Animals ; Heart Ventricles ; cytology ; Lipid Bilayers ; Potassium Channels ; Sarcolemma ; physiology ; Swine

Self-assembled lipid films provide new insights into the structure-function relationships of biomolecules at the molecular level. It has potential applications in biology and bionics. In this paper, with regard to atomic force microscopy (AFM) characterization, the surface structures and growth kinetics of self-assembled lipid films as well as their applications in high-resolution AFM imaging of surface-immobilized biomolecules such as proteins, DNA and enzymes are reviewed.
DNA ; chemistry ; Humans ; Lipid Bilayers ; chemistry ; Microscopy, Atomic Force ; methods ; Phospholipids ; chemistry ; Proteins ; chemistry

BACKGROUND: Acetone disrupts the cutaneous permeability barrier through the removal of stratum corneum lipids. This pertubation of barrier integrity stimulates a variety of homeostatic repair that ultimately results in the normalization of barrier function. OBJECT: To measure the effect of steroid on the barrier recovery of acetone applied skin. MATERIAL AND METHODS: The flank skin of 8~10 week old hairless mice was treated with acetone and then topical and systemic steroids were applied. Transepidermal water loss(TEWL) was checked after 0, 3, 6, 12 and 24 hours. Electron and light microscopic examination and ion capture cytochemistry were performed after 3, 6, 12 and 24 hours after systemic and topical steroids had been applied. RESULTS: The results were as follows ; 1) During 3~6 hours after experiment, the recovery rate of TEWL was most prominent in the group of acetone applied animal than other groups. 2) After 12 hours after acetone applied, formation of new stratum corneum was found in the groups of acetone applied or acetone applied skin with topical steroid application. But loss of stratum corneum was observed in the groups of high or low dose steroid injection. 3) Ruthenium tetroxide staining of acetone alone or topical steroid treated specimens after 12 hours experiment revealed that the lipid bilayer was partly impaired and fragmented. Intercellular spaces were widening and the lipid bilayer disappeared or was damaged in the groups of high or low dose steroid injection. 4) Six hours after acetone application, pattern of calcium distribution had been partially reestabilished in the group of acetone alone or topical steroid treated animals. But calcium content was still sparse and decreased from the stratum granulosum to basale in the groups of high or low dose steroid injection. CONCLUSION: In summary the present study demonstrates that steroid treatment acutely delays recovery rate of TEWL, inhibits normalization of calcium gradient or epidermal lipid synthesis that leads to abnormalities in permeability barrier homeostasis.
Acetone ; Animals ; Calcium ; Extracellular Space ; Histocytochemistry ; Homeostasis ; Lipid Bilayers ; Mice ; Mice, Hairless* ; Permeability ; Ruthenium ; Skin ; Steroids

Intracellular transduction of hydrophilic macromolecules has been problematic owing to the biochemical restriction imposed by lipid bilayer of the cytoplasmic membrane. Several technologies have been developed to improve the intracellular delivery of the large molecules for therapeutic purpose, including cell penetrating peptide. Cell penetrating peptides or cell permeable peptides (CPPs) were initially discovered based on the potency of certain full-length proteins or proteins to translocate across the plasma membrane. Currently, CPPs are broadly applied for intracellular delivery of biologically functional molecules in vivo and vitro, varying from small molecules, peptides, proteins, liposomes and nucleic acids. With introducing the history and characteristics of CPPs, this review will focus on the intracellular transduction mechanism and application of CPPs.
Cell Membrane ; Cell-Penetrating Peptides ; Endocytosis ; Lipid Bilayers ; Liposomes ; Nucleic Acids ; Peptides ; Proteins

