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Volume 73 (1997)
- Issue 4 Pages 263-
- Issue 3 Pages 185-
- Issue 2 Pages 105-
- Issue 1 Pages 1-
Volume 73, Issue 3
Displaying 1-12 of 12 articles from this issue
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Ray Kanagawa, Takeo Wada, Tsukasa Sanada, Mami Ojima, Yoshiyuki Inada1997 Volume 73 Issue 3 Pages 185-190
Published: 1997
Released on J-STAGE: April 06, 2006
JOURNAL FREE ACCESSThe regional hemodynamic effects of candesartan cilexetil (TCV-116), a selective angiotensin II AT1-receptor antagonist, and enalapril, an angiotensin-converting enzyme inhibitor, were compared in conscious spontaneously hypertensive rats (SHR). A 7-day repeated administration study was carried out. TCV-116 (1 mg/kg, p.o.)and enalapril (10 mg/kg, p.o.)reduced blood pressure to the same extent 5 hr after administration on the 1st and the 7th day. At these points, the cardiac index and organ or tissue blood flow were measured by the non-radioactive colored dye-extraction microsphere technique. Repeated administration of TCV-116, and single and repeated administration of enalapril significantly increased renal blood flow without any changes in the cardiac index. TCV-116 and enalapril also tended to increase splanchnic blood flow following the 1st dose but not the 7th dose. No significant changes in blood flow were observed in the brain, heart, adrenal, skin and skeletal muscle. These results suggest that the antihypertensive effects of TCV-116 and enalapril are attributable to the systemic reduction of vascular resistance caused by the dilatation of blood vessels. These hemodynamic effects of TCV-116, like those of enalapril, may be beneficial in the treatment of hypertension.View full abstractDownload PDF (470K) -
Masahiro Moriyama, Syoichi Yamashita, Katsushi Furuno, Tomoaki Sato, H ...1997 Volume 73 Issue 3 Pages 191-196
Published: 1997
Released on J-STAGE: April 06, 2006
JOURNAL FREE ACCESSThe effect of lactation on the pharmacokinetics of phenobarbital (PB) after delivery was studied in female rats. Non-pregnant animals received PB 20 mg/kg/day twice for 6-7 days before mating, during pregnancy and after delivery. Chronic PB did not significantly influence changes in the body weight of rats after delivery. On the first post-delivery day, the plasma PB concentration in the PB-treated rats was significantly higher than that in PB-treated, non-pregnant rats (non-pregnant rats); and thereafter, it gradually decreased until ablactation on the 20th day. After ablactation, plasma PB concentrations gradually returned to the level before delivery. In PB-treated rats, pharmacokinetic parameters (Cmax, AUC0-12)of PB between 0 and 12 hr after a single oral administration were significantly decreased during lactation. These results suggest that PB administered during lactation is transferred in part to offspring through maternal milk.View full abstractDownload PDF (362K) -
Akira Warashina1997 Volume 73 Issue 3 Pages 197-205
Published: 1997
Released on J-STAGE: April 06, 2006
JOURNAL FREE ACCESSEffects of indomethacin on catecholamine secretion evoked by receptor agonists, muscarine, bradykinin or histamine, in rat adrenal chromaffin cells were studied. Indomethacin at 200 μM increased a sustained component of secretion during stimulation with muscarine, bradykinin and histamine by a factor of 2.3, 2.1 and 2.9, respectively, whereas it did not significantly alter basal, high-K+ and nicotine-evoked secretions. Although indomethacin at above 400 μM dose-dependently increased basal secretion, the amount of secretion induced by indomethacin alone was much smaller than that in muscarine-evoked secretion as compared at the same concentration of indomethacin applied. Bradykinin-evoked secretion and its potentiation by indomethacin were not inhibited by 