Dendritic attenuation of synaptic potentials in the CA1 region of rat hippocampal slices detected with an optical method

We directly measured fast excitatory postsynaptic potentials (EPSPs) along the dendrites of hippocampal CA1 pyramidal neurons by employing an optical method to study how synaptic potentials spread along the dendrites. Rat hippocampal slices were stained with a fluorescent voltage-sensitive dye JPW1114 and optical signals were monitored with a 16 x 16 photodiode array system. A stimulating electrode was placed either at stratum lacunosum moleculare to activate perforant fibers that make synaptic contacts to the distal apical dendrites or at stratum oriens to induce EPSPs at the basal dendrites of CA1 pyramidal cells. CNQX-sensitive components of the optical signals, which were assumed to be population EPSPs, were isolated. Propagation and attenuation of the CNQX components were successfully observed with the optical method. At the cell body layer, the peak of the CNQX-sensitive component was delayed by 17.08 +/- 1.64 ms from the input sites. Additionally we performed a simulation study to estimate the passive membrane parameters of the apical dendrites. Estimated apparent specific internal axial resistance (Ri) following stratum lacunosum moleculare stimulation was 76.0 +/- 4.2 Omega.cm and apparent specific membrane resistance (Rm) was 27.8 +/- 2.1 kOmega.cm2 (assuming the specific membrane capacitance of dendrites Cm = 1.6 microF/cm2). These values are comparable to those previously reported. When synaptic inputs were applied at stratum oriens, these apparent passive membrane parameters were different (high Ri and low Rm), suggesting that nonuniform dendritic membrane conductance or voltage-dependent conductances which are active near the resting potential may contribute to the measured passive membrane properties.

Cytokine expression in rat molar gingival periodontal tissues after topical application of lipopolysaccharide

It is well known that proinflammatory cytokines produced by host cells play an important role in periodontal tissue destruction. However, the localization of the cytokines in in vivo periodontal tissues during development of periodontal disease has not been determined. Immunohistochemical expression of proinflammatory cytokines including IL-1alpha, IL-1beta, and TNF-alpha was examined at 1 and 3 h, and 1, 2, 3, and 7 days after topical application of lipopolysaccharide (LPS; 5 mg/ml in physiological saline) from E. coli into the rat molar gingival sulcus. In the normal periodontal tissues, a small number of cytokine-positive epithelial cells were seen in the junctional epithelium (JE), oral sulcular and oral gingival epithelium, in addition to macrophages infiltrating in the subjunctional epithelial area and osteoblasts lining the alveolar bone surface. Epithelial remnants of Malassez existing throughout periodontal ligament were intensely positive for IL-1beta but negative for the other two cytokines. At 3 h after the LPS treatment, almost all cells in the JE were strongly positive for the cytokines examined. In addition, several cytokine-positive cells, including neutrophils, macrophages, and fibroblasts, were seen in the subjunctional epithelial connective tissue. At day 2, expression of the cytokines in the JE gradually decreased, while cytokine-positive cells in the connective tissue increased in number. Positive staining of the cytokines was seen in osteoclasts and preosteoclasts which appeared along the alveolar bone margin in this period. The number of cytokine-positive cells decreased by day 7. These findings indicate that, in addition to macrophages, neutrophils, and fibroblasts, the JE cells are a potent source of TNF-alpha, IL-1alpha, and IL-1beta reacting to LPS application, and suggest that JE cells may play an important role in the first line of defense against LPS challenge, and the proinflammatory cytokines transiently produced by various host cells may be involved in the initiation of inflammation and subsequent periodontal tissue destruction.

Erythrocyte creatine as a marker of excessive erythrocyte destruction due to hypersplenism in patients with liver cirrhosis

OBJECTIVE

Erythrocyte creatine is a sensitive marker of erythrocyte age, and can be used to detect slight and continuous hemolysis. Excessive blood cell destruction caused by increased spleen function is important evidence of hypersplenism. This study evaluates the usefulness of erythrocyte creatine as a sensitive marker of excessive erythrocyte destruction due to hypersplenism in patients with liver cirrhosis.

DESIGN AND METHOD

Erythrocyte creatine was determined by an enzymatic method in 50 patients with postnecrotic liver cirrhosis and 50 healthy controls. The spleen size was measured by ultrasonography and expressed as a spleen index.

