Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Empirical Research on Early Internationalization of Firms in Sufficiently-Sized Domestic Market Country

Early internationalization and success in foreign markets play an important role in both a firm’s growth and its impact on the global economy. We conducted a study on Japanese high-tech startups to investigate the factors that derive early internationalization in firms founded in countries with a large domestic market, despite the absence of strong incentives to operate overseas. Quantitative data were collected from 71 startups and analyzed with PLS-SEM (Partial least squares path modeling). Our result showed that the factors we extracted from the previous studies on the internationalization process in small-size markets would also apply in countries with large domestic markets. In addition, considerations and the types of technology, which we extracted from qualitative research, verified the effect. According to our mediator analysis, an entrepreneur’s international orientation explains certain conditions related to a domestic market that affect a firms’ decision to pursue early internationalization. Our study makes contributions at multiple levels, benefiting entrepreneurs who are considering overseas expansion as well as policymakers who aim to promote early internationalization efforts.

Endotoxin Metabolism Reflects Hepatic Functional Reserve in End-Stage Liver Disease

BACKGROUND

The hepatic clearance of endotoxin (Et) may reflect hepatic functional reserve and ischemic injury to hepatocytes. Therefore, we examined the relationships between Et activity (EA) and the metrics Pediatric End-Stage Liver Disease (PELD)/Model of End-Stage Liver Disease (MELD) score and alanine transaminase (ALT) levels in the postoperative period.

METHODS

We performed 8 living-donor liver transplantations (LDLTs) for biliary atresia at our center from April 2012 to December 2012. EA was measured by means of an Et activity assay (EAA) in samples collected from a vein 1 day before LDLT, from the portal vein during the intraoperative anhepatic phase, from an artery 1 hour after reperfusion, from an artery on postoperative day (POD) 1, and from an artery or vein at PODs 7 and 14.

RESULTS

EAs generally remained at low levels. EA at the reperfusion period was significantly lowest. The correlation coefficient for the preoperative MELD/PELD score and the EAA was 0.837, and the corresponding P value was .009; thus, there was a significant relationship between the preoperative MELD/PELD score and the EAA. The correlation coefficients for ALT at POD 1 and EA during the anhepatic phase, at 1 hour after reperfusion, and at POD 1 were 0.64, 0.43, and 0.38, respectively, and the P values for these correlations were .08, .67, and .34. Thus, we observed that ALT and EA generally tended to be somewhat directly correlated, but no significant relationships between these 2 metrics were observed.

CONCLUSIONS

Endotoxin metabolism reflects the hepatic functional reserve capacity of end-stage liver disease.

Antibody Drug Treatment for Steroid-Resistant Rejection After Pediatric Living Donor Liver Transplantation: A Single-Center Experience

BACKGROUND

Antibody drugs have been used to treat steroid-resistant rejection (SRR) after liver transplantation. Although anti-thymocyte globulin has been used for SRR after liver transplantation in place of muromonab-CD3 since 2011 in Japan, the effectiveness of anti-thymocyte globulin after pediatric living-donor liver transplantation (LDLT) has not yet been reported. The aim of this study was to evaluate the effectiveness of antibody drug treatment for SRR after pediatric LDLT in our single center.

METHODS

Between May 2001 and December 2013, 220 pediatric LDLTs were performed. Initial immunosuppression after LDLT included tacrolimus and methylprednisolone therapy. Acute rejection was diagnosed by use of a liver biopsy and the administration of steroid pulse treatment, and SRR was defined as acute rejection refractory to the steroid pulse treatment.

RESULTS

Acute rejection and SRR occurred in 74 (33.6%) and 16 patients (7.3%), respectively. The graft survival rates of non-SRR and SRR were 92.4% and 87.5%, respectively (P = .464). The median concentration of alanine aminotransferase before and after the administration of antibody drug was 193.5 mU/mL (range, 8-508) and 78 mU/mL (range, 9-655), respectively (P = .012). The median rejection activity index before and after the administration of antibody drugs was 5 (range, 2-9) and 1 (range, 0-9), respectively (P = .004). After antibody drug treatment, 12 patients had cytomegalovirus infections, 2 patients had Epstein-Barr virus infections, 3 patients had respiratory infections, and 1 patient had encephalitis. The cause of death in 1 patient with SRR was recurrence of infant fulminant hepatic failure.

CONCLUSIONS

Antibody drug treatment for SRR after pediatric LDLT is safe and effective.

Relationship Between Graft Liver Function and the Change of Graft Liver and Spleen Volumes After Technical Variant Liver Transplantation

BACKGROUND

Although there have been a few reports describing the changes of graft liver and spleen volumes after liver transplantation (LT), little is known about the relationship between graft liver function and the changes of these volumes after technical variant liver transplantation (TVLT). We therefore performed a retrospective study to investigate the relationship between graft liver function and these volumes after TVLT.

METHODS

We retrospectively investigated the cases of 140 TVLT procedures that were performed in our department between July 1987 and October 2012 and in which follow-up was conducted at our department. We calculated the graft liver volume to standard liver volume (GV/SLV) ratio, the spleen volume to standard spleen volume (SV/SSV) ratio, and the spleen volume to graft liver volume (S/L) ratio by CT volumetry. We clarified the relationship between graft liver function (according to the pathological findings) and the graft liver and spleen volumes at 2, 5, and 10 years after TVLT.

RESULTS

In the normal liver function group, the GV/SLV, SV/SSV, and S/L ratios decreased until 6 months after TVLT and then converged at 10 years after TVLT to 0.95, 1.27, and 0.27, respectively. In the graft liver failure group, the GV/SLV, SV/SSV, and S/L ratios at 10 years after TVLT were 0.67, 5.01, and 1.55, respectively. A significant correlation was observed between the GV/SLV ratio and the presence of mild liver fibrosis at 2 and 5 years after TVLT (P = .03 and P = .04, respectively).

CONCLUSIONS

Post-transplant CT-volumetry is a noninvasive and effective means of evaluating graft liver status.

Management of intra-abdominal drain after living donor liver transplantation

BACKGROUND

There have been few reports on the management of intra-abdominal drains after living donor liver transplantation (LDLT). We retrospectively investigated changes in ascitic data related to management of an intra-abdominal drain.

PATIENTS AND METHODS

Between March 2008 and June 2009, we performed 28 LDLT. On the first and the fifth postoperative day (POD) after LDLT, we examined the number of ascites cells and cell fractions as well as performed biochemical examination and cultures.

RESULTS

The day of removal of the drain for massive ascites (10 mL/kg/d or more) was 14.2 ± 5.4 POD; for less than 10 mL/kg/d it was 8.7 ± 1.9 POD (P < .001). Nine patients were ascites culture positive; long-term placement of the drain caused an infection in two patients.

CONCLUSIONS

When the amount of ascitic fluid on the fifth POD after LDLT was small, it was important to assess the properties of the ascitic fluid because of the possibility of a drain infection or of poor drainage. If the ascitic neutrophil count is less than 250/mm(3) or the examined ascites is normal, intra-abdominal drains should be removed.

