal gland, have been reported in senescence-accelerated mouse models and several types of cells, its impact and mechanism on the senescence of human dental pulp cells (HDPCs) remains unknown. In this study, we examined the impact of melatonin on cellular premature senescence of HDPCs. Here, we found that melatonin markedly inhibited senescent characteristics of HDPCs after exposure to hydrogen peroxide (H₂O₂), including the increase in senescence-associated β-galactosidase (SA-β-gal)-positive HDPCs and the upregulation of p21 protein, an indicator for senescence. In addition, as melatonin attenuated H₂O₂-stimulated phosphorylation of c-Jun N-terminal kinase (JNK), while selective inhibition of JNK activity with SP600125 significantly attenuated H₂O₂-induced increase in SA-beta-gal activity. Results reveal that melatonin antagonizes premature senescence of HDPCs via JNK pathway. Thus, melatonin may have therapeutic potential to prevent stress-induced premature senescence, possibly correlated with development of dental pulp diseases, and to maintain oral health across the life span.

Effect of hypoxia on angiogenesis-related proteins in human dental pulp cells

Dental pulp is a highly vascularized tissue with high regenerative potential. Revascularization of severed vasculature in the tooth is required for pulp healing during avulsed tooth treatment. In this study, the relative expression of angiogenesis-related proteins was determined in human dental pulp cells using a human angiogenesis proteome profiler array. The proteome profiler array detected differentially expressed angiogenesis-related factors under conditions of hypoxia, which enhances the angiogenic potential of dental pulp cells. We confirmed that hypoxia regulates the mRNA expression of angiogenesis-related factors, including CXCL16 in dental pulp cells. Furthermore, conditioned media of hypoxic pulp cells induced tube-like structures of vascular endothelial cells, which were reduced by the neutralization of CXCL16 function. In conclusion, our data show that angiogenesis-related factors are differentially expressed by hypoxia in dental pulp cells and suggest that CXCL16 may involve in the revascularization of hypoxic dental pulp.

Porphyromonas gingivalis Lipopolysaccharide Regulates Migration of Vascular Smooth Muscle Cells

Porphyromonas gingivalis, a foremost periodontal pathogen, has been known to cause periodontal diseases. Epidemiologic evidences have indicated the involvement of P. gingivalis in the development of cardiovascular diseases. In this study, we show that the P. gingivalis lipopolysaccharide increases the mRNA expression and protein secretion of interleukin-6 in vascular smooth muscle cells. We demonstrate that P. gingivalis LPS activates the extracellular signal-regulated kinase 1/2 (ERK1/2), p38 mitogen-activated protein kinase (MAPK), and Akt, which mediate the IL-6 expression in vascular smooth muscle cells. Also, P. gingivalis LPS stimulates the vascular smooth muscle cell migration, which is a critical step for the progression of atherosclerosis. Moreover, neutralization of the IL-6 function inhibits the migration of vascular smooth muscle cells induced by P. gingivalis LPS. Taken together, these results indicate that P. gingivalis LPS promotes the expression of IL-6, which in turn increases the migration of vascular smooth muscle cells.

Involvement of Heme Oxygenase-1 in Orexin-A-induced Angiogenesis in Vascular Endothelial Cells

The cytoprotective enzyme heme oxygenase-1 (HO-1) influences endothelial cell survival, proliferation, inflammatory response, and angiogenesis in response to various angiogenic stimuli. In this study, we investigate the involvement of HO-1 in the angiogenic activity of orexin-A. We showed that orexin-A stimulates expression and activity of HO-1 in human umbilical vein endothelial cells (HUVECs). Furthermore, we showed that inhibition of HO-1 by tin (Sn) protoporphryin-IX (SnPP) reduced orexin-A-induced angiogenesis in vivo and ex vivo. Orexin-A-stimulated endothelial tube formation and chemotactic activity were also blocked in SnPP-treated vascular endothelial cells. Orexin-A treatment increased the expression of nuclear factor erythroid-derived 2 related factor 2 (Nrf2), and antioxidant response element (ARE) luciferase activity, leading to induction of HO-1. Collectively, these findings indicate that HO-1 plays a role as an important mediator of orexin-A-induced angiogenesis, and provide new possibilities for therapeutic approaches in pathophysiological conditions associated with angiogenesis.

