Calcium channel blockers improve hypoxia/hypoglycemia-induced impairment of rat hippocampal 2-deoxyglucose uptake in vitro after ethanol withdrawal

The aim of the present study was to determine whether calcium channel antagonists attenuated hypoxia/hypoglycemia- or glutamate-induced reduction in 2-deoxyglucose (2-DG) uptake of hippocampal slices obtained from ethanol withdrawal rats. Ethanol withdrawal significantly potentiated the hypoxia/hypoglycemia- and glutamate-induced reductions in 2-DG uptake of hippocampal slices. Both nifedipine and flunarizine exhibited attenuating effects on ethanol withdrawal-induced potentiation of impairment of 2-DG uptake caused by hypoxia/hypoglycemia or glutamate. Hypoxia/hypoglycemia-induced deficit of 2-DG uptake was prevented by ethanol, but chronic consumption of ethanol resulted in the development of tolerance to neuroprotective effect. These findings suggest that the increased sensitivity of neurons to ischemic damage by ischemia may involve in the increased activity of calcium channels in the hippocampus.

Aneurysmal dilatation of the pulmonary trunk with mild pulmonic stenosis

We present the unusual case of a 72-year-old woman whose chest X-ray showed an abnormal left hilar shadow. A pulmonary angiogram revealed an aneurysm in the pulmonary artery with a diameter of 55 mm that extended from the main pulmonary trunk to its bifurcation. Mild pulmonic stenosis with a systolic pressure gradient of 18 mmHg across the pulmonic valve was recognized. Mild dilatation of the ascending aorta was also present. The pressure gradient across the pulmonic valve was lower than is typical for an aneurysmal dilatation, suggesting that this patient represented a case of idiopathic pulmonary artery dilatation. We suspected the presence of a congenital structural alteration common to the pulmonary artery and the ascending aorta.

Comparison of myocardial ischemia induced by endothelin vs. mechanical stenosis in pigs

We have determined the transmural distribution of myocardial flow and ischemia during endothelin (ET-1) infusion and compared these results with the effects of mechanical stenosis. In anesthetized pigs, coronary flow was reduced 15, 30, and 50% from baseline values with a mechanical stenosis (n = 7) or increasing doses of intracoronary ET-1 (n = 8). The inner-to-outer flow ratio decreased with decreasing total flow during mechanical stenosis, and S-T segment elevation occurred predominantly in the subendocardium. In contrast, the inner-to-outer flow ratio exceeded 1.0 and actually increased during ET-1 infusion. ET-1 limited the electrocardiographic evidence of subendocardial ischemia and attenuated contractile dysfunction compared with mechanical stenosis at the same coronary flows, even though lactate flux was similar. Reactive hyperemia was retained with ET-1, even when coronary flow was reduced enough to cause lactate production. These results demonstrate a more uniform transmural distribution of flow caused by microvascular constriction than by a large-vessel stenosis.

Soybean phytoestrogen intake and cancer risk

Because many Western diseases are hormone-dependent cancers, we have postulated that the Western diet, compared with a vegetarian or semi-vegetarian diet, may alter hormone production, metabolism or action at the cellular level. Recently, our interest has been focused on the cancer-protective role of some hormone-like diphenolic phytoestrogens of dietary origin, the lignans and isoflavonoids. The precursors of the biologically active compounds originate in soybean products (mainly isoflavonoids but also lignans), as well as whole grain cereals, seeds, probably berries and nuts (mainly lignans). The plant lignan and isoflavonoid glycosides are converted by intestinal bacteria to hormone-like compounds with weak estrogenic and antioxidative activity; they have now been shown to influence not only sex hormone metabolism and biological activity but also intracellular enzymes, protein synthesis, growth factor action, malignant cell proliferation, differentiation and angiogenesis, making them strong candidates for a role as natural cancer protective compounds. Epidemiological investigations support this hypothesis, because the highest levels of these compounds are found in countries or regions with low cancer incidence. This report is a review of results that suggest that the diphenolic isoflavonoids and lignans are natural cancer-protective compounds.

