The impact of wheelchair propulsion based physical activity on functional recovery in stroke rehabilitation: a multicenter observational study.

PURPOSE: We aimed to evaluate the relationship between the daily wheelchair self-propulsion distance and functional recovery in subacute stroke survivors. METHODS: Seventy-four patients with stroke were prospectively recruited from four convalescent rehabilitation hospitals. All participants were unable to walk independently and required manual wheelchairs for locomotion on admission. The daily wheelchair self-propulsion distance was measured using a cycle computer that was connected to a touch switch to exclude the assistance-propulsion distance. The outcome measures were represented as the relative gain of the Functional Independence Measure (FIM) effectiveness during hospitalization. Moreover, a better functional recovery was defined as a FIM effectiveness > 50%. Participants were categorized into three groups according to tertiles of the average daily wheelchair self-propulsion distance: lowest tertile (T1, ≤0.59 km/day); middle tertile (T2, 0.60-1.23 km/day); and highest tertile (T3, ≥1.24 km/day). RESULTS: Multivariate logistic regression analysis adjusted for baseline characteristics showed that the T2 and T3 groups had a significant association with better FIM effectiveness, and their odds ratios (95% confidence interval, p) were 7.26 (1.13-45.85, p = .038), and 10.19 (1.15-91.75, p = .035), respectively. CONCLUSIONS: The daily wheelchair self-propulsion distance was significantly associated with functional recovery in subacute stroke survivors.IMPLICATIONS FOR REHABILITATIONNon-ambulatory stroke survivors can obtain extra independent physical activity by using wheelchair self-propulsion, when they do not have someone to assist them with walking.This multicenter observational study revealed that the self-propulsion distance of a manual-wheelchair was significantly associated with functional recovery in subacute stroke survivors.

Measurement of self-propulsion distance of wheelchair using cycle computer excluding assistance distance by touch switch: A pilot study.

Objective: Although the propulsion distance of a wheelchair is measured by some devices, measuring self-propulsion distance, excluding assistance propulsion distance by the caregiver, is difficult. This is a pilot study conducted to verify whether the propulsion distance of wheelchair users, excluding the assistance propulsion distance, can be measured using a cycle computer by attaching the touch switch.Methods: The wheelchair propulsion distance was measured using a cycle computer. We connected the touch switch and the cycle computer to the wheelchair to exclude assistance propulsion distance. We set the cycle computer to stop recording while the caregiver was touching the sensor. To confirm the propulsion distance using the cycle computer, the volunteer propelled the wheelchair on a rectangular facility with a total distance of 181 m, and the examiner confirmed the propulsion distance. The validation test to confirm the accuracy of the touch switch attached to the cycle computer was performed on a 50-m straight runway. The volunteer and caregiver propelled the wheelchair alternately by 10 m and continued until 50 m. The examiner confirmed the distance after 50-m propulsion.Results: In the 181-m rectangular facility, the propulsion distance that the volunteer propelled the wheelchair with the cycle computer was 180 m. In the 50-m straight runway, the propulsion distance was 30 m with caregiver assistance for 20 m.Conclusion: The present study showed that our modified device could measure the self-propulsion distance, excluding assistance propulsion distance in wheelchair users.

Impact of physical, cognitive, and psychological functions on incident homebound status after discharge among hospitalized older patients: A clinical-based prospective study.