Isolation And Development Of Quantification Method For Cyanidin-3-glucoside And Cyanidin-3-rutinoside In Mulberry Fruit By High-performance Countercurrent Chromatography And High-performance Liquid Chromatography

Cyanidin-3-glucoside (C3G) and cyanidin-3-rutinoside (C3R) were isolated by high-performance countercurrent chromatography (HPCCC) using a two-phase solvent system composed of tert-butyl methyl ether/n-butanol/acetonitrile/water/trifluoroacetic acid (1 : 3 : 1 : 5 : 0.01, v/v) to give pure C3G (34.1 mg) and C3R (14.3 mg) from 1.5 g crude mulberry fruit extract. Using the pure C3G and C3R, a reliable high-performance liquid chromatography (HPLC) method was developed and validated to determine the C3G and C3R contents in mulberry fruit. C3G and C3R were separated simultaneously using an Eclipse XDB-C18 column (4.6 x 250 mm I.D., 5 microm) coupled with a photodiode array detector (PDA). The gradient elution of the mobile phase consisting of acetonitrile (0.5% formic acid) and water (0.5% formic acid) was applied (1.0 mL/min), and the detection wavelength was 520 nm. The calibration curves of C3G and C3R showed good linearity (both with r2 = 0.9996) in the concentration range 15.625 - 500 microg/mL, and the relative standard deviations (RSD%) of intra- and interday variability were in the ranges 2.1 - 8.2% and 4.1 - 17.1%, respectively. The accuracies were ranged 96.5 - 102.6% for C3G and C3R, respectively. The developed HPLC method was used to determine the contents of C3G and C3R in newly harvested mulberry from eight different provinces of Korea.

A Neuromedin B Receptor Blockade Inhibits the Growth of Human Oral Cancer Cells

Neuromedin B (NMB) acts as a growth factor or a morphogen and plays a role in cancer progression. Indeed, the NMB receptor (NMB-R) is overexpressed in different types of tumors. In our current study, we investigated the involvement of NMB-R in the proliferation of oral cancer cells. Human oral squamous cell carcinoma (SCC) and human oral cancer cells, SCC-25 cells were found to be NMB-R-positive. The NMB-R antagonist PD168368 inhibited the proliferation of SCC-25 cells and reduced their colony formation capacity. We also found that PD168368 induced the cell cycle arrest and apoptosis of SCC-25 cells in a dose-/time-dependent manner. Overall, this antitumor activity of PD168368 in human oral cancer cells suggests that NMB-R is a potential target for the future prevention and treatment of human cancers.

Establishment and Significance of Bioequivalence Recommendations for Individual Products-Drugs Acting on Circulatory System and Others

Along with the enactment of a law separating the prescribing and dispensing of drugs in Korea in 2000, attempts at reducing medical expenses by generic substitution have been allowed since August 2001 so long as generic products are bioequivalent to the original products. In the pharmaceutical industry, the required development and investment to make generic products are much less in terms of time and money. Thus, the number of bioequivalence studies in Korea has increased. This has resulted in the need for bioequivalence recommendations (guidelines), taking into account the circumstances of the Korean pharmaceutical industry. In this paper, we provide procedures for making bioequivalence determinations for individual products acting on the circulatory system (30 drugs, 2011), the components of which are widely accepted for the development of generic products in Korea. These recommendations correspond with international guidelines, such as those of the US FDA and EMEA. For the 30 drugs that act on the circulatory system, we examined each in terms of subject selection (healthy volunteers vs. patients), dosage strength, dosage route, analytes to measure, and evaluation parameters, and prepared bioequivalence recommendations for individual products through an analysis of many published papers, US FDA and EMEA guidelines, and clinical trial websites. Based on the bioequivalence recommendations for individual products, we had several meetings in which KFDA officers (members of the New Drug Research team and the Office of Generic Drugs), three pharmacy professors with expertise in drug analysis and pharmacokinetics, and three professors of medicine with extensive experience in clinical trials participated to confirm and discuss the contents. Finally, the bioequivalence recommendations for individual products were provided on the KFDA website. The individual bioequivalence recommendations have been used by KFDA officers in drug evaluations and bioequivalency testing to improve consistency, clarity, and professionalism in the drug evaluation process. These recommendations will be useful for domestic pharmaceutical companies by shortening the time and cost associated with bioequivalence studies, especially in terms of standardized trial designs, dosage forms, and analytical methods.

