In vivo and in vitro anti-tumour activity of dimaprit

Dimaprit, a histamine H2-receptor agonist, injected daily i.p. to fibrosarcoma-bearing mice, induced a decrease in tumour growth and an increase in survival. Dimaprit, added to tumour cell cultures (10(-4) M), inhibited the incorporation of 3H-thymidine while embryonic cell cultures were unaffected. This particular anti-tumour activity is probably H2-independent as histamine and impromidine have no effect on tumour cell cultures.     

Enzymatic sulfation of steroids--XX. Effects of ten drugs on the hepatic glucocorticoid sulfotransferase activity of rats in vitro and in vivo

The effects of ten drugs on hepatic glucocorticoid sulfotransferase activity (HGSTA) were examined in male rats. The enzyme activity per 100 g body weight was elevated 152, 94.9, 140, 140, 73.1, 63.9, 76.9, and 140% after administration of daily i.p. doses of 111 mg spironolactone/kg (6-10 days), 66.7 mg WIN-24540/kg (6-10 days), 150 mg metyrapone/kg (19-31 days), 33.3 mg pentachlorophenol/kg (9-16 days), 16.5 mg aspirin/kg (10-16 days), 90.5 mg alloxan/kg (23.27 days), 104 mg aminoglutethimide/kg (12-20 days), and 16.8 mg propranolol/kg (21-27 days). Shorter experimental periods or lower drug doses caused smaller effects on HGSTA. Most notably, spironolactone (111 mg/kg) and WIN-24540 (66.7 mg/kg) caused 50-75% elevation of HGSTA in 2 days. Effects of WIN-24540, aspirin and pentachlorophenol were due mostly to elevation of hepatic levels of sulfotransferase III (STIII), the glucocorticoid-preferring sulfotransferase of rat liver. Effects of the other test drugs were due to elevation of hepatic levels of sulfotransferases I and II (STI and STII), which much prefer dehydroepiandrosterone as substrate, but also catalyze glucocorticoid sulfation. Enzyme inhibition studies showed that the test drugs interacted with the HGSTA in vitro in a fashion that appeared to be related to the in vivo effects already described. None of the drugs interacted exclusively with STI, STII or STIII in vitro. However, some differences of the strengths of individual drug-sulfotransferase interactions were observed. The drug effects are discussed in relation to drug and glucocorticoid actions.     

2-(2-噻吩)乙胺的合成

目的：改进药物中间体２－（２－噻吩）乙胺的合成方法,使之适合工业化生产。方法：以噻吩为原料,经Ｖｉｌｓｍｅｉｅｒ反应制得噻吩甲醛,再将Ｄａｒｚｅｎ反应、水解、脱羧、与盐酸羟胺缩合等用一锅煮方法制得噻吩－２－乙醛肟,再经Ｒａｎｅｙ Ｎｉ还原得目的物２－（２－噻吩）乙胺。结果：总收率可达７０．０９％,略高于文献。结论：此方法适合工业化生产。     

Selective impairment of atrioventricular conduction by 2-(2-pyridyl)-ethylamine and 2-(2-thiazolyl)-ethylamine, two histamine H1-receptor agonists.

To further characterize the receptor mediating histamine-induced impairment of atrioventricular conduction, the effects of two selective histamine H1-receptor agonists, 2-(2-pyridyl)-ethylamine (PEA) and 2-(2-thiazolyl)-ethylamine (ThEA), were investigated using the isolated guinea pig heart. These effects were compared with those of histamine and other selective agonists. PEA and ThEA produced a weak stimulation of cardiac rate and contractility; however, they produced a marked prolongation of atrioventricular conduction. The orders of relative potencies observed substantiate the hypothesis that H2-receptors mediate the positive inotropic and chronotropic effects and H1-receptors mediate the negative dromotropic effect of histamine.     

