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Volume 103 (1994)
- Issue 6 Pages 245-
- Issue 5 Pages 193-
- Issue 4 Pages 141-
- Issue 3 Pages 83-
- Issue 2 Pages 43-
- Issue 1 Pages 1-
Volume 103, Issue 5
Displaying 1-5 of 5 articles from this issue
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Akinori AKAIKE1994 Volume 103 Issue 5 Pages 193-201
Published: 1994
Released on J-STAGE: February 06, 2007
JOURNAL FREE ACCESSGlutamate is acknowledged as an excitatory neurotransmitter in the vertebrate central nervous system (CNS). Glutamate is also postulated to play an important role in the pathogenesis of the neuronal cell loss that is associated with several neurological disease states in the CNS. Glutamate cytotoxicity in the cortical and retinal neurons in culture is mediated by nitric oxide (NO). As the excitatory action of glutamate is regulated by other neurotransmitters, the cytotoxic action of glutamate may be affected by other endogenous substances. We have used the term “neuroprotective factor” for endogenous substances having neuroprotective actions against glutamate cytotoxicity. We have previously found that cholecystokinin (CCK) prevented glutamate toxicity in the cortical neurons in culture. The evidence has suggested that CCKB-receptor stimulation causes suppression of a step in NO formation triggered by N-methyl-D-aspartate (NMDA) receptors. Nicotinic acetylcholine also protected cultured cortical neurons against NMDA receptor-mediated glutamate toxicity. In the cultured retinal neurons, dopamine prevented NMDA receptor-mediated glutamate cytotoxicity via D1-receptors. These substances may have a role to promote cell survival in the life-regulatory function of the CNS.View full abstractDownload PDF (22174K) -
Takashi OHNO, Makoto KATORI1994 Volume 103 Issue 5 Pages 203-209
Published: 1994
Released on J-STAGE: February 06, 2007
JOURNAL FREE ACCESSThe greater curvature of the stomach of fasted rats was cut under urethane anesthesia (1.25 g/kg, i.p.). The dorsal side of the glandular stomach was fixed in a plastic chamber by facing the mucosal side to the chamber and perfused with warm Tyrode solution at 37°C. A window made by partial removal of the serosa, the muscularis externa and the submucosa allowed us to observe the basal part of the mucosal microcirculation through the muscularis mucosae. Images of the microcirculation were transmitted through a TV camera to a TV monitor screen and recorded on videotapes by a videotaperecorder. The diameters of the arterioles, collecting venules and venules were measured by an image analyzer. Arterioles, running along the muscularis mucosae, responded to acetylcholine and epinephrine applied on the window, by dilatation and constriction, respectively, but the collecting venules and venules showed no changes in diameter. Application of 50% ethanol on the mucosal side caused dilatation of the arterioles and constriction of the collecting venules and venules. This method may be useful for analyzing the mechanisms of gastric mucosal injury and those of the effects of vasoactive agents on the gastric mucosal microcirculation.View full abstractDownload PDF (18507K) -
Tsuneichi HASHIMOTO, Masashi KATSURA, Kinya KURIYAMA1994 Volume 103 Issue 5 Pages 211-217
Published: 1994
Released on J-STAGE: February 06, 2007
JOURNAL FREE ACCESSEffects of AE0047, a novel calcium antagonist, on monoamine, acetylcholine (ACh) and neuroactive amino acid contents in rat brain were examined. Cerebral ACh content was elevated by the administration of AE0047 (100 mg/kg, p.o.). Striatal norepinephrine and dopamine contents were decreased and increased, respectively, following the administration of 10 mg/kg and 100 mg/kg of AE0047. The administration of AE0047 (10, 30 and 100 mg/kg, p.o.) invariably induced increases in 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid contents in the cerebral cortex. Although AE0047 (100 mg/kg, p.o.) had no effect on the tryptophan hydroxylase activity in the cerebral cortex, striatum and hippocampus, in vitro addition of 10-8-10-6M AE0047 induced a significant increase of [14C]5-HT uptake into cerebral cortical slices. AE0047 administration (30 and 100 mg/kg, p.o.) also induced a significant decrease of cortical taurine content. These results suggest that AE0047 may be a drug that stimulates 5-HT turnover via the accentuation of 5-HT uptake.View full abstractDownload PDF (15287K) -
Korebumi MINAKAMI1994 Volume 103 Issue 5 Pages 219-229
Published: 1994
Released on J-STAGE: February 06, 2007
JOURNAL FREE ACCESSHyperammonemia due to inherited deficiency of enzymes in the liver is also found in sparse-fur (spf) mice, which have OTC (ornithine transcarbamylase) deficiency, a high concentration of ammonia in the blood and a high concentration of glutamine and tryptophan after weaning. Abnormal behavior was observed during the hyperammonemic period in spf mice. Autonomic locomotor activity in spf mice during this period was enhanced under light but suppressed in the dark. The circadian rhythm of autonomic locomotor activity disappeared from 3 to 5 weeks and reappeared at 8 weeks. The frequency of the head twitch response induced by 5-methoxy-N, N-dimethyltryptamine (5-MeODMT) decreased in the hyperammonemic period, in which the concentration of brain tryptophan (Trp) and 5-hydroxyindoleacetic acid (5-HIAA) increased, the ratio of 5-HIAA to serotonin (5-HT) in the brain increased and [3H]-ketanserin binding to 5-HT2 receptor significantly decreased in the frontal cortex and whole brain. Down regulation in the postsynaptic 5-HT2 receptor may have provoked the inhibition of 5-MeODMT-induced head twitch response. The abnormal behavior of spf mice may derive from increased tryptophan in the brain due to hyperammonemia, increased 5-HT turnover rate and down regulation in the postsynaptic 5-HT2 receptor.View full abstractDownload PDF (20732K) -
Kyomi TOYODA, Masaki KITAHARA, Toshie YAMASHITA, Chizuru SHUDO, Yukino ...1994 Volume 103 Issue 5 Pages 231-239
Published: 1994
Released on J-STAGE: February 06, 2007
JOURNAL FREE ACCESSWe studied the effect of efonidipine hydrochloride [NZ-105:(±)-2-[benzyl(phenyl) amino] ethyl 1, 4-dihydro-2, 6-dimethyl-5-(5, 5-dimethyl-2-oxo-1, 3, 2-dioxaphosphorinan-2-yl)-4-(3-nitrophenyl)-3-pyridinecarboxylate hydrochloride ethanol], a newly synthesized dihydropyridine calcium antagonist, on atherosclerosis in 1% cholesterol-fed rabbits. NZ-105 (10, 30 and 100 mg/kg) was orally administrated to the animals twice a day for 10 weeks. NZ-105 did not cause any significant change in the plasma lipid levels. The area of atherosclerotic lesion was reduced by 37% (P<0.05) in the aortic arch and by 54% (P>0.05) in the thoracic aorta of rabbits administrated 100 mg/kg of NZ-105. The content of cholesterol ester in the aorta was also reduced by 64% (P<0.05) in the aortic arch and by 73% (P>0.05) in the thoracic aorta. These results suggest that NZ-105 may suppress the developement of atherosclerosis without affecting the plasma lipids.View full abstractDownload PDF (19352K)
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