RESULTS

The patients with splenomegaly showed significantly higher erythrocyte creatine than those without splenomegaly (p < 0.005) and healthy controls (p < 0.001), but there was no significant difference in erythrocyte creatine between healthy controls and those without splenomegaly. Fourteen (93%) of the 15 patients with abnormally high erythrocyte creatine (> 1.8 micromol/g hemoglobin) had splenomegaly. There were no significant differences in reticulocyte count between healthy controls and the patients with and without splenomegaly. Erythrocyte creatine showed good correlations with spleen index (r = 0.67; p < 0.001) and reticulocytes (r = 0.63; p < 0.001).

CONCLUSIONS

Erythrocyte creatine can be used for predicting erythropoietic status and estimating hypersplenism in patients with liver cirrhosis.

Successful hyperbaric oxygen treatment of life-threatening hemorrhagic cystitis after allogeneic bone marrow transplantation

Hemorrhagic cystitis (HC) is a major cause of morbidity after allogeneic bone marrow transplantation (BMT). Many therapies have been investigated to prevent or treat HC, but effective treatment for HC is still limited. While the efficacy of hyperbaric oxygen therapy has been established for HC due to chemotherapy and/or radiation therapy, its role in HC occurring after allogeneic BMT has yet to be defined. We report two cases of life-threatening late-onset HC after allogeneic BMT in children, which resolved after treatment with hyperbaric oxygen.

Association of structural polymorphisms in the human period3 gene with delayed sleep phase syndrome

Recent progress in biological clock research has facilitated genetic analysis of circadian rhythm sleep disorders, such as delayed sleep phase syndrome (DSPS) and non-24-h sleep-wake syndrome (N-24). We analyzed the human period3 (hPer3) gene, one of the human homologs of the Drosophila clock-gene period (Per), as a possible candidate for rhythm disorder susceptibility. All of the coding exons in the hPer3 gene were screened for polymorphisms by a PCR-based strategy using genomic DNA samples from sleep disorder patients and control subjects. We identified six sequence variations with amino acid changes, of which five were common and predicted four haplotypes of the hPer3 gene. One of the haplotypes was significantly associated with DSPS (Bonferroni's corrected P = 0.037; odds ratio = 7.79; 95% CI 1.59-38.3) in our study population. Our results suggest that structural polymorphisms in the hPer3 gene may be implicated in the pathogenesis of DSPS.

[Cytotoxic activity and cytokine gene induction of Asp-hemolysin to vascular endothelial cells]

We examined the effects of Asp-hemolysin from Aspergillus fumigatus Fresenius-Muramatsu strain on the viability and cytokine gene expression of human umbilical vein endothelial cells (HUVEC). The cell viability of HUVEC was reduced to 50% by 100 micrograms/ml of Asp-hemolysin. However, lower concentration of Asp-hemolysin (< 30 micrograms/ml) had no effect on the cell viability. The mRNA expression of such cytokines as tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 beta, IL-6, IL-8 and granulocyte-macrophage colony stimulating factor (GM-CSF) were also observed in HUVEC cultured with 30 micrograms/ml of Asp-hemolysin.

[Effects of low density lipoprotein and oxidized low density lipoprotein on the cytotoxic activity of Asp-hemolysin to murine macrophages]

We examined the effects of human low density lipoprotein (LDL) and oxidized LDL (Ox-LDL) on the cytotoxic activity of Asp-hemolysin from Aspergillus fumigatus Fresenius-Muramatsu strain to mouse peritoneal macrophages (M phi). The inhibitory effects of LDL and Ox-LDL on the cytotoxic activity of Asp-hemolysin to M phi increased in a dose-dependent manner, and the effect of Ox-LDL was greater than the inhibitory effect of LDL. Furthermore, the binding of Asp-hemolysin to LDL or Ox-LDL was observed by western blot analysis of the culture medium. These results suggest that the inhibition by LDL or Ox-LDL on the cytotoxic activity of Asp-hemolysin to M phi was due to the binding of LDL or Ox-LDL to Asp-hemolysin in the culture medium.

Visualization of oxygen-concentration-dependent production of nitric oxide in rat hippocampal slices during aglycemia

Our novel fluorescent indicator, DAF-FM, permits the bioimaging of nitric oxide (NO) in living cells with high resolution in space and time, with stable intensity above pH 5.8. A membrane-permeable derivative, DAF-FM DA, was applied to imaging of NO generated in rat hippocampal slices by exposure to an aglycemic medium. NO production was observed mainly in the CA1 area, and was dependent on the concentration of O(2). During exposure to an anoxic-aglycemic medium, NO was hardly produced, while marked elevation of intracellular Ca(2+) was observed. Production of NO increased sharply as soon as the perfusate was changed to the normal medium. These results suggest that NO synthase is activated after reperfusion rather than during ischemia.

