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PubMed1980

A topographic measurement of brain pH.

The ability of neutral red to serve as an internal pH indicator in biological systems was tested in the rat brain after parenteral adminstration of the dye. The injected dye is avidly taken up by the brain cells and is distributed mainly in intracellular organelles. The ratio of optical signals recorded from the frozen brain at 445 and 530 nm and compared with calibration curves provides pH values. Color transition of neutral red ranges from 6.0 to 8.0 pH units. Topographic application of this method is particularly useful in studying local pH changes in brains with developing ischemic foci.

Acid-Base Equilibrium↗
PubMed1989

Enhanced take of spontaneous murine tumors in mice treated with inhibitors of macrophage and/or NK cell function.

Both macrophages and NK cells have been suggested to play a role in recognizing and eliminating early, in situ neoplasms. Therefore we studied the effect of inhibitors of macrophage and/or NK cell function on the take of transplantable spontaneous murine tumors in syngeneic mice. The treatment of animals with trypan blue, a selective inhibitor of macrophage function, decreased considerably the period of latency of BSP3 adenocarcinoma; however, it did not increase the take of SP4, SP82 and SP84 adenocarcinomas. The treatment of recipients with neutral red, a selective inhibitor of NK cell function, enhanced the take of SP4 adenocarcinoma. The treatment of mice with agents depressing both macrophage and NK cell function (silica or carrageenan) decreased the both macrophage and NK cell function (silica or carrageenan) decreased the period of latency and/or increased the take of SP4, SP82 and SP84 adenocarcinomas. Carrageenan or a combined treatment with both trypan blue and neutral red also enhanced the take of BaF1, a benzo(a)pyrene-induced fibrosarcoma. We concluded that both macrophages and NK cells may function as effector cells of an antitumoral surveillance system.

Adenocarcinoma↗
PubMed1999

[Quaternary ammonium cytotoxicity in a human conjunctival cell line].

PURPOSE: Ophthalmic preparations can induce conjunctival toxicity, often caused by preservatives. The aim of this study was to evaluate in vitro cytotoxicity of quaternary ammonium. METHODS: Cytotoxicity tests were done on a continuous human conjunctival cell line using microplate cold light cytofluorimetry. Membrane integrity (neutral red test), DNA condensation (Hoechst 33342 test) and reactive oxygen species (ROS) production (dichlorofluorescein diacetate and hydroethidine tests) were evaluated on living cells treated with different concentrations of benzalkonium chloride, benzododecinium bromide and cetrimide (0.00001 to 0.01%) after 15 minutes of treatment or 15 minutes and 24 hours of cell recovery. RESULTS: All the compounds tested showed similar in vitro effects. Using the neutral red test, we observed a decrease in membrane integrity even at 0.005% and 0.01% (p < 0.001) and after a short time (15 minutes). A stimulation of ROS production (H2O2 and O2) was observed at 0.00001% and above (p < 0.001), associated with a chromatine condensation due to an apoptotic phenomenon. CONCLUSION: A necrotic phenomenon is suggested at high concentrations of quaternary ammonium preservatives whereas an apoptotic mechanism exists for lower concentrations. This toxicity observed in vitro can explain some of the ocular surface damage caused by long-term use of preserved eye-drops.

Anti-Infective Agents, Local↗
PubMed1998

Chemical and biological studies of a new cigarette that primarily heats tobacco. Part 2. In vitro toxicology of mainstream smoke condensate.