20 μM nifedipine but were suppressed by 0.5 mM Ni2+. The cyclooxygenase inhibitor, ibuprofen (200 μM)did not mimic the effect of indomethacin; prostaglandin E2 (20 μM)and arachidonic acid (100 μM)did not significantly alter either bradykinin-evoked secretion itself or its potentiation by indomethacin. Bradykinin increased the intracellular free Ca2+ concentration, [Ca2+]i, in cells loaded with indo-1, and this response was enhanced in the presence of indomethacin. These results suggest that indomethacin may promote Ca2+ entry to potentiate agonist-evoked catecholamine secretions through a novel action that is not directly related to the inhibition of cyclooxygenase activity with indomethacin.View full abstractDownload PDF (582K) -
Ching-Wei Chang, Feng-Nien Ko, Ming-Jai Su, Yang-Chang Wu, Che-Ming Te ...1997 Volume 73 Issue 3 Pages 207-214
Published: 1997
Released on J-STAGE: April 06, 2006
JOURNAL FREE ACCESSOcoteine, isolated from Cassytha filiformis, was found to be an α1-adrenoceptor blocking agent in rat thoracic aorta as revealed by its competitive antagonism of phenylephrine-induced vasoconstriction (pA2=7.67±0.09). Removal of endothelium from the aorta did not affect its antagonistic potency (pA2=7.97±0.07). [3H]-Inositol monophosphate formation caused by noradrenaline (3 μM) was suppressed by ocoteine (10 μM) and prazosin (3 μM). Ocoteine did not affect the contraction induced by U46619, prostaglandin F2α or angiotensin II, but inhibited slightly those by high K+ and endothelin I. Neither the cyclic AMP nor cyclic GMP content of rat thoracic aorta was changed by ocoteine (10 μM). Comparing the EC50 values, the potency of ocoteine against 5-hydroxytryptamine (5-HT) was about 60 times less than that against phenylephrine. Ocoteine (10 μM)also slightly antagonized the clonidine-induced inhibition of the twitch response evoked by field stimulation in rat vas deferens. In guinea pig trachea, the contraction caused by carbachol, histamine, neurokinin A or leukotriene C4 and β2-adrenoceptor-mediated relaxing responses induced by isoprenaline were not affected by ocoteine (10 μM). The voltage clamp study in rat ventricular single myocytes revealed that ocoteine (3, 10 μM) inhibited steady state outward currents, but not transient outward currents or slow inward Ca2+ currents. It is concluded that ocoteine is a selective α1-adrenoceptor antagonist in isolated rat thoracic aorta. At high concentrations, it also blocks 5-HT receptors and Na+ and steady state outward currents in rat ventricular myocytes.View full abstractDownload PDF (598K) -
Manabu Matsunaga, Yuji Uemura, Yuri Yonemoto, Kazumi Kanai, Hironori E ...1997 Volume 73 Issue 3 Pages 215-220
Published: 1997
Released on J-STAGE: April 06, 2006
JOURNAL FREE ACCESSPotency and duration of muscle relaxant activity of eperisone hydrochloride were examined after percutaneous administration in the intercollicular decerebrated rat rigidity model and compared to those of eperisone after intravenous injection. A continuous movement was loaded on the hindlimb of the rat model to maintain stable rigidity. The tonus of the hindlimb was recorded by EMG from the triceps surae and was quantified by using the public domain NIH Image program. Eperisone ointment administered percutaneously showed significant muscle relaxant activity at 8.4 cm2 (4.2 mg of eperisone) /rat. The effect was dose-dependent and lasted over 60 min. Intravenously injected eperisone showed significant activity at 1.25 mg/kg, but the decrease of tone was lost within 30 min after injection. Plasma eperisone levels were monitored in the same model, and they were well correlated to the dosage. These results suggest that percutaneously administered eperisone is absorbed efficiently and shows potent and long-lasting muscle relaxant activity.View full abstractDownload PDF (407K) -