The Parker Flex-Tip™ tracheal tube makes endotracheal intubation with the Bullard laryngoscope easier and faster

BACKGROUND

The Bullard laryngoscope can be useful in management of difficult airway. When the endotracheal tube is advanced over the original Bullard laryngoscope stylet, the endotracheal tube sometimes makes contact with structures around the vocal cords, especially the right arytenoids. A similar problem also occurs with flexible fibreoptic intubation and it has been shown that use of the Parker Flex-Tip tube usually resolves the problem. In this study we tested our hypothesis that use of the Parker Flex-Tip tube might improve endotracheal tube passage with the Bullard laryngoscope.

METHODS

Forty patients scheduled for elective anaesthesia were randomly assigned into group ST (standard tube) or Group PT (Parker Flex-Tip tube). The time taken to achieve successful endotracheal tube placement after obtaining the best laryngeal view, the number of attempts at intubation and the incidences of successful intubation at first attempt and of re-direction of the Bullard laryngoscope during intubation were recorded. Unpaired t-test and chi2-test were employed and P < 0.05 was considered significant.

RESULTS

Use of the Parker Flex-Tip tube reduced the time required for successful endotracheal tube placement after the best laryngeal view was obtained from 14 +/- 6 to 6 +/- 2 s (P < 0.01). It also reduced the incidence of requirement for re-direction of the Bullard laryngoscope during intubation from 10/19 to 1/19 (P < 0.01). The incidence of successful intubation at the first attempt (18/19 vs. 15/19) was higher in the PT group but the difference was not statistically significant.

CONCLUSIONS

During intubation with the Bullard laryngoscope, use of the Parker Flex-Tip tube is associated with more rapid success and a lower incidence of re-direction of the Bullard laryngoscope during endotracheal intubation when compared to a standard endotracheal tube.

Arytenoid cartilage dislocation caused by a double-lumen endobronchial tube

Following surgery requiring the use of a double-lumen endobronchial tube, a patient immediately complained of persistent severe hoarseness. On the third day after the operation, fibreoptic laryngoscopy revealed posterolateral dislocation of the left arytenoid cartilage. By the sixth day of the operation, a slight improvement was observed in the hoarseness without treatment and a spontaneous recovery of arytenoid cartilage dislocation was expected. The patient did not consent to surgical treatment, and therefore a conservative therapy was selected. Ten weeks after the operation, it was found that the dislocated left arytenoid cartilage had spontaneously repositioned and the patient regained his normal voice. The causes and treatment options are discussed.

[A case with cerebral subcortical hemorrhage following the administration of phenylpropanolamine]

A 21-year-old woman experienced severe headache and nausea one hour after taking pills containing 160 mg of phenylpropanolamine for common cold. She had no previous history of drug abuse or hypertension. Physical examination revealed slight left-sided hemiparesis. Her blood pressure was 100/52 mmHg. Subcortical hemorrhage was noted in the right frontal lobe with a cranial computed tomography. On the seventh hospital day, cerebral angiography demonstrated with segmental narrowing of a branch of the right anterior cerebral artery, indicating the presence of focal angitis. This finding disappeared on the 35th hospital day. In the majority of the reported cases of the intracerebal hemorrhage associated with the ingestion of phenylpropanolamine, focal angitis rather than induced hypertension is considered to be a causative factor for hemorrhage. Thus, we would like to emphasize that the administration of phenylpropanolamine should be avoided, even to the patients without hypertention or past history of intracerebral hemorrhage.

Decreased body temperature dependent appearance of behavioral despair in the forced swimming test in mice

Effects of body temperature on the immobile response and brain glucose metabolism were examined in the forced swimming test in mice. The first experiment was performed to study behavior, after initial periods of vigorous activity, a characteristic immobile posture occurred when the water was 25 and 35 degrees C. However, several minutes after forced swimming at 25 degrees C, significantly decreased spontaneous motility occurred in a time-dependent manner, but no changes was observed at 35 degrees C. Our interpretation was that mechanisms of acquisition and retention of the forced swim-induced immobile response differed. Body temperature was also significantly decreased at 25 degrees C but not at 35 degrees C in the forced swimming test. This lowering of body temperature almost paralleled the immobile response. The second experiment was a biochemical study in which the uptake of [(14)C] 2-deoxy-d-glucose into the brain significantly decreased after forced swimming at 25 degrees C but did not change in the forced swim loaded mice when the water was 35 degrees C. These results suggested two types of immobile mechanisms in the forced swimming test: (1) an early phase acquisition of the immobile response which might be related to adaptive response and (2) a late phase to retain the immobile response which might be related to the decrease in brain glucose metabolism.

Occurrence and distribution of substance P receptors in the cerebral blood vessels of the rat

The distribution of immunoreactivity to the receptor for substance P was examined in the cerebral blood vessels of the rat. Substance P immunoreactivity has been demonstrated in the nerve fibers of the cerebral blood vessels. Recently, the production of substance P receptor specific antibody has enabled the detection of localization of the substance P receptor in the central nervous system. In this study, we examined the existence of nerve fibers with substance P receptor immunoreactivity in the cerebral blood vessels and the cranial ganglia innervating the cerebral blood vessels. Sprague-Dawley rats were perfused with fixative and the pial arteries and the cranial ganglia known to innervate the cerebral blood vessels, i.e., trigeminal, sphenopalatine, internal carotid, otic and superior cervical ganglia, were dissected. All specimens were incubated with anti-substance P receptor IgG, then stained by the avidin-biotin-peroxidase complex method. Numerous nerve fibers with varicosities forming plexuses, with substance P receptor immunoreactivity were observed on the walls of the major extracerebral arteries forming the circle of Willis and its branches. Substance P receptor immunoreactivity was also detected in the endothelium of the cerebral arteries. Substance P receptor immunoreactivity was positive in many neurons of the sphenopalatine ganglion, otic ganglion, trigeminal ganglion, superior cervical ganglion and internal carotid ganglion. The present study demonstrated the existence of nerve fibers with substance P receptor immunoreactivity in the cerebral blood vessels and the cranial ganglia that innervate the cerebral blood vessels. These findings are important in understanding the responsiveness of the cerebral blood vessels to substance P.

A novel antitumor compound, NC-190, induces topoisomerase II-dependent DNA cleavage and DNA fragmentation

A novel benzophenazine derivative, NC-190, is a potent antitumor compound. NC-190 has been shown to inhibit the DNA strand-passing activity of DNA topoisomerase II. We investigated further the mode of action of NC-190 against DNA topoisomerase II and DNA fragmentation. NC-190 inhibited the decatenation activity of purified topoisomerase II, but had only a weak inhibitory effect against topoisomerase I. A topoisomerase II-dependent DNA cleavage assay showed that NC-190 inhibited the enzyme activity by stabilizing a topoisomerase II-DNA cleavable complex. NC-190 induced growth inhibition, protein-linked DNA breaks, and DNA fragmentation in cultured HL-60 cells in a dose-dependent manner. These activities of NC-190 in HL-60 cells were comparable to those of etoposide (VP-16). These results demonstrate a good correlation among growth inhibition, topoisomerase II-dependent DNA cleavage, and DNA fragmentation induced by NC-190. A DNA unwinding assay showed that NC-190 had intercalating activity, but its activity appeared to be weaker than those of ethidium bromide and adriamycin. These results indicate that the mechanism by which NC-190 exhibits antitumor activity may be the inhibition of topoisomerase II.