The genotoxic and cytotoxic potential of mainstream cigarette smoke condensate (CSC) from a new cigarette that primarily heats tobacco (TOB-HT) was compared with that of CSC from a Kentucky reference low "tar" cigarette (1R4F) representative of the current US cigarette market, and Kentucky Reference 1R5F, representative of ultra-low "tar" cigarettes on the US market. TOB-HT was evaluated at concentrations which induced concentration-dependent positive responses with 1R4F and 1R5F in an in vitro toxicology test battery which included sister chromatid exchange, chromosome aberration, and neutral red cytotoxicity assays in CHO cells, and the Ames bacterial mutagenicity assay. CSC from 1R4F and 1R5F was positive in the Ames assay with Salmonella typhimurium strains TA98, TA100, TA1538 and TA1537, and negative with TA1535, while CSC from TOB-HT was negative in all five strains. CSC from 1R4F and 1R5F cigarettes was positive in sister chromatid exchange (SCE), chromosome aberration (CA) and neutral red cytotoxicity assays, while CSC from the TOB-HT cigarette yielded negative results in all the above endpoints. These data indicate that in these assays the genotoxic and cytotoxic potential of CSC from the new cigarette that primarily heats tobacco is significantly less than CSC from Kentucky reference 1R4F and 1R5F cigarettes, which are representative of cigarettes currently sold in the US.

Animals↗
PubMedDate not supplied

[Structural changes in sarcolemma with E-avitaminosis dystrophy].

Sorption properties of sarcolemma preparations isolated from skeletal muscles of normal and E-avitaminous rabbits were studied relative to organic ions. Analysis of isotherms of sarcolemma equilibrium binding of neutral red cations and turquoise direct lightfast "K" anions made it possible to determine the number of positively and negetively charged sorption centres, which fix the mentioned dyes. With E-avitaminous muscular dystrophy the number of the centres increases considerably. A larger number of the positively charged centres fixing the surquoise dye are found both in the control and in case of dystrophy. The calcium ions prevent the neutral red sorption and intensify the turquoise direct sorption. In the sarcolemma preparations isolated from the muscles of the E-avitaminous rabbits the content of calcium ions is almost twice as high and the number of sulphydryl groups is 30-40% less as compare to the normal level. The data presented evidence for structural changes in sarcolemma with E-avitaminous muscular dystrophy.

Animals↗
PubMed1987

In vitro cytotoxicity of organic pollutants to bluegill sunfish (BF-2) cells.

BF-2 cells, an established cell line derived from bluegill sunfish, (Lepomis macrochirus), were exposed to 18 organic toxicants, with cytotoxicity being assayed by the neutral red (NR) technique. Based on the concentration of toxicant that reduced lysosomal uptake of neutral red by 50% (NR50), the rank order of cytotoxicity was methyl mercury greater than pentachlorophenol greater than 2,3,5,6-tetrachlorophenol greater than 2,3,5-trichlorophenol greater than 2,3-dinitrotoluene greater than 2,4,6-trichlorophenol greater than 2,4-dichlorophenol greater than 2,4-dichlorotoluene greater than 6-chloro-3-hydroxytoluene greater than o-chlorotoluene greater than 4-chlorophenol greater than 2-chlorophenol, 2,4-dimethylphenol greater than 2,4-dinitrophenol greater than 4-nitrophenol greater than 3-methylphenol greater than phenol greater than toluene. Published in vivo LC50 values were identified for 11 of the 18 test agents and, with the exception of 2,4-dinitrophenol, there was a good correlation between the in vitro cytotoxicity of the test agents and their in vivo waterborne acute toxocity. The potencies of the substituted phenolics and chlorinated toluenes as determined by the in vitro cytotoxicity assay correlated strongly with their log octanol/water partition coefficients (log P). However, the toxicity of 2,3-dinitrotoluene in vitro, and apparently also in vivo, was not a function of its log P value.

Animals↗
PubMedDate not supplied

Cytotoxicity of amino alcohols to rat hepatoma-derived Fa32 cells.