[Therapeutic efficacy of hepatectomy in the treatment of hepatic metastases from breast cancer]

This study was performed to evaluate whether or not surgical excision of hepatic metastases from breast cancer has any effect on the prognosis. Between September 1985 and April 1993, eight patients with hepatic metastases (solitary in four cases, multiple in four cases) underwent hepatectomy. Two patients among them had other remote recurrence besides that arising in the liver. Right hepatectomy in two cases, left hepatectomy in one, extended left hepatectomy in one and partial hepatectomy in four were done. No postoperative complications developed. Four patients incurred liver recurrence within an average period of 11.5 months after hepatectomy, with three of average period of 11.5 months after hepatectomy, with three of them dying from the disease within 16 to 36 months after hepatectomy. The other four were free of liver recurrence and remained alive for 3 to 65 months post-operatively. The 50% survival time was 36 months after hepatectomy and 40 months after the discovery of hepatic metastases. Although hepatectomy could only be applied to a restricted number of patients and these results are obviously insufficient, we believe that surgical procedure for liver metastases from breast cancer, if possible, is undoubtedly beneficial in prolonging the survival in such patients.

Vessel tone affects transmural distribution of coronary flow during hypoperfusion

Subendocardial flow is selectively impaired during coronary hypoperfusion. Systolic compression of intramyocardial vessels not only stops capillary flow but empties vessels as well, leading to reversed flow in the arteries that penetrate the myocardium. The tone of these vessels influences the magnitude of flow oscillation during the cardiac cycle, but whether vessel tone is an independent determinant of subendocardial perfusion during coronary hypoperfusion has not been determined. The discovery of endothelin (ET-1) has made it possible to counteract metabolic vasodilation and increase vessel tone during hypoperfusion. A shunt from a carotid artery to the left anterior descending coronary artery was installed in open-chest pigs anesthetized with halothane. Arterial pressure and heart rate were held constant, and coronary pressure was reduced in stages by restricting shunt flow during intracoronary infusion of ET-1 (n = 7) or adenosine (n = 5). Microspheres were injected at each stage to determine layer flow. Coronary resistance was two- to three-fold higher and subendocardial flow was lower at similar coronary pressures in the animals receiving ET-1 than in those receiving adenosine. In contrast, flow distribution across the left ventricular wall was more homogeneous with ET-1 than with adenosine, even at coronary pressures low enough to cause lactate production and regional hypokinesis. These results demonstrate that vessel tone has an independent effect on absolute subendocardial flow as well as transmural flow distribution during coronary hypoperfusion.

Association of genetic alterations on chromosome 17 and loss of hormone receptors in breast cancer

To investigate possible relationships between genetic alterations and hormonal deregulation during breast cancer development and/or progression, we examined 616 primary breast cancers for loss of heterozygosity (LOH) at chromosomal regions 16q24, 17p13.3 and 17q21, and for amplifications of the ERBB2 and c-MYC loci. A comparison of oestrogen receptor (ER) and progesterone receptor (PgR) status in tumour cells with data concerning these genetic alterations revealed that LOH at 17q21 was significantly correlated with absence of oestrogen receptors (ER) (P < 0.0003) or progesterone receptors (PgR) (P < 0.0001), and with the absence of both (P < 0.0001). Similarly, a significant association was observed between amplification of ERBB2 and the absence of either ER or PgR. LOH at 17p13.3 was associated with the absence of PgR (P < 0.01). These data suggest a possible relationship between specific genetic changes on chromosome 17 and hormonal deregulation in the progression of breast cancer.

