The effects of alcohols in vitro on the nervous cell membrane measured by changes in the (Ca2+/Mg2+) ATPase activity and fluidity of the synaptosomal membrane

Deletion of the Golgi Ca2+-ATPase PMR1 gene potentiates antifungal effects of dodecanol that depend on intracellular Ca2+ accumulation in budding yeast

One strategy for overcoming infectious diseases caused by drug-resistant fungi involves combining drugs rendered inactive by resistance with agents targeting the drug resistance mechanism. The antifungal activity of n-dodecanol disappears as incubation time passes. In Saccharomyces cerevisiae, anethole, a principal component of anise oil, prolongs the transient antifungal effect of dodecanol by downregulating genes of multidrug efflux pumps, mainly PDR5. However, the detailed mechanisms of dodecanol's antifungal action and the anethole-induced prolonged antifungal action of dodecanol are unknown. Screening of S. cerevisiae strains lacking genes related to Ca2+ homeostasis and signaling identified a pmr1Δ strain lacking Golgi Ca2+-ATPase as more sensitive to dodecanol than the parental strain. Dodecanol and the dodecanol + anethole combination significantly increased intracellular Ca2+ levels in both strains, but the mutant failed to clear intracellular Ca2+ accumulation. Further, dodecanol and the drug combination reduced PMR1 expression and did not lead to specific localization of Pmr1p in the parental strain after 4-h treatment. By contrast with the parental strain, dodecanol did not stimulate PDR5 expression in pmr1Δ. Based on these observations, we propose that the antifungal activity of dodecanol is related to intracellular Ca2+ accumulation, possibly dependent on PMR1 function, with anethole enabling Ca2+ accumulation by restricting dodecanol efflux.

Effects of marjoram volatile oil and grape seed extract on ethanol toxicity in male rats

Natural dietary antioxidants are extensively studied for their ability to protect cells from miscellaneous damages. Marjoram volatile oil (Origanum majorana L., Lamiaceae) and grape seed extract (Vitis vinifera L., Vitaceae) are potent antioxidants. Effects of administration of marjoram volatile oil or grape seed extract on oral administration of ethanol, simultaneously, daily for 10 weeks were studied through determining epididymal spermatozoal analysis, serum testosterone level, weight and histopathological examination of testis, liver and brain. Glutathione level and lipid peroxidation content as malondialdehyde in the testis, liver and brain were measured. The repeated intake of a great amount of ethanol (10 ml/kg body weight, 25% v/v) was followed by fertility disturbances with low sperm count, impaired sperm motility and decrease in serum testosterone level. Moreover, ethanol toxicity induced significant alterations in the histological structures of the testis, liver and brain. The results revealed a significant increase in lipid peroxidation and decrease in the level of glutathione in the testis, liver and brain in the ethanol-treated group. However, co-administration of the extracts of protective plants resulted in minimizing the hazard effects of ethanol toxicity on male fertility, liver and brain tissues. It may be concluded that marjoram volatile oil and grape seed extract are useful herbal remedies, especially for controlling oxidative damages.

Naturally occurring antifungal agents against Zygosaccharomyces bailii and their synergism

Polygodial was found to exhibit a fungicidal activity against a food spoilage yeast, Zygosaccharomyces bailii, with the minimum fungicidal concentration (MFC) of 50 microg/mL (0.17 mM). The time-kill curve study showed that polygodial was fungicidal at any growth stage. The primary action of polygodial comes from its ability to disrupt the native membrane-associated function of integral proteins as nonionic surface active agents (surfactants) followed by a decrease in plasma membrane fluidity. The fungicidal activity of polygodial was increased 128-fold in combination with a sublethal amount (equivalent of 1/2 MFC) of anethole and vice versa relative to the fungicidal activity of anethole. The fungicidal activity of sorbic acid was enhanced 512-fold in combination with 1/2 MFC of polygodial. Conversely, the fungicidal activity of polygodial was enhanced 128-fold in combination with 1/2 MFC of sorbic acid.