Characterisation of L-tryptophan transporters in human placenta: a comparison of brush border and basal membrane vesicles

The mechanisms responsible for L-tryptophan transport at both the maternal- and fetal-facing surfaces of the term placenta have been determined in isolated membrane vesicles as part of a study on placental indoleamine 2,3-dioxygenase, the L-tryptophan-catabolising enzyme recently shown to regulate feto-maternal immunology. Brush border vesicle uptake of L-tryptophan is substantially into an osmotically active space. It is sodium independent and N-ethylmaleimide sensitive. Uptake of L-tryptophan, which is markedly stereospecific, has a Km of 26.3 microM and Vmax of 1.72 pmol (mg protein)(-1) s(-1) and is completely abolished by the L-system-specific substrate 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH). These findings are in keeping with L-tryptophan transport being exclusively via system L (induced by the heterodimeric heavy chain of CD98 and system L-amino acid transporter-1 (LAT-1)). 1-Methyl-tryptophan (which is a known competitive inhibitor of indoleamine 2,3-dioxygenase) is a competitive inhibitor of L-tryptophan flux through this transport system (Ki = 113 microM). Basal membrane transport of L-tryptophan is more complex. Uptake is slower than at the brush border and although, as in the brush border, uptake is sodium independent, it is less sensitive to N-ethylmaleimide. There is clear evidence that two systems contribute to basal membrane transport since BCH is (in sodium-free media) only a partial inhibitor whereas L-histidine and L-cysteine are fully effective. The simplest explanation of these and other findings is that the basal membrane possesses two systems, one of which is similar to that induced by the heavy chain of CD98 and system L-amino acid transporter-2 (LAT-2). The other appears to be system y+L since in the presence of BCH inhibition by L-leucine but not by L-lysine is sodium dependent. These findings suggest the existence of non-identical carrier-mediated transport systems for L-tryptophan in brush border and basal membranes. This asymmetry may explain net transplacental transfer of this amino acid.

The role of L-tryptophan transport in L-tryptophan degradation by indoleamine 2,3-dioxygenase in human placental explants

The physiological importance of L-tryptophan transport for placental indoleamine 2,3-dioxygenase-mediated degradation of L-tryptophan has been studied using human placental chorionic villous explants. L-Tryptophan influx into villous explants is supported exclusively by transport system L and is substantially inhibited by the L-system-specific substrate 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH) and also by 1-methyl-tryptophan which is also an inhibitor of indoleamine 2,3-dioxygenase. L-Tryptophan influx is enhanced 2.3-fold following in vitro culture of the villous explant. Interferon-gamma, which increases villous explant indoleamine 2,3-dioxygenase expression, has no effect on L-tryptophan influx. In explants both BCH and 1-methyl-tryptophan inhibit indoleamine 2,3-dioxygenase-mediated L-tryptophan degradation. This also applies when L-tryptophan degradation has been stimulated by interferon-gamma. These findings show transport of L-tryptophan into the trophoblast to be a rate-limiting step for indoleamine 2,3-dioxygenase-mediated L-tryptophan degradation and therefore for the normal physiology of mammalian pregnancy.

Low-threshold potassium channels and a low-threshold calcium channel regulate Ca2+ spike firing in the dendrites of cerebellar Purkinje neurons: a modeling study

Various types of voltage-gated ion channels are distributed along the dendrites of neurons in the central nervous system. We have recently shown experimentally that the dendrites of cerebellar Purkinje neurons contain low-threshold voltage-gated Ca(2+) channels and low-threshold voltage-gated K+ channels. Although we found that these channels are involved in regulating the onset of Ca(2+)-dependent action potentials in the dendrites, we were unable to identify which of the known types of low-threshold Ca2+ channels and K+ channels were responsible, since there was no reliable method of discriminating between them. Here, we have built a detailed compartmental model of a Purkinje neuron by incorporating two types of low-threshold Ca2+ channel (T-type and class-E, or R-type) and two types of low-threshold K+ channel (A-type and D-type), in addition to another eight voltage-gated channel types, using a compartmental model neuron simulator. The model reproduces the basic features of the depolarization-induced responses of Purkinje neurons, such as fast Na+ spikes in the soma, Ca2+ spikes in the dendrites, the slow onset of Ca2+ spikes, repetitive Ca2+ spikes in the presence of TTX, the marked shortening of Ca2+ spike onset in the presence of 4-aminopydridine, and the longer Ca2+ spike onset in the presence of Ni2+. Our model shows that the D-type K+ channel and the class-E Ca2+ channel regulate the onset of depolarization-induced Ca2+ spikes in Purkinje neurons. These channels might be involved in integrating synaptic inputs in Purkinje neurons.