[Primary lung cancer in young patients]

We studied the clinical characteristics and prognosis of patients, 40 years old or younger, in whom primary lung cancer was diagnosed and treated at National Nishigunma Hospital between 1982 and 1993, and compared them with those of 978 patients more than 40 years old. Younger patients numbered 30 (3.0%). Females accounted for 16 of the 30 cases (53.3%), a proportion higher than the female: male ratio for the older patients (27.8%). There were more smokers among the older patients (72.8%) than among the younger patients (53.3%) (p < 0.01). Adenocarcinoma was significantly more common (19/30, 63.3% vs 43.8%, p < 0.05) and squamous cell carcinoma was less common (3.30, 10.0% vs 34.3%, p < 0.05) in the younger patients than in the older patients. Median survival time in younger patients was 30.0 months, and in older patients it was 14.6 months, but we found no significant difference in survival between younger and older patients. In the younger group, all the cases of stage I or II disease were discovered during mass screening.

Nitric oxide synthase inhibitors block behavioral sensitization to methamphetamine in mice

Repeated administration of methamphetamine (1.0 mg/kg) once daily for 7 consecutive days resulted in an augmentation of the locomotor-activating effect of methamphetamine (0.5 mg/kg) challenged 72 h after the last injection. Administration of the nitric oxide (NO) synthase inhibitor, NG-nitro-L-arginine (10 and 30 mg/kg), before daily methamphetamine injections dose dependently prevented the development of behavioral sensitization to subsequent methamphetamine challenge. The mice given another NO synthase inhibitor, NG-nitro-L-arginine methyl ester (100 mg/kg), before daily methamphetamine injections showed significantly less locomotor activity in response to 0.5 mg/kg methamphetamine challenge than the mice given daily methamphetamine alone. Such effects were not observed when the inactive isomer, NG-nitro-D-arginine methyl ester (100 mg/kg), was administered daily prior to methamphetamine. Both NO synthase inhibitors exerted the acute effect to reduce spontaneous and methamphetamine-stimulated locomotor activity, while neither spontaneous locomotion nor hyperlocomotion in response to 1.0 mg/kg methamphetamine was altered 72 h after repeated administration of NG-nitro-L-arginine (30 mg/kg) or NG-nitro-L-arginine methyl ester (100 mg/kg) alone once daily for 7 days. On the other hand, pretreatment with the NMDA receptor antagonist, MK-801 ((+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate), at 0.2 mg/kg also suppressed the development of sensitization to the locomotor-activating effect of methamphetamine. These findings suggest that NO formation possibly mediated by NMDA receptors is involved in mechanisms underlying the development of behavioral sensitization to methamphetamine.

Effects of transient forebrain ischemia on long-term enhancement of dopamine release in rat striatal slices

We studied the effects of transient forebrain ischemia in vivo on long-term enhancement of dopamine (DA) release from rat striatal slices. One hour after the high-frequency tetanic stimulation (HFTS) or L-glutamate (10(-6) M) application in Mg(2+)-free medium to striatal slices, the high concentration of KCl (high K+)-evoked DA release was measured. Tetanic stimulation or L-glutamate application significantly potentiated the high-K(+)-evoked DA release. When striatal slices were prepared from rats exposed to 3 min of ischemia followed by 24-h survival, the enhancement of DA release by HFTS was unaffected by ischemia. In contrast, the enhancement of DA release by HFTS was impaired in rats exposed to 5 min or 10 min of ischemia. In addition, high K(+)-evoked DA release per se was significantly impaired by 10 min of ischemia. The enhancement of DA release elicited by pretreatment with L-glutamate was also impaired in the rats exposed to 5 min of ischemia. When striatal slices were prepared from rats exposed to 5 min of ischemia with 7-day survival, the enhancement of DA release by HFTS was still impaired. The present results indicate that the neuronal mechanisms of the enhancement of DA release may be more sensitive to impairment from short periods of ischemia. Furthermore, the results suggest that an impairment of long-term enhancement of DA release by ischemia may be related the dysfunction of motor performance in rats exposed to ischemia.