PURPOSE: Physical and cognitive/psychological functions are risk factors for incident homebound status. However, there are only a few studies exploring the factors related to homebound status in hospitalized older patients. The aim of this study was to determine the relationship between physical, and cognitive/psychological function at discharge among hospitalized older patients and the risk of undergoing homebound status after discharge. METHODS: We analyzed the cohort data of hospitalized older patients (age ≥65 years) with internal medical problems. The main outcome was the incidence of homebound status a month after discharge. Physical functions were measured by handgrip strength (HG), knee extension strength (KES), one-leg stance (OLS), and walking speed (WS). Cognitive and psychological functions were assessed using the Mini-Mental State Examination (MMSE) and Geriatric Depression Scale-5 (GDS-5), respectively. Poisson regression models were used to estimate the risk ratios (RR) and 95 % confidence intervals (CIs) of the relationships between physical, cognitive, and psychological functions as well as the homebound status. RESULTS: A total of 178 participants who completed the follow-up were analyzed mean age (standard deviation) 76.2 (6.9) years. A month after discharge, 23 participants were deemed homebound, for a cumulative incidence (95 %CI) of 12.9 % (8.0 %-17.8 %). The RR (95 %CI) estimated by Poisson regression were 3.51 (1.30-9.48), 0.15 (0.03-0.72) and 0.11 (0.01-0.92) for low KES, maximum WS and comfortable WS, respectively. However, HG, OLS, MMSE, and GDS-5 were not significantly associated with the incidence of homebound status. CONCLUSION: Physical functions can predict the incidence of homebound status after discharge among hospitalized older patients.

Relationship between physical activity levels during rehabilitation hospitalization and life-space mobility following discharge in stroke survivors: A multicenter prospective study.

BACKGROUND: Higher physical activity levels during hospitalization may benefit the life-space mobility, defined as the ability to move within environments that expand from one's home to the greater community, of stroke survivors following their discharge. OBJECTIVES: This study aimed to evaluate the relationship between physical activity levels during rehabilitation hospitalization and life-space mobility among stroke survivors three months after their discharge. METHODS: We recruited 84 stroke survivors as prospective participants from four convalescent rehabilitation hospitals. Physical activity levels during hospitalization were assessed using pedometers with a three-axis accelerometer, and their average step count over 14 consecutive days prior to discharge was used as the representative set of values. Pedometers were placed on the participant's waist or wrist on the non-paretic side. The Life-Space Assessment (LSA), a validated self-reporting measure for assessing community mobility, was implemented three months following participant discharge from rehabilitation hospitals via a mail-in survey method. To determine the relationship between the participants' level of physical activity during hospitalization and the LSA score following discharge, we performed multivariate regression analysis. RESULTS: A total of 75 participants (89.3%) completed the post-discharge survey and were therefore included in the analysis. The multiple regression analysis, controlled for age, balance function, walking endurance, fear of falling, and functional status, revealed that daily step counts were significantly associated with the LSA score three months after discharge (ß = 0.241, p = .026). CONCLUSIONS: Physical activity levels during hospitalization were significantly associated with the life-space mobility of stroke survivors following discharge.

Relationship between Sarcopenia and Swallowing Capacity in Community-Dwelling Older Women.

BACKGROUND: Swallowing disorders are a serious health concern among older adults. Previous studies reported that sarcopenia may affect swallowing disorders; however, whether sarcopenia is related to the capacity to swallow (measured according to swallowing speed) in community-dwelling older adults is unclear. OBJECTIVES: The aim of this study was to investigate the relationship between sarcopenia and swallowing capacity in community-dwelling older women. METHODS: This cross-sectional observational study was conducted among community-dwelling older women in Japan. The inclusion criteria were as follows: women aged ≥65 years, with the ability to walk independently, and without dysphagia. The exclusion criterion was a history of stroke or Parkinson's disease that directly caused dysphagia. The participants were divided into a sarcopenia and a healthy group based on the criteria of the Asian Working Group for Sarcopenia 2019. We measured swallowing speed (mL/s) as the swallowing capacity by conducting a 100-mL water-swallowing test. To assess the relationship between sarcopenia and swallowing capacity, we performed a multiple regression analysis. RESULTS: Two-hundred and sixty participants were enrolled in the study. Their mean age was 82.3 ± 6.9 years, and 61 (23.5%) of them displayed sarcopenia. The mean swallowing speed was 11.5 ± 4.9 mL/s, and 17 women (6.5%) exhibited choking or a wet-hoarse voice. Multiple regression analysis revealed that sarcopenia was related to the swallowing capacity after adjusting for age, the Mini-Mental State Examination, and the number of comorbidities (ß = -0.20, 95% CI -3.78 to -0.86, p = 0.002). CONCLUSIONS: We found that sarcopenia was related to the swallowing capacity in older women in this study. Future research should clarify whether a similar relationship exists in older men as well as the effect of sarcopenia on the swallowing capacity in older adults over a period of time.

