Tadashi Kurimoto

A new thromboxane receptor antagonist, Z-335, ameliorates experimental thrombosis without prolonging the rat tail bleeding time.

We investigated the antithrombotic activity of Z-335, a new thromboxane A2 receptor antagonist, using experimental thrombosis models, and also tested its effect on the rat tail bleeding time. Z-335 (0.1, 0.3, and 1 mg/kg, p.o.) dose-dependently prevented the occurrence of arachidonic acid-induced pulmonary thromboembolism in mice. During photochemically induced thrombosis in the femoral artery of guinea pigs, Z-335 (0.3, 1, and 3 mg/kg, i.v.) dose-dependently prolonged the time required to form thrombi. Moreover, Z-335 (10 mg/kg/day, p.o.) strongly suppressed lauric acid-induced hind limb injury in rats. Z-335 (0.3, 3, 30, and 300 mg/kg, p.o.) did not prolong the tail bleeding time in rats. These results strongly suggest that Z-335 ameliorates experimental thrombosis without prolonging the rat tail bleeding time, and may therefore be a useful antithrombotic drug.

Antiplatelet effect of Z-335, a new orally active and long-lasting thromboxane receptor antagonist

We investigated the pharmacological characteristics of Z-335 ((+/-)-sodium[2-[4-(chlorophenylsulfonylaminomethyl)indan-5-yl]ace tate monohydrate), a new indan derivative. Z-335 inhibited the specific binding of [3H]SQ-29548 to human platelets and guinea pig platelet membranes. The IC50 values of Z-335 for human platelets and guinea pig platelet membranes were 29.9 +/- 3.1 nM with a slope of 1.09 +/- 0.05 and 32.5 +/- 1.7 nM with a slope of 1.07 +/- 0.02, respectively. Z-335 inhibited thromboxane A2 receptor-mediated human and guinea pig platelet aggregation in vitro and oral administration of this drug to guinea pigs inhibited U-46619- and collagen-induced platelet aggregation for 24 h. Z-335 dose-dependently prevented the occurrence of U-46619-induced pulmonary thromboembolism in mice and the protective effect of this drug (0.3 and 3 mg/kg, p.o.) lasted for 24 h. These results strongly suggest that Z-335 is a potent, orally active and long-lasting thromboxane A2 receptor antagonist, which may be useful as an antiplatelet drug.

Anti‐Tumor Mechanism of Z‐100, an Immunomodulatory Arabinomannan Extracted from Mycobacterium tuberculosis Strain Aoyama B, on Pulmonary Metastases of B16F10 Melanoma: Restoration of Helper T Cell Responses via Suppression of Glucocorticoid‐Genesis

In the present study, the anti‐tumor mechanism of Z‐100 was investigated with the use of pulmonary metastasis of B16F10 melanoma. In B16F10 mice, Th1 cytokine production (IL‐2, IFN‐γ) was suppressed in comparison with normal mice. On the other hand, Th2 cytokine production (IL‐4, IL‐10) was increased in the B16F10 mice. The administration of Z‐100 to B16F10 mice restored the balance of Th1/Th2 cell responses from the Th2 dominant state to the normal state. Z‐100 significantly suppressed the pulmonary metastasis of B16F10 melanoma in a dose‐dependent manner. These results suggest that Z‐100 restored the breakdown of Th1 cell responses, resulting in the suppression of pulmonary metastasis of B16F10 melanoma. Moreover, Z‐100 decreased the corticosterone levels, which is known to suppress the Th1 cell responses, in both serum specimens and splenic tissue, and the steroidogenic CYP11A1 mRNA expression in CD4+ T cells. These results suggest that a suppression of pulmonary metastasis and restoration of Th1/Th2 cell responses by Z‐100 may be due to the decrease in the corticosterone levels and the steroidogenic CYP11A1 mRNA expression of CD4+ T cells in B16F10 mice. Further, the role of Th1 cytokine, IFN‐γ, on these activities of Z‐100 was examined. The suppressive effects of Z‐100 on pulmonary metastasis and restoration of Th1/Th2 cell responses were eliminated by the administration of anti‐IFN‐γ mAb. Moreover, the suppressive effects of Z‐100 on glucocorticoid‐genesis were eliminated by the administration of anti‐IFN‐γ mAb. These results suggest that Z‐100 restores the balance of Th1/Th2 cell responses via the suppression of glucocorticoid‐genesis by Z‐100‐induced IFN‐γ. IFN‐γ acts as a key cytokine in anti‐tumor activities of Z‐100.