NG-nitro-L-arginine protects against hypoxia/hypoglycemia-induced decrease in CA1 presynaptic spikes in rat hippocampal slices

The effects of nitric oxide (NO) synthase inhibitors on the hypoxia/hypoglycemia-induced decrease in CA1 presynaptic fiber spikes elicited by stimulation of the Schaffer collaterals were investigated using rat hippocampal slices. Drugs were added to normal medium for 10 min before incubation under hypoxic/hypoglycemic conditions (15 min), and after a 3-h washout, the CA1 presynaptic potential was measured. Treatment with NG-nitro-L-arginine methyl ester but not with NG-nitro-D-arginine methyl ester produced a concentration-dependent attenuation of the hypoxia/hypoglycemia-induced decrease in presynaptic fiber spikes. In contrast, treatment with precursors of NO in the arginine-to-NO pathway, such as sodium nitroprusside, S-nitro-N-acetylpenicillamine and N-morpholino sydnonimine exacerbated the 15-min hypoxia/hypoglycemia-induced decrease in the CA1 presynaptic potential. The neuroprotective effect of NG-nitro-L-arginine methyl aster was significantly attenuated by co-treatment with L-arginine. The present results suggest a facilitatory role of NO production in hypoxia/hypoglycemia-induced presynaptic dysfunction in CA1 regions of hippocampal slices.

Attenuating effect of bifemelane on an impairment of mealtime-associated activity rhythm in aged and MK-801-treated rats

In the present experiment, we examined the attenuating effect of bifemelane hydrochloride (BF), 4-(o-benzyl phenoxy)-N-methylbutylamine hydrochloride, on the impairment of time perception caused by daily scheduled feeding using aged and MK-801-treated rats. When feeding was restricted to a single meal at a fixed time of day (1300-1700 h) for six successive days, young rats exhibited intense locomotor activity 1-3 h before feeding time. Intense locomotor activity was observed for 1200-1700 h even on the fasting day (day 7; mealtime-associated activity). Mealtime-associated activity was impaired in 24-mo-old rats and also in N-methyl-D-aspartate receptor antagonist, MK-801-treated rats. Daily injections of bifemelane at 1700 h for six successive days significantly attenuated the impairment of mealtime-associated activity on the seventh day in a dose-dependent manner in aged rats. In addition, cotreatment of MK-801 with bifemelane blocked the MK-801-induced impairment of mealtime-associated activity. The present study suggests that bifemelane has an enhancing effect on learning and memory performance, such as spatial and temporal perception.

Accessibility to tissue-specific genes from methylation profiles of mouse brain genomic DNA

The DNA methylation status of a large number of genomic loci is visualized simultaneously and quantitatively as two-dimensional gel spots in the newly developed restriction landmark genomic scanning with a methylation-sensitive restriction enzyme (RLGS-M). Here, we demonstrate that RLGS-M using NorI as a methylation-sensitive enzyme could also scan gene loci of mammalian genomes, since almost all of the NotI loci corresponding to randomly chosen RLGS-M spots were located near or in transcriptional units (6 out of 7 NotI-linking clones) when mouse brain genomic DNA was used. This supports the previous prediction that most NotI sites are located in CpG islands (Lindsay and Bird, Nature 1987, 327, 336-338). Furthermore, beginning with RLGS-M spots we examined how to approach their corresponding RNA messages, whose expression may be associated with methylation. We compared RLGS-M patterns among various developmental stages of the mouse brain from embryonic day 9.5 to postnatal 8 weeks or among in vitro cell lines, and detected alterations of RLGS-M spots which were due to methylation of NotI sites. Two experiments using NotI-linking clones or polymerase chain reaction (PCR) were carried out to approach to their corresponding RNA messages. Consequently, we isolated two PCR-amplified clones (# 15 and # 91) which corresponded to methylatable loci and gave positive signals to mRNA from the adult brain. Furthermore, we identified two NotI-linking clones (C211 and C198) whose corresponding NotI loci localized near or at transcriptional units and were methylated in cell lines.(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinical and laboratory studies on SY5555 in pediatric infectious diseases]

