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Volume 96 (1990)
- Issue 6 Pages 289-
- Issue 5 Pages 205-
- Issue 4 Pages 141-
- Issue 3 Pages 85-
- Issue 2 Pages 41-
- Issue 1 Pages 1-
Volume 96, Issue 6
Displaying 1-6 of 6 articles from this issue
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Hideaki KARAKI1990 Volume 96 Issue 6 Pages 289-299
Published: 1990
Released on J-STAGE: February 20, 2007
JOURNAL FREE ACCESSSimultaneous measurements of cytoplasmic Ca2+ level ([Ca2+]1) and muscle contraction in smooth muscle indicated that [Ca2+]1 gradually decreases during sustained contraction. This time-dependent dissociation has been explained by the latch bridge hypothesis, positive cooperativity between phosphorylated and non-phosphorylated crossbridges, involvement of cytoskeleton phosphorylation, or connection between myosin and actin filaments by caldesmon. Furthermore, it has been found that receptor agonists induce greater contraction than high K+ for a given increase in [Ca2+]1. This stimulus-dependent dissociation may be due to the receptor agonists-induced activation of protein kinase C which in turn decreases the inhibitory effect of calponin on the actin-myosin interaction, resulting in an apparent Ca2+ sensitization. Thus, the contractions induced by receptor agonists are due not only to the increase in [Ca2+]1 but also to the increase in Ca2+ sensitivity of contractile elements. Ca2+ channel blockers inhibit the increase in [Ca2+]1 but not the Ca2+ sensitization, and this may be the reason why these blockers are relatively weak inhibitors of the contraction induced by receptor agonists. By contrast, cyclic AMP and cyclic GMP decrease the Ca2+ sensitivity of contractile elements in addition to their effects to decrease [Ca2+]1.View full abstractDownload PDF (10071K) -
Yutaka MATSUOKA, Tsutomu URUNO, Makoto YAMADA, Yuri KANETAKE, Akiko MI ...1990 Volume 96 Issue 6 Pages 301-306
Published: 1990
Released on J-STAGE: February 20, 2007
JOURNAL FREE ACCESSEffects of lactulose on transit of charcoal meals and the luminal water and insoluble contents in the intestinal tract of rats and mice were investigated. The ED50 value for lactulose to induce diarrhea was 3.8 g/kg (p.o.). The sufficient dose (5.4 and 8.6 g/kg, p.o.) needed to produce diarrhea increased the luminal water content of the small intestine and the caecum in rats and mice and sped transit of the intestinal charcoal in mice. In addition, the administration of lactulose at 5.4 g/kg significantly decreased the luminal insoluble contents of the rat small intestine. These results indicate the cathartic effect of lactulose in smaller animals such as rats as well as humans and suggest the possible application of full doses of lactulose to flush the luminal contents from the small intestine.View full abstractDownload PDF (4513K) -
Hisayoshi KATO, Tomoyuki YONETA, Akihiko YOSHIDA, Masayuki OZEKI, Eiji ...1990 Volume 96 Issue 6 Pages 307-313
Published: 1990
Released on J-STAGE: February 20, 2007
JOURNAL FREE ACCESSInteraction of CN-100, a novel non-steroidal anti-inflammatory drug, with biopolymers were investigated. In collagen induced rat platelet aggregation, the inhibitory effect of CN-100 was almost equipotent as indomethacin (IM) but less potent than that of pranoprofen (PP). The effect of CN-100 on rat platelet aggregation induced by arachidonic acid (AA) was less potent than that of IM and PP. CN-100 inhibited rat platelet functions, serotonin release and malondialdehyde formation, induced by collagen more potently than those induced by AA. In heat-induced rat erythrocyte lysis and Ca2+-induced liposome aggregation, the inhibitory effect of CN-100 was less potent than IM but more than those of PP. CN-100 was inhibited with heat denaturation of BSA, and the effect was more potent than IM and PP. The metachromagy based on the binding of an azodye, HABA, to BSA was potentiated weakly by CN-100, but IM had no effect on it. CN-100 and IM increased the fluorescence of the binding of dansyl amide (site I probe) to BSA. These results support that there is considerable interaction between CN-100 and membrane protein, and this effect influences the membrane to increase its stability.View full abstractDownload PDF (5677K) -