Partial characterization of binding sites of VA-045, a novel apovincaminic acid derivative, in rat brain membranes

1. We characterized the binding sites of VA-045 [(+)-eburunamenine-14- carboxylic acid (2-nitroxyethyl)ester] in the rat brain. 2. VA-045 showed no affinity for various types of well-known neurotransmitter-related receptors or channels. However, radiolabeled VA-045 ([3H]VA-045) bound to rat brain membranes in a saturable and reversible manner. The Kd and Bmax values of [3H]VA-045 binding were 58.2 nM and 2685 fmol/mg of protein, respectively. 3. The largest specific binding of [3H]VA-045 was observed in the cerebellum, among seven brain regions, and in subcellular synaptosomes. 4. Specific binding of [3H]VA-045 was inhibited by VA-045 (Ki = 0.06 microM), a levorotatory enantiomer of VA-045 (VA-213) and its structural analog, vinpocentine. Moreover, compounds with calmodulin antagonistic activity inhibited the [3H]VA-045 binding. 5. These results suggest that VA-045 binds to specific sites, which may resemble calmodulin, on synaptic membranes in the brain.

Prostacyclin analogue TTC-909 reduces memory impairment in rats with cerebral embolism

The effects of the stable prostacyclin analogue TTC-909 on memory impairment in the water maze task and on neuronal damage were studied in rats with cerebral embolism induced by injecting polyvinyl acetate (PVA) into the right internal carotid artery and the ensuing embolism extending out into the right middle cerebral artery. Areas supplied by the lenticulostriate artery were most markedly damaged. In the water maze test, the PVA-embolized rats took longer to reach the platform than did the nontreated control rats. To some extent, repeated administrations of TTC-909 (200 ng/kg, IV) overcame this impairment in water maze learning in the rats. We assume that the vasodilating effects of TTC-909 maintain this blood supply to the ischemic area and that TTC-909 prevents the development of thrombosis around the PVA particles in the arterial capillaries, as a result of antiplatelet aggregative effects. These two mechanisms are likely to be involved in memory improvement. TTC-909 may prove effective for treating subjects with stroke and other cerebrovascular disorders.

Depolarization and hypoxia-induced cell damage in serum-free cultures of the rat cortex, and related extracellular glutamate changes

Experiments were carried out to clarify the influence of K+-induced chronic membrane depolarization on cytotoxicity and changes in extracellular glutamate, as induced by hypoxia in serum-free cortical cultures. Excitotoxic cell death was examined by measuring lactic dehydrogenase (LDH) activity released into the culture medium. In culture grown in the presence of 25 mM K+, morphological injury occurred during a 4 h exposure to hypoxia, together with a substantial efflux of LDH. In hypoxic cultures, extracellular glutamate concentrations were elevated and these responses were absent in cultures grown in physiological medium (K+ = 5.4 mM), even with 16 h of hypoxia. In cultures at 25 mM K+, the cytotoxicity induced by hypoxia was attenuated by NMDA receptor antagonists, in a concentration dependent manner. We also examined the effects of excitatory amino acids, agonists of the main glutamate receptor classes (glutamate, NMDA, kainate, and AMPA). In both 5.4 nM and 25 mM K+ cultures, a dose dependent release of LDH was induced by a long exposure to glutamate receptor agonists, although the release of LDH in the 5.4 mM K+ was less than that in the 25 mM K+ cultures. Despite of the expression of the glutamate receptor in the 5.4 mM K+ cultures, hypoxic neuronal damage did not occur. These results suggest that when cultures grown in a chronically depolarizing environment are exposed to hypoxia, they are damaged by an excitotoxic mechanism in which the main cause seems to be the glutamate released into the medium at high extracellular levels.

Expression of prostaglandin H synthase-2 in endotoxic shock induced in rats

We investigated the expression of prostaglandin H synthase-2 in rats subjected to endotoxic shock. The prostaglandin H synthase activities were assessed by measuring the plasma prostaglandins (PGE2 and 6-keto-PGF1 alpha) after arachidonic acid administration (3 mg/kg, i.v.). The plasma prostaglandin concentrations increased immediately after administration of arachidonic acid, reached a peak at 30-60 seconds, and then rapidly decreased. Lipopolysaccharide (1 mg/kg, i.v.) also increased the plasma prostaglandin concentrations, reached a peak 1 hour after administration, and then gradually decreased to normal levels. The production of plasma prostaglandin, induced by administration of arachidonic acid, was markedly enhanced in the lipopolysaccharide-treated rats. A low dose of acetylsalicylic acid (3 mg/kg, i.v.) blocked the prostaglandin production in the nontreated rats but not in the lipopolysaccharide-treated rats. In the latter group of rats, a high dose of acetylsalicylic acid (30 mg/kg, i.v.), given 10 to 30 minutes before administration of arachidonic acid, completely blocked the prostaglandin production, but recovery of this production was seen with acetylsalicylic acid (30 mg/kg) treatment at 1 to 2 hours before administration of arachidonic acid. These data suggest that pretreatment with lipopolysaccharide enhances the prostaglandin production by forming newly synthesized prostaglandin H synthase. Immunoblots of the levels of enzyme protein from rat aorta endothelial cells were analyzed. The enzyme protein cross-reacting with antibody against prostaglandin H synthase-2 was increased by lipopolysaccharide treatment in endothelial cells, and was constitutively expressed in the stomach, kidney and liver, but not in the lung and the intestine. The induction of prostaglandin H synthase-2 by lipopolysaccharide treatment was observed only in endothelial cells. The enhancement of the prostaglandin production in lipopolysaccharide-treated rats was blocked by pretreatment with dexamethasone, prior to administration of lipopolysaccharide, this suppression is apparently the result of a decrease of the prostaglandin H synthase-2 protein in endothelial cells, as determined by Western blotting. The enhanced production of prostaglandin, induced by lipopolysaccharide, seems to be due to the in vivo expression of prostaglandin H synthase-2.