Real-time, two-dimensional visualization of ischaemia-induced glutamate release from hippocampal slices

The involvement of excitatory amino acid (EAA) toxicity in ischaemia-induced neuronal cell death has long been suggested. However, in the hippocampus, the brain site most vulnerable to ischaemia, the detailed spatial and temporal patterns of EAA release are not yet known. To address this issue, we have developed a novel strategy for the continuous, real-time, two-dimensional monitoring of EAA release from brain slices. As EAA detector, we used a cell line transformed with the N-methyl-D-aspartate (NMDA) receptor, which is exclusively activated by EAAs, leading to an increase in the intracellular Ca(2+) level. Combined with a calcium imaging technique, the use of this cell line allowed the temporal and regional analysis of EAA release from a brain slice placed directly on top of the clonal cells in a culture dish. Using this strategy, we demonstrated ischaemia-induced EAA release in rat hippocampal slices. Increased EAA release was seen initially in the CA1 region, about 3 min after the beginning of ischaemia, then in the CA3 region and dentate gyrus, and, finally, throughout the hippocampal slice. Regional differences in extracellular EAA levels were also seen, with more EAA being released from the CA1 region than from the middle dentate gyrus. The present results are especially interesting as neurons in the CA1 region are more vulnerable to ischaemia than those in the CA3 region and dentate gyrus.

Flow cytometric analysis of hemetopoietic progenitor cells in peripheral blood stem cell harvest from patients with CD34 positive acute leukemia

We analyzed CD34 positive cells in peripheral blood stem cell harvest (PBSCH) using flow cytometry. PBSCH from CD34 positive acute myelogeous leukemia (AML-M2) patient contained 1.87% CD34 positive cells, of which 1.21% was represented by MRD.PBSCH from CD34 positive acute lymphoblast leukemia (ALL) patient contained 3.14% CD34 positive cells, of which 0.11% was accounted for by minimal residual disease (MRD). If PBSCH from CD34 positive acute leukemia patient is analyzed for CD34 monoclonal antibody alone, the presence of CD34 positive MRD may escape attention so that CD34 positive hematopoietic progenitor cells may be overestimated. To avoid this risk, it is necessary to analyze PBSCH using both CD34 monoclonal antibody and characteristic markers of leukemia cells that were found pre-treatment.

Peripheral ameloblastoma: biological profile based on 160 cases from the literature

The present profile of the peripheral ameloblastoma (PA) is based on a literature survey of 160 published tumour cases. The PA is an exophytic growth localized to the soft tissues overlying the tooth-bearing areas of the jaws, the initial diagnosis often being fibrous epulis. In most cases there is no radiological evidence of bone involvement, but a superficial bone erosion--known as cupping or saucerization--may be detected at operation. The PA accounts for 2-10% of all ameloblastomas. The overall average age is 52.1 years, slightly higher for males (52.9 years) than for females (50.6 years). Thus, the PA occurs at a significantly higher age than the intraosseous ameloblastoma (IA; 37.4 years). The male/female ratio amounts to 1.9:1, as opposed to 1.2:1 for the IA. The male/female ratio for the Japanese cases included in this survey is 2.5:1 as opposed to that of non-Japanese cases 1.4:1. As to the location of PA, the maxilla/mandible ratio is 1:2.6. The mandibular premolar region accounts for 32.6% of all sites. Five extra-gingival lesions have been reported under the term PA. As these cases most likely represent salivary gland tumours, they are not accepted under the diagnosis of PA. The odontogenic gingival epithelial hamartoma shows clinical, histological and behavioural features almost identical to the PA, and it is discussed whether this lesion and the PA should be considered one and the same entity. Pathogenetically, two major sources are discussed: remnants of the dental lamina and the oral surface epithelium. Histologically, the PA consists of proliferating odontogenic epithelium exhibiting the same histomorphological cell types and patterns as seen in the IA. The stroma is that of a mature, fibrous connective tissue. The indolent biological behaviour dictates a conservative therapeutical approach. It is discussed whether PA is a true neoplastic counterpart of the IA or rather an odontogenic hamartomatous lesion. Six cases of malignant PA have been reported.