Mutant p53-Notch1 Signaling Axis Is Involved in Curcumin-Induced Apoptosis of Breast Cancer Cells

Notch1 has been reported to be highly expressed in triple-negative and other subtypes of breast cancer. Mutant p53 (R280K) is overexpressed in MDA-MB-231 triple-negative human breast cancer cells. The present study aimed to determine whether the mutant p53 can be a potent transcriptional activator of the Notch1 in MDA-MB-231 cells, and explore the role of this mutant p53-Notch1 axis in curcumin-induced apoptosis. We found that curcumin treatment resulted in an induction of apoptosis in MDA-MB-231 cells, together with downregulation of Notch1 and its downstream target, Hes1. This reduction in Notch1 expression was determined to be due to the decreased activity of endogenous mutant p53. We confirmed the suppressive effect of curcumin on Notch1 transcription by performing a Notch1 promoter-driven reporter assay and identified a putative p53-binding site in the Notch1 promoter by EMSA and chromatin immunoprecipitation analysis. Overexpression of mutant p53 increased Notch1 promoter activity, whereas knockdown of mutant p53 by small interfering RNA suppressed Notch1 expression, leading to the induction of cellular apoptosis. Moreover, curcumin-induced apoptosis was further enhanced by the knockdown of Notch1 or mutant p53, but it was decreased by the overexpression of active Notch1. Taken together, our results demonstrate, for the first time, that Notch1 is a transcriptional target of mutant p53 in breast cancer cells and suggest that the targeting of mutant p53 and/or Notch1 may be combined with a chemotherapeutic strategy to improve the response of breast cancer cells to curcumin.

Severe Pulmonary Hypertension Caused by Pulmonary Artery Stenosis in a Patient with Behcet's Disease Treated by Balloon Angioplasty / 대한내과학회지

Pulmonary artery stenosis that causes pulmonary hypertension is usually observed in congenital anomalies and is seldom observed in adults. A 47-year-old female patient came to the hospital for aggravated dyspnea and peripheral edema. Severe pulmonary hypertension was found on an echocardiography examination, along with dilation of the main pulmonary artery and alias flow at the bifurcation sites of both pulmonary arteries. Under coronary angio-computed tomography, 70% high grade stenosis was observed on both sides of the proximal pulmonary arteries without showing atherosclerotic plaque or a thrombus. The patient's symptoms improved after performing pulmonary artery angiography and angioplasty. Thus, we report our experience of a patient with Behcet's disease and severe pulmonary hypertension caused by pulmonary artery stenosis, which was treated with percutaneous pulmonary angioplasty.

The Effect of Lidocaine.HCl on the Fluidity of Native and Model Membrane Lipid Bilayers

The purpose of this study is to investigated the mechanism of pharmacological action of local anesthetic and provide the basic information about the development of new effective local anesthetics. Fluorescent probe techniques were used to evaluate the effect of lidocaine.HCl on the physical properties (transbilayer asymmetric lateral and rotational mobility, annular lipid fluidity and protein distribution) of synaptosomal plasma membrane vesicles (SPMV) isolated from bovine cerebral cortex, and liposomes of total lipids (SPMVTL) and phospholipids (SPMVPL) extracted from the SPMV. An experimental procedure was used based on selective quenching of 1,3-di(1-pyrenyl)propane (Py-3-Py) and 1,6-diphenyl-1,3,5-hexatriene (DPH) by trinitrophenyl groups, and radiationless energy transfer from the tryptophans of membrane proteins to Py-3-Py. Lidocaine.HCl increased the bulk lateral and rotational mobility of neuronal and model membrane lipid bilayes, and had a greater fluidizing effect on the inner monolayer than the outer monolayer. Lidocaine.HCl increased annular lipid fluidity in SPMV lipid bilayers. It also caused membrane proteins to cluster. The most important finding of this study is that there is far greater increase in annular lipid fluidity than that in lateral and rotational mobilities by lidocaine.HCl. Lidocaine.HCl alters the stereo or dynamics of the proteins in the lipid bilayers by combining with lipids, especially with the annular lipids. In conclusion, the present data suggest that lidocaine, in addition to its direct interaction with proteins, concurrently interacts with membrane lipids, fluidizing the membrane, and thus inducing conformational changes of proteins known to be intimately associated with membrane lipid.