Amino alcohols are used as emulsifying agents in dry-cleaning soaps, wax removers, cosmetics, paints and insecticides. The cytotoxicities of 12 amino alcohols, which differed in chain length, position of the amino and alcohol groups, and the presence of an additional phenyl group, were determined by the neutral red uptake inhibition assay with normally cultured, glutathione-depleted or antioxidant-enriched Fa32 rat hepatoma-derived cells. Glutathione depletion and antioxidant enrichment were achieved by including 50(M L-buthionine-S,R-sulphoximine (BSO) or 100(M (-tocopherol acetate (vitamin E) in the culture medium for 24 hours before and during the assay. The cytotoxicity of the amino alcohols observed after treatment for 24 hours was expressed as the concentration of compound needed to induce a 50% reduction in neutral red uptake (NI50). The observed NI50 values ranged from 3mM to 30mM. The individual stereoisomers and a racemic mixture of 1-amino-2-propanol exhibited similar cytotoxicities (with normally cultured Fa32 cells, and vitamin E- and BSO-treated cultures). Similar NI50 values for D-(+)-2-amino-1-propanol, 3-amino-1-propanol and the L-, D- or DL- forms of 1-amino-2-propanol, indicated that the position of the amino group had little influence on the cytotoxicities of the amino alcohols. In contrast, the position of the hydroxyl group appeared to play an important role for the toxicity of the compound, as indicated by the significantly different NI50 values for 4-amino-1-butanol and 4-amino-2-butanol. An additional phenyl group greatly increased the cytotoxicity of 2-amino-1,3-propanediol. For most of the compounds, cytotoxicity increased when GSH was depleted, and decreased when the cells were enriched with vitamin E. This indicated that most of the tested chemicals interact with GSH, either directly or indirectly, by processes which generate oxygen free-radicals. Decreased toxicity was found for most of the chemicals administered to vitamin E-enriched cells, indicating that reactive oxygen species could be involved in the toxicity of the amino alcohols.

Amino Alcohols↗
PubMed2001

Disruption of metallothionein expression with antisense oligonucleotides abolishes protection against cadmium cytotoxicity in molluscan hemocytes.

The relationship between metallothionein (MT) induction and cytotoxicity was examined in isolated oyster hemocytes exposed in vitro to cadmium, copper, and zinc. In all cases MT induction increased to peak levels with increased metal dose, then declined with continued increases in dose. The effectiveness of these metals as inducers of MT was cadmium > copper > zinc, with cadmium the most effective inducer in magnitude of induction and sensitivity to dose. Cytotoxicity of the metals, based on decreases in lysosomal neutral red retention times, was copper > cadmium > zinc. Zinc was relatively nontoxic and a poor inducer of MT. Cadmium, which was intermediate in toxicity, required concentrations in excess of that causing peak induction of MT to have substantial effects on lysosomal membrane integrity. In contrast, copper was highly cytotoxic at concentrations below that which resulted in peak MT induction. This reversal in the rank order of cadmium and copper suggested that the toxicity of cadmium was tempered by the protective effects of MT. This was verified by disrupting MT expression with antisense phosphorothioate-substituted oligodeoxynucleotides. Administration of 2.5 microM CdCl(2), which induced MT but had no effect on lysosomal membrane stability when administered alone, reduced neutral red retention time to 41% of control levels when administered in the presence of antisense. The resulting toxicity was greater than that caused by a comparable concentration of copper. The findings represented evidence that expression of MT protects against cadmium toxicity in an estuarine mollusc.

Animals↗
PubMed2005

Lysosomal responses as a diagnostic tool for the detection of chronic petroleum pollution at Todos os Santos Bay, Brazil.

Coastal marine environments, especially semienclosed systems such as bays, are under unrelenting stress caused by urban and industrial development. Biomonitoring plays a vital role in strategies to identify, assess, and control stressors. However, due to the magnitude of the challenge there is a demand for new and innovative approaches to provide timely and accessible information to environmental managers and policy makers. The present work aimed to assess hydrocarbon levels in sediments from petroleum-related industrial areas at Todos os Santos Bay (Brazil) and associate them to toxicity-induced responses (neutral red retention (NRR) assay) by the burrowing clam Anomalocardia brasiliana. Surface sediments collected during the dry and rainy seasons were analyzed for aliphatic and aromatic hydrocarbons. At the control site, hydrocarbon levels were low and mainly biogenic. The aliphatic hydrocarbon ("total unresolved complex mixture," alkanes, and isoprenoids) concentrations indicated a chronic situation with very little "fresh" oil contamination at the oil-related sites. The polycyclic aromatic hydrocarbons indicated sites moderately contaminated by chronic oil and some pyrolytic input. The effects of those contaminants were assessed by the lysosomal NRR assay applied to A. brasiliana hemocytes. Sediment toxicity at the oil-related sites was evidenced by the lowered capacity of the lysosomes to retain the neutral red dye compared to results from the control site. This research indicates that the NRR assay is a useful and efficient screening technique able to discriminate polluted from clean sites.

