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Volume 95 (1990)
- Issue 6 Pages 279-
- Issue 5 Pages 229-
- Issue 4 Pages 139-
- Issue 3 Pages 83-
- Issue 2 Pages 47-
- Issue 1 Pages 7-
Volume 95, Issue 5
Displaying 1-6 of 6 articles from this issue
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Sakutaro TADOKORO, Hisashi KURIBARA1990 Volume 95 Issue 5 Pages 229-238
Published: 1990
Released on J-STAGE: February 20, 2007
JOURNAL FREE ACCESSIt has been well-known that a chronic abuse of amphetamines induces schizophrenia-like psychotic symptoms, namely amphetamine psychosis. When amphetamines are repeatedly administered to rodents, a reverse tolerance (behavioral sensitization) to the ambulationincreasing and/or stereotypy-producing effect is observed. The process of the reverse tolerance is affected by various factors. A clear reverse tolerance is produced when optimal doses of the drug (2 mg/kg, s.c. for mice, and 0.5 ?? 1 mg/kg, s.c., for rats) is administered at intervals of longer than 1 day rather than a shorter interval. Furthermore, the animal has to be put into a freely mobile situation during the presence of the acute drug effect. A cross reverse tolerance is observed between certain types of drugs that show an ambulation-increasing effect, although the potencies are different among the drugs. A reverse tolerance to the stereotypy (in particular sniffing and head-bobbing)producing effect is also observed when comparatively higher doses of methamphetamine are repeatedly administered. The process is qualitatively identical with the reverse tolerance to the ambulation-increasing effect produced by the repeated administration of comparatively smaller doses. The reverse-tolerance, once established, to both ambulation-increasing and stereotypy-producing effects is almost irreversible even with various treatments such as repeated post-treatment with antipsychotics. The characteristics of reverse tolerance to methamphetamine in animals might be closely correlated to the amphetamine psychosis in humans. It is also necessary to search for a method that effectively reduces the established reverse tolerance to amphetamines.View full abstractDownload PDF (9119K) -
Yoichi YAMAUCHI, Junya IKUTA, Sadahiro SHIMIZU, Masaki NAKAMURA1990 Volume 95 Issue 5 Pages 239-246
Published: 1990
Released on J-STAGE: February 20, 2007
JOURNAL FREE ACCESSWe examined the effect of dilazep dihydrochloride (dilazep) on ischemia and reperfusioninduced cerebral injury in spontaneously hypertensive rats (SHRs). Ataxia and loss of the righting reflex were noted in some SHR after 4 hr occlusion of the bilateral common carotid arteries; and 11 of 15 animals died within 72 hr after reperfusion. One hour after reperfusion, the cerebral water content increased significantly. The chemiluminescence value in the brain homogenate increased slightly during occlusion; and following reperfusion, there was a transient but marked further increase, indicating the acceleration of lipid peroxidation that resulted from free radical reactions. The i.v. infusion of dilazep (0.3 ?? 3 mg/kg/hr for 4 hr) during occlusion dose-dependently reduced the appearances of neurological symptoms and mortality during occlusion and after reperfusion. The increase in cerebral water content and chemiluminescence value were clearly prevented by dilazep (3 mg/kg/hr). It is concluded that dilazep possesses the ability to prevent the appearances of neurological symptoms and brain edema induced by ischemia and reperfusion. The suppression of lipid peroxidation may be involved in the mechanism of the preventive effect of dilazep on cerebral injury.View full abstractDownload PDF (6995K) -
Susumu OKABE, Tadashi NISHIDA, Hideki IGATA, Keiko TAKAGI1990 Volume 95 Issue 5 Pages 247-256
Published: 1990
Released on J-STAGE: February 20, 2007
