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Volume 88 (1986)
- Issue 6 Pages 403-
- Issue 5 Pages 331-
- Issue 4 Pages 255-
- Issue 3 Pages 173-
- Issue 2 Pages 65-
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Volume 88, Issue 6
Displaying 1-8 of 8 articles from this issue
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Kazuo ICHIHARA1986 Volume 88 Issue 6 Pages 403-412
Published: 1986
Released on J-STAGE: March 02, 2007
JOURNAL FREE ACCESSThe effect of several kinds of antianginal drugs: nitrates, coronary vasodilators, β-adrenergic blocking agents and calcium entry blocking agents on the myocardial metabolism and myocardial acidosis during ischemia was studied in the dog heart in vivo. Ischemia was induced by ligating the left anterior descending coronary artery. Ischemia accelerated anaerobic metabolism in the myocardium, in which glycogen breakdown, accumulation of glycolytic intermediates, loss of high energy phosphate and tissue acidosis occurred. Nitroglycerin, β-adrenergic blocking agents such as propranolol, and some calcium entry blocking agents such as diltiazem and flunarizine prevented the myocardial metabolism from shifting to an anaerobic metabolism in spite of ischemia. However, coronary vasodilators and the dihydropyridine type of calcium entry blocking agents were not capable of reducing changes in the myocardial metabolism and myocardial acidosis during ischemia. The author makes a point in the present review that all the drugs which dilate coronary artery are not always effective on the ischemic myocardium.View full abstractDownload PDF (8229K) -
Johji YAMAHARA, Shinji TANAKA, Hisashi MATSUDA, Tokunosuke SAWADA, Haj ...1986 Volume 88 Issue 6 Pages 413-423
Published: 1986
Released on J-STAGE: March 02, 2007
JOURNAL FREE ACCESSThe effects of bufadienolides (bufalin, bufotalin, cinobufagin, cinobufotalin, gamabufotalin and resibufogenin) isolated from Toad Cake was compared to that of cardenolides (digitoxin and ouabain) on cardiac function in a guinea-pig working heart preparation. All the steroids showed the cardiotonic effect in a concentration-dependent manner, and the minimum threshold concentration was 10-8M for bufalin, cinobufagin, gamabufotalin and digitoxin and 10-7M for bufotalin, cinobufotalin and ouabain. In addition, the order of maximum efficacy of cardiotonic action was as follows: cinobufagin (3 × 10-7 M) =ouabain(3 × 10-7M)>digitoxin (1 × 10-7M)=gamabufotalin (3 × 10-7M)>cinobufotalin (3 × 10-7M)>bufotalin (1 × 10-7M). The effect of cinobufagin was examined on experimentally induced heart failure caused by acute local ischemia through ligation of the left anterior descending coronary artery in perfused guinea-pig heart. Cinobufagin (3 × 10-7M) and digitoxin (1 × 10-7M) reestablished the coronary flow of perfused guinea-pig heart to 90% and 98% of the level prior to the coronary artery ligation. The cardiac output and left ventricular pressure of perfused heart were increased to the level prior to the acute local ischemia, and the left ventricular work was increased by cinobufagin (3 × 10-7M) and digitoxin (1 × 10-7M) to 108% and 106%, respectively, of the pre-ligation level. These results indicate that cinobufagin possesses strong cardiotonic action, similar, to digitoxin, in experimentally induced heart failure due to acute local ischemia.View full abstractDownload PDF (7337K) -
Toshizoh ISHIKAWA, Takefumi SAKABE, Yoshinori NISHIYAMA, Masanori ABE, ...1986 Volume 88 Issue 6 Pages 425-431
Published: 1986
Released on J-STAGE: March 02, 2007
JOURNAL FREE ACCESSThe effects of S-Adenosyl-L-methionine (SAMe) on cerebral monoamine turnover at 60 min of reoxygenation after hypoxia (Pao2, 31-35 mmHg) for 15 min were studied in 44 rats anesthetized with nitrous oxide. The accumulations of monoamine metabolities: 3-methoxy 4-hydroxyphenylglycol (MHPG), 3, 4-dihydroxyphenylacetic acid (DOPAC), homovanilic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were determined after probenecid. The accumulations of noradrenaline (NA) and dopamine (DA) were also determined after pargyline. In the non-treated group, there was an impairment of degredation of NA to MHPG and of DA to DOPAC or HVA in the control group (no hypoxia). These changes were accompanied by higher levels of NA and DA in the