Animals↗
PubMed1988

Structure-activity relationships for diorganotins, chlorinated benzenes, and chlorinated anilines established with bluegill sunfish BF-2 cells.

The bluegill sunfish (Lepomis macrochirus) BF-2 cell line, propagated at 34 degrees C, served as target for evaluation of the acute toxicities of various classes of aquatic pollutants, using the neutral red cytotoxicity assay. For a series of chlorinated benzenes and anilines, the sequence of cytotoxicity was dependent on the degree of chlorination and on their hydrophobicity, as described by their logarithmic octanol/water partition coefficients (log P values). With increasing numbers of chlorine atoms in the ring structure or with increasing log P values, greater cytotoxicity was observed. For a series of diorganotins, the sequence of cytotoxicity was dependent on the length of the carbon chain and upon their hydrophobicity, as described by Hansch pi parameters. Thus, increasing the chain length or increasing the Hansch pi parameter resulted in greater cytotoxicity. Similar structure-activity relationships for these classes of test agents have been previously established using acute toxicity LC50 assays with aquatic species. The ability of the neutral red in vitro cytotoxicity assay, with cultured fish cells as the bioindicators, to mimic the acute toxicity data obtained from the LC50 assays suggests its utility as a tool for preliminary screening (tier I testing) of aquatic pollutants.

Aniline Compounds↗
PubMed2005

Cadmium chloride-induced DNA and lysosomal damage in a hepatoma cell line.

Cadmium is a toxic metal and no uniform mechanism of toxicity has so far been proposed. The aim of this study was to investigate the biochemical effects of cadmium chloride in a rat hepatoma cell line (HTC cells) and the cellular events mediating DNA damage. HTC cells were exposed to various concentrations of cadmium chloride for 5 and 8 h and lysosomal damage was assessed with the neutral red assay (NR) and fluorescence microscopy. Mitochondrial integrity was assessed from ATP levels and DNA damage determined with the single cell gel electrophoresis/comet assay. The formation of reactive oxygen species (ROS) was also determined under the same experimental conditions with the dichlorofluorescein assay. Cytotoxicity was assessed with the LDH leakage assay and the levels of glutathione were measured and correlated with the other effects. The results indicate that lysosomal damage occurs at a lower concentration of cadmium chloride (20 microM) than DNA damage (500 microM) in HTC cells. The latter effect was accompanied by an increase of reactive oxygen species without any significant LDH leakage whereas lysosomal damage was significant as determined by the neutral red assay and confirmed with fluorescence microscopy. The effect of CdCl2 on mitochondria and glutathione levels were observed at concentrations or incubation times higher than the ones required to induce lysosomal damage. The data suggest that DNA damage may be due to the formation of reactive oxygen species. It is possible that cadmium induced lysosomal damage is an earlier event than DNA damage and can mediate other cellular events that lead to cell death.

Adenosine Triphosphate↗
PubMed1996

Galvanic corrosion and cytotoxic effects of amalgam and gallium alloys coupled to titanium.