Acute and subchronic effects of lead on the central and peripheral nervous systems in rats in combination with alcohol

Humans are exposed, either simultaneously or sequentially, to various chemicals, including the neurotoxicants lead and ethanol. The aim of the present work was to investigate the changes in the spontaneous cortical activity (electrocorticogram; ECoG) and in the stimulus-dependent evoked potentials (EPs) recorded from rats pre-treated with alcohol and treated with lead acutely (intraperitoneally) or subchronically (by gavage). The measured parameters were spectral composition of the ECoG, amplitude and the latency of the stimulus-evoked cortical potential, as well as compound action potential amplitude, conduction velocity, and relative and absolute refractory period in a peripheral nerve. With subchronic lead and alcohol treatment, significant increase in the frequency of spontaneous activity and slight decrease in the EP amplitude were seen. In acute administration, EP amplitude increased and conduction velocity of the tail nerve decreased significantly. Our results showed that, in a combined exposure situation which is likely to happen also in humans, the known effects of neurotoxic heavy metals can be more severe.

Influence of pyrethroids and piperonyl butoxide on the Ca2+-ATPase activity of rat brain synaptosomes and leukocyte membranes

Pyrethroids are widely used insecticides of low acute toxicity in mammals but the consequences of long-term exposure are of concern. Their insecticidal action is related to neurotoxicity and, in addition, there are indications of mammalian immunotoxicity. In order to clarify structure-activity relationships of the membrane interactions of pyrethroids, the present study compared the influence of selected pyrethroids, i.e. permethrin and the more water soluble esbiol (S-bioallethrin), both type I, and cyfluthrin, type II, on the Ca(2+)-ATPase activity of rat brain synaptosomes and peritoneal leukocyte membranes. The pyrethroids were tested alone as well as mixed with the enhancing substance piperonyl butoxide (PBO) at concentration ratios of 1:5 and 1:10. At the highest concentration tested, permethrin (10 microM) alone inhibited the ATPase activity of leukocyte membranes by 20%, whereas the synaptosomes were affected less. Esbiol and cyfluthrin alone did not affect either membrane preparation significantly, whereas PBO (50 microM) alone caused 10-15% inhibition. Mixtures of either pyrethroid with PBO inhibited the ATPase activity of both types of membranes (up to 40% inhibition) in a synergistic manner, which always tended to be supra-additive. With esbiol a true potentiation took place. The synergistic interaction between pyrethroid and PBO was most apparent with mixtures of a concentration ratio of 1:5. The ATPase activity of leukocyte membranes tended to be more susceptible to inhibition than that of synaptosomes. The results are in accordance with the assumption that the mammalian toxicity of pyrethroids can be ascribed to a general disturbance of cell membrane function in neuronal tissue. The results indicate that it may also be the case in the immune apparatus.

Modes of antifungal action of (2E)-alkenals against Saccharomyces cerevisiae

A series of aliphatic (2E)-alkenals from C(5) to C(14) were tested for their antifungal activity against Saccharomyces cerevisiae ATCC 7754. (2E)-Undecenal (C(11)) was found to be the most effective with the minimum fungicidal concentration (MFC) of 6.25 microgram/mL, followed by (2E)-decenal (C(10)) with an MFC of 12.5 microgram/mL. The time-kill curve study showed that (2E)-undecenal was fungicidal against S. cerevisiae at any growth stage, and this activity was not influenced by pH values. The (2E)-alkenals inhibited glucose-induced acidification by inhibiting the plasma membrane H(+)-ATPase. The primary antifungal action of medium-chain (C(9)-C(12)) (2E)-alkenals against S. cerevisiae comes from their ability to function as nonionic surface-active agents (surfactants), disrupting the native membrane-associated function nonspecifically. Hence, the antifungal activity of (2E)-alkenals is mediated by biophysical processes, and the maximum activity can be obtained when the balance between the hydrophilic and hydrophobic portions becomes the most appropriate.