Eri KOJIMA, Norihiko TAMURA, Yasushi HIGASHIDE, Bunsho LEE, Tetsuaki Y ...1990 Volume 96 Issue 6 Pages 315-321
Published: 1990
Released on J-STAGE: February 20, 2007
JOURNAL FREE ACCESSThe effects of alminoprofen, a nonsteroidal anti-inflammatory agent, on the experimental animal models of allergic reactions were examined and compared with those of ibuprofen. Alminoprofen at 30 mg/kg given intraduodenally significantly suppressed passive anaphylactic bronchoconstrictions, while ibuprofen did not at the same doses. In vitro studies revealed that alminoprofen, in contrast to ibuprofen, exerted an inhibitory effect on arachidonate 5-lipoxygenase activity which initiates the bio-synthesis of leukotrienes. Alminoprofen inhibited arachidonic acid-induced ear edema in mice and homologous passive cutaneous anaphylaxis in rats at high doses, while ibuprofen did not at the high doses. From its characteristic feature of inhibitory effects on 5-lipoxygenase activity and the experimental model of type I allergic reaction, it is suggested that alminoprofen is a new type of nonsteroidal anti-inflammatory agent.View full abstractDownload PDF (5708K) -
Kazumasa ANDO, Emiko ISONO, Takako KUBOTA, Hideki IMOKAWA, Hajime INOU ...1990 Volume 96 Issue 6 Pages 323-332
Published: 1990
Released on J-STAGE: February 20, 2007
JOURNAL FREE ACCESSThe experimental ear burn model in mice was developed in order to research the wound surface on a burn injury biochemically, and the following results were obtained : 1) The ear weight tended to increase up to 3 hr after preparation of the burn and then decreased subsequently. 2) Significant increase in leakage of Evans blue (EB) dye into the ear was observed in the burn group as compared to the non-burnt group. The amount of EB dye leaked per ear became the maximum in 3 hr which was similar to the increase in ear weight. 3) Correlation between the ear weight after burn and the amount of EB dye leaked into the ear on the burned site was observed up to 6 hr after preparation of the burn. 4) Vasopermeability of the ear was depressed with antihistamine treatment, but non-steroidal anti-inflammatory drugs had no effect. The ear weight of glucocorticoid-treated mice tended to be decreased as compared with the weight of the burned ear. 5) The histamine contents in the burned ear did not change, but the bradykinin contents significantly increased after the burn.View full abstractDownload PDF (7177K) -
Iturou IDA, Takayasu ASAMI, Hisashi KURIBARA, Yukiteru MACHIYAMA, Saku ...1990 Volume 96 Issue 6 Pages 333-341
Published: 1990
Released on J-STAGE: February 20, 2007
JOURNAL FREE ACCESSBehavioral characteristics of ceruletide, a cholecystokinin-like decapeptide, were investigated by means of ambulatory activity in mice. Ceruletide at 100 and 300 μg/kg, i.p. slightly but significantly decreased the mouse's activity for 20 min. Therefore, 100 μg/kg of ceruletide was used in the experiment of combined administration with the central-acting drugs. Ceruletide reduced the increased activity which was produced by methamphetamine (2 mg/kg, s.c.), ephedrine (80 mg/kg, i.p.), methylphenidate (4 mg/kg, s.c.), cocaine (20 mg/kg, s.c), mazindol (2.5 mg/kg, s.c.), apomorphine (0.5 mg/kg, s.c.), bromocriptine (8 mg/kg, i.p.), scopolamine (0.5 mg/kg, s.c.), caffeine (10 mg/kg, s.c.) and morphine (20 mg/kg, s.c.) with different potencies and durations. The mice that had experienced ceruletide at 3 μg/kg for 5 times at intervals of 3 ?? 4 days demonstrated a significant increase in the sensitivity to methamphetamine, although the same treatment with 10 ?? 300 μg/kg of ceruletide was without effect. On the other hand, when 3 ?? 300 μg/kg of ceruletide was combined with 2 mg/kg of methamphetamine, the development of reverse tolerance to the ambulation-increasing effect of methaphetamine was inhibited dependently on the doses of ceruletide. However, the reverse tolerance to methamphetamine once established was scarcely modified by ceruletide when it was administered afterwards.View full abstractDownload PDF (7183K)
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