Prolonged inhibition of an antigen-specific IgE response in vivo by monoclonal antibody against lymphocyte function-associated antigen-1

Intraperitoneal injection of ovalbumin (OVA) into BALB/c mice caused the induction of OVA-specific IgE production in vivo. However, administration of monoclonal antibody against lymphocyte function-associated antigen-1 (anti-LFA-1 mAb) at days 0 and 1 after OVA immunization resulted in an inhibition of OVA-specific primary and secondary IgE production in a dose-dependent manner. The inhibition of the antigen-specific IgE response due to anti-LFA-1 mAb was seen up to 8 weeks after anti-LFA-1 mAb administration. The OVA-specific IgG1 response was also blocked by anti-LFA-1 mAb. The spleen cells obtained from OVA-immunized mice showed enhanced proliferation against secondary stimulation with OVA in vitro. However, the spleen cells obtained from the mice treated with both OVA and anti-LFA-1 mAb revealed a markedly decreased proliferative responses to OVA, while they showed no reduced responses against keyhole limpet hemocyanin stimulation, indicating that anti-LFA-1 mAb might induce antigen-specific anergy in vivo. It was also demonstrated that treatment of the mice with anti-LFA-1 mAb significantly inhibited the interleukin-4-producing ability of OVA-immunized mouse spleen cells. These results demonstrated that LFA-1-dependent cell-cell interaction is essential for the production of IgE in vivo and may be important in IgE-dependent allergic disease.

Establishment of a T cell-dependent nude mouse liver injury model induced by Propionibacterium acnes and LPS

Normal ICR mice developed severe liver injury when they were given intravenous injections of Propionibacterium acnes and lipopolysaccharide (LPS) with a 7 day interval. In contrast, T cell-deficient ICR nude mice were resistant to P. acnes and LPS-induced liver injury. However, athymic ICR nude mice, which were treated with cell transfer of normal ICR mouse spleen cells (10(8) cells) or ICR mouse nylon-wool passed splenic T-enriched cells (over 10(7) cells), showed severe liver injury as assessed by elevation of serum transaminase activities. Histological analyses also demonstrated that the transferred cells migrated into the liver of nude mice to induce liver injury. However, depletion of both CD4+ T cells and CD8+ T cells from transferred cell populations caused a marked decrease in the elevation of serum transaminase, indicating the actual involvement of T cells in liver injury. Moreover, in vivo administration of anti-LFA-1 mAb blocked P. acnes and LPS-induced liver injury in nude mice following T cell transfer. Thus, this model will provide a new strategy to investigate T cell-dependent cell-cell interaction during the induction of liver damage.

Elongation of the side chain of analogs of 1 alpha,25-dihydroxyvitamin D3 prevents osteopenia in a rat model

Five analogs of 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3] [1], 26,27-dimethyl-1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2(Me)2D3] [2], 26,27-dimethyl-1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2(Et)2D3] [3], 26,27-dipropyl-1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2(Pr)2D3] [4], 26,27-dimethyl-24,24-difluoro-1 alpha,25-dihydroxyvitamin D3 [24F2-1,25(OH)2(Me)2D3], and [5] 24a-homo-24,24-difluoro-1 alpha,25- dihydroxyvitamin D3 [24aF2-homo-1,25(OH)2D3] were investigated to clarify the possibility that prevents osteopenia induced in rats by ovariectomy and sciatic neurotomy. The objective of our studies was to determine whether these analogs may be effective for treatment of subjects with osteoporosis. 1,25(OH)2(Me)2D3, 24F2-1,25(OH)2(Me)2D3, and 24aF2-homo-1,25(OH)2D3 prevented decreases in bone mineral density (BMD) of the femur, as measured by dual energy X-ray absorptiometry (DXA). The potency of 1,25(OH)2(Me)2D3 in this test was higher than that of 1,25(OH)2D3. The potencies of 24F2-1,25(OH)2(Me)2D3 and 24aF2-homo-1,25(OH)2D3 were similar to that of 1,25(OH)2D3. On the other hand, though 1,25(OH)2(Et)2D3 and 1,25(OH)2(Pr)2D3 had a preventive effect on the decrease in BMD, the potency of two analogs was lower than that of 1,25(OH)2D3. Decreases in cortical and trabecular bone areas of the femur were prevented by three analogs of 1,25(OH)2D3, 1,25(OH)2(Me)2D3, 24F2-1,25(OH)2(Me)2D3, and 24aF2-homo-1,25(OH)2D3. Serum calcium (Ca) concentration was elevated at the last administration of three analogs of 1,25(OH)2D3, 1,25(OH)2(Me)2D3, 24F2-1,25(OH)2-(Me)2D3 and 24aF2-homo-1,25(OH)2D3.(ABSTRACT TRUNCATED AT 250 WORDS)

Characteristics of binding of [3H]NE-100, a novel sigma-receptor ligand, to guinea-pig brain membranes

We examined the characteristics of binding of radiolabeled N,N-dipropyl-2-[4-methoxy-3-(2-phenyl-ethoxy)phenyl]- ethylamine monohydrochloride ([3H] NE-100), a highly potent and selective sigma-receptor ligand, to guinea-pig brain membranes. [3H]NE-100 showed saturable and reversible binding to sigma binding sites. A dissociation constant (Kd) and maximal numbers of binding sites (Bmax) obtained from Scatchard plot analysis were 1.2 +/- 0.1 nM and 1049.3 +/- 115.1 fmol/mg protein (n = 3), respectively. NE-100 was the most potent inhibitor of [3H]NE-100 binding among several structurally dissimilar sigma-receptor ligands, including haloperidol and (+)-pentazocine. (+)-Benzomorphanes had more than a 10-fold potent inhibitory activity over (-)-benzomorphanes, with regard to [3H]NE-100 binding. The binding of [3H]NE-100 was not influenced by histaminergic, dopaminergic, adrenergic, serotonergic cholinergic or glutaminergic agents at 10(-7) M. GTP-gamma-S and phenytoin also did not affect the binding of [3H]NE-100. A higher [3H]NE-100 binding was observed in the cerebellum and medulla oblongata. Except for the nuclear fraction, the highest level of [3H]NE-100 binding to subcellular fractions was observed in microsomal fractions. These results suggest that NE-100 selectively binds, with a high affinity, to sigma-1 binding sites in guinea-pig brain membranes, as an "antagonist".

Hepatoprotective effect of SY-640, a novel acetamide derivative, on Propionibacterium acnes and lipopolysaccharide-induced liver injury in mice

The hepatoprotective effect of SY-640 on Propionibacterium acnes and lipopolysaccharide-induced liver injury in mice and its protective mechanism were examined. Oral administration of SY-640, 150 mg/kg once daily for 7 days, significantly inhibited Propionibacterium acnes and lipopolysaccharide-induced liver injury, but a single administration was without effect. Liver-infiltrating cells (T-lymphocytes and macrophages) play an important role in Propionibacterium and lipopolysaccharide-induced liver injury and express a higher level of leukocyte function-associated antigen-1. SY-640 inhibited the number of liver-infiltrating cells and attenuated the increased expression of leukocyte function-associated antigen-1 on these cells. Tumor necrosis factor-alpha mediated Propionibacterium acnes and lipopolysaccharide-induced liver injury, and SY-640 inhibited the elevation of the serum tumor necrosis factor-alpha concentration after injection of lipopolysaccharide in Propionibacterium acnes-primed mice. The putative effects of SY-640 are inhibitory effects on infiltration into the liver and on activation of T-lymphocytes and macrophages after Propionibacterium acnes-priming, and attenuation of expression of cell adhesion molecules such as leukocyte function-associated antigen-1. The immunological effect of SY-640 is likely to be closely related to the inhibition of Propionibacterium and lipopolysaccharide-induced liver injury.