DDPH抑制豚鼠单个心室肌细胞L-钙电流和钠电流(英文)

目的:研究1-(2,6-二甲基苯氧基)-2-(3,4-二甲氧基苯乙氨基)丙烷盐酸盐(DDPH)对豚鼠心室肌细胞L-型钙电流和钠电流的作用。方法:全细胞膜片箝技术。结果:(1)DDPH(3-300μmol·L~(-1))浓度依赖性地抑制L-型钙电流,IC_(50)为28.5μmol·L~(-1)(95％可信限:14.3-42.7μmol·L~(-1))。维拉帕米0.3-30μmol/L浓度依赖性地抑制钙电流,IC_(50)为1.8μmol·L~(-1)(95％可信限:1.3-2.3μmol·L~(-1))。美西律100μmol·L~(-1)对钙电流无影响。DDPH30μmol·L~(-1)使用依赖性阻滞钙电流,1Hz时抑制率为58％±13％(n=5,P<0.01),3Hz时为76％±11％(n=5,P<0.01)。(2)DDPH(20-320μmol·L~(-1))浓度依赖性抑制钠电流,IC_(50)为89.0μmol·L~(-1)(95％可信限:68.7-109.3μmol·L~(-1))。美西律抑制钠电流的IC_(50)为32.2μmol·L~(-1)(95％可信限:11.7-52.7μmol·L~(-1))。维拉帕米10μmol·L~(-1)对钠电流无影响(P>0.05).DDPH80μmol·L~(-1)对钠电流无使用依赖性阻滞。结论:DDPH抑制豚鼠心室肌细胞L-型钙电流和钠电流,但抑制钙电流的作用弱于维拉帕米,抑制钠电流的作用弱于美西律。     

Histamine receptors in the guinea pig ileum

Summary Histamine and some related compounds acting selectively on H₂-or H₁-receptors were tested for their ability to contract the guinea pig ileum, in the usual whole ileum preparation and in the longitudinal muscle preparation. The concentrations elicited by histamine in both kinds of preparations were not potentiated by cimetidine or metiamide and were not inhibited by administration of H₂ receptor selective agonists in doses which were subthreshold for contracting the guinea pig ileum; higher doses of the H₂ agonists could actually potentiate the effect of histamine. The results obtained suggest that H₂ receptors with relaxing effect do not occur in the guinea pig ileum or at least that they are not involved in the contraction of the longitudinal muscle layers. The possibility that a sub-type of H₂ receptors with properties different from those of the classical H₂ receptors so far known, exists in the guinea pig ileum, cannot be excluded.     

In vivo diminution by chelators of snake venom-provoked hemorrhage and in vitro inhibition of proteolytic activity

Topical application of alcohol-soluble metal-complexing agents, particularly α-mercapto-β-(2-furyl)acrylic acid (MFA)1, diminished the severity of hemorrhages caused by s.c. injection to mice of thirteen hemorrhagic pit viper venoms and two viper venoms. Metal dependency of the alkaline protease activity ranged from 0 to 100% for these venoms, plus one non-hemorrhagic pit viper venom; MFA completely inhibited this activity in six pit viper and two viper venoms. The presence of zinc-dependent proteases in venoms of Crotalus atrox and Bitis arietans was indicated. Less compelling evidence suggested the presence of zinc metalloproteases in at least 11 of 14 other venoms. The potencies of hemorrhagic and alkaline protease activities were not related in the venoms and we did not investigate if metalloproteases were the targets of chelator antagonism of hemorrhage development. Topically active chelators may be useful as adjunctive therapy in some snake envenomations.     

The interaction of 1-(2(diarylmethoxy)ethyl)aziridines with histamine receptors in the longitudinal muscle strip of the guinea pig ileum.

