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Volume 106, Issue 4
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Shuji KANEKO1995 Volume 106 Issue 4 Pages 243-253
Published: 1995
Released on J-STAGE: February 06, 2007
JOURNAL FREE ACCESSXenopus oocytes has been utilized to analyze the intracellular signaling and coupling mechanisms between neurotransmitter receptors and ion channels. (1) The GTP-binding protein-coupled intracellular signaling pathway was analyzed in oocytes expressing metabotropic receptors by brain mRNA. These metabotropic receptors are commonly linked to the sequence of phosphoinositide metabolism, intracellular Ca2+ increase and opening of Ca2+-dependent Cl- channels. An antisense DNA study indicated that a specific subtype of GTP-binding protein is involved in the coupling of each metabotropic receptor. (2) Effects of central acting drugs on the functions of glutamate receptor subtypes and voltage-dependent Ca2+ channels were evaluated, and the data were compared with the results from conventional in vitro assays using brain preparations. (3) A series of experiments on κ-opioid receptors indicated that is κ-opioid receptors can couple with multiple signaling systems in the oocytes via GTP-binding proteins Gi/Go, which involves mobilization of intracellular Ca2+ through phosphoinositide metabolism, synergistic potentiation of cyclic AMP production, and inhibition of voltage-dependent Ca2+ channels.View full abstractDownload PDF (7770K) -
Akira HIRASAWA, Takeo AWAJI, Gozoh TSUJIMOTO1995 Volume 106 Issue 4 Pages 255-261
Published: 1995
Released on J-STAGE: February 06, 2007
JOURNAL FREE ACCESSTo study the physiological regulation of the receptor protein, a fluorescent probe and detection system for α1B-adrenergic receptors have been developed. By using the anti-peptide antibody developed against the α1B-adrenergic receptor NH2-terminus, we have examined the agonistregulated α1B-adrenergic receptor redistribution in desensitized cells. Flow cytometry analysis showed that anti-peptide antibody against α1B-adrenergic receptor specifically identifies the receptor in CHO cells, COS-7 cells that were transfected with α1B-adrenergic receptor cDNA and rat hepatocytes. Using a fluoro-labeled receptor ligand, BODIPY FL-prazosin, as a probe, cell surface α1-adrenergic receptor subtypes can be detected by flow cytometry. Laser scanning confocal microscopy visualized the agonist-regulated redistribution process of α1B-adrenergic receptor in living cells; thus, following phenylephrine (10-6 M) stimulation, receptor antigen at the cell surface rapidly internalized and clustered together in a cell within 30 min. The results showed that the antibody and fluoro-labeled ligand are valuable tools for studying the localization and functional role of the α1-adrenergic receptor subtype.View full abstractDownload PDF (5682K) -
Shigeru ITO, Raita HIGASHINO, Takao TANAKA, Mineo TAKEI, Tadashi KURIM ...1995 Volume 106 Issue 4 Pages 263-270
Published: 1995
Released on J-STAGE: February 06, 2007
JOURNAL FREE ACCESSWe studied the effects of efonidipine hydrochloride [NZ-105:(±)-2-[benzyl (phenyl) amino] ethyl 1, 4-dihydro-2, 6-dimethyl-5-(5, 5-dimethyl-2-oxo-1, 3, 2-dioxaphosphorinan-2-yl)-4-(3-nitrophenyl)-3-pyridinecarboxylate hydrochloride ethanol] and nisoldipine on endothelial cell-induced low density lipoprotein (LDL) modification. The modification of LDL by cultured rat endothelial cells was performed by incubating 3 μg protein/well LDL with 5 μM CuSO4 for 24 hr at 37°C in the presence of confluent cells. The extent of modification was assayed by measuring the thiobarbituric acid-reactive substances (TBARS). Efonidipine hydrochloride reduced the TBARS level in a dose-dependent manner. At 3×10-7 M, efonidipine hydrochloride showed a significant effect. On the other hand, the significant effect of nisoldipine was observed only at 10-5 M. Thus the action of efonidipine hydrochloride on the inhibition of LDL-modification was much more potent than that of nisoldipine. As the modification of LDL was thought to play a key role in the initiation and progression of atherosclerosis, efonidipine hydrochloride may be useful against atherosclerosis.View full abstractDownload PDF (5925K) -
Hiroshi OCHI, Yukihiro YASUNAGA, Mamoru MATSUURA, Noriko TOMOMATSU, Ka ...1995 Volume 106 Issue 4 Pages 271-277
Published: 1995
Released on J-STAGE: February 06, 2007
JOURNAL FREE ACCESSThe analgesic mechanism of Y-23023, a new non-steroidal anti-inflammatory drug, was investigated in the writhing response induced by intraperitoneal injection of kaolin and captopril in mice. Y-23023 (0.1-1 mg/kg, p.o.) suppressed the writhing frequency in a dose-dependent manner. Y-23023 also significantly reduced the increased levels of prostaglandin (PG) and bradykinin (BK) in the peritoneal cavity. In contrast, indomethacin, diclofenac sodium, loxoprofen sodium and mefenamic acid inhibited the writhing response, but their efficacies were lower than that of Y-23023. The peritoneal PG levels were dose-dependently reduced to the same extent as Y-23023, whereas the BK levels were not. M1, an active metabolite of Y-23023, inhibited the cyclooxygenase from sheep vesicular gland in a concentration-dependent manner, and its potency was similar to that of indomethacin. These results suggest that in addition to the suppressive effect on PG production via inhibition of cyclooxygenase, the inhibitory effect on BK production is involved in the analgesic action of Y-23023, unlike indomethacin and diclofenac sodium.View full abstractDownload PDF (5199K) -
Akira TAKAHARA, Hirohisa UCHIDA, Tomoyuki KONDA, Hideki DOHMOTO, Ryota ...1995 Volume 106 Issue 4 Pages 279-287
Published: 1995
Released on J-STAGE: February 06, 2007
JOURNAL FREE ACCESSAntihypertensive effects of repeated oral administration of cilnidipine in 2K 1 C renal hypertensive dogs were compared with those of nicardipine. On the first day, oral administration of cilnidipine (3 mg/kg) or nicardipine (3 mg/kg) markedly lowered both systolic and diastolic blood pressure 1 hr after administration. The hypotensive effects of cilnidipine were longer compared with those of nicardipine. Both drugs elevated the heart rate and plasma renin activity. On the 8th and 15th days, similar responses were obtained by repeated administrations of cilnidipine and nicardipine. After withdrawal of these drugs, no rebound phenomena in blood pressure were observed. The changes in mean blood pressure were correlated with plasma cilnidipine or nicardipine concentrations that were obtained at each time of blood pressure measurement (r=-0.598; P<0.001 and r=-0.594; P<0.001, respectively). These results suggest that stable and long-acting antihypertensive effects of cilnidipine for 15 consecutive days in renal hypertensive dogs are related to the change in plasma drug concentrations.View full abstractDownload PDF (5994K) -
Hidee ISHII, Yasuo SASAKI, Toshihide IKEMURA, Shigeto KITAMURA, Kenji ...1995 Volume 106 Issue 4 Pages 289-298
Published: 1995
Released on J-STAGE: February 06, 2007
JOURNAL FREE ACCESSThe present experiment was carried out to elucidate the antiallergic properties of KW-4679. Oral administration of KW-4679 showed a dose-dependent inhibition on the IgE-mediated 48-hr homologous PCA in rats, with an ID50 value of 0.04 mg/kg. Passive anaphylactic bronchoconstriction in guinea pigs mediated by IgE-like homologous antibody against ovalbumin was prevented dose-dependently by treatment with KW-4679 at doses of 0.03-1 mg/kg, p.o. KW-4679 also inhibited the IgE-mediated active anaphylactic bronchoconstriction in rats. In passively sensitized guinea pigs, the inhalation of aerosol antigen decreased the dynamic compliance of the lung and increased the mean pulmonary resistance. Pretreatment with KW-4679 (0.03-1 mg/kg, p.o.) inhibited antigen-induced airway obstructions. Oral administration of KW-4679 significantly protected rats from compound 48/80-induced lethality. These results indicate that KW-4679 might be useful in the treatment of allergic diseases such as asthma.View full abstractDownload PDF (7578K)
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