Effects of HL-004, a novel ACAT inhibitor, on cholesterol accumulation and removal in cultured smooth muscle cells from stroke-prone spontaneously hypertensive rats (SHRSP)

The cholesterol metabolism of cultured smooth muscle cells (SMC) from the thoracic aorta of SMC from stroke-prone spontaneously hypertensive rats (SHRSP) and Wistar-Kyoto rats (WKY) was compared. SMC from SHRSP had a higher acylCoA:cholesterol acyltransferase (ACAT) activity and accumulated more cholesterol than those from WKY. By using SMC from SHRSP, the effects of a novel ACAT inhibitor, HL-004, on the accumulation and removal of cholesterol were investigated. HL-004 inhibited microsomal ACAT activity from rabbit liver, intestine, aorta, and cultured SMC of SHRSP with 50% inhibition (IC50) values of 2.2, 1.7, 7.9, and 20 nM, respectively. HL-004 suppressed the accumulation of the intracellular cholesteryl ester (CE), but did not affect the intracellular free cholesterol (FC) content. Removal of cholesterol from the lipid-loaded SMC was accelerated by HL-004. These effects of HL-004 on cholesterol levels showed a good parallel to ACAT inhibition. It would thus appear that the suppression of cholesterol accumulation and the removal of cholesterol in SMC by HL-004 can be attributed to its ACAT inhibition in the cell, which reduces the content of intracellular CE.

The sigma-selective ligand NE-100 attenuates the effect of phencyclidine in a rat diving model

1. Phencyclidine (PCP) reduces the latency of rats diving into a water-filled pool from a hidden platform, without stereotyped behavior. 2. The sigma-selective ligand, NE-100 (N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]-ethyl-amine monohydrochloride), attenuates the effects of PCP in this procedure. 3. The serotonin2 (5-HT2) antagonist, ritanserin, and the sigma receptor ligands, 1-(cyclopropylmethyl)-4-[2'(4"-fluorophenyl)-2'-oxoethyl]- piperidine HBr (Dup734), 4-[2'-(4"-cyanophenyl)-2'-oxoethyl]-1- (cyclopropylmethyl)piperidine (XJ448), alpha-(4-fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazine butanol (BMY14802) and rimcazole similarly attenuate the effects of PCP. 4. The dopamine D2/sigma ligands, haloperidol and cis-N-(1-benzyl-2-methyl-pyrrolidin-3-yl)-2-methoxy-5-chloro-4- methylaminobenzamide (YM-09151-2) completely reverse the effects of PCP, whereas the same dose ranges of these drugs produce sedation. 5. The dopamine D2-selective antagonist, sulpiride, has no apparent effect on the PCP latency to the rat dive. 6. Thus, PCP-induced diving behavior was improved by sigma ligands and the 5-HT2 antagonist. This model of negative symptoms in an experimental animal will facilitate experiments on drug treatments for schizophrenia.

Calcium current in rat diabetic ventricular myocytes

The magnitude and kinetics of the L-type calcium current were compared in single left ventricular myocytes isolated from 8-mo-old (8M) and 19-mo-old (19M) genetically diabetic rats (WBN/Kob rats) and age-matched control rats. A diabetic state occurred at 19M but not at 8M. The left ventricular contractility was reduced in 19M WBN/Kob rats compared with age-matched control rats. The duration of the action potential was longer in 19M WBN/Kob rats than in the age-matched control rats. Peak inward current density was similar between diabetic rats and age-matched control rats. In addition, aging did not affect the current density at 8M or 19M. The various kinetic parameters of the L-type calcium current were not different between 19M diabetic and control cell types. The percent increase in the amplitude of the calcium current induced by isoproterenol was less in diabetic cells at the age of 19M, but not at the age of 8M, compared with age-matched control cells. Forskolin (10(-5) M), intracellularly applied adenosine 3',5'-cyclic monophosphate (5 x 10(-5) M), and guanosine 5'-[gamma-thio]triphosphate (10(-4) M) were equally effective in increasing the current in 19M diabetic and age-matched control cell types. The present study demonstrates that the basal calcium current density and kinetic parameters of the current were not altered. However, a decrease in response to beta-stimulation occurred in genetically diabetic rats compared with control rats.

Differences in metabolism between 26,26,26,27,27,27-hexafluoro-1 alpha, 25-dihydroxyvitamin D3 and 1 alpha, 25-dihydroxyvitamin D3 in cultured neonatal mouse calvaria

We investigated the metabolism of 26,26,26,27,27,27-hexafluoro-1 alpha,25-dihydroxyvitamin D3 (26,27-F6-1,25(OH)2D3, ST-630) and 1 alpha,25-dihydroxyvitamin (1,25(OH)2D3) in cultured neonatal mouse calvaria to elucidate why ST-630 is more potent than 1,25(OH)2D3 in stimulating bone resorption in organ culture. The metabolites were extracted with ethyl acetate or chloroform/methanol (1:1) from cultured calvaria or medium incubated with [3H]-ST-630 or [3H]-1,25(OH)2D3 for various periods, and separated by high performance liquid chromatography. [3H]-ST-630 in cultured calvaria was converted to [3H]-26,26,26,27,27,27-hexafluoro-1 alpha,23(S),25-trihydroxyvitamin D3(26,27-F6-1,23,25(OH)3D3,ST-232), which stimulated bone resorption equipotently as 1,25(OH)2D3. The amount of [3H]-ST-232 produced in the bone increased with passage of the culture period. In contrast, the amount of [3H]-ST-630 in the bones decreased in the 2 day cultures. In the medium, [3H]-ST-630 was hardly detectable for 2 days. This suggests that ST-630 is metabolized to ST-232 which is retained in the bones. On the other hand, some [3H]-1,25(OH)2D3 was metabolized to inactive forms detectable in the medium. Therefore, the high potency of ST-630 in stimulating bone resorption in organ culture may be associated with a difference between ST-630 and 1,25(OH)2D3 in the mode of metabolism in the cultured bones.

