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Volume 89 (1987)
- Issue 6 Pages 317-
- Issue 5 Pages 243-
- Issue 4 Pages 169-
- Issue 3 Pages 103-
- Issue 2 Pages 55-
- Issue 1 Pages 1-
Volume 89, Issue 6
Displaying 1-6 of 6 articles from this issue
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Yoichiro OGAWA, Shoichi IMAI1987 Volume 89 Issue 6 Pages 317-322
Published: 1987
Released on J-STAGE: February 23, 2007
JOURNAL FREE ACCESS3, 4-Diaminopyridine (3, 4-DAP), which is known to decrease K. conductance, produced spontaneous repetitive phasic contractions of a regular (28/60) and an irregular. (15/60) cycle or tonic contraction (16/60) following a latent period of 5 ?? 100 min in isolated porcine coronary arteries. Effects of pinacidil, a newly-synthesized vasodilator, were investigated using the preparation in which 3, 4-DAP produced phasic contractions of the regular cycle in comparison with those of various vasodilators. Pinacidil produced dose-dependent prolongation of the cycle and reduced the peak tension and the tension at the relaxation phase, a mode of action that closely resembles that of nicorandil, suggesting the increase in K conductance and hyperpolarization. Nifedipine (10-8M) and dilazep (10-4M) markedly reduced the peak tension, while adenosine, dipyridamole and nitroglycerin did not produce such effects. The latter three drugs produced a prolongation of the cycle and reduced the tension of the relaxation phase. These data suggest that reduction of K conductance and activation of the voltage-dependent Ca channel may play an important role in initiation of the spontaneous repetitive phasic contraction in porcine coronary artery.View full abstractDownload PDF (3956K) -
Masato NANRI, Hiroshi KANETO1987 Volume 89 Issue 6 Pages 323-329
Published: 1987
Released on J-STAGE: February 23, 2007
JOURNAL FREE ACCESSBased on the results of a previous report that prolyl endopeptidase (PPCE) inhibitors facilitated the acquisition of active avoidance response and retarded the extinction of the response, further studies were made on the effect of PPCE inhibitors on learning and the memory process. Using mice, tests were performed both in the light-dark discrimination Y-maze task and the lever-press task of the water reinforcement schedule, and mice were also tested in the acquisition and retention of one-trial “step-through” passive avoidance task. The effect of PPCE inhibitors were investigated both in control and electroconvulsive shock- or scopolamine-induced amnesic animals. Z-Pro-p, the most potent in hibitor among 5 compounds tested in this study, and arginine vasopressin (AVP) facilitated the learning process and retarded the extinction of the acquired response in all tests. Suc-Pro-p was also effective in the Y-maze and passive avoidance test. Thus, the effect of the test compounds were parallel with their in vitro activities as PPCE inhibitor. These results suggest that the anti-amnesic effect of PPCE inhibitors is partially attributable to their effect on the breakdown of the biologically active peptides which are involved in the memory process, such as AVP, in the brain.View full abstractDownload PDF (5568K) -
Hiroyuki NAKAMICHI, Matsutaro MURAKAMI, Shigenori MIZUSAWA, Yasushi KO ...1987 Volume 89 Issue 6 Pages 331-337
Published: 1987
Released on J-STAGE: February 23, 2007
JOURNAL FREE ACCESSThe following 4 Wistar rat groups were sacrificed by microwave irradiation after measuring blood pressure and heart rate: 1) saline control (1 ml/kg, i.v.), 2) clonidine alone (50 μg/kg, i.v.). 3) prazosin pretreated (0.1 mg/kg, i.v.), 4) yohimbine pretreated (1 mg/kg, i.v.) . Cyclic nucleotides were analyzed in seven brain regions. Clonidine decreased blood pressure and heart rate 20 min after administration. These effects of clonidine were inhibited by yohimbine. Clonidine increased the levels of cyclic AMP in the medulla oblongata (including pons) and hypothalamus. Prazosin attenuated the cyclic AMP-increasing action of clonidine in the cerebellum. Yohimbine inhibited this action of clonidine in the cerebellum, striatum and hippocampus. Clonidine reduced cyclic GMP levels in the hypothalamus and striatum. Prazosin potentiated the cyclic GMP-reducing action of clonidine in the medulla oblongata. Yohimbine attenuated this action of clonidine in the medulla oblongata and hypothalamus. From these results, it is concluded that clonidine changes the levels of cyclic nucleotides in brain regions, especially in the part of the autonomic nervous center. In addition, it is indicated that α1- or α2-adrenoceptor plays a different role in the regulation of brain cyclic nucleotides, region by region.View full abstractDownload PDF (4711K) -
Shigenori WATANABE, Hisashi OHTA, Kimihiro YAMASHITA, Masuo OHNO, Yosh ...1987 Volume 89 Issue 6 Pages 339-354
Published: 1987
Released on J-STAGE: February 23, 2007