Clinical effects of SY5555 dry syrup, a new oral penem antibiotic, were analysed in 20 children with various bacterial infections. Ages of the patients varied from 8 months to 14 years. Doses of SY5555 were varied from 12.8 mg/kg/day to 30.5 mg/kg/day, and it was administered in 3 divided dosages. Clinical efficacy rates were as follows; 6/7 in acute bronchitis, 5/5 in pharyngotonsillitis, 3/3 in acute otitis media and 2/2 in cystitis and 3/3 in impetigo contagiosa. The overall rate was 95.0% (19/20). Bacteriologically, eradications were obtained with 1/2 strains of Streptococcus pyogenes, 3/3 of Staphylococcus aureus, 1/1 of Haemophilus influenzae, and each of Staphylococcus epidermidis, Haemophilus parainfluenzae, coagulase-negative staphylococci and Serratia marcescens. Diarrhea was observed in 1 patient. And elevated eosinophiles or GPT was observed in one patient each. In vivo pharmacokinetics of SY5555 was examined in 2 cases. Peak plasma levels were observed at 1 hour after dosage in one patient and at 2 hours in another upon oral administration of 8.3 mg/kg of SY5555, and peak levels were 2.44 and 1.38 micrograms/ml respectively. Half-lives of SY5555 were 1.39 and 0.59 hr. Concentrations of SY5555 in urine after administration were 70.2 (2-4 hrs.) to 91.0 (0-5 hrs.) micrograms/ml, respectively. SY5555 dry syrup is considered as an useful and safe antibiotic in treating the infectious diseases in children.

Methylphenidate for the management of somatization in terminal cancer patients

We report a case that illustrates methylphenidate's (MP) usefulness in the management of psychological distress and associated somatization in the palliative-care setting. A 60-year-old man affected by terminal cancer of the prostate had been complaining of increasing physical pain, without any evidence of significant disease progression, opioid toxicity, or previous history of drug addiction. Because of patient's denial, the team had been unsuccessful in identifying any potential emotional factors affecting his physical suffering. MP could both counteract opioid-induced sedation and improve pain control through a positive action on patient's mood. In spite of a rapid development of tolerance, which required a subsequent escalation in MP daily doses, the drug was well tolerated and the patient could die in good physical comfort 2 weeks later.

A spot cloning method for restriction landmark genomic scanning

We introduce two new methods for target cloning of DNA fragments corresponding to spots on the two-dimensional profile of restriction landmark genomic scanning (RLGS). One is a restriction trapper-based method and the other is a polymerase chain reaction (PCR) mediated method. Both are designed to select the target DNA fragments from a large amount of unlabeled background DNA fragments in the RLGS gel which produce background clones. The restriction trapper method is simple, with a cloning efficiency that is not biased by the length of the target DNA nor by its GC content. On the other hand, the PCR-mediated method is efficient for cloning DNA fragments from a small amount of starting materials. These methods provide us with powerful tools for isolating DNA clones identified by the RLGS system as interesting spots. This paper reports the precise protocols of these methods and discusses their application and usefulness.

[Pulmonary embolectomy for massive pulmonary embolism]

Surgical cases of massive pulmonary embolism remain rare in Japan. To discuss the surgical problems, clinical courses of 4 patients who underwent pulmonary embolectomy under cardiopulmonary bypass at our hospital for the last six years were reviewed. There were 2 men and 2 women; ranging from 41 to 72 years (mean age, 63 years), 1 of whom had deep venous thrombosis of the lower extremity as a predisposing factor. The initial disease recurred in 2 patients. Shock occurred in 3 patients preoperatively, 2 of whom had sudden syncope. Cardiac arrest occurred before and during pulmonary arteriography (PAG) in 1 patient. The systolic pulmonary arterial pressure rose to between 60 and 80 mmHg in all patients except for 1 of whom it was not measured. The diagnosis was established in 3 patients by PAG and clinically in the remaining recurrent patient. Thrombolysis was not effective in all patients, then pulmonary embolectomy was performed between four hours and five days after the onset of the disease. One patient with preoperative cardiac arrest died of low output syndrome and severe respiratory failure, but 3 survived with clinical improvement. Development of the prompt and noninvasive diagnostic procedure, rapid cardiopulmonary support in severe cases and an early decision to operate are required to improve the operative results. Partial resection of the lung was obliged due to massive endobronchial hemorrhage after embolectomy in 1 recurred patient. Compression of the lungs and embolectomy using a balloon catheter should be performed carefully to prevent injuring pulmonary arteries. Implantation of an inferior vena cava filter may be beneficial for the selected patient to prevent recurrence of the disease.