The aim of this study was to examine and compare the galvanic corrosion of a conventional, a dispersed high-copper, and a palladium-enriched spherical high-copper amalgam and a gallium alloy coupled to titanium in saline and cell culture solutions, and to evaluate the effects of the couples on cultured cells. The potentials and charge transfers between amalgams and titanium were measured by electrochemical corrosion methods. Cytotoxicity of the couples, as indicated by the uptake of neutral red vital stain, was determined in 24-h direct contact human gingival fibroblast cell cultures. Results of this study indicated that before connecting the high-copper amalgams to titanium, the amalgams exhibited more positive potentials which resulted in initial negative charge transfers, i.e. corrosion of titanium. However, this initial corrosion appeared to cause titanium to passivate, and a shift in galvanic currents to positive charge transfers, i.e. corrosion of the amalgam samples. Lower galvanic currents were measured for the amalgam-titanium couples as compared to the gallium alloy-titanium couple. Coupling the conventional or the palladium-enriched high-copper amalgams to titanium did not significantly affect the uptake of neutral red as compared to cells not exposed to any test alloy. However, significant cytotoxic effects were observed when the dispersed-type high-copper amalgam and the gallium alloy were coupled to titanium. Even though the corrosion currents measured for these couples were less than gold alloys coupled to amalgam, these results suggest there is the potential for released galvanic corrosion products to become cytotoxic. These data warrant further investigations into the effects of coupling amalgam and gallium alloys to titanium in the oral environment.

Alloys↗
PubMedDate not supplied

Comparison of in vitro cell toxicity with in vivo eye irritation.

The effects of 26 different cosmetic ingredients (e.g., permanent wave and hair dye compounds, emulsifiers, resins, and detergents such as quats) were assessed by four end points indicative for qualitatively and quantitatively different cytotoxicity: (1) neutral red uptake reduction after 24 h of treatment (NR-90 and NR-50); (2) cell detachment from culture dish after 4 h of treatment (CD-25); (3) growth inhibition after 48 h of treatment (GI-50); and (4) membrane permeability measured by fluorescent dye retention (fluorescence shift FS-25) and dye exclusion (viability ratio VR-25). The cytotoxicity potentials of the test agents were ranked for each in vitro test and compared with the in vivo eye irritation in guinea pigs (Draize test) after application of 5 or 2.5% (w/v) solutions of the same test batches. Strong irritants could be easily detected by most of the in vitro tests, but the neutral red uptake assay (especially NR-50) was the only one that was able to distinguish the minimally irritating test agents from strong irritants as well as from nonirritants. (I) All three extremely irritating quaternary ammonia compounds were identified as the strongest cytotoxic agents. (II) Nine out of 12 minimally irritating substances (mainly emulsifiers and resins) were ranked in the intermediate group. (III) Eight out of 11 non-or practically nonirritating chemicals (mainly permanent wave compounds) showed cytotoxic effects at very high concentrations only. The distinction of these three groups was better by means of NR-50 than by NR-90 data. At least two of the other cell tests (CD-25, GI-50, FS-25, and VR-25) had to be considered to allow an adequate interpretation of in vitro cytotoxicity.

Animals↗
PubMed1991

Tracking of proton flow during transition from anaerobiosis to steady state. 1. Response of matrix pH indicators.

1. The kinetics of acidification and realkalinization of the matrix after addition of nigericin to respiring and non-respiring mitochondria, recorded by intramitochondrial pH indicators such as neutral red and 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF), is complementary to that recorded by extramitochondrial pH indicators. The extent of acidification decreases with the logarithm of the KCl concentration and is inhibited by Pi and ammonium ions. 2. Proton translocation during respiration has been compared with proton extraction from matrix bulk water. During oxygen pulses to EGTA-untreated mitochondria, BCECF records an extraction of protons from matrix bulk water of about 2-3 nmol H+/mg, reduced to 1-2 nmol H+/mg in EGTA-treated mitochondria. Since the amount of proton translocation required to achieve steady state is of the order of 6-7 nmol H+/mg, it appears that 75-90% of the protons are not extracted from matrix bulk water. Only a slight response is recorded by neutral red. 3. The effect of permeant cations and of uncouplers on the distribution of proton extraction between membrane and matrix bulk water has been studied in presteady state. During Sr2+ uptake, proton extrusion into cytosolic bulk water, as well as proton extraction from matrix bulk water, corresponds almost to 100% of the protons translocated by the redox proton pumps. In the absence of Sr2+, parallel to the disappearance of the proton extrusion in cytosolic bulk water, the proton extraction from matrix bulk water diminishes to about 20% of the proton translocation. 4. The mechanism by which divalent cation uptake and protonophoric uncouplers affect the distribution of proton extraction between matrix bulk water and membrane domains and the nature of the membrane domains are discussed.

