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Volume 47 (1988)
- Issue 4 Pages 333-
- Issue 3 Pages 209-
- Issue 2 Pages 107-
- Issue 1 Pages 1-
Volume 47, Issue 2
Displaying 1-13 of 13 articles from this issue
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Tadashi MIZUTA, Tomio SEGAWA1988 Volume 47 Issue 2 Pages 107-113
Published: 1988
Released on J-STAGE: August 25, 2006
JOURNAL FREE ACCESSThe effects of chronic treatment with imipramine, a tricyclic antidepressant, or lithium, an antimanic-depressive illness drug, on postsynaptic serotonin-1A (5-HT1A) and 5-HT1B sites and on presynaptic 5-HT3 sites in the frontal cortex and hippocampus from rat brains were studied. Chronic i.p. administration (21 days) of imipramine reduced the maximum number of binding sites (Bmax) for postsynaptic 5-HT1A as monitored by the radioligands 3H-5-HT or 3H-8-hydroxy-2-(di-n-propylamino)tetralin (3H-8-OH-DPAT), but did not change the Bmax for postsynaptic 5-HT1B and presynaptic 5-HT3 in either the frontal cortex or the hippocampus. Chronic i.p. administration (21 days) of lithium reduced the Bmax for postsynaptic 5-HT1A sites in the hippocampus, but not in the frontal cortex. There was a specific difference between imipramine and lithium regarding the inhibitory effect on postsynaptic 5-HT1A sites in the frontal cortex. In addition, lithium decreased the affinity of presynaptic 5-HT3 sites in the hippocampus. These findings may be also consistent with the inhibitory effect of lithium on presynaptic autoreceptors, which results in an increase of 5-HT release. It is concluded that enhanced 5-HT neurotransmission which develops during chronic treatment with imipramine or lithium seems to be related to the down-regulation of postsynaptic 5-HT1A receptors in addition to postsynaptic 5-HT2 receptors, which may also have an important role in the antidepressant effects of these drugs.View full abstractDownload PDF (334K) -
Tatsuyuki TSUBOMURA, Kazuyoshi KURAHASHI, Toshihiro OKAMOTO, Motohatsu ...1988 Volume 47 Issue 2 Pages 115-122
Published: 1988
Released on J-STAGE: August 25, 2006
JOURNAL FREE ACCESSExperiments were performed on cats anesthetized with pentobarbital sodium and gallamine triethiodide. Gastric motility was recorded by a balloon method. The excitatory response to electrical stimulation of the vagal trunk was composed of an initial response during the stimulation period and a late response following stimulation. The maximal excitation of the initial response was elicited by a short pulse duration and that of the late response by a long pulse duration. The initial response was inhibited by treatment with hexamethonium or atropine. The late response was hexamethonium-resistant. This hexamethonium-resistant response was inhibited by atropine, hemicholinium and morphine, and enhanced by physostigmine. Treatment with (D-Pro2, D-Trp7, 9)-substance P did not affect the hexamethonium-resistant response. Treatment with morphine inhibited the late response without affecting the initial response. From these results, it was suggested that the initial excitatory response was probably due to the activation of the parasympathetic cholinergic fibers. The late response might be due to the activation of the vagal afferent cholinergic fibers, since the pharmacological nature of the late response was similar to that in the cat with supranodose vagotomy (surviving afferent fibers) in our previous reports.View full abstractDownload PDF (384K) -
Jyunji YAMAMOTO1988 Volume 47 Issue 2 Pages 123-134
Published: 1988
Released on J-STAGE: August 25, 2006