Extensive splicing changes in an ALS/FTD transgenic mouse model overexpressing cytoplasmic fused in sarcoma.

Mutations in RNA-binding proteins (RBPs) such as TAR DNA-binding protein 43 (TDP-43) and fused in sarcoma (FUS) are associated with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Recent evidence suggests that RNA dysregulation mediated by aberrant RBPs may play a critical role in neurodegeneration, but the underlying molecular mechanisms are largely unknown. In this study, we performed whole transcriptome profiling of various brain tissues of a transgenic (Tg) mouse model of ALS/FTD overexpressing the exogenous nuclear localization signal deletion mutant of human FUS (ΔNLS-FUS) to investigate changes associated with the early stages of ALS/FTD. Although there were not many differences in expression profiles between wild-type and Tg mice, we found that Sema3g was significantly upregulated in the frontal cortex and hippocampus of Tg mice. Interestingly, analysis of alternative splicing events identified widespread exons that were differentially regulated in Tg mice in a tissue-specific manner. Our study thus identified aberrant splicing regulation mediated by mutant FUS during the early stages of ALS/FTD. Targeting this aberrant splicing regulation represents a potential therapeutic strategy for ALS/FTD.

Factors associated with functional recovery in Japanese patients with convalescent stroke stratified by age: a multicenter observational study.

Factors associated with functional recovery after stroke may differ by age demographics because the aging process leads to various regressive changes. The aim of this study was to identify factors related to functional recovery in Japanese patients with convalescent stroke stratified by age. A multicenter retrospective observational study was conducted in 243 patients from six convalescent inpatient rehabilitation wards. Participants were categorized into three groups: 40-64, 65-74, and ≥75 years. Demographic data, laboratory data, physical function, and cognitive function were collected upon admission, and outcome measures were represented using the relative gain of the Functional Independence Measure (FIM effectiveness) during hospitalization. Stepwise multivariate logistic analysis was performed to identify the significant factors for functional recovery in each group. In the 40-64 years group, stroke type [odds ratio (OR), 10.38; 95% confidence interval (CI), 2.22-48.59], spatial neglect (OR, 7.61; 95% CI, 2.07-28.00), and memory disorder (OR, 4.68; 95% CI, 1.08-20.30) were shown to be significant factors. In the 65-74 years group, only memory disorder (OR, 3.42; 95% CI, 1.19-9.81) was significant. In the ≥75 years group, low albumin level (OR, 3.35; 95% CI, 1.05-10.67), severe motor impairment (OR, 5.11; 95% CI, 1.14-22.97), and memory disorder (OR, 4.34; 95% CI, 1.43-13.23) were significantly related to poor functional recovery. In conclusions, the findings showed that there were different trends among the factors related to poststroke functional recovery among the three age groups.

Selective corticotropin-releasing factor 1 receptor antagonist E2508 reduces restraint stress-induced defecation and visceral pain in rat models.

N-Cyclopropylmethyl-7-(2,6-dimethoxy-4-methoxymethylphenyl)-2-ethyl-N-(tetrahydro-2H-pyran-4-ylmethyl)pyrazolo[1,5-a]pyridin-3-amine tosylate (E2508) is a newly discovered selective corticotropin-releasing factor 1 receptor antagonist. Here, we investigated the effects of E2508 on wrap restraint stress-induced defecation and visceral pain in rats. Oral pretreatment with E2508 dose-dependently decreased stool weights after 20min wrap restraint stress and significant effects were observed at doses of 30 and 100mg/kg. However, E2508 did not affect basal defecation at doses up to 100mg/kg. In contrast, alosetron, a 5-HT3 receptor antagonist, decreased both wrap restraint stress-induced and basal stool output at a dose of 0.1mg/kg. In a rat visceral pain model, subcutaneous injections of both E2508 (0.01 and 0.1mg/kg) and alosetron (0.001 and 0.01mg/kg) significantly decreased the number of abdominal muscle contractions induced by colonic distention, suggesting these drugs reduced visceral pain. Together, these results demonstrate E2508 has the potential to be an effective therapy for the treatment of irritable bowel syndrome with a lower risk of adverse events such as constipation compared with the current clinically used 5-HT3 receptor antagonist.