Immunological responses after vaccination pre- and post-surgery in dogs

The effects of several commercially available vaccinations pre- and post-surgery on immune responses by monitoring the blastogenic responses of lymphocytes and humoral antibody responses in dogs were examined. Twenty clinical patients presented for surgery were studied. Canine parvovirus (CPV) serum antibody titers increased by twofold or more in 17 of 20 dogs and many dogs had an increase by day 7. In 3 of 4 dogs moderate hemagglutination inhibition (HI) titers (128 to 256) at the time of vaccination increased by twofold or more. Canine distemper virus serum antibody titers in 4 of 8 dogs with HI titers (< or = 32) at the time of vaccination had increased by twofold or more. In the blastogenic responses of lymphocytes to Concanavalin A and phytohemagglutinin, most dogs responded with a slight decrease following vaccination, but no significant change was noted. No adverse reaction caused by vaccination was noted and comparatively good production of serum antibody titers (CPV especially) was seen. Vaccination pre- and post-surgery neither induce severe immunosuppression, nor potentiate the severity of concurrent disease, and did not cause inapparent infection to become clinically apparent.

Single photon emission computed tomography to determine effective hepatic blood flow and intrahepatic shunting

The noninvasive determination of effective hepatic blood flow, intrahepatic shunted blood flow, intrahepatic shunt index, and total hepatic blood flow was investigated by using the sequential single photon emission computed tomography. This method was performed for a period of 10 minutes following an intravenous injection of 99mTc-(Sn)-N-pyridoxyl-5-methyltryptophan and a venous blood sampling. This study comprised 8 healthy volunteers, 16 patients with chronic hepatitis, and 33 patients with liver cirrhosis. The intrahepatic shunt index measured with this method coincided with the intrahepatic shunt index determined by catheterization, indicating the high reliability of this procedure. The effective hepatic blood flow in patients with liver cirrhosis was significantly lower than that in the healthy controls and the chronic hepatitis group. The intrahepatic shunted blood flow was significantly higher in patients with liver cirrhosis compared with the flow in healthy controls. The intrahepatic shunt index was also significantly higher in patients with liver cirrhosis compared with the index of healthy controls and those with chronic hepatitis. No substantial differences were noted in the total hepatic blood flow among the three groups. The effective hepatic blood flow, the intrahepatic shunted blood flow, and the intrahepatic shunt index, correlated with the serum albumin concentration, the serum cholinesterase level, and the plasma indocyanine green attenuation rate. From these results, it was concluded that the present procedure constitutes a reliable and effective method for the noninvasive determination of hepatic blood flows. Consequently, it will be of high clinical value for assessing the functional and the pathological alterations of the liver.

Basal cell carcinoma with eccrine differentiation

We describe a light, electron microscopic, and immunohistochemical study of basal cell carcinoma with eccrine differentiation. The cytoplasm did not stain with fat stain on cryostat sections, but contained numerous gland-like structures. Immunohistochemistry on formalin fixed, paraffin embedded tissues using antibodies to human involucrin, thirteen kinds of cytokeratin, S-100 protein, and carcinoembryonic antigen (CEA) was performed. We found that tumor cells were positive for keratin, PKK1, MA-903, No 8, No 19, AE 1, AE 3, and 5 + 8. Tumor cells were negative for S-100 protein, CEA, and the other antigens examined. Electron microscopy demonstrated short microvilli and amorphous materials within the intracytoplasmic cavity. We concluded that this tumor is basal cell carcinoma with eccrine differentiation.