Diurnal fluctuation of sleep propensity and hormonal secretion across the menstrual cycle

BACKGROUND

The fact that most women experience sleep changes across the menstrual cycle is thought to be associated with changes in circadian rhythms; however, few studies have investigated this relationship.

METHODS

We applied an ultrashort sleep-wake schedule to eight healthy women and studied diurnal fluctuations in sleep propensity, sleepiness, rectal temperature, and serum concentrations of melatonin, thyroid-stimulating hormone, and cortisol in the follicular and luteal phases.

RESULTS

In the luteal phase, amplitude of core body temperature, total melatonin secretions, and amplitudes of TSH and cortisol rhythms were significantly decreased, whereas sleepiness and occurrence of slow-wave sleep during the daytime were significantly increased. Differences in the amount of daytime slow-wave sleep across the menstrual cycle were positively correlated with differences in the daily mean rectal temperature.

CONCLUSIONS

The findings suggest that the amplitude of circadian oscillation may be dampened in the luteal phase. Increased daytime sleepiness in the luteal phase may be associated with increased daytime slow-wave sleep, due possibly to changes in thermoregulation in the luteal phase.

Altered phase relation between sleep timing and core body temperature rhythm in delayed sleep phase syndrome and non-24-hour sleep-wake syndrome in humans

Changes in the phase relation between sleep timing and the circadian pacemaker are suspected to have an etiological significance in circadian rhythm sleep disorders. Simultaneous recordings of rest-activity and rectal temperature in seven sighted delayed sleep phase syndrome (DSPS) patients, seven sighted non-24-h sleep-wake syndrome (non-24) patients, and 14 healthy controls were made for 10-14 days continuously in the subjects' homes. We found that sleep length and the interval from the body temperature (BT) trough to sleep offset were significantly longer in both non-24 and DSPS patients than in the controls, and that the interval between sleep onset and the BT trough was significantly less in the non-24 patients than in the DSPS patients and the controls. We postulate these alterations in phase relation to be associated with phase changes of the circadian pacemaker via different illumination timings.

Reduced expression of CD44 variant 9 is related to lymph node metastasis and poor survival in squamous cell carcinoma of tongue

Expression of CD44v9 was immunohistochemically studied in 120 biopsy specimens from primary squamous cell carcinoma (SCC) of the tongue and correlated with clinicopathological findings of the SCCs. The tumors were classified into three groups according to immunostaining pattern of CD44v9; 53 cases with distinct positivity in all cancer cells except for those in the central part of nests (Group 1, non-reduced group), 42 cases with reduced expression in peripheral cells of nests (Group 2, reduced group), and 25 cases with complete disappearance of the expression in one or more nests (Group 3, negative group). Nineteen of 25 (76%) tumors in Group 3 and 14 of 42 (33%) in Group 2 exhibited lymph node metastasis, compared with only 8 of 53 (15%) in Group 1. The average survival time in Groups 1, 2 and 3 was 4496+/-204, 3866+/-379 and 2719+/-359 days, respectively and became shorter with the reduction of CD44v9 expression. These results suggest that the down-regulation of CD44v9 in SCC of the tongue may relate to the detachment of tumor cells from primary lesions, establishment of lymph node metastasis and consequently the death of patients.

The design of cyclic AMP--recognizing oligopeptides and evaluation of its capability for cyclic AMP recognition using an electrochemical system

A novel 17-mer peptide ligand for cyclic AMP was designed using the amino acid sequences of essential subsites in various cyclic AMP-dependent protein kinase (protein kinase A) families. The Au disk electrode, which was modified with the designed 17-mer oligopeptide, responded to cyclic AMP but virtually did not respond to any other cyclic nucleotides using the ion channel sensor mechanism. On the other hand, a scrambled peptide, which had the same amino acid composition as and had an amino acid sequence different from the 17-mer oligopeptide, did not respond to any nucleotides. This indicates that the designed 17-mer peptide actually acted as a selective ligand for cyclic AMP. This ligand-designing strategy using peptide sequences in target-binding proteins may possibly be extended to the design of peptide ligands for other second messengers.