Effect of copper overload together with ethanol uptake on hippocampal neurons

Copper is an essential trace element which forms an integral component of many enzymes. While trace amounts of copper are needed to sustain life, excess copper is extremely toxic in the brain. Also, ethanol intake causes morphological changes in the brain. The present study aims to investigate effects of copper overload with ethanol intake in hippocampal neuron numbers of rat brain. Control and experimental group of rats (n = 6 for each group) were fed ad libitum. Experimental group were given ethanol with copper in drinking water each day for ten days. Control group animals were given only drinking water during this period. Afterwards, animals were decapitated and their brains were removed by craniotomy. Frozen brains were cut by a cryostat. Sections collected via systematic random sampling were stained with hematoxylin and eosin. On microscopic images obtained from pyramidal cell layers in hippocampus, total neuron numbers were estimated using the optical fractionator method. We observed that pyramidal neuron numbers in the subdivisions of hippocampus were significantly lower in the experimental group than in the control group. These results suggest that copper overdose with ethanol intake can cause neuronal loss in hippocampus of rat brain.

Modes of antifungal action of alkanols against Saccharomyces cerevisiae

Primary aliphatic alcohols from C(6) to C(13) were tested for their antifungal activity against Saccharomyces cerevisiae. Undecanol was found to be the most potent fungicide followed by decanol. The time-kill curve study showed that undecanol was fungicidal against S. cerevisiae at any growth stages. This fungicidal activity was not influenced by pH values. The alcohols tested inhibited glucose-induced acidification by inhibiting the plasma membrane H(+)-ATPase. The primary antifungal action of amphipathic medium-chain (C(9)-C(12)) alkanols comes mainly from their ability as nonionic surfactants to disrupt the native membrane-associated function of the integral proteins. Hence, the antifungal activity of alkanols is mediated by biophysical process, and the maximum activity can be obtained when balance between hydrophilic and hydrophobic portions becomes the most appropriate.

Antifungal activity of octyl gallate

Antifungal activities of propyl (C3), octyl (C8) and dodecyl (C12) gallates (3,4,5-trihydroxybenzoate) were tested against Saccharomyces cerevisiae ATCC7754 and Zygosaccharomyces bailii ATCC 60483. Octyl gallate was found to be the only active compound with the minimum fungicidal concentration of 25 microg/ml (89 microM) against S. cerevisiae and of 50 microg/ml (177 microM) against Z. bailii, respectively. The inactivation study showed that octyl gallate was fungicidal against both S. cerevisiae and Z. bailii at any stage of growth. These fungicidal activities were not influenced by pH values. Octyl gallate at 100 microg /ml reduced plasma membrane fluidity to 48% of control. On the other hand, dodecyl gallate at the same concentration reduced it to 76% of control. Only octyl gallate inhibited glucose-induced medium acidification, indicating direct or indirect inhibition of plasma membrane H +-ATPase. The primary fungicidal activity of octyl gallate comes from its ability to act as a nonionic surface-active agent (surfactant), though it can not be inferred that membrane damage, such as a decrease in the membrane fluidity, is the only cause of the lethal effect.

Influence of the physical states of membrane surface area and center area on lysosomal proton permeability

The physical state of the lysosomal membrane was modulated with the membrane fluidizers n-propanol and n-octanol and with the membrane rigidifiers cholesteryl hemisuccinate and cholesterol. Membrane fluidity was examined by the steady-state fluorescence anisotropy of 2-(9-anthroyloxy) palmitic acid and 16-(9-anthroyloxy) palmitic acid. Fluidizing the membranes at the surface and center areas increased the proton permeability coefficient by 92.8 and 18.0%, respectively. Rigidifying the membranes at the surface and center areas decreased the coefficient by 68.2 and 40.2%, respectively. Proton leakage of the lysosomes increased and decreased similar to the coefficient changes with the treatments. The results indicate that lysosomal proton permeability is affected by its membrane's physical state, and the physical state of the membrane surface area affects the proton permeability more markedly. The proton permeability coefficient of liposomes was similar to that of lysosomes, suggesting that efflux of lysosomal protons might occur through the lipid part of the bilayer but not transmembrane proteins.

