Membrane effects of trifluoperazine, dibucaine and praziquantel on human erythrocytes

Trifluoperazine (TFP) is a potent antipsychotic agent, dibucaine (DBC) is a local anaesthetic and praziquantel (PZQ) is a highly effective agent against schistosomiasis. The present work was conducted to (i) investigate the cytotoxic effects of TFP, DEC

Pathways involved in trifluoperazine-, dibucaine- and praziquantel-induced hemolysis

This work elucidates differences in the hemolytic pathway developed by the antipsychotic trifluoperazine (TFP), the local anesthetic dibucaine (DBC) and the antihelminthic praziquantel (PZQ). Their partition coefficients (P) were measured at pH 7.4 between n-octanol, microsomes, liposomes, erythrocyte ghosts and n-octanol/water. The effective drug:lipid molar ratios for the onset of membrane solubilization (Re-SAT) and complete hemolysis (Re-SOL) were calculated from the experimental P values and compared with a classical surface-active compound treatment [Lichtenberg, D. Biochim. Biophys. Acta 821 (1985) 470-478]. The contribution of charged/uncharged forms of TFP and DEC for the hemolytic activity was also analyzed. In all cases the hemolytic phenomena could be related to the monomeric drug insertion into the membrane. Only for TFP at isosmotic condition lysis occurs at concentrations beyond the CR;IC of the drug, indicating that micellization facilitates TFP hemolytic effect, while DEC and PZQ reach a real membrane saturation at their monomeric form. (C) 2000 Elsevier Science B.V. All rights reserved.8328910

Effect of bilirubin on toxicity induced by trifluoperazine, dibucaine and praziquantel to erythrocytes

Unconjugated bilirubin (UCB), like trifluoperazine (TFP), dibucaine (DBC) and praziquantel (PZQ), induces erythrocyte morphological changes, lysis and lipid exfoliation. In the present study we determined whether TFP, DBC and PZQ toxicity to erythrocyte

MOUSE-LIVER MICROSOMES (MLM) PROTECT ERYTHROCYTES AGAINST TRIFLUOPERAZINE (TFP) INDUCED AND MECHANICAL HEMOLYSIS WHICH ARE DUE TO TFP MICROSOMAL TRANSFORMATION AND TO THE ACTION OF AN UNIDENTIFIED WATER-SOLUBLE MICROSOMAL FACTOR (UF)

Trifluoperazine (TFP), a phenothiazine derivative, produces either hemolysis or protection of erythrocytes under isosmotic conditions in a dose-dependent manner. The hemolytic effect of TFP is abolished in the presence of mouse liver microsomes (MLM) which is due, in part, to drug incorporation, transformation and a MLM enzyme driven metabolism. An unidentified water-soluble factor (or factors) derived from MLM has been found to protect erythrocytes against both mechanical and TFP-induced isosmotic hemolysis.19434935

Effect of bilirubin on toxicity induced by trifluoperazine, dibucaine and praziquantel to erythrocytes

Unconjugated bilirubin (UCB), like trifluoperazine (TFP), dibucaine (DBC) and praziquantel (PZQ), induces erythrocyte morphological changes, lysis and lipid exfoliation. In the present study we determined whether TFP, DBC and PZQ toxicity to erythrocytes was potentiated or reverted by UCB. Human erythrocytes were either treated or non-treated with 34.2 mu mol/L UCB for 10 min prior to the incubation with toxic concentrations of TFP (0.12 mmol/L). DEC (1.5 mmol/L) or PZQ (3.0 mmol/L). for 1 h (37 degreesC). Studies of toxic effects included morphological analysis of erythrocytes, evaluation of hemoglobin release and loss of membrane lipids. Although UCB has an echinocytogenic effect, its coincubation with TFP or PZQ did not alter the stomatocytogenic effect of the drug but enhanced DBC-induced stomatocytosis. Cell fusion was a common feature in experiments with DEC. Injurious effect of DEC to erythrocytes was potentiated by UCB as manifested by a marked increase in hemolysis (171%, p <0.05), and in elution of membrane cholesterol (73%. p <0.01) and phospholipids (123%, p <0.01). In opposite, toxic events produced by TFP and PZQ to erythrocytes were not aggravated by UCB. Interestingly, UCB prevented the loss of membrane cholesterol by PZQ (-36%. p <0.01), as well as that of phospholipids by TFP (-28%, p <0.05). These findings indicate that UCB potentiates DEC injury to erythrocytes, while protects membrane lipid elution by PZQ and TFP. Therefore, the relation of the benefits and risks of the administration of DEC to jaundiced patients should be carefully considered. (C) 2001 Elsevier Science Inc. All rights reserved.69886387