Two deletion mutations in the hydroxymethylbilane synthase gene in two unrelated Japanese patients with acute intermittent porphyria

Acute intermittent porphyria (AIP) is an autosomal dominant inherited disease caused by a decreased activity of hydroxymethylbilane synthase (HMBS). Regarding the abnormalities of the HMBS gene, many different mutations have been reported worldwide; however, few families from Japan have been studied. In this work, we investigated the presence of mutations in two unrelated Japanese patients with AIP. Mutational analysis was performed using the polymerase chain reaction-single strand conformation polymorphism (SSCP) method, followed by DNA sequencing. Reliable restriction enzyme cleavage assays were also established for the pedigree analyses. Unique SSCP patterns were noted in exons 12 and 15 of the HMBS gene. Sequencing revealed different mutations in each patient: a two-base deletion of CT at nucleotide 730-731 (730delCT), and also a two-base deletion of CA at position 982-983 (982delCA). Both of the deletion mutations lead to truncated proteins with an abnormal C-terminus, which would be expected to decrease the stability and/or activity of HMBS. Using the cleavage assays, we were able to definitively identify gene carriers in the family. This study adds a novel mutation to those that have been previously reported, and emphasizes that molecular analysis would be very useful not only for the identification of asymptomatic gene carriers in the family but also for the detection of ancestral founders in porphyria families.

Evolution of meal patterns and food choices of Japanese-American females born in the United States

OBJECTIVES

To examine trends in meal patterns and food choices across two generations of Japanese-American females born in the USA.

DESIGN

Cross-sectional cohort study.

SETTING

Gardena, a suburb of Los Angeles, California.

SUBJECTS

One-hundred and seventy-six Japanese-American females, participating in a morning exercise class from December 1998 to January 1999.

INTERVENTION

Eighty-eight Nisei (second generation) mothers and their Sansei (third generation) daughters completed a food frequency questionnaire, answering questions regarding meal patterns and consumption frequency of 51 food items.

RESULTS

The Sansei ate fewer meals per day compared with the Nisei. Mean frequencies of takeout foods and eating out were higher in the Sansei vs the Nisei. Mean intake of meats and eggs were similar between the two groups. However, mean consumption of traditional Japanese complement foods including fish, vegetables and legumes was lower in the Sansei vs the Nisei. Intake of more 'Westernized' accessory foods, including salty snacks, regular soft drinks and alcoholic beverages, was higher in the Sansei vs the Nisei.

CONCLUSION

Findings from this study indicate that meal patterns and food choices have changed in succeeding generations of Japanese-American females from traditional fare to a diet containing many complement and accessory foods that are higher in fat, sugar, sodium and calories. Health professionals should be advised to consider the whole diet in making nutrition recommendations to this population as well as providing information to this group on the nutritional benefits of many traditional foods. European Journal of Clinical Nutrition (2000) 54, 665-670.

T-477, a novel Ca(2+)- and Na(+) channel blocker, prevents veratridine-induced neuronal injury

To evaluate the effect of (R)-(+)-2-(4-chlorophenyl)-2, 3-dihydro-4-diethyl aminoacetyl-4H-1,4-benzothiazine hydrochloride (T-477), a novel Na(+)- and Ca(2+) channel blocker, on neuronal injury in vitro, we studied veratridine-induced injury in cultured rat hippocampal neurons. Neurons swelled extensively 10 min after the addition of veratridine, and returned to their initial size within 2 h. Intracellular Na(+) and Ca(2+) concentrations and amino acid release from the cells, in particular, that of glutamate, increased after the treatment with veratridine. Approximately 70% of neurons died within 24 h. T-477 inhibited both veratridine-induced swelling and death in a concentration-dependent manner. Moreover, T-477 concentration dependently reduced the increases in Na(+) and Ca(2+) influx and amino acid release. These results suggest that T-477 prevented the veratridine-induced influx of Na(+) and, thereby, reduced neuronal swelling. This, combined with the effects of T-477 on the inhibition of Ca(2+) influx and glutamate release, possibly by the blockade of Na(+) channels, may be the mechanism by which T-477 protects neurons from death induced by veratridine.

Effects of small dose of brotizolam on P300

Nine healthy men (mean age, 22.2 years) participated in two experimental sessions cross-overed randomly in a double blind manner; one with a placebo and the other with 0.125 mg of brotizolam (BTZ) administered in the morning. Resting electroencephalogram and event-related potential under oddball paradigm was recorded before and 1, 2, 4, 6 and 8 h after the administration. Mean 30-msec bin amplitude from 240 msec to 450 msec after the stimulus was compared between placebo and drug sessions in order to observe P300. Brotizolam reduced the amplitude of P300 at 6 h after administration. It was noted that the effects of BTZ were most marked at Fz.