Gating of somatosensory evoked responses during active finger movements magnetoencephalographic studies

The "gating" effects caused by active finger movements on somatosensory evoked magnetic fields (SEFs) following stimulation of the median nerve were examined in normal subjects. The effects of the interfering stimulus were best demonstrated by subtracting the "interference" wave forms from the "control" wave forms to derive the "difference" wave form. The short-latency cortical deflections, N20m-P20m, P30m-N30m and P25m-N35m were significantly attenuated with no latency changes. In contrast, the following middle-latency deflections, the N40m-P40m and the P60m-N60m were clearly changed in terms of latency and duration by the interference. The D30m-U30m and the U60m-D60m in the "difference" wave form were derived from these interference changes. It is considered that the gating effects on all deflections took place in the hemisphere contralateral to the stimulated median nerve, because all of the equivalent current dipoles (ECDs) of the short- and the middle-latency deflections in the "control", "interference" and "difference" wave forms were located there. The gating effects on the short-latency deflections were suggested to be due to the interactions between the neurons in areas 1 and 3b, which were activated by sensory inputs from cutaneous mechanoreceptors, and the neurons in area 3a which were activated by sensory inputs from the muscle spindles. The gating effects on the middle-latency deflections may mainly be due to the excitations of neurons in area 4 caused by either continuous movement-related activities or by sensory inputs spreading from the sensory cortex.

A role of sigma receptors on hypoxia/hypoglycemia-induced decrease in CA1 presynaptic fiber spikes in rat hippocampal slices

Effects of sigma receptor agonists or antagonists on hypoxia/hypoglycemia-induced decrease in CA1 presynaptic fiber spikes elicited by the stimulation of Schaffer collaterals were investigated using rat hippocampal slices. Treatment with sigma receptor antagonists such as haloperidol, NE-100 and rimcazole produced a concentration-dependent attenuation of the hypoxia/hypoglycemia-induced decrease in CA1 presynaptic fiber spikes. The order of potency of protection against hypoxia/hypoglycemia-induced reduction in CA1 presynaptic potential was: NE-100 = haloperidol > rimcazole. Treatment with sigma receptor agonist DTG potentiated the hypoxia/hypoglycemia-induced decrease in the CA1 presynaptic potential, whereas SKF10047 which possesses an affinity for phencyclidine site attenuated the decrease of potential. NE-100 antagonized a functional deficit induced by DTG, but unaffected the improving effect induced by SKF10047. The present results suggest a facilitatory role of sigma receptor stimulation in hypoxia/hypoglycemia-induced an impairment of neurophysiological functions in CA1 presynaptic regions of hippocampal slices.

Glutathione protects against hypoxic/hypoglycemic decreases in 2-deoxyglucose uptake and presynaptic spikes in hippocampal slices

The effects of glutathione, its analogue: YM737 (N-(N-gamma-L-glutamyl-L- cysteinyl) glycine l-isopropyl ester sulfate monohydrate), a monoester of glutathione, and N-acetyl-L-cysteine on hypoxia/hypoglycemia-induced decreases in CA1 presynaptic fiber spikes and 2-deoxyglucose uptake were investigated using rat hippocampal slices. The drugs were added to normal medium for 30 min before the incubation under hypoxic/hypoglycemic conditions (20 min), and, after a 3-h washout, presynaptic potential or 2-deoxyglucose uptake in hippocampal slices was measured. Treatment with glutathione, YM737 and N-acetyl-L-cysteine produced an attenuation of the hypoxia/hypoglycemia-induced decrease in presynaptic fiber spikes and 2-deoxyglucose uptake. The order of potency for neuroprotective action was YM737 > or = N-acetyl-L-cysteine > glutathione. The present results suggest a role for glutathione in improving hypoxia/hypoglycemia-induced dysfunction of hippocampal regions.