Effects of VA-045, a novel apovincaminic acid derivative, on age-related impairment evidence in electroencephalograph, caudate spindle, a passive avoidance task and cerebral blood flow in rats

1. The ability of VA-045 to improve aged-related impairment on electroencephalograph (EEG), caudate spindle, performance on a passive avoidance task and cerebral blood flow (CBF) were evaluated in rats. 2. The cortical EEG of the aged rats showed a higher incidence of spontaneous spindle burst (SSB) than seen in young rats. VA-045 decreased the incidence of SSB in aged rats. In contrast, vinpocetine increased the incidence of SSB in aged rats. 3. Electrical stimulation of the striatum in aged rats lead to a higher incidence of neocortical high voltage spindle (CS) than seen in young rats. In young rats, VA-045 had no effect on the CS, whereas an age-related increase in CS was blocked by VA-045, but was enhanced by vinpocetine. 4. There were no differences in the cortical EEG arousal response elicited by stimulation of the reticular formation of the brain stem in rats of all ages. VA-045 and vinpocetine had no effect on the cortical EEG arousal response in both young and aged rats. 5. VA-045, but not vinpocetine, attenuated the age-related decreased step through latency (STL) on a passive avoidance task. VA-045 and vinpocetine did not enhance the acquisition of learning behavior in a passive avoidance task in young rats. 6. VA-045 increased the cerebral blood flow (CBF) in both young and aged rats and the potency in aged rats was greater than that in young rats. Vinpocetine had no effect on CBF in either young or aged rats. 7. The pharmacological effects of VA-045 on age-related neuronal dysfunction are discussed.

Effect of NE-100, a novel sigma receptor ligand, on phencyclidine-induced cognitive dysfunction

N,N-Dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]-ethylamine monohydrochloride (NE-100) is a selective and potent sigma receptor ligand. We investigated the effects of NE-100 on phencyclidine (PCP)-induced cognitive dysfunction in rats in a water maze task. NE-100 significantly shortened the PCP-induced prolonged swimming latency as did 1-(cyclopropylmethyl)-4-[2'(4"-fluorophenyl)-2'-oxoethyl]- piperidine monohydrobromide (Dup 734), 4-[2'-(4"-cyanophenyl)-2'-oxoethyl]-1-(cyclopropyl-methyl)pi peridine (XJ 448), alpha-(4-fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazine butanol (BMY 14802) and rimcazole, all of which are sigma receptor ligands and possibly antagonists. Ritanserin, a 5-HT2 receptor antagonist, also showed a tendency to shorten swimming latencies. Latencies of haloperidol-, cis-N-(1-benzyl-2-methyl-pyrrolidin-3-yl)-2-methoxy-5-chloro-4-met hyl- aminobenzamide (YM-09151-2)- and sulpiride-, dopamine D2 receptor antagonists, treated groups did not differ from that seen in the PCP-treated group. Thus, PCP-induced cognitive dysfunction may be improved by sigma receptor ligands.

Effects of CD-832, a dihydropyridine derivative with a nitrate ester moiety on rabbit femoral artery and vein

We investigated the effects of CD-832 ((4R)-(-)-2-(nicotinoyl-amino)ethyl 3-nitroxypropyl 1,4-dihydro-2,6-dimethyl-4,3-nitrophenyl, 3,5-pyridine dicarboxylate), a dihydropyridine derivative with a nitrate ester moiety, on contractile responses in rabbit femoral arteries and veins. CD-832 (10(-8) to 10(-6) M and nifedipine inhibited the 64 mM KCl-induced and 10(-6) M norepinephrine-induced contractions of rabbit femoral arteries, while nitro compounds had no effect on the contractions. CD-832 (10(-8) to 10(-6) M) and nitro compounds inhibited the 10(-6) M norepinephrine-induced contractions in rabbit femoral veins, while other Ca2+ channel antagonists had little effect. The inhibitory effects of CD-832 (10(-7) M) on norepinephrine-induced contractions were antagonized by treatment with methylene blue (10(-5) M). These results indicate that CD-832 potently relaxes venous smooth muscle, and that it may be a useful agent for the treatment of angina pectoris.

Structure-activity relationships of unsaturated long chain fatty acids in relation to the inhibition of gastric H+,K(+)-ATPase

Structure-activity analyses of the effects of unsaturated fatty acids on the inhibition of gastric H+,K(+)-ATPase were carried out. Saturated fatty acids are poor inhibitors of H+,K(+)-ATPase, compared with unsaturated ones. Among the cis-unsaturated fatty acids with one double bond, there was an optimal carbon chain length for the inhibitory of the enzyme, and 10-nonadecenoic acid (C19:1) was the most potent inhibitor. The inhibitory activity was not altered by a change in the position of the double bond. The cis-fatty acids were more potent than the corresponding trans-fatty acids. Esterification of the acid moiety resulted in a decrease of the inhibitory activity. However, conversion of the acid moiety into alcohol and amide did not decrease the activity. These findings suggest that two moieties of unsaturated fatty acids are important in the interaction with the gastric H+,K(+)-ATPase, the carbon chain, which may have some hydrophobic interactions with the enzyme, and the terminal functional group (acid moiety), which may interact with hydrophilic interactions such as through hydrogen bonds with the enzyme.

Temperature-dependent alteration of 1,25-dihydroxy-vitamin D3 receptor macromolecules in MC3T3-E1 cells: affinity of hexafluoro analog of 1,25-dihydroxyvitamin D3, ST-630, for these forms

The binding properties of [3H]1,25-dihydroxyvitamin D3 (1,25(OH)2D3) to 1,25(OH)2D3 receptor in mouse osteoblastic MC3T3-E1 cells and the affinity of 26,26,26,27,27,27-hexafluoro-1,25-dihydroxyvitamin D3 (ST-630) were examined. Sucrose density gradient experiments demonstrated that [3H]1,25(OH)2D3 bound to the 6S macromolecule in the cytosol of MC3T3-E1 cells at 4 degrees C. The inhibitory effect of 1,25(OH)2D3 was compared with that of ST-630. However, at 30 degrees C, only the 3.7S macromolecule was labeled, and 1,25(OH)2D3 and ST-630 demonstrated similar affinity for the 3.7S macromolecule. Under the lower temperature condition, the cytosol from MC3T3-E1 cells showed one binding site for [3H]1,25(OH)2D3 with Kd of 0.31 nM and Bmax of 13.0 fmol/mg protein, respectively. Furthermore, from the competitive binding experiments at 4 degrees C, the affinity of ST-630 was 6.4-fold lower than that of 1,25(OH)2D3. These results suggest that the 6S macromolecule formed at the lower temperature in MC3T3-E1 cells has a property of 1,25(OH)2D3 receptor, but ST-630 has a higher affinity for 3.7S macromolecule and it may be comparable to 1,25(OH)2D3.

Changes in the extracellular concentrations of amino acids in the rat striatum during transient focal cerebral ischemia

Although considerable evidence supports a role for amino acids in transient global cerebral ischemia and permanent focal cerebral ischemia, effects of transient focal cerebral ischemia on the extracellular concentrations of amino acids have not been reported. Accordingly, our study was undertaken to examine the patterns of changes of extracellular glutamate, aspartate, GABA, taurine, glutamine, alanine, and phosphoethanolamine in the striatum of transient focal cerebral ischemia, as evidence to support their pathogenic roles. Focal ischemia was induced using the middle cerebral artery occlusion model, with no need for craniotomy. Microdialysis was used to sample the brain's extracellular space before, during, and after the ischemic period. One hour of middle cerebral artery occlusion followed by recirculation caused neuronal damage that was common in the frontoparietal cortex and the lateral segment of the caudate nucleus. During 1 h of ischemia, the largest increase occurred for GABA and moderate increases were observed for taurine, glutamate, and aspartate. Alanine, which is a nonneuroactive amino acid, increased little. After recirculation, the levels of glutamate and aspartate reverted to normal baseline values right after reperfusion. Despite these rapid normalizations, neuronal damage occurred. Therefore, uptake of excitatory amino acids can still be restored after 1 h of middle cerebral artery occlusion, and tissue damage occurs even though high extracellular levels of glutamate are not maintained.