JOURNAL FREE ACCESSIn the present study, the influences of cholinergic (ACh), dopaminergic (DA), noradrenergic, serotonergic and γ-aminobutyric acid (GABA) ergic system activation and blocking agents on the cortical (CT) and hippocampal (HC) EEG power spectra were investigated in rabbits. The AChergic agents, physostigmine and atropine, produced marked increases or decreases in peak powers, the changes of which were inversely related to each other, but similar to those of the normal behavioral states. The other agents did not always produce changes. ACh seems to play an important role in the regulation of peak powers. Apomorphine shifted the theta wave peak to higher frequencies and haloperidol shifted it to lower frequencies. The other drugs did not cause a shift. DA seems to regulate peak frequency. These findings suggest that ACh is important for the regulation of consciousness between the wakefulness and SWS states and suggest that DA is involved in the production of REM sleep.View full abstractDownload PDF (611K) -
Yoshiyuki INADA, Katsumi ITOH, Kazuhide KAMIYA, Hirosada SUGIHARA, Koh ...1988 Volume 47 Issue 2 Pages 135-141
Published: 1988
Released on J-STAGE: August 25, 2006
JOURNAL FREE ACCESSThe synthetic design and the biological activities of structurally new angiotensin converting enzyme (ACE) inhibitors, (R)-3-amino-4-oxo-2, 3, 4, 5-tetrahydro-1, 5-benzothiazepine-5-acetic acid derivatives, are described. A number of compounds in this series showed potent ACE inhibitory activity in vitro and in vivo. Structure-activity studies indicated that a piperidyl moiety on the amino group at the 3-position in this series conferred long-lasting ACE inhibitory activity and that the duration of activity depended on the length of the carbon chain in the 1-carboxy-ω-(4-piperidyl)alkyl group. (R)-3-[(S)-1-carboxy-5-(4-piperidyl)-pentyl]amino -4-oxo-2, 3, 4, 5-tetrahydro-1, 5-benzothiazepine-5-acetic acid (CV5975) was selected as the most promising ACE inhibitor for further studies because of its marked inhibitory activity.View full abstractDownload PDF (340K) -
Takashige NISHIKAWA, Yuichi TOMORI, Sukehide YAMASHITA, Shin-ichiro SH ...1988 Volume 47 Issue 2 Pages 143-150
Published: 1988
Released on J-STAGE: August 25, 2006
JOURNAL FREE ACCESSLysophosphatidic acid (LPA), a metabolite of phosphatidic acid (PA) by phospholipases of the A2 type, markedly inhibited the synaptic membrane (Na++K+)-ATPase activity from rat cerebral cortices in incubation media containing free Ca2+ concentrations below 4.7×10-6M. This effect of LPA was dose-dependent, and the minimum effective concentration was 10-6 g/ml. The inhibitory action of LPA was more potent than that of PA. Lysophosphatidylinositol (LPI) and lysophosphatidylethanolamine (LPE) at 10-5 g/ml had little or no effect on this enzyme activity. These results suggest that LPA may partly play a role in the depolarization and/or increase in intracellular calcium concentrations in the brain.View full abstractDownload PDF (447K) -
Mikio NAKAMURA, Kunie KAMATA, Hakubun INOUE, Minoru INABA1988 Volume 47 Issue 2 Pages 151-157
Published: 1988
Released on J-STAGE: August 25, 2006
JOURNAL FREE ACCESSIt is considered that adrenomedullary secretion of adrenaline is centrally regulated by various endogenous substances. Recently, opioid peptides have been reported as one of this group of endogenous substances. However, the receptor through which these endogenous opioid peptides regulate adrenomedullary adrenaline secretion has not been elucidated. In the present study, various opioid peptides were administered intracerebroventricularly in conscious, unrestrained rats, and blood catecholamine levels were measured at various periods to determine which cerebral opioid peptide receptor is involved in the mechanism of basal adrenomedullary adrenaline secretion. The results indicate that δ-receptor stimulation has a positive effect on basal adrenomedullary adrenaline secretion, while μ- and κ-receptors are not involved in this mechanism.View full abstractDownload PDF (329K) -
Nobuyuki TAKAOKA, Chiaki HARA, Nobuya OGAWA1988 Volume 47 Issue 2 Pages 159-168
Published: 1988
Released on J-STAGE: August 25, 2006