Minoru Kanda, Koji Eto, Nobuaki Tanabe, Atsushi Sugiyama, Keitaro Hash ...1997 Volume 73 Issue 3 Pages 221-228
Published: 1997
Released on J-STAGE: April 06, 2006
JOURNAL FREE ACCESSThis study was conducted to evaluate effects of the aldose reductase inhibitor ONO-2235 on the contractile response to acetylcholine of the urinary bladder dome of streptozotocin-induced diabetes mellitus (DM)rats and simultaneously observe the changes in the function and number of muscarinic receptors and the sorbitol content of the bladder. The contractile response to acetylcholine increased 51 % in the DM rat bladder dome compared to the normal rats; however, this was attenuated to a 10% increase by administration of 100 mg/kg ONO-2235 for 2 weeks. Treatment with ONO-2235 significantly decreased the specific [3H]quinuclidinyl benzilate binding in DM rats. However there was no significant dose-dependency among the ONO-2235-treated groups. The sorbitol levels of the sciatic nerve and the bladder were higher in the DM rats compared to the control rats; ONO-2235 decreased the level, although it did not completely reverse them to the control level. These results suggest that an aldose reductase inhibitor attenuates the increase of the muscarinic receptor number and normalizes the enhanced contractile response to acetylcholine caused by hyperglycemia and diuresis, probably through suppression of the polyol-pathway in the DM rat bladder dome.View full abstractDownload PDF (593K) -
Hiroshi Satoh, Shoichi Asano, Rika Maeda, Izumi Murakami, Ikuko Inada, ...1997 Volume 73 Issue 3 Pages 229-241
Published: 1997
Released on J-STAGE: April 06, 2006
JOURNAL FREE ACCESSWe found indomethacin aggravates healed gastric ulcers (ulcer relapse)in rats. In the present study, we examined the effects of human basic fibroblast growth factor (bFGF)mutein CS23 (TGP-580)and histamine H2-receptor antagonists (H2-RAs)on ulcer relapse in this model. In male SD rats, gastric ulcers were induced in the antrum by injection of acetic acid. Indomethacin (1 mg/kg/day)given s.c. for 2 weeks starting 4 weeks after the operation aggravated the healed ulcer; the areas with and without indomethacin were 4.8±1.4 and 0.4±0.3 mm2, respectively. Drugs were given orally once daily for 4 weeks starting 2 days after the operation or for the 2-week indomethacin administration period. Treatment with ranitidine (100 mg/kg), cimetidine (100 mg/kg)and TGP-580 (0.1 mg/kg)for 4 weeks accelerated the healing. The aggravation by indomethacin was significantly inhibited by pretreatment with TGP-580 and mildly inhibited by cimetidine but not ranitidine. When the drugs were co-administered with indomethacin for 2 weeks, the aggravation was significantly prevented by ranitidine and mildly inhibited by cimetidine and TGP-580. Both TGP-580 and H2-RAs can prevent the ulcer relapse induced by indomethacin but via different modes of action: TGP-580 inhibits relapse mainly by acting on the process of healing, while H2-RAs act mainly on the process of aggravation.View full abstractDownload PDF (1171K) -
Ikumi Arai, Takao Shimazoe, Shigenobu Shibata, Hirotaka Inoue, Akiko Y ...1997 Volume 73 Issue 3 Pages 243-246
Published: 1997
Released on J-STAGE: April 06, 2006
JOURNAL FREE ACCESSWe studied the roles of metabotropic glutamate receptors in methamphetamine (MAP)induced sensitization of dopamine (DA) release from striatal slices. Rats were first treated with MAP (1 mg/kg, i.p.) once daily for 6 consecutive days. After a 6-day withdrawal, DA release from striatal slices evoked by ±-1-aminocyclopentane-trans-1, 3-dicarboxylic acid (trans-ACPD)was measured. transACPD-induced DA release was significantly enhanced in MAP-sensitized rats, but the inactive form of trans-ACPD (1R, 3S-ACPD) did not enhance DA release. The active form of trans-ACPD (1S, 3R-ACPD) (0.1 mM) -evoked DA release was attenuated by treatment with 0.4 MM RS-α-methyl-4-carboxyphenylglycine, a metabotropic glutamate receptor antagonist. The present results suggest that metabotropic glutamate receptors play an important role in expression of MAP-induced sensitization.View full abstractDownload PDF (268K) -