Z-335, a new thromboxane A2 receptor antagonist, prevents arterial thrombosis induced by ferric chloride in rats

We examined the antithrombotic effect of Z-335 ((+/-)-sodium [2-(4-chlorophenylsulfonylaminomethyl)indan-5-yl]acetate monohydrate), an orally active thromboxane A(2) receptor (TP-receptor) antagonist that ameliorates experimental gangrene, using a rat arterial thrombosis model. The thrombi were induced by topical application of 50% ferric chloride solution to the rats abdominal artery. Z-335 (0.3-3 mg/kg, p.o.) inhibited thrombus formation in a dose-dependent manner. The antithrombotic effect of Z-335 (1 and 3 mg/kg, p.o.) was almost equivalent with that of cilostazol (100 mg/kg, p.o.), a selective phosphodiesterase type III inhibitor. The effect of Z-335 (3 mg/kg, p.o.), but not cilostazol, persisted for 16 h. Z-335, but not cilostazol, inhibited platelet aggregation induced by U-46619 (a TP-receptor agonist, 9, 11-dideoxy-9alpha,11alpha-methanoepoxy prostaglandin F(2alpha)) for 16 h in rat whole blood. Histopathological examination also revealed that Z-335 prevented ferric chloride-induced thrombus formation. These results suggest that Z-335 may prevent ferric chloride-induced arterial thrombosis through its antiplatelet action by blocking TP-receptor activation.

The anticonvulsant effect of citalopram on El mice, and the levels of tryptophan and tyrosine and their metabolites in the brain.

Serotonin (5-HT) plays an important role in the seizures of El mice since the seizure threshold of El mice correlates with the 5-HT concentration in the central nervous system. In this study, the anticonvulsant effect of a 5-HT reuptake blocker, citalopram, was evaluated behaviorally and biochemically. El mouse convulsions were inhibited by oral administration of citalopram for 2 weeks. Citalopram increased tryptophan and tyrosine amounts, and decreased the 5-HT, 5-hydroxy-indoleacetic acid, kynurenine, and dopamine amounts in the brain. These findings show that citalopram depresses monoaminergic metabolism. Given the known convulsant effect of kynurenine, it is suggested that its decrease by citalopram may involve attenuation of El mice seizures.

Synthesis and thromboxane A2 antagonistic activity of indane derivatives

Abstract A new series of indane derivatives were prepared and evaluated for their thromboxane A 2 (TXA 2 , 1 ) antagonistic activity. Among these compounds, 24a (Z-335) was found to be a potent TXA 2 antagonist in oral administration.

Dual-acting agents with α1-adrenoceptor antagonistic and steroid 5α-reductase inhibitory activities. Synthesis and evaluation of arylpiperazine derivatives

A series of arylpiperazine derivatives were prepared and evaluated for their alpha1-adrenoceptor antagonistic activities and 5alpha-reductase inhibitory activities. SAR study led to the identification of the potent dual-acting compound 2f, which had a pA2 value of 7.5 for alpha1-adrenoceptor antagonism and an IC50 value of 1.5 nM for 5alpha-reductase inhibition.