cerebral cortex, hypothalamus and striatum than those of the control group. In the group treated with 100 mg/kg SAMe plus 38 mg/kg mannitol 3 min after the start of reoxygenation, there were no significant changes in these metabolities and amines. Mannitol alone did not cause significant changes. There were no changes in serotonin and 5-HIAA in any of the groups studied. The effects of SAMe were studied in an additional 16 awake rats. MHPG in all regions measured after probenecid in the rats treated with SAMe was higher than that without SAMe. It appears that SAMe ameliorates perturbation of cerebral catecholamine turnover produced by reoxygenation after hypoxia.View full abstractDownload PDF (5125K) -
Mitsuo HANAZUKA, Daijiro HORII, Susumu MIZOGAMI1986 Volume 88 Issue 6 Pages 433-441
Published: 1986
Released on J-STAGE: March 02, 2007
JOURNAL FREE ACCESSα-Adrenoceptor blocking activities and vascular relaxation activities of terazosin, a new antihypertensive agent, were studied. 1) Terazosin had no effect on Ba2+, serotonin, angiotensin II and Ca2+ induced contractions in the isolated rat aorta. 2) Terazosin competitively inhibited norepinephrine (NE) and phenylephrine (PE) induced contractions of the isolated rat aorta, and their pA2 values were 9.28 and 8.74, respectively. The potency of terazosin in the NE induced contraction was about 0.11, 8 and 176 times more than prazosin, phentolamine and yohimbine, respectively. The potency of terazosin in the PE induced contraction was about 0.09, 6 and 60 times more than prazosin, phentolamine and yohimbine. 3) Terazosin (i.v.) competitively inhibited the PE induced pressor response. The “pA2” values of postsynaptic α-adrenoceptor blocking activity was 5.22, and its potency was about 0.05, 5 and 62.5 times more than prazosin, phentolamine and yohimbine, respectively. Terazosin (0.3 mg/kg, i.v. or less) did not show any significant effect on clonidine induced bradycardia during electrical stimulation of cardiac sympathetic nerve, whereas prazosin (0.3 mg/kg), phentolamine (0.1 mg/kg) and yohimbine (0.1 mg/kg) antagonized the effect of clonidine by 37%, 80.6% and 63.3%, respectively. 4) Terazosin, 0.3 and 1 mg/kg, p.o., antagonized the PE (3 μg/kg, i.v.) induced pressor response in conscious unrestrained rats. This effect lasted for 8 hr in the case of 0.3 mg/kg and lasted for 12 hr in the case of 1 mg/kg. Thus, it is strong suggested that the antihypertensive effect of terazosin is based on the postsynaptic α-adrenoceptor blocking action.View full abstractDownload PDF (5959K) -
Wasako ODA, Reiko FUKUNAGA, Etsuko ICHIKAWA, Yukiko KUNUGI-UEHARA, Jun ...1986 Volume 88 Issue 6 Pages 443-448
Published: 1986
Released on J-STAGE: March 02, 2007
JOURNAL FREE ACCESSProperties of the ATP-dependent H+-transport system in rat brain synaptosomes were examined using the acridine orange fluorescence quenching method. ATP-dependent H+-accumulation assessed by the quenching of acridine orange fluorescence was observed with the synaptosomes treated with hypotonic solution (hypotonic shock-synaptosomes), but not with the intact synaptosomes. With hypotonic shock-synaptosomes, H+-transport was activated in the presence of Cl- or Br-. However, this transport activity was markedly reduced in the presence of Mes-, N03-, I- or SCN-. On the other hand, H+-transport activity was less effective with cations other than K+ in the following decreasing order of potency: K+>Cs+>Na+>Li+. The H+-transport activity was inhibited by 0.3 mM ethacrynic acid, 10 μM 4-acetamide-4′-isothiocyanostilbene-2, 2′-disulfonic acid or 1 mM 4-aminopyridine to 39.2%, 36.3%, or 33.1%, of the control, respectively, but was not inhibited by 1 mMouabain, 500 μM vanadate, 10 μM picrotoxin and 100 μM γ-aminobutyric acid. These results suggest that the ATP binding site of the synaptosomal ATP-dependent H+-transport system exists on the internal surface of synaptosomal plasma membranes and that the H+-transport system is stimulated by the presence of Cl- or Br- and by K+ movement through the K+ channel.View full abstractDownload PDF (4482K) -
Yoshitaka INO, Kunihiko SUZUKI, Takuo SATO, Masahiro IWAKI1986 Volume 88 Issue 6 Pages 449-455
Published: 1986
Released on J-STAGE: March 02, 2007