Katsuo Kamata, Tsuyoshi Hayashi, Fujio Umeda1997 Volume 73 Issue 3 Pages 247-250
Published: 1997
Released on J-STAGE: April 06, 2006
JOURNAL FREE ACCESSWe recently reported that cyclopiazonic acid (CPA)r eleases a novel endothelium-derived relaxing factor that is not prostacyclin, nitric oxide or endothelium-derived hyperpolarizing factor in rat mesenteric arterial bed. The acetylcholine-induced vasodilatation of the isolated mesenteric bed in spontaneously hypertensive rats (SHR) was not different from that in Wistar Kyoto rats (WKY), but it was significantly smaller in streptozotocin (STZ) -induced diabetic rats than in age-matched controls. The CPAinduced vasodilatation was not affected in SHR or in STZ-induced diabetic rats. These results suggest that the CPA-induced endothelium-dependent vasodilatation is resistant to the effects of diabetes.View full abstractDownload PDF (266K) -
Tomohisa Mori, Kenshi Murase, Jiro Tanaka, Yasuyuki Ichimaru1997 Volume 73 Issue 3 Pages 251-254
Published: 1997
Released on J-STAGE: April 06, 2006
JOURNAL FREE ACCESSEffects of D3-receptor agonists, 7-OH-DPAT and PD128907, on the D1-receptor agonist SKF81297-induced hyperactivity in mice were examined. 7-OH-DPAT and PD128907 significantly suppressed the SKF81297-induced hyperactivity at low doses, but significantly potentiated the hyperactivity at high doses. These D3-agonists alone had no effect on the motor activity. A κ-receptor agonist that reduces dopamine release had no effect on the SKF81297-induced hyperactivity. These results suggest that lower doses of 7-OH-DPAT and PD128907 may negatively influence the D1-receptor mediated behaviors via post synaptic D3-receptors. On the other hand, higher doses of these compounds may positively influence these behaviors via D2 or D3-receptors.View full abstractDownload PDF (258K) -
Shu-ichi Kojima1997 Volume 73 Issue 3 Pages 255-257
Published: 1997
Released on J-STAGE: April 06, 2006
JOURNAL FREE ACCESSIn the guinea pig distal colon, calcitonin gene-related peptide (CGRP, 0.1 30 nM) produced a concentration-dependent inhibition in electrically-evoked nonadrenergic noncholinergic (NANC)contractions and exogenous substance P-induced contractions. Both the inhibitory actions of CGRP were insensitive to human CGRP(8-37) (1-3 μM), a CGRP1 receptor antagonist. These results indicate that in the distal colon, CGRP inhibits electrically-evoked NANC contraction through a postjunctional mechanism, in contrast to our previously described results that CGRP enhances the NANC contraction of guinea pig proximal colon via a prejunctinal mechanism.View full abstractDownload PDF (176K) -
Tomio Okamura, Jian-Xin Zhang, Kenji Kangawa, Noboru Toda1997 Volume 73 Issue 3 Pages 259-261
Published: 1997
Released on J-STAGE: April 06, 2006
JOURNAL FREE ACCESSAdrenomedullin (AM)inhibited the pressor action caused by transmural electrical stimulation in perfused isolated canine mesenteric arteries. The inhibitory potency of AM was greater than that of calcitonin gene-related peptide (CGRP) or proadrenomedullin NH2-terminal 20 peptide (PAMP). [8-37]CGRP did not affect the inhibitory action of AM, but suppressed the CGRP-induced inhibition. It may be concluded that AM has an ability to inhibit adrenergic neuronal transmission without the mediation of CGRP1 receptors in the peripheral vasculature, and this inhibition partly participates in the potent hypotensive action of AM.View full abstractDownload PDF (214K)
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