Similar effects of ether phospholipids, PAF and lyso-PAF on the Ca(2+)-ATPase activity of rat brain synaptosomes and leukocyte membranes

The present study is an extension of our previous work with the antineoplastic ether phospholipid ET-18-OCH3 (edelfosine), which was shown to affect the activity of the Ca(2+)-ATPase of rat brain synaptosomes and peritoneal leukocyte membranes. The effect of ET-18-OCH3 was compared with that of the 16-carbon chain analogue ET-16-OCH3 as well as with the structurally related 16- and 18-carbon PAFs (platelet-activating factors) and lyso-PAFs. In addition, the two alkylphosphocholines D-20166 and D-21266 (perifosine) were included in the investigation. The influence of all of the compounds followed the same pattern, i.e., the Ca(2+)-ATPase activity of the synaptosomes was increased over a relatively narrow concentration range (peak at 20-30 microM) and that of the leukocyte membranes was inhibited in a concentration-dependent manner by 10-50 microM concentrations of the drugs. Ether phospholipids with an 18-carbon chain at C-1 were more potent than those with a 16-carbon chain. All of the compounds increased the activity of the synaptosomal ATPase to the same extend (ca. 50%). With the exception of lyso-PAF, all inhibited the enzyme activity of leukocyte membranes by 60-70%, whereas lyso-PAF was less effective (ca. 50% inhibition). The concentration range of activity for PAF and lyso-PAF indicates that their effect on the enzyme activity was caused by receptor-independent mechanisms. The ether phospholipids and alkylphosphocholines are suggested to act by accumulating in the membranes and thereby altering the character of the lipid environment of the enzyme rather than by a direct interaction with the Ca(2+)-ATPase.

Ethanol potentiates lead-induced inhibition of rat brain antioxidant defense systems

We investigated the effect of alcohol (3 g/kg body weight intragastrically) on lead-induced (50 mg/kg body weight intragastrically) oxidative stress in adult rat brain. Ethanol was found to potentiate the accumulation of lead in the rat brain by 100%. Lead and ethanol in combination also enhanced lipid peroxidation, a deteriorative process of biomembranes, and markedly decreased the antioxidant capacity of neuronal cells in terms of reduced activities of antioxidant enzymes i.e., superoxide dismutase, catalase and glutathione peroxidase. Further, the activity of glutathione reductase was also significantly decreased in lead and ethanol co-exposed animals as compared to only lead-treated animals, which had altered glutathione status. The results of the present study show that ethanol makes the adult rat brain more susceptible to the neurotoxic effects of lead by accentuating the oxidative stress induced by lead.

Influence of probes for calcium-calmodulin and protein kinase C signalling on the plasma membrane Ca2+-ATPase activity of rat synaptosomes and leukocyte membranes

The influence of selected inhibitors of calcium signalling on the plasma membrane Ca2+-ATPase activity of rat synaptosomes and peritoneal leukocyte membranes was studied. The calmodulin inhibitor calmidazolium was an efficient inhibitor (50%) of the synaptosomal Ca2+-ATPase activity in a manner competitive with phosphatidylserine. The inhibition by CGS 9343B (30%) was not counteracted by phosphatidylserine. The intracellular calcium antagonist TMB-8 and the protein kinase inhibitor staurosporine and the derivatives CGP 41251 and CGP 42700 hardly affected the synaptosomal Ca2+-ATPase activity. The flavonoid quercetin was a more effective inhibitor of the ATPase activity of synaptosomal than of leukocyte membranes. Phloretin, at relatively high concentrations, caused only a modest inhibition of synaptosomes. The protein kinase C inhibitor sphingosine was a weak inhibitor of the synaptosomal but an effective inhibitor of the leukocyte membrane Ca2+-ATPase activity. The antineoplastic ether phospholipids BM 41.440 (ilmofosine) and ET-18-OCH3 (edelfosine) effectively inhibited the leukocyte membranes whereas the ATPase activity of synaptosomes was significantly increased by 20 microM and slightly inhibited by higher concentrations of these agents. The analogue hexadecylphosphocholine (miltefosine) did not affect the ATPase activity of the synaptosomes and only inhibited that of the leukocyte membranes at concentrations above 20 microM. These results show that several test substances of current interest affect the activity of the plasma membrane Ca2+-ATPase. The effects depend on the origin of the membranes. The investigation does not permit a distinction between direct effects on the enzyme and an interference with its membrane environment although the latter is indicated for the ether phospholipids.