The time course of the onset and decline of histamine antagonism by 1-(2-(diarylmethoxy)ethyl)aziridines, compounds which could be expected to have H1-receptor alkylating properties, was investigated on the longitudinal muscle strip of the guinea pig ileum. Experiments were performed with normal preparations and with muscle strips pretreated with a prostaglandin synthesis inhibitor in order to prevent spontaneous rise of muscle tone. In contrast to the previously reported observation that antihistaminic potency decreased with prolongation of the preincubation time, histamine antagonism by the aziridine compounds remained at a constant level for more than 60 min in the presence of indomethacin. This indicated that the aziridines are not hydrolyzed either directly in solution or after interaction with the tissue since the supposed hydrolysis product had a significantly lower antihistaminic activity. A comparison between 1-(2-diphenylmethoxy)ethyl)aziridine and diphenhydramine showed the former compound to have a slightly more rapid onset and a considerably more rapid decline of histamine receptor blockade. It was concluded that 1-(2-(diarylmethoxy)ethyl)aziridines did not alkylate the histamine H1-receptor in the longitudinal muscle layer of the guinea pig ileum.     

Neuroprotective activity of selective mGlu1 and mGlu5 antagonists in vitro and in vivo

The neuroprotective potential of allosteric mGlu5 and mGlu1 antagonists such as 6-methyl-2-(phenylethynyl)-pyridin (MPEP)/[(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine (MTEP) and (3-ethyl-2-methyl-quinolin-6-yl)-(4-methoxy-cyclohexyl)-methanone methanesulfonate (EMQMCM), was tested in vitro in organotypic hippocampal cultures and in the middle cerebral artery occlusion model of stroke in vivo. Both classes of agent have high selectivity toward mGlu sub-types and are active in animal models of various diseases indicating satisfactory CNS penetration. In organotypic hippocampal cultures MPEP showed high neuroprotective potency against sub-chronic (12 days) insult produced by 3-NP with an IC50 of c.a. 70 nM. In contrast, although the mGlu1 antagonist EMQMCM was also protective, it seems to be weaker yielding an IC50 of c.a. 1 microM. Similarly, in the transient (90 min) middle cerebral artery occlusion model of ischaemia in rats, MTEP seems to be more effective than EMQMCM. MTEP, at 2.5 mg/kg and at 5 mg/kg provided 50 and 70% neuroprotection if injected 2 h after the onset of ischaemia. At a dose of 5 mg/kg, significant (50%) neuroprotection was also seen if the treatment was delayed by 4 h. EMQMCM was not protective at 5 mg/kg (given 2 h after occlusion) but at 10 mg/kg 50% of neuroprotection was observed. The present data support stronger neuroprotective potential of mGlu5 than mGlu1 antagonists.     

DDPH对豚鼠心室肌细胞延迟整流钾电流两种成分的抑制作用

目的:研究1-(2,6-二甲基苯氧基)-2-(3,4-二甲氧基苯乙氨基)丙烷盐酸盐(DDPH)对豚鼠心室肌细胞快激活(I_(Kr))和慢激活(I_(Ks))延迟整流钾电流的作用.方法:全细胞膜片箝技术.结果:DDPH 0.1-100μmol/L浓度依赖性抑制I_(Kr),I_Kr-tail[IC_(50)(μmol/L)为6.1,95％可信限为(2.8—13.5)].DDPH同时浓度依赖性抑制 I_(Ks),I_(Ks-tail[IC_(50)(μmol/L)为12.5,95％可信限为(4.8-32.2)].DDPH(10 μmol/L)不影响I_(Kr)和I_(Ks)的电压依赖性激活过程,给药前I_(Kr)的半激活电压(V_(1/2),mV)和斜率因子(k,mV)分别为(-21.7±0.8)和(5.9±0.8),给药后分别为(-23.5±2.4)和(8.1±2.2),无统计学意义(P>0.05).用药前后I_(Ks)的半激活电压和斜率因子的差异亦无统计学意义(P>0.05),用药前分别为(27.0±0.8)和(14.9± 0.9),用药后分别为(27.1±0.7)和(16.6±0.8).DDPH(<10μmol/L)可抑制 I_(Kr)和 I_(Ks)的去激活过程,并且加快I_(Kr)的失活.结论:DDPH抑制I_(Kr)和I_(Ks)无选择性.且主要作用于其去激活过程,而非激活过程.DDPH进一步通过加速其失活过程抑制I_(Kr).     