JOURNAL FREE ACCESSThe purpose of the present study was to induce a state of depression including both the elements of behavioral despair and chronic stress. Therefore, this study was performed under the hypothesis that a long-term exposure of rats to the experimental situation of difficult to escape from foot-shock in a Skinner box might produce animals with a state of depression containing both the elements. Male Wistar strain rats were trained to press a lever to escape from foot-shock under a fixed ratio (FR) schedule. After the training, rats were exposed daily to a schedule consisting of 20 trials (the early 10 trials, FR 5; the later 10 trials, FR 20) once a day. The exposure resulted in reduction of the number of lever presses and successful escape in FR 20. Only the animals whose number of escapes, reduced to under 20% in FR 20 were treated with psychotropic drugs once a day for 4 days. The results showed that the reduced number of escapes was most improved by antidepressants (imipramine or mianserin), but not by haloperidol and methamphetamine. Although subchronic treatment with chlordiazepoxide partially recovered the reduced escape, the efficiency of lever pressing to escape from foot-shock was lower than that with the antidepressants. The results of the present study suggest that the behavioral suppression observed in this study might include characteristics similar to a state of depression.View full abstractDownload PDF (467K) -
Keiko KAWAMOTO, Akira TOUCHI, Koichi SUGENO, Takashi MATSUBARA1988 Volume 47 Issue 2 Pages 169-178
Published: 1988
Released on J-STAGE: August 25, 2006
JOURNAL FREE ACCESSLiver microsomal vitamin K epoxide reductase activity was determined by measuring the formation of menaquinone-4 from the substrate menaquinone-4 2, 3-epoxide. The enzyme was active when dithiothreitol (DTT) was used as a reducing agent, and the activity increased gradually with increasing concentrations of DTT. Glutathione and cysteine also functioned as reductants, but these physiological reductants showed less than 15% of the activity detected with 0.5 mM DTT. Addition of various beta-lactam antibiotics to the assay mixture for vitamin K epoxide reductase caused a slight inhibition of the activity. N-Methyltetrazolethiol (NMTT) and other heterocyclic thiol compounds also inhibited the enzyme activity in vitro depending on their concentrations. Most of these antibiotics and heterocyclic thiol compounds inhibited the enzyme activity only 10-25% in the in vitro assay system even when higher concentrations were added (5-10 mM). Among the compounds tested, methyl-thiadiazolethiol was the only compound that caused 50% inhibition of the enzyme activity. NMTT-induced inhibition was diminished gradually by increasing DTT concentrations. Kinetic analysis of the inhibitory action of heterocyclic thiol compounds showed competitive inhibition against the reductant DTT and non-competitive inhibition against the substrate. On the other hand, warfarin, a typical anticoagulant, showed different patterns in the inhibitory action: non-competitive inhibition against DTT and mixed-type inhibition against the substrate.View full abstractDownload PDF (500K) -
Junji KAMIZAKI, Kazumasa SHIMIZU, Shinjiro NAKAJYO, Norimoto URAKAWA1988 Volume 47 Issue 2 Pages 179-188
Published: 1988
Released on J-STAGE: August 25, 2006
JOURNAL FREE ACCESSIn the present paper, effects of high K+/Na+ deficient solution on the rat uterus were examined on the mechanical response, wet weight of the tissue or rate of oxygen consumption, and they were compared with those in rat urinary bladder. In the uterus, isosmotic substitution of K+ for Na+ in a physiological saltsolution (PSS) induced a contraction followed by a small sustained contraction, while hyperosmotic addition of KCl to PSS induced a sustained contraction. The hyperosmotic KCl addition increased the rate of oxygen consumption in comparison with that in PSS, and the substituted high K+/Na+ deficient solution decreased it as compared with that in the hyperosmotic KCl addition. Similar results were shown in the urinary bladder. At 120 min after application of the substituted