JOURNAL FREE ACCESSWe examined the effects of a new histamine H2-receptor antagonist, 3-amino-4-{4-(4-(1-piperidinomethyl)-2-pyridyloxy)-cis-2-butenylamino}-3-cyclobutene-1, 2-dione hydrochloride (IT-066), on gastric acid secretion and the healing process of experimental ulcers in rats and dogs. Famotidine, a well-established H2-receptor antagonist, was used as the reference drug. Male Donryu rats (240 ?? 260 g) and Beagle dogs of both sexes (8 ?? 10 kg), having Heidenhain pouches, were used. IT-066 dose-dependently inhibited the basal gastric acid secretion of rats, and this inhibition significantly persisted for 12 hr. In addition, the agent significantly inhibited histamine-stimulated acid secretion in both normal rats and rats with acetic acid ulcers. IT-066, given p.o. twice daily for 2 and 3 weeks after ulceration, significantly accelerated both spontaneous and delayed healing (with indomethacin) of acetic acid-induced gastric ulcers in rats. The effects of IT-066 on acid secretion and ulcer healing were almost the same or slightly more potent than those observed with famotidine. IT-066, when given i.v. or p.o., dose-dependently inhibited the gastric acid secretion stimulated by histamine, pentagastrin, or carbachol in dogs. The antisecretory effects of the agent on histamine-stimulated acid secretion significantly persisted for more than 6 hr. These results indicate that IT-066 appears to be a promising antisecretory and anti-ulcer agent.View full abstractDownload PDF (7971K) -
Masao SEIKI, Shigeru UEKI, Yoshiaki TANAKA, Mitsuo SOEDA, Yuko HORI, H ...1990 Volume 95 Issue 5 Pages 257-269
Published: 1990
Released on J-STAGE: February 20, 2007
JOURNAL FREE ACCESSWe investigated the anti-ulcer effects of zinc L-carnosine (Z-103) using several acute experimental models of gastric and duodenal lesions in rats. Effects of Z-103 on various gastric functions, e.g., antacid (in vitro), anti-pepsin (in vitro), gastric secretion, mucosal potential difference (PD) and mucus contents were also examined. Z-103 given orally prevented development of gastric lesions induced by water immersion stress, histamine, HCl-aspirin, HCl-ethanol and also duodenal ulcers induced by mepirizole in a dosedependent manner. In vitro, Z-103 had a greater antacid effect than sodium bicarbonate; and moreover, the potency of its anti-peptic action (IC50=8.7 mM) was higher than those of several other drugs (sodium bicarbonate, sucrose sulfate and aceglutamide aluminum). Intragastric treatment of Z-103 (100 mg/kg alone tended to increase PD, and it also significantly inhibited the decrease in PD induced by aspirin. In addition, pretreatment with Z-103 at 10 and 30 mg/kg (p.o.) significantly prevented the decrease in mucus contents in the gastric mucosa and also mucosal lesions by oral administration of ethanol. On the other hand, Z-103 was not so effective on both basal (pylorus-ligation preparation) and histamine-stimulated gastric secretion (Heidenhain pouch preparation). These results suggest that Z-103 is useful for the treatment of gastric and duodenal ulcers in humans.View full abstractDownload PDF (9485K) -
Fumio NAMBU, Toshimichi IMAI, Mitsuru ADACHI, Terumi TAKAHASHI1990 Volume 95 Issue 5 Pages 271-277
Published: 1990
Released on J-STAGE: February 20, 2007
JOURNAL FREE ACCESSTo elucidate the possible involvement of thromboxane A2 (TXA2) in airway hyperresponsiveness, we examined the effect of OKY-046, a potent and selective inhibitor of TXA2 synthetase, on airway hyperresponsiveness induced by ozone exposure in dogs. Ozone exposure (3 ppm, 2 hr) markedly increased airway responsiveness to inhaled methacholine without affecting basal respiratory resistance. Although ozone also caused a slight but significant increase in neutrophil number in the bronchoalveolar lavage fluid, there was no correlation between, the level of airway hyperresponsiveness and increased neutrophil number. Although OKY-046 significantly inhibited the increases in airway hyperresponsiveness in a dose-dependent manner at doses ranging from 100 to 300 mg/kg, p.o., the compound did not affect the basal airway responsiveness and respiratory resistance at 300 mg/kg, p.o. Inhalation of the subthreshold concentration (i.e., the highest dose which did not cause bronchoconstriction) of STA2 (a stable TXA2 mimetic agent) elicited a significant increase in airway responsiveness to methacholine. These results suggest that TXA2 may play a role in mediating ozone-induced airway hyperresponsiveness. However, the accumulation of neutrophils in the airway lumen may not be essential for the development of airway hyperresponsiveness.View full abstractDownload PDF (5229K) -
[in Japanese]1990 Volume 95 Issue 5 Pages 279-281
Published: 1990
Released on J-STAGE: February 20, 2007
JOURNAL FREE ACCESSDownload PDF (2353K)
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