Lipid peroxidation and antioxidant defense enzymes in various regions of adult rat brain after co-exposure to cadmium and ethanol

Effect of cadmium (1 mg/kg body weight) and ethanol (2 g/kg body weight) exposure, alone as well as in combination, on essential trace metal homeostasis, lipid peroxidation and antioxidant defense enzymes in various regions of the adult rat brain was investigated. It was observed that cadmium when administered along with ethanol accumulated significantly in corpus striatum (3.5 fold) and cerebral cortex (3.0 fold) compared to the cadmium treated group. The ethanol induced accumulation of cadmium led to significant depletion in the levels of essential trace metals like zinc and copper in these regions of the brain. Further, cadmium or ethanol alone did not show any significant effect on lipid peroxidation and antioxidant defense enzymes in any of the regions of the adult brain but when given in combination, caused a significant increase in lipid peroxidation and markedly decreased the activities of antioxidant defense enzymes like glutathione peroxidase, superoxide dismutase and catalase particularly in corpus striatum and cerebral cortex. Structural alterations produced by increased lipid peroxidation after cadmium and ethanol co-exposure may have profound effect on the activities of membrane bound enzymes and hence may lead to functional impairment. The results of the present study imply that ethanol renders the adult brain more susceptible to the neurotoxic effects of cadmium. Corpus striatum and cerebral cortex are more vulnerable to the toxic effects of cadmium under the influence of ethanol than other regions of the brain.

Effect of organic solvents on nervous cell membrane as measured by changes in the (Ca2+/Mg2+) ATPase activity and fluidity of synaptosomal membrane

The effect of various solvents on the central nervous system was studied by using rat brain synaptosomal membranes as an in vitro model. The activity of (Ca2+/Mg2+) ATPase and the membrane fluidity was determined. The alteration of the ATPase activity depended on the physio-chemical characteristics of the solvent in question. Incubation with aliphatic alkanes caused a stimulation of the ATPase activity whereas mixed hydrocarbons as kerosene, white spirit and gasoline inhibited the enzyme. Incubation with chlorinated hydrocarbons caused a biphasic response dependent on the concentration. Oxygen-containing hydrocarbons exhibited various effects as found after incubation with hydrocarbons. The different effects of the solvents on the ATPase activity suggest that the lipophilicity of the solvents is one of more parameters affecting the membrane. Furthermore, the biphasic response following the incubation with chlorinated hydrocarbons indicates that more mechanisms are involved in the enzyme effect. The membrane fluidity is increased with higher concentrations of the solvents. From the results it is concluded that the ATPase activity depends not only on the membrane fluidity and volume, but also on the hydrophilic vicinity of the enzyme molecule.

Effects of simultaneous ethanol and toluene exposure on nerve cells measured by changes in synaptosomal calcium uptake and (Ca2+/Mg2+)-ATPase activity

The effect of simultaneous exposure of rats to toluene and ethanol on synaptosomal calcium uptake and (Ca2+/Mg2+)-ATPase activity was studied. Rats were exposed to 500 p.p.m. toluene by inhalation for 12 hr a day during four weeks. During the exposure period, the rats had access to 5% sucrose solution containing 20% ethanol or to 5% sucrose solution alone. Rats drinking ethanol exhibited a smaller weight gain than rats drinking water alone. Furthermore, rats exposed simultaneously to toluene and ethanol had a higher ethanol intake than unexposed rats. The toluene exposure caused a higher synaptosomal calcium uptake in vitro. Ethanol intake did not change the synaptosomal calcium uptake in vitro. The synaptosomal calcium uptake in rats exposed to toluene and ethanol was nearly identical to that measured in control rats. In vivo exposure to toluene, or ethanol, or toluene/ethanol simultaneously did not affect the (Ca2+/Mg2+)-ATPase activity in vitro. Incubation with toluene in vitro decreased the (Ca2+/Mg2+)-ATPase activity in a concentration dependent manner. Ethanol had only a slight effect on the enzyme. Simultaneous incubation with toluene and ethanol showed an antagonistic effect of ethanol on the toluene inhibition of the ATPase activity.