Quantitative assessment of human erythrocyte membrane solubilization by Triton X-100

We report here a quantitative analysis of the interaction of the non-ionic surfactant Triton X-100 with human erythrocyte membranes. By applying a classical treatment for the interpretation of the action of surface active compounds to the hemolytic curves, we could calculate parameters such as R-e-the effective surfactant/lipid molar ratio for erythrocyte membrane saturation (R-e(sat)) and total lysis (R-e(sol))-and K-b, the binding constant of Triton X-100 to human erythrocyte membranes. The K-b (5900 M-1) and R-e (1.58 and 2.14) values presented here are in good agreement with literature data for Triton X-100 solubilization of model phospholipid membranes. (C) 2002 Elsevier Science B.V. All rights reserved.9711

Biological membranes and liposomes protect red blood cell (RBC) against trifluoperazine-induced hemolysis

This study extends the previous observations on the action of the liver microsomal membranes and of the water-soluble hepatic species against spontaneous ("mechanical") and trifluoperazine (TFP)-induced red blood cell (RBC) lysis. Mouse liver microsomes (MLM) were exhaustively washed in order to avoid overlapped protective effect of the membrane associated water-soluble. species and tested for the protection they afforded. The protective capacity of rough and smooth MLM was compared as was that of the RBC ghosts and liposomes. Both biomembranes and liposomes were found to protect RBC against TFP-induced lysis in a concentration-dependent manner. The effectiveness of the biomembranes was greater than that of the liposomes.21112713

A new look at the hemolytic effect of local anesthetics, considering their real membrane/water partitioning at pH 7.4

The interaction of local anesthetics (LA) with biological and phospholipid bilayers was investigated regarding the contribution of their structure and physicochemical properties to membrane partition and to erythrocyte solubilization. We measured the partition into phospholipid vesicles-at pH 5.0 and 10.5-and the biphasic hemolytic effect on rat erythrocytes of., benzocaine, chloroprocaine, procaine, tetracaine, bupivacaine, mepivacaine, lidocaine, prilocaine, and dibucaine. At pH 7.4, the binding of uncharged and charged LA to the membranes was considered, since it results in an ionization constant (pK(app)) different from that observed for the anesthetic in the aqueous phase (pK(w)). Even though it occurred at a pH at which there is a predominance of the charged species, hemolysis was greatly influenced by the uncharged species, revealing that the disrupting effect of LA on these membranes is mainly a consequence of hydrophobic interactions. The correlation between the hemolytic activity and the LA potency shows that hemolytic experiments could be used for the prediction of activity in the development of new LA molecules. (C) 2004 Elsevier B.V. All rights reserved.110321322

Thermodynamic and Structural Characterization of Zwitterionic Micelles of the Membrane Protein Solubilizing Amidosulfobetaine Surfactants ASB-14 and ASB-16

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Surface tension and isothermal titration calorimetry (ITC) were used to determine the critical micelle concentration (cmc) of the zwitterionic amidosulfobetaine surfactants ASB-14 and ASB-16 (linear-allcylamidopropyldi-methylammoniopropanosulfonates) at 25 degrees C. The cmc and the heat of micellizabon were determined from 15 to 75 degrees C by ITC for both surfactants. The increase in temperature caused significant changes in the enthalpy and in the entropy of micellization, with small changes in the standard Gibbs energy (Delta G(mic)), which is consistent to an enthalpy-entropy compensation with a compensatory temperature of 311 K (ASB-14) and 314 K (ASB-16). In the studied temperature range, the heat capacity of micellization (Delta C(p)(mic)) was essentially constant. The experimental Delta C(p)(mic) was lower than that expected if only hydrophobic interactions were considered, suggesting that polar interactions at the head groups are of significant importance in the thermodynamics of micelle formation by these surfactants. Indeed, a NMR NOESY spectrum showed NOES that are improbable to occur within the same monomer, resulting from interactions at the polar head groups involving more than one monomer. The ITC and NMR results indicate a tilt in the polar headgroup favoring the polar interactions. We have also observed COSY correlations typical of dipolar interactions that could be recovered with the partial alignment of the molecule in solution, which results in an anisotropic tumbling. The anisotropy suggested an ellipsoidal shape of the micelles, which results in a positive magnetic susceptibility, and ultimately in orientation induced by the magnetic field. Such an ellipsoidal shape was confirmed from results obtained by SAXS experiments that revealed aggregation numbers of 108 and 168 for ASB-14 and ASB-16 micelles, respectively. This study characterizes an interesting micelle system that can be used in the study of membrane proteins by solution NMR. spectroscopy.271382488256Financiadora de Estudos e Projetos (FINEP/CT-Infra)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES