The effect of sodium metabisulfite on visual evoked potentials in rats with hypercholesterolemia

This study aimed to investigate the effects of hypercholesterolemia on visual evoked potentials (VEPs) and sulfite additional effects. Rats were assigned as follows: control (C), sulfite (S), hypercholesterolemia (H), vitamin E (E), sulfite + vitamin E (SE), hypercholesterolemia + sulfite (HS), hypercholesterolemia + vitamin E (HE), and hypercholesterolemia + sulfite + vitamin E (HSE). Hypercholesterolemic diet led significant increase in plasma cholesterol levels of rats. Brain thiobarbituric acid reactive substances (TBARS) levels were significantly increased in S, E, SE, HE and HSE groups compared with C. TBARS levels were increased in HE and HSE groups as compared to HS group. Nitrite levels were decreased in S, SE, H, HS and HSE groups compared with C. Nitrite level was notably increased in the HE group compared with H group. Sulfite exposure prolonged N1 and P3 latencies of VEP in group S compared with C. Prolonged VEP latencies by sulfite were significantly decreased by vitamin E in SE group. Cholesterol rich diet increased VEP latencies in comparison with control latencies. Sulfite gave rise to an additional increase in P3 latency in HS group compared with H group. Vitamin E-treated animals had notably shortened latencies of VEP components in HE and HSE groups according to the H and HS groups, respectively.     

The effect of sodium metabisulfite on visual evoked potentials in rats with hypercholesterolemia

This study aimed to investigate the effects of hypercholesterolemia on visual evoked potentials (VEPs) and sulfite additional effects. Rats were assigned as follows: control (C), sulfite (S), hypercholesterolemia (H), vitamin E (E), sulfite + vitamin E (SE), hypercholesterolemia + sulfite (HS), hypercholesterolemia + vitamin E (HE), and hypercholesterolemia + sulfite + vitamin E (HSE). Hypercholesterolemic diet led significant increase in plasma cholesterol levels of rats. Brain thiobarbituric acid reactive substances (TBARS) levels were significantly increased in S, E, SE, HE and HSE groups compared with C. TBARS levels were increased in HE and HSE groups as compared to HS group. Nitrite levels were decreased in S, SE, H, HS and HSE groups compared with C. Nitrite level was notably increased in the HE group compared with H group. Sulfite exposure prolonged N1 and P3 latencies of VEP in group S compared with C. Prolonged VEP latencies by sulfite were significantly decreased by vitamin E in SE group. Cholesterol rich diet increased VEP latencies in comparison with control latencies. Sulfite gave rise to an additional increase in P3 latency in HS group compared with H group. Vitamin E-treated animals had notably shortened latencies of VEP components in HE and HSE groups according to the H and HS groups, respectively.     

环氧丙烷染毒对视觉诱发电位的急性作用

选用４０只雄性Ｗｉｓｔａｒ大鼠,随机分成环氧丙烷（ＰＯ）染毒组与对照组,采用静式吸入染毒,以５档计算浓度分别为３００,５００,１０００,２０００,５０００ｍｇ／ｍ３,对实验组大鼠每次染毒２小时,染毒结束后,立即测定闪光视觉诱发电位（ＦＥＰ）和模式翻转视觉诱发电位（ＰＲＥＰ）,分析各波（Ｐ１、Ｎ１、Ｐ２,Ｎ２和Ｎ１、Ｐ１、Ｎ２）潜伏期及其波幅（Ｎ１－Ｐ２、Ｐ２－Ｎ２和Ｎ１－Ｐ１、Ｐ１－Ｎ２）。大鼠在２０００ｍｇ／ｍ３染毒时,ＰＲＥＰ测定中Ｎ２波潜伏期显著延长。５０００ｍｇ／ｍ３浓度时,ＰＲＥＰ和ＦＥＰ各波潜伏期均有显著延长,于第２天已部分恢复,但波幅未见改变。这说明ＰＯ对中枢神经系统产生功能性抑制作用。然而低浓度ＰＯ染毒时就出现呼吸道刺激症状,远早于诱发电位的变化;高浓度时有明显呼吸系统刺激症状,出现呼吸困难。因此,急性ＰＯ染毒对中枢神经的抑制作用较小,主要为呼吸系统刺激作用     

Inhibitory effect of midbrain raphe stimulation on cortical evoked potentials in rats

Stimulation of the midbrain raphe (MR) area in rats induced a decrease of the peripherally evoked potentials in the primary sensory cortex.The inhibition was blocked by relatively small doses of strychnine whereas picrotoxine was ineffective. Low doses of LSD₂₅, markedly potentiate the effect of MR stimulation.     

Studies on the effect of drugs on somatosensory cortical evoked potentials (author's transl)

The effect of the following drugs in therapeutic doses on somatosensory cortical evoked potentials was studied: methamphetamine, chlorpromazine, imipramine, diazepam, phenobarbital, pethidine, and novaminesulfone. Physiological saline was used as control. Each of these compounds was studied in 5 healthy subjects. Three evoked potentials were recorded before, and another three after administration of the drug. Each potential was averaged from 1024 single stimuli. None of the drugs, led to marked changes of the evoked potential, i.e., all data (latencies, amplitudes) were within the double standard deviation of the data obtained in normal subjects in a previous study. Although no significant changes were seen, some trends could be observed: methamphetamine and imipramine produced a decrease in the latency of the first positive peak, chlorpromazine increased the latency of the third positive peak. The amplitude of the third peak was reduced under phenobarbital. It is concluded that the drugs investigated in the presents study do not produce significant changes in the somatosensory cortical evoked potential and therefore drug application may be continued when evoked potentials are used for diagnostic purposes.     

Dose-dependent effect of nutritional sulfite intake on visual evoked potentials and lipid peroxidation

The aim of this study was to clarify the dose-dependent effect of sulfite (SO₃²⁻) ingestion on brain and retina by means of electrophysiological and biochemical parameters. Fifty two male Wistar rats, aged 3 months, were randomized into four experimental groups of 13 rats as follows; control (C), sulfite treated groups (S₁; 10 mg/kg/day, S₂; 100 mg/kg/day, S₃; 260 mg/kg/day). Control rats were administered distilled water, while the other three groups were given sodium metabisulfite (Na₂S₂O₅) of amounts mentioned above, via gavage for a period of 35 days.All components of visual evoked potential (VEP) were prolonged in S₂ and S₃ groups compared with S₁ and C groups. Plasma-S-sulfonate levels, which are an indicator of sulfur dioxide (SO₂) exposure, were increased in Na₂S₂O₅ treated groups in a dose-dependent manner. Furthermore, the significant increments in thiobarbituric acid reactive substances (TBARS) and 4-hydroxy-2-nonenal (4-HNE) levels occurred with increasing intake of Na₂S₂O₅. Though not significant, glutathione (GSH) and oxidized glutathione (GSSG) levels were observed to decrease with increasing doses of Na₂S₂O₅.In conclusion, Na₂S₂O₅ treatment in rats caused a dose-dependent increase in lipid peroxidation and all VEP latencies. The data indicate that lipid peroxidation could play an important role in sulfite toxicity.     

Effect of delta 9-tetrahydrocannabinol on cortical evoked potentials

It has been shown on cats with the help of the registration of evoked potentials of the visual, somatosensory and associative areas of the brain cortex that delta-9 tetrahydrocannabinol in a dose of 1.5 mg/kg diminishes the amplitude of the primary responses in all the areas whereas in a dose of 3.5 mg/kg it influences both early and late components of evoked potentials interfering with their similarity in the definite areas of the brain cortex.     

Influence of staphylococcal alpha-hemolysin on cortical sensory evoked potentials

Staphylococcal alpha-hemolysin injected iv into rabbits causes disappearance of the brain bioelectric activity, with particular involvement of the thalamic region. The toxin produces disintegration of the electronegative component of evoked potentials produced by sciatic nerve stimulation. It is postulated that alpha-hemolysin acts on both specific and nonspecific thalamic structures. Observed differences concern only the sequence of action on individual parts of the afferent system.     

Tobacco effects on cortical evoked potentials to task stimuli

Cortical evoked potentials (EP) were investigated in a group of female smokers in separate smoking and non-smoking sessions. In a constant-fore-period S1-S2 reaction time paradigm, EPs were averaged separately to auditory warning (S1) stimuli and visual imperative (S2) stimuli under 4 conditions: (a) a single-choice S1-S2 sequence with no auditory distraction task; (b) a single-choice S1-S2 sequence with concomitant auditory distraction task; (c) a four-choice S1-S2 sequence with no auditory distraction task; (d) a four-choice S1-S2 sequence with concomitant auditory distraction task. Two individual EP peaks, N1 and P2 and one peak-to-peak measure, N1-P2, were involved in amplitude analysis of S1 and S2 stimuli. Tobacco significantly improved the decision time (DT) component of reaction time and increased N1 amplitudes to S1 stimuli. Tobacco also interacted with task complexity to reduce P2 amplitudes to S1. No significant tobacco effects were observed with EPs to S2. The results are discussed in relation to improved attention and information processing.     

Dose dependent effects of alcohol on visual evoked potentials

The effects of various alcohol doses on components of the visual evoked potential were investigated. Using a repeated measures, Latin square design, five alcohol dose conditions were administered to ten male subjects: 0.00 (placebo); 0.28; 0.36; 0.54 and 0.72 g/kg total body weight. EEG responses to a reversing checker board stimulus were measured in a standard oddball paradigm. In the alcohol conditions, latencies of the P1 and P2 components of the VEP were unaffected. However, reaction time, and the latencies of N2 and P3 displayed significant dose related increases with increasing blood alcohol levels. Further, RMS power of the P3 complex was reduced by higher alcohol doses, as was the N2-P3 amplitude difference at central and parietal sites. It is concluded that the latency and power of the endogenous components of the VEP are altered by alcohol, without effects being seen in earlier components.     

皮层损伤对听觉中潜伏期诱发电位的影响

作者对经CT和手术证实的脑外伤致幕上皮层损害的病人应用MLAEP检测,结合临床表现进行观察研究。采用急性颅脑损伤病人20例(男15例,女5例)。结果提示不同病例组和对照组间Pa—PL和Pa—Amp有显著性差异。而Na—PL、Na—Amp多在正常范围内,表现为Pa、Na的分离。结果支持Pa起源为非单一结构并为双侧性的观点,并提示Na起源可能位于脑的深在部位神经核团,Pa产生于双侧皮层和皮层下结构,此结果与国外学者报道相一致。     

Visually evoked cortical potentials obtained using checker patterns can detect ethambutol-induced visual toxicity in albino rats

We determined whether visually evoked cortical potentials obtained using checker patterns (P-VECPs) and albino rats would reveal visual damage induced by ethambutol (EB). Findings were compared in cases of detection of visual damage between by P-VECPs and by flash visually evoked cortical potentials (F-VECPs). Twelve adult albino male Crj:CD(SD)IGS rats were grouped into four, three per group: control, 250PS, 500PS, and 500SC groups. In the 250PS and 500PS groups, rats were administered EB orally for the first 2 weeks and then subcutaneously for the second 2 weeks to 250 and 500 mg/kg, respectively. In the 500SC group, rats were given 500 mg/kg of EB subcutaneously for 4 weeks. Rats in the control group were given the vehicle orally for the first 2 weeks and then subcutaneouly for the second 2 weeks. P-VECPs and F-VECPs were carried out prior to initiation of drug administration and at the 1st, 2nd, 3rd, and 4th weeks of the administration. Prolongation of P1 latency in the P-VECPs was evident in both the 500PS and the 500SC groups at the 4th week, while no marked changes were observed in the F-VECPs. Thus, P-VECPs in albino rats can detect visual damage induced by EB even when F-VECPs cannot do so. These studies suggest that P-VECPs are useful for evaluating the visual toxicity of drugs.     

The effect of probenecid on the in vitro absorption of cardiac glycosides

Experiments on the everted sac preparation of the mouse small intestine show that digitoxin absorption and sodium, glucose and water transport are decreased under anaerobic conditions, changed potassium medium contents, omission of glucose and by probenecid, mersalyl and ethacrynic acid. The net absorption of digoxin and ouabain is nearly unchanged in these experiments obviously because a simultaneous increase of the passive diffusion compensates more or less the inhibition of active mechanisms.Therefore the results show that digitoxin absorption is partially mediated by energy resp. oxygen dependent processes. The used methods are not appropriate to demonstrate a similar active transport system for polar glycosides.     

Effects of calcitonin on human auditory and visual evoked brain potentials

Besides its Ca⁺⁺-regulative effects, calcitonin is known to diminish sensitivity to painful stimuli. The present study aimed to clarify whether calcitonin has similar effects on stimulus processing in other modalities. Effects of calcitonin were assessed on brain potentials recorded from the human scalp which were evoked either by auditory clicks or visual checkerboard pattern-reversals. Twelve healthy men were tested in a double-blind intra-subject design receiving either 0.1 IU/kg salmon calcitonin (sCT) or 1.0 IU/kg sCT or saline solution during a 20 min IV infusion. sCT significantly increased latency of wave V of the brainstem auditory evoked potential (BAEP). Effects on BAEP wave V increased in magnitude with increasing dose of sCT and with decreasing intensity of the click stimulus. There was also a slight increase in latency of the N80 of the pattern-reversal visual evoked potential (PR-VEP). Additionally, subjects rated themselves as less activated following the high dose of sCT compared to placebo. The pattern of results is in accord with a slowing or inhibitory influence of calcitonin on auditory and visual sensory processing, thus paralleling findings concerning calcitonin effects on the perception of painful somatosensory stimuli.     

The effects of prenatal exposure to buprenorphine or methadone on infant visual evoked potentials

This study compared the neurological development of 4 month old infants exposed to buprenorphine or methadone during pregnancy to that of a control group of non-exposed infants. Participants were 30 buprenorphine-maintained women, 22 methadone-maintained women and 33 non opioid-dependent controls, and their infants. Women were enrolled during pregnancy as part of an open-label non-randomised flexible-dosing longitudinal study. Groups were matched for maternal age, parity, gravida, and tobacco and alcohol use. Infant neurological development was assessed by measuring latency of pattern reversal visual evoked potentials (VEP). One-way between groups analyses of variance (ANOVA) were conducted to test the statistical significance of differences between the mean latencies of the peak response to two different sized checkerboard patterns (48′ and 69′ of retinal arc). Infants prenatally exposed to methadone had significantly prolonged latencies, compared with infants in the control group and infants prenatally exposed to buprenorphine, in response to checks of 48′ and 69′. VEP latencies of infants prenatally exposed to buprenorphine did not differ significantly from controls for either check size. After adjustment for covariates, prenatal exposure to methadone remained a significant predictor of VEP response to checks of 48′, but not 69′. Maternal self-reported used of marijuana during pregnancy made a significant unique contribution to the variance in P1 latencies for both check sizes. Data from this controlled, non-randomised study suggest that buprenorphine may confer an advantage over methadone as a maintenance drug during pregnancy in terms of infant neural development at 4 months of age.     

强心苷类抗癌作用研究进展

强心苷类物质可分为外源性强心苷类和内源性强心苷类。该文主要阐述了强心苷类的抗癌作用机制与其抑制Na+,K+-ATP酶、缺氧诱导因子-1、成纤维细胞生长因子、核转录因子及拓扑异构酶的活性,阻断雌激素受体,诱导细胞凋亡以及细胞毒作用相关;简要阐述了强心苷类对乳腺癌及前列腺癌等恶性肿瘤的作用效果以及内源性强心苷类与癌症的可能关系。