BACKGROUND: The epidermal permeability barrier necessary for terrestrial life resides in the intercellular spaces of the stratum corneum and is composed of lipids. OBJECTIVE: Since strrtum corneum lipid may be important for the permeability barrier, we studied the differences and effects of experimentally altered barrier function using acetone and tape-stripping technique. METHODS: The permeability barrier of hairless mouse was disrupted by tape-stripping and acetone treatment and the recovery rate was assessed by histochemical staining, electron microscopic examination and lipid analysis. RESULTS: Although the transepidermal water loss recovered completely by 48 hours in both of the acute models, acetone treated samples seem to have on over-all better recovery rate than tape-stripped samples. The return of barrier function to normal in both tape-stripped and acetone-treated skin was accompanied by a comparable return of normal nile red and ruthenium tetroxide staining. The amount of lipid in stratum corneum paralleled both the return of barrier function towards normal and the extent of prior damage to the barrier in acetone treated skin, yet, the lipid synthesis in tape-stripped skin showed a slower return of lipid content. CONCLUSION: The difference in the recovery rate of the two acute models may be due to the fact that acetone mainly extracts intercellular lipids, whereas, tape-stripping has a prolonged effect by removal of comeocyte in addition to the intercellular lipids. This shows the importance of comeocytes as well as the intercellular lipid bilayer in the recovery of normal barrier function.
Acetone* ; Animals ; Extracellular Space ; Lipid Bilayers ; Mice ; Mice, Hairless ; Permeability ; Ruthenium ; Skin ; Water

BACKGROUND: Topical irritants disrupt the cutaneous permeability barrier through the removal of stratum comeum lipids. This perturbation of barrier integrity stimulates a variety of homeostatic repair responses that ultimately result in the normalization of bamer function. Object To measure the effect of desoxymethasone ointment, vaseline and hydrobase on the barrier recovery of benzalkonium chloride (BKC) imtated skin. MATERIALS AND METHODS: The left flank skin of 2-3 monthold hairless mice was treated with BKC and then desoxymethasone ointment, vaseline and hydrobase were applied. Transepidermal water loss (TEWL) was checked after 0, 3, 6, 9, 12, 15, 18, 21 and 24 hours. Electron microscopic examination was performed after 3 and 24 hours after desoxymethasone, vaseline and hydrobase had been applied. RESULTS: The recovery of TEWL was most prominantly observed in the desoxymethasone ointment treated group followed by vaseline and hydrobase. Electron microscopic examination using ruthenium tetroxide fixation revealed that secretion and numbers of lamellar bodies and complete formatice of lipid bilayers were most prominent at desoxymethasone ointment and vaseline treated group. CONCLUSION: Desoxymethasone ointment, vaseline and hydrobase can be good agents in improving bamer recovery after exposure to irritant material.
Animals ; Benzalkonium Compounds* ; Desoximetasone* ; Irritants ; Lipid Bilayers ; Mice ; Mice, Hairless* ; Permeability ; Petrolatum* ; Ruthenium ; Skin*

This study examined the mechanism of action of a local anesthetic, lidocaine.HCl. Energy transfer between the surface fluorescent probe, 1-anilinonaphthalene-8-sulfonic acid, and the hydrophobic fluorescent probe, 1,3-di(1-pyrenyl) propane, was used to determine the effect of lidocaine.HCl on the thickness (D) of the synaptosomal plasma membrane vesicles (SPMV) isolated from the bovine cerebral cortex, and liposomes of the total lipids (SPMVTL) and phospholipids (SPMVPL) extracted from the SPMV. The thickness (D) of the intact SPMV, SPMVTL and SPMVPL were 1.044+/-0.008, 0.914+/-0.005 and 0.890+/-0.003 (arbitrary units, n=5) at 37degrees C (pH 7.4), respectively. Lidocaine.HCl decreased the thickness of the neuronal and model membrane lipid bilayers in a dose-dependent manner with a significant decrease in the thickness, even at 0.1 mM. The decreasing effect of lidocaine.HCl on the membrane thickness might be responsible for some, but not all of its anesthetic action.
Anilino Naphthalenesulfonates ; Cell Membrane ; Cerebral Cortex ; Energy Transfer ; Lipid Bilayers ; Liposomes ; Membranes ; Neurons ; Phospholipids ; Propane