2-(2-噻吩)乙胺的新法合成

噻吩和氯乙酰氯经付-克反应得到2-氯乙酰噻吩,氨解得到的2-氨基乙酰噻吩再用85%水合肼还原得到2-(2-噻吩)乙胺,总收率70%.     

On the interaction of drugs with the cholinergic nervous system—III: Tolerance to phencyclidine derivatives: In vivo and in vitro studies

A possible contribution of metabolic processes to the tolerance to cyclohexamine (l-(l-phenylcyclohexyl) ethylamine) was investigated by determining the kinetics of brain and liver uptake of the labeled drug. A similar time course was found for both naive and tolerant mice. In addition, the amount of the drug uptaken by the brain was found to be linearly dependent on the dose injected in both groups. The possibility of adaptive changes in brain enzymes was investigated using mouse brain acetylcholinesterase (AcChE, E.C.3.1.1.7) as a model of a putative enzyme, affected by phencyclidine derivatives. Although brain AcChE is believed to be chronically affected by these drugs in vivo, no measurable changes could be observed in the amount, the affinity towards diverse ligands or the kinetic properties of this enzyme, between naive, cyclohexamine-tolerant and physostigmine tolerant mice. Possible changes in receptors as the mechanism of tolerance induction were tested by determining the amount of the central muscarinic receptor and its affinity towards a highly specific antimuscarinic ligand in vitro. When comparing naive animals to mice tolerant to cyclohexamine, physostigmine and oxotremorine, no measurable differences could be found in any of these parameters. Repeated injections of cyclohexamine together with scopolamine prevented tolerance development to the former. The possibility of homeostatic events as tolerance mechanism is presented and discussed.     

In vivo and in vitro metabolism of 2-methylnaphthalene in the guinea pig

The metabolism of 2-methylnaphthalene (2-MN) in guinea pigs (in vivo and in vitro) was investigated. Excretion of 2-MN from guinea pigs took place rapidly. In the first 24 hr, nearly 80% of the orally administered 2-[3H]-MN was excreted in the urine in the form of several metabolites, and about 10% of it was recovered in the feces. The major metabolites in the urine were oxidative products of the methyl group of 2-MN (naphthoic acid and its glycine and glucuronic acid conjugates) and accounted for 76% of the total urinary radioactivity in the first 24 hr. S-(7-Methyl-1-naphthyl)cysteine and glucuronic acid and sulfate conjugates of 7-methyl-1-naphthol were also identified as minor metabolites (18% of the total urinary radioactivity). As an in vitro metabolite, the formation of S-(7-methyl-1-naphthyl)glutathione was indicated using the 9,000g supernatant of the homogenate of guinea pig liver. The oral administration of 2-MN (500 mg/kg) to guinea pigs significantly lowered the trichloroacetic acid-soluble sulfhydryl content in the liver.     

Pharmacological activities of Lantana trifolia on isolated guinea pig trachea and rat phrenic nerve diaphragm

A methanol extract of L. trifolia produced bronchodilation of isolated guinea pig trachea comparable to that of salbutamol. The plant extract reduced bronchoconstriction induced by histamine, 5-HT and acetylcholine on isolated guinea pig trachea. Physostigmine failed to inhibit neuromuscular blocking activity of the extract on rat phrenic nerve diaphragm.     

Cloning and sequence of guinea pig interleukin 2 (IL-2)

Interleukin 2 (IL-2) is a T-cell proliferation factor released from TH0- and TH1-type helper T-cells and is an essential cytokine for certain immune responses. We reported here cloning and sequence of IL-2 cDNA in guinea pigs, which have been used for a long time in various immunological experiments and in vivo screening tests for skin sensitization potential of chemicals. Consequently, a cDNA clone was obtained encoding guinea pig IL-2 of 520 bp in length, which contained a complete open reading frame. Alignment of the amino acid sequence with human IL-2 indicates that guinea pig IL-2 is composed of 20 amino acids (aa) of a signal peptide and 132 aa of a mature peptide with a predicted molecular weight of 15 133. Guinea pig IL-2 has an amino acid homology of 62% with human IL-2, 52% with murine IL-2, and 55% with rat IL-2. In addition, guinea pig IL-2 has a possible N-linked glycosylation site as seen in bovine and porcine IL-2. Received: 8 April 1998 / Accepted: 1 July 1998     