ATP-Dependent Transport of a Novel Thromboxane A2 Receptor Antagonist, [2-(4-Chlorophenylsulfonylaminomethyl)-Indan-5-yl]Acetate (Z-335) and Its Xenobiotic Taurine Conjugate (Z-335-Tau) by Rat Bile Canalicular Membrane Vesicles

AbstractPurpose. The characteristics of bile canalicular transport processes for xenobiotic taurine conjugates have not yet been clarified. To elucidate the biliary excretion characteristics of xenobiotic taurine conjugates, we investigated the transport of a novel thromboxane A2 receptor antagonist, Z-335, and its taurine conjugate (Z-335-Tau) across the bile canalicular membrane. Methods. We examined the uptake of Z-335 and Z-335-Tau by isolated bile canalicular membrane vesicles (CMVs) from Sprague Dawley and Eisai-hyperbilirubinemic rats (EHBRs) which EHBRs have a hereditary defect of canalicular multidrug resistance-associated protein 2 (Mrp2) function. Also, the in vitro and in vivo kinetics of Z-335-Tau uptake and excretion were compared. Results. Z-335 uptake by CMVs from normal rats exhibited marked ATP-dependence, whereas ATP-dependent uptake of Z-335 into CMVs from EHBRs was not observed. In contrast, Z-335-Tau uptake into CMVs from both normal rats and EHBRs was ATP dependent. The initial uptake velocity was concentration-dependent, with an in vitro Michaelis constant for initial uptake of 189 μM, which was similar to the in vivo value. Conclusions. The biliary excretion of Z-335 involves Mrp2, whereas that of Z-335-Tau involves active transport systems that remain intact in EHBRs and show marked ATP dependence, which ATP-dependent transport is involved in the biliary excretion of Z-335-Tau in vivo.

Pharmacodynamic analysis of steroid 5α-reductase inhibitory actions of Z-350 in rat prostate

The pharmacodynamics of (S)-4-[3-[4-[1-(4-methylphenyl)-3-[4-(2-methoxyphenyl)piperazine-1-yl]propoxy]benzoyl]indole-1-yl] butyric acid hydrochloride (Z-350), which has alpha(1)-adrenoceptor antagonistic and steroid 5alpha-reductase inhibitory effects, were investigated in rats. The disposition of Z-350 was a function of linear kinetics at doses from 1 to 30 mg/kg; the bioavailability was calculated to be 65.2%. The inhibition of 5alpha-reductase was dependent on the concentration of Z-350 in plasma and in the prostate. Analysis of the relationship between the concentration in the prostate and the inhibition seen after a single oral administration showed that the Hill constant was almost 1.0 and EC(50)(n(H)) was 47.4 ng/g of tissue; these parameters did not change after multiple administration. Z-350 inhibited 5alpha-reductase 1 h after oral administration at a dose of 3 mg/kg; maximum inhibition was observed after 2-4 h, and the inhibition (%) was maintained for 24 h after oral administration.

Distinct Effects of Z-335, a New Thromboxane A2 Receptor Antagonist, on Rabbit Platelets and Aortic Smooth Muscle

The effect of a novel thromboxane A2 receptor (TP) antagonist, (±)-sodium[2-(4-chlorophenylsulfonylaminomethyl)- indan-5-yl]acetate monohydrate (Z-335), on the U46619-induced responses was compared between rabbit platelets and aorta. Z-335 inhibited platelet shape change induced by U46619 with higher efficacy than SQ29548, a common TP antagonist. The U46619-induced platelet aggregation was inhibited by Z-335 in a noncompetitive manner, while it was competitively inhibited by SQ29548. Z-335 inhibited U46619-induced vasoconstriction of rabbit aorta with higher efficacy than SQ29548. The pA2 value of Z-335 in aortic vasoconstriction was significantly higher than in platelet shape change. The competitive binding study showed the higher pKi value of Z-335 against [3H]-SQ29548 binding in rabbit aortic smooth muscle cells than in platelets. These data suggest that Z-335 has useful characteristics of TP antagonism.