JOURNAL FREE ACCESSElectroencephalographic (EEG) effect of quinupramine was investigated in unanesthetized rabbits with chronic electrode implants, and it was compared with those of imipramine and amitriptyline. Quinupramine (0.56 ?? 3.2 mg/kg) induced a marked drowsy pattern of spontaneous EEG: high voltage slow waves increased in the cortex, while the hippocampal theta rhythm was desynchronized. Imipramine (1.0 ?? 5.6 mg/kg) and amitriptyline (0.56 ?? 3.2 mg/kg) also elicited similar EEG effects. The EEG arousal response to auditory stimulation and to electric stimulation of the mesencephalic reticular formation, posterior hypothalamus and centromedian thalamus was markedly suppressed by quinupramine, imipramine and amitriptyline. The EEG arousal response induced by i.v. injection of physostigmine was markedly suppressed by quinupramine, amitriptyline and imipramine. Quinupramine showed no significant effect on the photic driving response and recruiting response. Quinupramine slightly enhanced the limbic afterdischarges elicited by either hippocampal or amygdaloid stimulation, while amitriptyline and imipramine caused an initial suppression followed by a quick recovery. The EEG effects of quinupramine were similar to those of amitriptyline in both qualitative and quantitative aspects.View full abstractDownload PDF (12199K) -
Kazuhiro GOTO, Mamoru SUEKAWA, Masaki ABURADA, Eikichi HOSOYA1987 Volume 89 Issue 6 Pages 355-363
Published: 1987
Released on J-STAGE: February 23, 2007
JOURNAL FREE ACCESSThe protective effects of TJ-8007 (Tsumura-Zokumeito, Traditional chinese medicine) against cerebral anoxia were investigated with various experimental models in mice and rats. 1) In histotoxic anoxia, TJ-8007 (0.3 ?? 3.0g/kg, p.o.) dose-dependently demonstrated a protective effect on coma induced by a sublethal dose of KCN (1.8 mg/kg, i.v.) in mice. Ifenprodil (30 mg/kg, p.o.) tended to reduce the coma time, but papaverine (100 mg/kg, p.o.) showed a negative effect. 2) TJ-8007 (0.3 ?? 3.0 g/kg, p.o.) dose-dependently tended to prolong the survival time of mice subjected to a lethal dose of KCN (3.0 mg/kg, i.v.), TJ-8007 also improved the survival rate at the dose of 3.0 g/kg. Ifenprodil (30 mg/kg, p.o.) or papaverine (100 mg/kg, p.o.) exerted a similar effect on the survival time, but did not affect the mortality. 3) In the normobaric hypoxia with a gas mixture of 96% N2 and 4% O2, TJ-8007 (0.3 ?? 3.0g/kg, p.o.) did not affect the survival time of mice. On the other hand, papaverine (100 mg/kg, p.o.) prolonged the survival time, and phenytoin (100 mg/kg, p.o.) showed a marked protective effect, but ifenprodil (30 mg/kg, p.o.) produced an adverse effect. 4) In the asphyxic anoxia induced by stopping artificial respiration of immovable rats, TJ-8007 (1.0, 3.0 g/kg, p.o.) showed a protective effect on the fall of systemic blood pressure and on the decline of heart rate; furthermore, it dose-dependently prolonged the disappearance time of cortical activity. Also, phenytoin (100 mg/kg, p.o.) tended to protect against the fall of blood pressure and prolonged the cortical resistance time. However, these protective effects of phenytoin were less than that of TJ-8007 at the dose of 3.0 g/kg. Ifenprodil (30 mg/kg, p.o.) did not affect the cortical resistance time. As described above, TJ-8007 demonstrated protective effects in a dose-dependent manner against the brain damages induced by cerebral anoxia.View full abstractDownload PDF (6479K) -
Toshiro KANAZAWA, Noboru TODA1987 Volume 89 Issue 6 Pages 365-373
Published: 1987
Released on J-STAGE: February 23, 2007
JOURNAL FREE ACCESSIn helical strips of dog cerebral and peripheral arteries, KB-2796 (1-[bis(4-fluorophenyl)-methyl]-4-(2, 3, 4-trimethoxybenzyl)piperazine dihydrochloride), a new Ca2+ entry blocker, inhibited the contractile responses induced by K+, prostaglandin (PG) F2α and serotonin in a non-competitive manner. KB-2796 inhibited the contraction induced by K+ more effectively than those induced by PGF2α or serotonin. In cerebral arteries, the inhibition produced by KB-2796 was more prominent than in peripheral arteries. In renal arteries, serotonin produced contractions in concentrations 200 ?? 1, 200 times higher than those sufficient to contract the other arteries. KB-2796 inhibited renal arterial contractions induced by serotonin and K+ to a similar extent. In renal arteries depolarized by replacement of the entire amount of NaCl in the bathing medium with KCl, PGF2α produced additional contraction of the artery, whereas serotonin did not contract the artery. These results suggest that KB-2796 inhibits the contractility of cerebroarterial smooth muscle more preferentially than that of other arteries. The contractile response to serotonin of the renal artery appears to be associated with the voltage-dependent influx of Ca2+ as suggested in the cerebral arteries.View full abstractDownload PDF (6229K)
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