Role of cyclic GMP in inhibitory effects of CD-349 in isolated blood vessels

1. We investigated the effects of CD-349, a dihydropyridine derivative with nitrate ester, on contractile responses induced by high K+, norepinephrine (NE) and Ca2+ in isolated rabbit aorta. 2. CD-349 (10(-9)-10(-5) M) and nifedipine (10(-9)-10(-5) M) equally inhibited the 64 mM KCl-induced contraction of the aortic strips in a concentration-dependent manner. 8-Br-cyclic GMP (10(-3) M) did not inhibit the KCl-induced contraction of the aortic strips. 3. CD-349 (10(-8)-10(-5) M) and 8-Br-cyclic GMP (10(-6)-10(-3) M) inhibited the 10(-6) M NE-induced contraction of the aortic strips in a concentration-dependent manner. However, nifedipine had no effect on the NE-induced contraction in rabbit aorta. 4. The inhibitory effects of CD-349 on NE-induced contraction were antagonized by treatment with methylene blue and oxyhemoglobin, while they were augmented by treatment with zaprinast. 5. CD-349 (10(-8)-10(-5) M) and 8-Br-cyclic GMP (10(-5)-10(-4) M) inhibited the NE-induced phasic contraction and Ca(2+)-induced contraction of the aortic strips preincubated with NE in Ca(2+)-free medium. However, nifedipine (10(-5) M) had little or no effect on both NE-induced phasic contraction and Ca(2+)-induced contraction of the aortic strips preincubated with NE in Ca(2+)-free medium. 6. CD-349 (10(-7)-10(-5) M) increased the levels of cyclic GMP in rabbit aorta. 7. These results indicate that CD-349 has a hybrid property deriving from Ca(2+)-antagonist and cyclic GMP increasing agents.

Changes in locomotor activity and passive avoidance task performance induced by cerebral ischemia in Mongolian gerbils

BACKGROUND AND PURPOSE

We investigated changes in locomotor activity, passive avoidance task performance, and hippocampal CA1 neurons induced by cerebral ischemia in Mongolian gerbils to examine the relation between these behavioral changes and CA1 neuronal damage.

METHODS

Spontaneous locomotor activity was measured using the open field method before and 1, 3, 7, 14, or 28 days after 1- to 5-minute occlusion of the bilateral common carotid arteries. Locomotor activity after the second episode of 5-minute ischemia was also measured at 1-month intervals. The passive avoidance task was performed 7 or 28 days after induced ischemia. Histopathological changes in CA1 neurons after ischemia were assessed.

RESULTS

Locomotor activity was increased 1 and 3 days after induced ischemia but not 14 and 28 days later. When the gerbils were again subjected to 5-minute ischemia 1 month after the initial 5-minute induced ischemia, locomotor activity even 1 day later was significantly increased. In contrast, passive avoidance impairment depended on the duration of ischemia, as determined 7 and 28 days after induced ischemia. Hippocampal CA1 neuronal damage was progressive, that is, changes in CA1 neurons were apparent even 1 day after 5 minutes of induced ischemia, and the CA1 neurons disappeared 7 days after 5 minutes of ischemia.

CONCLUSIONS

Passive avoidance impairment after ischemia is related to damage of CA1 neurons. Changes in locomotor activity after induced ischemia do not seem to be linked to CA1 neuronal damage.

NE-100, a novel potent sigma ligand, preferentially binds to sigma 1 binding sites in guinea pig brain

The selectivity of N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]-ethylamine monohydrochloride (NE-100) for sigma 1 and sigma 2 binding sites was studied by means of binding of [3H](+)-pentazocine and [3H]1,3-di-o-tolylguanidine ([3H]DTG) in guinea pig brain. NE-100 inhibited [3H](+)-pentazocine binding to sigma 1 binding sites potently with an IC50 value of 1.54 +/- 0.26 nM while it had a weak effect on [3H]DTG binding to sigma 2 binding sites. The inhibitory effect of NE-100 on [3H](+)-pentazocine was 55 times more potent than that on [3H]DTG binding. These results suggest that NE-100 is a potent and selective ligand for sigma 1 binding sites.

A rat model of phencyclidine psychosis

Phencyclidine (PCP)-induced behavior in rats was investigated in water maze and diving behavior tasks. The swimming and diving latencies of PCP-treated groups placed in a water maze apparatus were gradually shortened, and prolonged, respectively, while rats in a control group performed well. In all rats, stereotyped behavior and hyperlocomotion were absent. We propose that this animal model induced by lower doses of PCP may be useful for further studies to research schizophrenia.

Effects of an apovincaminic acid derivative VA-045 on neuronal activity in rat brain stem reticular formation

Extracellular single unit and spontaneous cortical electroencephalographic (ECoG) recordings were made in the brain stem reticular formation (RF) and the frontal cortex, respectively, of urethane-anesthetized rats. VA-045, an apovincaminic acid derivative had no significant effects on the spontaneous firing rate of the RF neurons and ECoG. Closed head injury (CHI) was induced by dropping a 400 g weight through a tube from 70 cm on a steel helmet placed on the vertex. CHI led to a reduction in the firing rate of RF neurons and ECoG synchronization. VA-045 dose-dependently reversed the CHI-induced decrease in the firing rate of RF and led to ECoG desyncronization. Clonidine, an alpha 2 adrenoceptor agonist, and scopolamine, a muscarinic receptor antagonist, also reduced the firing rate of RF neurons and led to ECoG synchronization. VA-045 dose-dependently antagonized the effects of clonidine, but not the effects of scopolamine on RF neuronal activity and ECoG. Thus, VA-045 has an ameliorating effect on the CHI-induced depression of neuronal activity in the RF. A central alpha 2 adrenoceptor antagonistic action may be involved.

Involvement of protein kinase C activation in regulation of acetylcholine release from rat hippocampal slices by minaprine

Involvement of protein kinase C (PKC) activation in the regulation of acetylcholine (ACh) release from rat hippocampal slices by minaprine, [3(2-morpholinoethylamino)-4-methyl-6-phenylpyridazine] was investigated. Phorbol esters such as 4 beta-phorbol 12,13-dibutylate (PDBu) and 12-o-tetradecanoylphorbol 13-acetate (TPA) enhanced high K(+)-evoked [3H]ACh release from rat hippocampal slices. The enhancing effect of phorbol ester was attenuated by PKC inhibitors, staurosporine and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7). However, the inactive phorbol analogue, 4 alpha-phorbol 12,13-didecanoate (PDD) had no effect on [3H]ACh release. Minaprine and 4-aminopyridine (4-AP) attenuated the inhibitory effect of 5-hydroxytryptamine (5-HT) on high K(+)-evoked [3H]ACh release from rat hippocampal slices. The attenuating effect of minaprine on the inhibition of [3H]ACh release by 5-HT was prevented by staurosporine, while that of 4-AP was not influenced. Furthermore, PDBu blocked voltage-dependent, rapidly inactivating 42K efflux from rat brain synaptosomes. These results suggest that minaprine attenuates the inhibitory effect of 5-HT on ACh release via PKC activation in rat hippocampus, and that the blockade of the K+ channel with PKC activation might be involved in the action of minaprine.