Selective corticotropin-releasing factor 1 receptor antagonist E2508 has potent antidepressant-like and anxiolytic-like properties in rodent models.

Corticotropin-releasing factor (CRF) is a hormone secreted by the hypothalamus in response to stress, and CRF antagonists may be effective for the treatment of stress-related disorders including major depressive and anxiety disorders. Here, we investigated the in vivo pharmacological profile of N-cyclopropylmethyl-7-(2,6-dimethoxy-4-methoxymethylphenyl)-2-ethyl-N-(tetrahydro-2H-pyran-4-ylmethyl)pyrazolo[1,5-a]pyridin-3-amine tosylate (E2508), a recently synthesized, orally active CRF1 receptor antagonist. Oral administration of a single dose of E2508 (3 or 10mg/kg), but not fluoxetine (30mg/kg), a selective serotonin reuptake inhibitor (SSRI), significantly shortened immobility time in rats in the forced swim test. E2508 (10, 30, or 100mg/kg) also showed an antidepressant-like effect in the forced swim test in mice, with no sedative or muscle relaxant effects for doses up to 100mg/kg. Moreover, E2508 (5 or 20mg/kg) significantly reduced anxiety-like behavior in the rat defensive burying test. Diazepam, a benzodiazepine anxiolytic agent, also showed an anxiolytic effect in the defensive burying test at the same dose that induced a muscle relaxant effect in mice. Administration of E2508 (30mg/kg) for 14 consecutive days did not affect sexual behavior. By contrast, fluoxetine (30mg/kg) administration for ≥7 consecutive days decreased sexual behavior. These results indicate that E2508 has both potent antidepressant-like and anxiolytic-like effects in rodent models, and is well tolerated compared with a commonly prescribed therapeutic SSRI or benzodiazepine.

Synthesis and structure-activity relationships of 8-substituted-2-aryl-5-alkylaminoquinolines: Potent, orally active corticotropin-releasing factor-1 receptor antagonists.

We previously reported a series of 8-methyl-2-aryl-5-alkylaminoquinolines as a novel class of corticotropin-releasing factor-1 (CRF(1)) receptor antagonists. A critical issue encountered for this series of compounds was low aqueous solubility at physiological pH (pH 7.4). To address this issue, derivatization at key sites (R(2), R(3), R(5), R(5'), and R(8)) was performed and the relationships between structure and solubility were examined. As a result, it was revealed that introduction of a methoxy substituent at the C(8) position had a positive impact on the solubility of the derivatives. Consequently, through in vivo and in vitro biological studies, compound 21d was identified as a potent, orally active CRF(1) receptor antagonist with improved physicochemical properties.

Design, synthesis, and structure-activity relationships of novel pyrazolo[5,1-b]thiazole derivatives as potent and orally active corticotropin-releasing factor 1 receptor antagonists.

This paper describes the design, synthesis, and structure-activity relationships of a novel series of 7-dialkylamino-3-phenyl-6-methoxy pyrazolo[5,1-b]thiazole derivatives for use as selective antagonists of the corticotropin-releasing factor 1 (CRF(1)) receptor. The most promising compound, N-butyl-3-[4-(ethoxymethyl)-2,6-dimethoxyphenyl]-6-methoxy-N-(tetrahydro-2H-pyran-4-yl)pyrazolo[5,1-b][1,3]thiazole-7-amine (6t), showed high affinity (IC(50) = 70 nM) and functional antagonism (IC(50) = 7.1 nM) for the human CRF(1) receptor as well as dose-dependent inhibition of the CRF-induced increase in the plasma adrenocorticotropic hormone (ACTH) concentration at a dose of 30 mg/kg (po). Further, in the light/dark test in mice, the compound 6t showed anxiolytic activity at a dose of 30 mg/kg (po).

Serofendic acid promotes stellation induced by cAMP and cGMP analogs in cultured cortical astrocytes.

We investigated the effect of serofendic acid, a neuroprotective substance derived from fetal calf serum, on the morphological changes in cultured cortical astrocytes. Cultured astrocytes developed a stellate morphology with several processes following exposure to dibutylyl cAMP (dbcAMP), a membrane-permeable cAMP analog; 8-Br-cGMP, a membrane-permeable cGMP analog; or phorbol-12-myristate-13-acetate (PMA), a protein kinase C activator. Serofendic acid significantly accelerated the stellation induced by dbcAMP- and 8-Br-cGMP. In contrast, the PMA-induced stellation was not affected by serofendic acid. Next, we attempted to elucidate the mechanism underlying the dbcAMP-induced stellation and explore the site of action of serofendic acid. Both the stellation induced by dbcAMP and the promotional effect of serofendic acid were partially inhibited by KT5720, a specific protein kinase A (PKA) inhibitor. Furthermore, serofendic acid failed to facilitate the stellation induced by Y-27632, an inhibitor of Rho-associated kinase (ROCK). These results indicate that serofendic acid promotes dbcAMP- and 8-Br-cGMP-induced stellation and the promotional effect on dbcAMP-induced stellation is mediated at least partly by the regulation of PKA activity and not by controlling ROCK activity.

Synthesis and pharmacological profile of serofendic acids A and B.

We present efficient syntheses of serofendic acids A and B (SA-A and SA-B), novel neuroprotective substances isolated from fetal calf serum. Biological and pharmacological evaluation showed that SA-A and SA-B have potent protective action against glutamate-induced neurotoxicity, but do not interact directly with glutamate receptors. A pharmacokinetic study showed that they have good oral bioavailability in rats. The results indicate that SA-A and SA-B are potential lead compounds for candidate drugs to treat various neurological disorders.

Synthesis and neuroprotective effects of serofendic acid analogues.

Analogues of serofendic acid were prepared and their protective effects against L-glutamate (Glu)-induced neurotoxicity were examined using primary cultures of rat cortical neurons. Some analogues exhibited similar neuroprotective activity to that of serofendic acid.

Serofendic acid, a neuroprotective substance derived from fetal calf serum, inhibits mitochondrial membrane depolarization and caspase-3 activation.

We have previously reported that a neuroprotective substance, serofendic acid, was purified and isolated from fetal calf serum. Here, we investigated the effect of serofendic acid on glutamate-induced apoptosis using rat primary cultures of cortical neurons. Exposure of the cortical cultures to relatively low concentration of glutamate (100 microM) induced neuronal death and nuclear fragmentation. Glutamate exposure also induced a transient increase in caspase-3 activity. A membrane-permeable inhibitor of caspase-3 (DEVD-CHO) prevented the glutamate neurotoxicity. Serofendic acid (0.01-10 microM) markedly prevented glutamate-induced apoptotic neuronal death and nuclear fragmentation. To elucidate the protective mechanism of serofendic acid, we first examined the effect on the glutamate-induced increase in intracellular Ca2+ concentration. Glutamate-induced increase in intracellular Ca2+ concentration was significantly inhibited by MK-801, a NMDA receptor antagonist, but not by serofendic acid. Next, we investigated the effect of serofendic acid on the loss of mitochondrial membrane potential induced by glutamate by using a fluorescence indicator, tetramethylrhodamine methyl ester (TMRM). Glutamate exposure resulted in a rapid reduction of TMRM fluorescence, indicating that mitochondrial membrane was depolarized by glutamate. Serofendic acid prevented the loss of mitochondrial membrane potential following glutamate exposure. Moreover, serofendic acid reduced the activation of caspase-3 induced by glutamate. Finally, serofendic acid directly inhibited the activity of recombinant human caspase-3, -7 and -8 at higher concentrations. These results indicate that serofendic acid prevents glutamate-induced apoptosis in cultured cortical neurons by the prevention of loss of mitochondrial membrane potential and the reduction of the process of caspase-3 activation.

Nitric oxide-mediated effect of nipradilol, an alpha- and beta-adrenergic blocker, on glutamate neurotoxicity in rat cortical cultures.

Nipradilol (3,4-dihydro-8-(2-hydroxy-3-isopropylamino)propoxy-3-nitroxy-2H-1-benzopyran) is used clinically as an anti-glaucoma ophthalmic solution in Japan, and was recently reported to suppress N-methyl-d-aspartate-induced retinal damage in rats. Here we investigated cytotoxic and cytoprotective actions of nipradilol on primary cultures of rat cortical neurons. Treatment of cortical cultures with a high concentration (500 microM) of nipradilol significantly reduced cell viability, increased lactate dehydrogenase (LDH) release and nitrite concentration in culture medium, whereas desnitro-nipradilol (3,4-dihydro-8-(2-hydroxy-3-isopropylamino)propoxy-3-hydroxy-2H-1-benzopyran) had no significant effects. Nipradilol-induced neuronal damage was inhibited by S-hexylglutathione, a glutathione S-transferase inhibitor, and FeTPPS (5,10,15,20-tetrakis(4-sulfonatophenyl)prophyrinato iron (III) chloride), a peroxynitrite decomposition catalyst. On the other hand, relatively low concentrations (10-100 microM) of nipradilol but not desnitro-nipradilol prevented neuronal cell death induced by 24 h application of 100 microM glutamate. Importantly, neuroprotective concentration (100 microM) of nipradilol suppressed glutamate-induced elevation of intracellular Ca2+ concentrations, but had no effect on intracellular cyclic GMP levels. Hence, nipradilol can protect cultured cortical neurons against glutamate neurotoxicity via cyclic GMP-independent mechanisms, and nitric oxide (NO) released from the nitoroxy moiety of nipradilol may mediate neuroprotective effect through the modulation of NMDA receptor function.

Glutamate excitotoxicity is involved in cell death caused by tributyltin in cultured rat cortical neurons.

Tributyltin, an endocrine-disrupting chemical, has been used as a heat stabilizer, agricultural pesticide, and component of antifouling paints. In this study, the neurotoxicity of tributyltin was investigated in cultured rat cortical neurons. Tributyltin caused marked time- and dose-dependent increases in the number of trypan blue-stained cells. Measurement of extracellular glutamate concentration showed that glutamate release was induced by tributyltin. Application of the glutamate receptor antagonists MK-801 and CNQX decreased the neurotoxicity. These results suggest that released glutamate and glutamate receptors are involved in tributyltin toxicity. Next, we examined whether various factors, believed to be involved in glutamate excitotoxicity also influence tributyltin toxicity. Cell death induced by tributyltin was found to be reduced by alpha-tocopherol (a membrane-permeable antioxidant), SB202190 (a p38 mitogen-activated protein kinase inhibitor), and U-0126 (an extracellular signal-regulated protein kinase kinase inhibitor). MK-801 and CNQX decreased the phosphorylation of ERK, but not that of p38. A caspase-3 inhibitor had no effect on tributyltin toxicity, and tributyltin did not change the nuclear morphology. These results suggest that the glutamate excitotoxicity caused by tributyltin is unrelated to apoptosis. In conclusion, we demonstrated that tributyltin induced glutamate release and subsequent activation of glutamate receptors, leading to neuronal death. We propose two independent neuronal death pathways by tributyltin; one is glutamate receptor-dependent cell death via ERK phosphorylation, and the other may be glutamate receptor-independent cell death via p38 activation.

Neuroprotective effect of 1-methyl-1,2,3,4-tetrahydroisoquinoline on cultured rat mesencephalic neurons in the presence or absence of various neurotoxins.