Using the planar lipid bilayer method, we investigated the effect of d-tubocurarine (dTC) on the extracellular side of large-conductance Ca2+-activated K+ channel from rat brain. When the initial open probability (Po) of the channel was relatively high, dTC decreased channel activity in a concentration dependent manner. In contrast, when the initial Po was lower, sub-micro molar dTC increased channel activity by destabilizing the closed states of the channel. Further addition of dTC up to micro molar range decreased channel activity. This dual effect of dTC implicates that there exist at least two different binding sites for dTC.
Animals ; Binding Sites ; Brain* ; Lipid Bilayers* ; Molar ; Potassium Channels, Calcium-Activated* ; Rats* ; Tubocurarine*

Voltage-gated sodium channels (VGSCs) are widely distributed in most cells and tissues, performing many physiological functions. As one kind of membrane proteins in the lipid bilayer, whether lipid composition plays a role in the gating and pharmacological sensitivity of VGSCs still remains unknown. Through the application of sphingomyelinase D (SMaseD), the gating and pharmacological sensitivity of the endogenous VGSCs in neuroblastoma ND7-23 cell line to BmK I and BmK AS, two sodium channel-specific modulators from the venom of Buthus martensi Karsch (BmK), were assessed before and after lipid modification. The results showed that, in ND7-23 cells, SMaseD did not change the gating properties of VGSCs. However, SMaseD application altered the slope factor of activation with the treatment of 30 nmol/L BmK I, but caused no significant effects at 100 and 500 nmol/L BmK I. With low concentration of BmK I (30 and 100 nmol/L) treatment, the application of SMaseD exerted hyperpolarizing effects on both slow-inactivation and steady-state inactivation, and increased the recovery time constant, whereas total inactivation and recovery remained unaltered at 500 nmol/L BmK I. Meanwhile, SMaseD modulation hyperpolarized the voltage dependence of slow-inactivation at 0.1 nmol/L BmK AS and altered the slope factor of slow-inactivation at 10 nmol/L BmK AS, whereas other parameters remained unchanged. These results indicated a possibility that the lipid bilayer would disturb the pharmacological sensitivity of VGSCs for the first time, which might open a new way of developing new drugs for treating sodium channelopathies.
Cell Line, Tumor ; Humans ; Lipid Bilayers ; chemistry ; Neuroblastoma ; Scorpion Venoms ; chemistry ; Sodium Channel Blockers ; chemistry ; Voltage-Gated Sodium Channels ; physiology

This study was aimed to establish a method to create a stable planar lipid bilayer membranes (PLBMs), in which large conductance calcium-activated potassium channels (BK) were reconstituted. Using spreading method, PLBMs were prepared by decane lipid fluid consisting of N-weathered mixture of phosphatidylcholine and cholesterol at 3:1 ratio. After successful incorporation of BKchannel into PLBMs, single channel characteristics of BKwere studied by patch clamp method. The results showed that i) the single channel conductance of BKwas (206.8 ± 16.9) pS; ii) the activities of BKchannel were voltage dependent; iii) in the bath solution without Ca, there was almost no BKchannel activities regardless of under hyperpolarization or repolarization conditions; iv) under the condition of +40 mV membrane potential, BKchannels were activated in a Caconcentration dependent manner; v) when [Ca] was increased from 1 μmol/L to 100 μmol/L, both the channel open probability and the average open time were increased, and the average close time was decreased from (32.2 ± 2.8) ms to (2.1 ± 1.8) ms; vi) the reverse potential of the reconstituted BKwas -30 mV when [K] was at 40/140 mmol/L (Cis/Trans). These results suggest that the spreading method could serve as a new method for preparing PLBMs and the reconstituted BKinto PLBMs showed similar electrophysiological characteristics to natural BKchannels, so the PLBMs with incorporated BKcan be used in the studies of pharmacology and dynamics of BKchannel.
Animals ; Calcium ; chemistry ; Electrophysiological Phenomena ; Large-Conductance Calcium-Activated Potassium Channels ; chemistry ; Lipid Bilayers ; chemistry ; Membrane Potentials ; Patch-Clamp Techniques