2,4-Dinitrophenol↗
PubMed1992

Evaluation of surfactant cytotoxicity potential by primary cultures of ocular tissues: I. Characterization of rabbit corneal epithelial cells and initial injury and delayed toxicity studies.

This investigation was undertaken to develop cytotoxicity assay systems using primary cultures of rabbit corneal epithelial cells as an experimental model to evaluate oculotoxic agents and the ability of these in vitro assay systems to predict irritancy potential and delayed toxicity. We have characterized the epithelial nature of the cultures by identifying keratins with antikeratin antibodies (AE1/AE3) and by demonstrating metabolic enzymes important to the integrity of the cells: lactate dehydrogenase, glucose 6-phosphate dehydrogenase and aldolase. Eight surfactants were compared and ranked according to their cytotoxic potential. We evaluated cytotoxicity by measuring leakage of the cytosolic enzyme, lactate dehydrogenase, into the medium, by making morphological observations and by assessing lysosomal neutral red uptake and mitochondrial 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction. The cells were treated for 1 h with the surfactants and the possibility of delayed toxicity was evaluated 24 h after removal of the surfactant. The cytotoxicity of the different types of surfactants as shown by all the tests was cationic > anionic = amphoteric > non-ionic. Triton X-100, a non-ionic surfactant but a severe irritant, had a ranking similar to anionic surfactants. The in vitro rankings corresponded well to reported in vivo Draize rabbit eye test data. The 24-h test for lactate dehydrogenase leakage showed that mild and non-irritating surfactants did not demonstrate any subsequent damage after a 1-h exposure, but the extreme and severe surfactants continued to show further damage after the 1-h exposure. These in vitro findings were similar to reported in vivo results. The neutral red and MTT tests did not adequately predict the prolonged toxicity of the more irritating surfactants, as was demonstrated by the lactate dehydrogenase leakage test. We conclude that in vitro cytotoxicity assays using primary cultures of rabbit corneal epithelial cells may be used to rank the cytotoxic potential of surfactants, but only the lactate dehydrogenase leakage test was able to assess prolonged cell injury.

Animal Testing Alternatives↗
PubMed1999

Characteristics of 5-HT-containing chemoreceptor cells of the chicken aortic body.

1. Voltage-dependent and oxygen-sensitive currents in 5-HT-containing epithelioid cells isolated from chicken thoracic aorta were examined using the whole-cell patch clamp technique. 5-HT immunoreactive cells were identified with Neutral Red. The release of 5-HT from chicken thoracic aorta in the presence of excess KCl and veratridine was also examined using HPLC. 2. At a holding potential of -70 mV with CsCl pipette solution, depolarizing steps between -30 and +60 mV produced inward currents that were blocked by tetrodotoxin (0.2 microM). In the presence of tetrodotoxin and BaCl2 (5 mM), depolarizing steps evoked slow inward currents that were sensitive to CoCl2 (2 mM). Nifedipine (1 microM) decreased the currents to 79.4 +/- 1.7 %, and omega-conotoxin GVIA (1 microM) to 20.2 +/- 3.8 %. 3. When KCl pipette solution was used, depolarizing potentials positive to -40 mV caused outward currents that were inhibited by tetraethylammonium chloride. The K+ currents evoked by depolarizing steps to +20 mV were reduced to 90.3 +/- 0.8 % by hypoxia in five out of seven cells. Two cells failed to respond to hypoxia. The K+ current response was partly decreased by Neutral Red (20 microM). 4. Excess KCl (60 mM) and veratridine (30 microM) both caused the release of 5-HT from aortic strips. 5-HT outputs induced by both stimuli were partly inhibited by nifedipine (1 microM) and by omega-conotoxin GVIA (1 microM), and were abolished by these drugs in combination and by extracellular Ca2+ removal. 5. These results suggest that epithelioid cells containing 5-HT act as chemoreceptor cells in the chicken aortic body, having voltage-dependent Na+, K+, and L- and N-type Ca2+ channels, and oxygen-sensitive K+ channels.