high K+/Na+ deficient solution, the relative wet weight increased in the uterus, but did not change in the urinary bladder. Both the decrease in the developed tension and the increase in the wet weight of the uterus were prevented by the hyperosmotic addition of sucrose. In the urinary bladder, the decreased tension was significantly prevented by the hyperosmotic addition of NaCl to the PSS or substitution of pyruvate or oxalacetate for glucose, whereas it was slightly prevented by the hyperosmotic addition of sucrose. From these results, it is suggested that the decrease of the developed tension in isosmotically substituted high K+/Na+ deficient solution in rat uterus is probably due to cell swelling and that the inhibition of contraction in urinary bladder is mainly caused by the inhibition of glucose utilization by Na+ deficiency in the medium.View full abstractDownload PDF (466K) -
Keisuke SATOH, Kazuo NUNOKI, Toshikazu GOTO, Makoto HOSONO, Hiroo HASH ...1988 Volume 47 Issue 2 Pages 189-195
Published: 1988
Released on J-STAGE: August 25, 2006
JOURNAL FREE ACCESSThe efficacy of MCI-154, a new pyridazinone cardiotonic agent, in improving heart failure was assessed in dog heart-lung preparations in which cardiac function had been severely depressed by pentobarbital. MCI-154 in doses of 10-100 μig improved the cardiac function curve and restored it to the control level at 100 μg. At this dose, MCI-154 neither produced an increase in heart rate beyond the control value nor induced arrhythmias. The effects of MCI-154 were not affected by atenolol, a cardioselective β1-blocker. These results indicate that MCI-154 would be of potential use in the treatment of heart failure.View full abstractDownload PDF (285K) -
Ikuko KIMURA, Tomoko NAKAMURA, Masayasu KIMURA1988 Volume 47 Issue 2 Pages 197-199
Published: 1988
Released on J-STAGE: August 25, 2006
JOURNAL FREE ACCESSCa2+-dependent slow action potentials (AP) were investigated in diaphragm muscles of alloxan-diabetic mice in comparison with normal muscles. Slow APs observed in diabetic muscles were significantly decreased in amplitude and duration. The slow APs which were generated at a stimulation frequency of once every 15 sec decayed more rapidly in diabetic muscles. Fatigue, however, developed regardless of the presence of verapamil (10 μM) in contrast to the quicker development of fatigue in normal muscles in response to verapamil.View full abstractDownload PDF (161K) -
Hidekazu ARATANI, Yukari NISHIDA, Michio TERASAWA, Yutaka MARUYAMA1988 Volume 47 Issue 2 Pages 200-203
Published: 1988
Released on J-STAGE: August 25, 2006
JOURNAL FREE ACCESSEffect of etizolam on platelet activating factor (PAF) and N-formyl-methionyl-leucyl-phenylalanine (FMLP)-induced superoxide anion (O2-) production in guinea pig polymorphonuclear leukocytes (PMNL) was investigated. Etizolam showed the inhibitory effect on PAF-induced O2- production concentration dependently, with an IC50 value of 4.7 μM, but it had no inhibitory effect on FMLP-induced O2- production at 100 μM. These results suggest that etizolam has a selectively strong inhibitory effect on PAF-induced O2- production in guinea pig PMNL.View full abstractDownload PDF (176K) -
Noboru TODA, Hisashi ONOUE1988 Volume 47 Issue 2 Pages 204-207
Published: 1988
Released on J-STAGE: August 25, 2006
JOURNAL FREE ACCESSConcentration-response curve for prostaglandin (PG) F2α in helical strips of dog cerebral, coronary and mesenteric arteries were compared in control media and in those in which all the NaCl was replaced with isomolar KCl. Contractile responses to PGF2α in concentrations up to 2×10-6 M in cerebral arteries, to 10-5 M in coronary arteries and to 5×10-7 M in mesenteric arteries were not attenuated by excess K+. Contractions caused by PGF2α, at least at these concentrations or lower, may not be associated with membrane depolarization.View full abstractDownload PDF (169K)
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