NE-100, a novel sigma receptor ligand: effect on phencyclidine-induced behaviors in rats, dogs and monkeys

Phencyclidine (PCP)-induced psychosis is a useful animal model for studies on schizophrenia. N, N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)-phenyl]- ethylamine monohydrochloride (NE-100) had no effect on conditioned avoidance responses (CAR) in rats, whereas, the PCP-induced impairment of avoidance inhibition was attenuated by NE-100. The PCP-induced ataxia or decreased attention in rhesus monkeys was to some extent overcome by NE-100. In dogs, PCP-induced either head-weaving behavior or ataxia, effects which were blocked by NE-100. Administration of PCP led to an increase in beta-2 and a decrease in delta relative power (RP) activity in cortical background spectral electroencephalographics (ECoG) in dogs. While NE-100 in itself showed no significant change in beta-2 and delta RP, NE-100 did block the PCP-induced beta-2 increase and delta decrease. These findings indicate that NE-100 attenuates the effect of PCP in experimental animals. This drug is being considered as a therapeutic for the treatment of patients in the schizophrenia.

NS-398, a new anti-inflammatory agent, selectively inhibits prostaglandin G/H synthase/cyclooxygenase (COX-2) activity in vitro

NS-398 is a novel anti-inflammatory and analgesic agent which produces much fewer gastrointestinal lesions in rats. Recently, two forms of cyclooxygenase have been identified: a COX-1 first purified from ram seminal vesicles and a newly discovered mitogen-inducible form (COX-2). Effects of NS-398 on activities of these two distinct forms of COX were investigated. COX-1 purified from ram seminal vesicles and COX-2 isolated from sheep placenta (purity was 70%) were used. The COX-1 activity was completely unaffected by 10(-4) M NS-398, whereas the COX-2 activity was concentration-dependently inhibited, the IC50 value being 3.8 x 10(-6) M. Indomethacin inhibited both COX-1 and COX-2 activity to the same degree, the IC50 values being 7.4 x 10(-7) M and 9.7 x 10(-7) M, respectively. The anti-inflammatory and analgesic effects of NS-398 were almost as potent as indomethacin, the effective dose range being 0.3 approximately 5 mg/kg in rats. The gastrointestinal lesions related to NS-398 were not significant following a dose of 1000 mg/kg given orally. NS-398 is the first documented agent to have selective inhibition for COX-2, which may result in the less gastrointestinal toxicity.

Determination of nitrite by high-performance liquid chromatography system with electrochemical detector: measurement of nitric oxide synthase activity in rat cerebellum cytosol

A simple and sensitive assay method for NO synthase activity is described. Using glassy carbon as electrode and 30% methanol solution with 10 mM NH4Cl as mobile phase, NO2- can be measured without disturbing ECD-detectable substance in NO synthase assay mixture. The NO2- production in the assay mixture of rat cerebellum: NO synthase increased with protein and in a time-dependent manner. The Km value for the substrate, L-arginine, was 1.25 microM. The enzyme activity was inhibited in a concentration-dependent manner by a NO synthase inhibitor, NNA. The Ki value for NNA was 0.166 +/- 0.060 microM. This ECD-HPLC method for determining NO synthase activity has advantages compared with the diazo-coupling method of the Greiss reagent and the isotopic method in which the conversion of the substrate, [14C]L-arginine, to the product, [14C]L-citrulline is measured; it is simple, sensitive and is convenient for studying the NO synthase activity with various compounds as the substrate.

Discrimination of (+)-3-PPP sites from DTG sites by FH-510, a novel potent sigma ligand, in rat brain

The effect of 5,8-dimethyl-4-(2-di-n-propylaminoethyl)carbazol monohydrochloride (FH-510) on the binding of sigma ligands such as [3H](+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ([3H](+)-3-PPP) and [3H]1,3-di-o-tolylguanidine ([3H]DTG) to rat brain membranes was studied. The inhibitory effect of FH-510 on [3H](+)-3-PPP binding to membranes of rat brain was 260 times more potent than that on [3H]DTG binding. Scatchard plot analysis showed that FH-510 inhibited [3H](+)-3-PPP binding in a competitive manner, while the inhibitory effect of FH-510 on [3H]DTG binding was noncompetitive. These results suggest that (+)-3-PPP sites could be discriminated from DTG sites, and that FH-510 binds preferentially to (+)-3-PPP recognition sites in rat brain.

CD-832, a new dihydropyridine derivative with both nitrate-like and Ca2+ channel antagonist vasodilator activities

We investigated the effects of CD-832 ((4R)-(-)-2-(nicotinoylamino)ethyl 3-nitroxypropyl 1,4-dihydro-2,6-dimethyl-4,3-nitrophenyl, 3,5-pyridine dicarboxylate), a new dihydropyridine derivative with nitrate ester, on contraction and relaxation responses induced by various vasoactive agents in rabbit aorta. CD-832 potently inhibited the specific binding of [3H](+)-PN200-110 to rat brain membranes. The IC50 values for [3](+)-PN200-110 binding were 2.8 nM and 4.9 nM in CD-832 and nifedipine, respectively. CD-832 (10(-8) to 10(-5) M), diltiazem (10(-8) to 10(-5) M) and benidipine (10(-8) to 10(-5) M) inhibited the 64 mM KCl-induced contraction of the aortic strips in a concentration-dependent manner. Neither nitroglycerin (10(-8) to 10(-5) M) nor nicorandil (10(-8) to 10(-5) M) affected the 64 mM KCl-induced contraction in rabbit aorta. CD-832 (10(-8) to 10(-5) M), nitroglycerin (10(-8) to 10(-5) M) and nicorandil (10(-5) M) had no effect on norepinephrine-induced contraction in rabbit aorta. Nitroglycerin (10(-5) M), atrial natriuretic peptide (10(-8) M), nicorandil (10(-5) M) and CD-832 (10(-7) to 10(-5) M) augmented the isoproterenol-induced relaxation responses of rabbit aorta precontracted with endothelin-1 (1 x 10(-7) to 2 x 10(-7) M). The effects of nitroglycerin (10(-5) M), nicorandil (10(-5) M) and CD-832 (10(-5) M) on isoproterenol-induced relaxation responses were antagonized by treatment with methylene blue (10(-5) M) and oxyhemoglobin (10(-5) M).(ABSTRACT TRUNCATED AT 250 WORDS)