JOURNAL FREE ACCESSInhibitory effects of nafamostat mesilate (nafamostat) on various enzymes were investigated, and they were compared with those of gabexate mesilate (gabexate), leupeptin, aprotinin and urinastatin in vitro. Nafamostat inhibited trypsin, plasmin, thrombin, pancreatic kallikrein, Clr- and Cls- more potently than gabexate and leupeptin. Gabexate and leupeptin did not inhibit pancreatic kallikrein and thrombin, respectively. Aprotinin inhibited trypsin, plasmin, pancreatic kallikrein and chymotrypsin. Urinastatin inhibited trypsin and chymotrypsin. Nafamostat inhibited the complement-mediated hemolysis in diluted serum more potently than gabexate and leupeptin, but aprotinin and urinastatin did not. Nafamostat, furthermore, inhibited the complement-mediated hemolysis in undiluted serum, but gabexate did not. Unlike aprotinin and urinastatin, nafamostat and gabexate inhibited α2-macroglobulin bound trypsin as well as free trypsin to the same extent. The inhibitory effect of gabexate toward trypsin was reduced more markedly than that of nafamostat after incubation with plasma at 37°C. These results show that nafamostat is more useful than other inhibitors such as gabexate, leupeptin, aprotinin and urinastatin.View full abstractDownload PDF (5153K) -
Masahiro MIZOTA, Yoshihiro OIKAWA, Kazuo NAKAYAMA, Kiyoshi MIZUGUCHI, ...1986 Volume 88 Issue 6 Pages 457-466
Published: 1986
Released on J-STAGE: March 02, 2007
JOURNAL FREE ACCESSWe investigated the pharmacological characteristics of MO-8282 as a novel antidepressant. MO-8282 inhibited the specific binding of 3H-clonidine to cerebro-cortical membrane fractions from rats about five times more potently than mianserin, and it competed with clonidine in the twitch response of the isolated guinea-pig ileum under field stimulation. The results indicated that MO-8282 possessed α2-adrenergic receptor blocking activity. MO-8282 in a dose of 30 mg/kg (p.o.) showed no inhibition against the uptake of noradrenaline, dopamine and serotonin in the rat brain, whereas mianserin inhibited the uptake of serotonin specifically. MO-8282, similar to mianserin, had no effect on spontaneous release of 3H-noradrenaline and slightly stimulated the release of 3H-serotonin from the rat cerebrocortical synaptosome. The turnover rate of noradrenaline in rat brain was accelerated by administration of MO-8282 (30 mg/kg) for 15 days; however, that of dopamine and serotonin was not affected. The above findings indicate that MO-8282, unlike tricyclic antidepressants, mainly exerts α2-adrenoceptor blocking action on the central noradrenergic system, similar to mianserin. In addition, the fact that MO-8282 unlike mianserin showed no inhibition against uptake of serotonin in brain suggests that the α2-adrenoceptor blocking of MO-8282 is more specific and potent than that of mianserin.View full abstractDownload PDF (7128K) -
Susumu OKABE, Koji TAKEUCHI, Yoshimi MORI, Osamu FURUKAWA, Yoshiharu Y ...1986 Volume 88 Issue 6 Pages 467-476
Published: 1986
Released on J-STAGE: March 02, 2007
JOURNAL FREE ACCESSWe studied the effects of KT1-32 (sodium guaiazulene 3-sulfonate) on development of various acute gastric lesions and duodenal ulcers induced in rats. Male Donryu or Sprague-Dawley rats (220-270 g), fasted (but allowed free access to water) for 24 or 48 hr before the experiments, were used. KT1-32 (dissolved in distilled water, 10-100 mg/kg), given p.o. or intraduodenally (i.d.), dose-dependently inhibited the development of gastric lesions induced by HCl·ethanol (60% ethanol in 150 mM HCl), HCl·aspirin (aspirin 100 mg/kg in 150 mM HCl) or aspirin (150 mg/kg in pylorus-ligated preparation) and Shay ulcers (14 hr pylorus ligation). KT1-32 (30 and 100 mg/kg), given p.o. twice (9.5 hr apart), significantly inhibited the development of duodenal ulcers induced by mepirizole (200 mg/kg, s.c.), but did not inhibit gastric lesions developed simultaneously. KT1-32 (30 and 100 mg/kg), given p.o. or i.d., significantly reduced gastric acid secretion when examined using pylorus ligation preparations. KT1-32 (100 mg/kg, i.d.) had no effect on basal and suppressed duodenal HCO3- secretion by mepirizole. These results suggest that KT1-32 is a promising drug for the treatment of gastritis and peptic ulcers.View full abstractDownload PDF (6847K)
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