Animals↗
PubMed2004

Imaging parallel fiber and climbing fiber responses and their short-term interactions in the mouse cerebellar cortex in vivo.

A major question in the study of cerebellar cortical function is how parallel fiber and climbing fiber inputs interact to shape information processing. Emphasis has been placed on the long-term effects due to conjunctive stimulation of climbing fibers and parallel fibers. Much less emphasis has been placed on short-term interactions and their spatial nature. To address this question the responses to parallel fiber and climbing fiber inputs and their short-term interaction were characterized using optical imaging with Neutral Red in the anesthetized mouse in vivo. Electrical stimulation of the cerebellar surface evoked an increase in fluorescence consisting of a transverse optical beam. The linear relationship between the optical responses and stimulus parameters, high spatial resolution and close coupling to the electrophysiological recordings show the utility of this imaging methodology. The majority of the optical response was due to activation of postsynaptic alpha-amino-3-hydroxyl-5-methyl-4-isoxazole propionate (AMPA) and metabotropic glutamate receptors with a minor contribution from the presynaptic parallel fibers. Stimulation of the inferior olive evoked parasagittal bands that were abolished by blocking AMPA glutamate receptors. Conjunctive stimulation of the cerebellar surface and inferior olive resulted in inhibition of the climbing fiber evoked optical responses. This lateral inhibition of the parasagittal bands extended out from both sides of an activated parallel fiber beam and was mediated by GABA(A) but not GABA(B) receptors. One hypothesized role for lateral inhibition of this type is to spatially focus the interactions between parallel fiber and climbing fiber input on Purkinje cells. In summary optical imaging with Neutral Red permitted visualization of cerebellar cortical responses to parallel fiber and climbing fiber activation. The GABA(A) dependent lateral inhibition of the climbing fiber evoked parasagittal bands by parallel fiber stimulation shows that cerebellar interneurons play a short-term role in shaping the responses of Purkinje cells to climbing fiber input.

Animals↗
PubMed1997

Comparative study of the damage produced by acute ethanol and acetaldehyde treatment in a human fetal hepatic cell line.

The effects of acute ethanol and acetaldehyde treatment on cell proliferation, cell adhesion capacity, neutral red incorporation into lysosomes, glutathione content, protein sulfhydryl compounds, lipid peroxidation, inner mitochondrial membrane integrity (MTT test), lactate dehydrogenase activity (LDH) and ultrastructural alterations were investigated in a human fetal hepatic cell line (WRL-68 cells). WRL-68 cells were used, due to the fact that, although this cell line expresses some hepatic characteristics, it does not express alcohol dehydrogenase or cytochrome P450 activity, so it could be a good model to study the effect of the toxic agents per se. Cells were exposed during 120 min with 200 mM ethanol or 10 mM acetaldehyde. Under these conditions, cells presented 100% viability and no morphological alteration was observed by light microscopy. Acetaldehyde-treated cells reduced their proliferative capacity drastically while the ethanol-treated ones presented no difference with control cells. Cell adhesion to substrate, measured as time required to adhere to the substrate and time required to detach from the substrate, was diminished in acetaldehyde WRL-68-treated cells. Cytotoxicity measures as neutral red and MTT test showed that acetaldehyde-treated cells presented more damage than ethanol-treated ones. Cellular respiratory capacity was compromised by acetaldehyde treatment due to 40% less oxygen consumption than control cells. Lipid peroxidation values, measured as malondialdehyde production, were higher in ethanol-treated WRL-68 cells (127%) than in acetaldehyde-treated ones (60%) to control cell values. Lactate dehydrogenase activity (LDH) in extracellular media of ethanol-treated cells presented the highest values. GSH content was reduced 95% and thiol protein content was diminished severely in acetaldehyde-treated cells. Transmission electron microscopy showed more ultrastructural alterations in cells treated with acetaldehyde. The results indicate that acetaldehyde, like ethanol, produced damage at cellular level, although more damage could be observed in acetaldehyde WRL-68-treated cells.

Acetaldehyde↗