1-Methyl-1,2,3,4-tetrahydroisoquinoline (1MeTIQ) is an endogenous brain amine and its content in parkinsonian brain is decreased compared with that in control brain. There is some evidence that 1MeTIQ protects dopaminergic neurons against dysfunction such as that seen in Parkinson's disease. In this study, we examined the neuroprotective effect of 1MeTIQ against four dopaminergic neurotoxins, 1-methyl-4-phenylpyridinuim ion, 6-hydroxydopamine, rotenone, and l-benzyl-1,2,3,4-tetrahydroisoquinoline, in cultured rat mesencephalic neurons. 1MeTIQ exerted neuroprotective action against all these toxins. Furthermore, (R)-1MeTIQ was neuroprotective, while (S)-1MeTIQ had little effect, indicating that the effect is stereoselective. The protective action of 1MeTIQ was most effective in mesencephalic neurons, especially in tyrosine hydroxylase-positive neurons. 1MeTIQ showed no affinity for dopamine receptors and did not influence the inhibition of mitochondrial respiratory complex I by rotenone, 1-methyl-4-phenylpyridinuim ion, or 1-benzyl-1,2,3,4-tetrahydroisoquinoline. These results raise the possibility that 1MeTIQ indirectly acts as an anti-oxidant such as the induction of anti-oxidative enzymes, because all these four neurotoxins can burden oxidative stress in common. This is the first report to confirm a protective effect of 1MeTIQ at the cultured neuron level, and it may have potential as a lead compound for the development of new agents to treat Parkinson's disease.

Serofendic acid prevents acute glutamate neurotoxicity in cultured cortical neurons.

We have previously reported that a novel neuroprotective substance named serofendic acid was purified and isolated from ether extract of fetal calf serum. In the present study, we investigated the effect of serofendic acid on acute neurotoxicity induced by L-glutamate (Glu) using primary cultures of rat cortical neurons. Exposure of cortical cultures to Glu for 1 h caused a marked decrease in cell viability, as determined by trypan blue exclusion. This acute Glu neurotoxicity was prevented by N-methyl-D-aspartate (NMDA) receptor antagonists, extracellular Ca(2+) removal, nitric oxide (NO) synthase inhibitor and NO scavenger. Serofendic acid prevented acute Glu neurotoxicity in a concentration-dependent manner. Acute neurotoxicity was induced by ionomycin, a Ca(2+) ionophore, and S-nitroso-L-cysteine, an NO donor. Serofendic acid also prevented both ionomycin- and S-nitroso-L-cysteine-induced neurotoxicity. Moreover, the protective effect of serofendic acid on acute Glu neurotoxicity was not affected by cycloheximide, a protein synthesis inhibitor, and actinomycin D, an RNA synthesis inhibitor. These results indicate that serofendic acid protects cultured cortical neurons from acute Glu neurotoxicity by reducing the cytotoxic action of NO and de novo protein synthesis is not required for this neuroprotection.

Antagonism of NMDA receptors by sigma receptor ligands attenuates chemical ischemia-induced neuronal death in vitro.

We investigated the effects of sigma receptor ligands on neuronal death induced by chemical ischemia using primary cultures of rat cerebral cortical neurons. The induction of chemical ischemia by sodium azide and 2-deoxy-D-glucose led to delayed neuronal death in a time- and concentration-dependent manner, as determined by trypan blue exclusion. The neurotoxicity was inhibited by N-methyl-D-aspartate (NMDA) receptor antagonists, indicating the involvement of glutamate. The sigma receptor ligands (+)-N-allylnormetazocine ((+)-SKF10,047) and haloperidol, but not carbetapentane and R(+)-3-(3-hydroxyphenyl)-N-propylpiperidine ((+)-3-PPP), prevented chemical ischemia-induced neurotoxicity in a concentration-dependent manner. The protective effects of (+)-SKF10,047 and haloperidol were not affected by the sigma receptor antagonists. (+)-SKF10,047 and haloperidol, but not carbetapentane and (+)-3PPP, inhibited the glutamate-induced increase in intracellular Ca(2+), and the inhibitory effects were not attenuated by sigma receptor antagonists. These results suggest that direct interaction with NMDA receptors but not sigma receptors is crucial to the neuroprotective effects of sigma receptor ligands with affinity for NMDA receptors.