Comparison of the antiviral effects of substituted benzimidazoles and guanidine in vitro and in vivo

6-[[(Hydroxyimino)phenyl]methyl]-1-[(1-methylethyl)sulfonyl]-1H-benzimidazole-2-amine (LY-122771-72) was substantially more active (and more toxic) than 2-(α-hydroxybenzyl) benzimidazole (HBB) and guanidine-HC1 in a microtiter assay system employing the inhibition of the cytopathic effect produced by 13 enteroviruses. In cell cultures HBB and guanidine were mutually ‘synergistic’ for each other but neither had a similar effect on LY122771-72 or its close relative LY127123. A mixture of HBB and guanidine when injected into infant mice would save them from the lethal effects of infections with coxsackie A9 and echo 9 viruses. It was further found that the substituted benzimidazoles LY122771-72 and LY127123, when given daily for 9 days, could save significant numbers of mice from death caused by echo 9, coxsackie A9 and A16 viruses. HBB alone was significantly effective in the treatment of mice infected with echo 9 and coxsackie A9 but not coxsackie A16 virus. Guanidine alone was effective treatment for mice infected with either echo 9 or coxsackie A16 viruses with striking activity against this latter infection, requiring only a 4 day treatment starting 58 h after virus inoculation.     

Tachyphylaxis to beta-adrenoceptor agonists in guinea pig airway smooth muscle in vivo and in vitro.

Beta-Adrenoceptor tachyphylaxis was induced by incubating spirally cut guinea pig tracheas with isoproterenol (2.4 x 10(-7) M) for 20 min. This incubation reduced the relaxant effects of catecholamines but not of dibutyryl cyclic AMP, theophylline or sodium nitrite. Tracheas incubated with norepinephrine, phosphodiesterase inhibitors or cyclic nucleotides became tachyphylactic to isoproterenol. Pretreatment with indomethacin prevented induction of tachyphylaxis. Incubation with adenosine, methoxamine or sodium nitrite did not induce beta-adrenoceptor tachyphylaxis. When we gave isoproterenol intramuscularly to guinea pigs, airway sensitivity to aerosolized histamine was unchanged but the toxicity of parenterally administered histamine was increased. A prolonged treatment with isoproterenol reduced airway sensitivity to histamine aerosols; this reduced sensitivity was reversed by indomethacin. Thus, beta-adrenoceptor tachyphylaxis may not explain increased toxicity of parenteral histamine after isoproterenol treatment. Elevated levels of cyclic AMP and an increased synthesis of prostaglandins may result in diminished response to beta-receptor stimulation.     

Anti-asthmatic effects of Perilla seed oil in the guinea pig in vitro and in vivo

The aim of this study was to investigate the anti-asthmatic effects of Perilla seed oil in vitro and in vivo in sensitized guinea pigs. Aerosolized antigen caused an immediate bronchoconstriction. Perilla seed oil per os inhibited the increase in lung resistance and the decrease in dynamic lung compliance in a dose-dependent manner with an ED50 (95 % confidence interval, CI) of 1.10 (0.98 - 1.24) g/kg and 1.07 (0.94 - 1.22) g/kg, respectively. Infiltration of leukocytes, mononuclear cells, eosinophils and neutrophils induced by inhaling antigen was also inhibited by Perilla seed oil in a dose-dependent manner with an ED50 (95 % CI) of 1.00 (0.86 - 1.15), 1.24 (1.10 - 1.38), 0.63 (0.51 - 0.77) and 0.61 (0.38 - 0.98) g/kg, respectively. Perilla seed oil (5 - 500 microg/mL) inhibited the slow reaction substance of anaphylaxis (SRS-A) release induced by antigen challenge in lung tissue of sensitized guinea pigs. It also inhibited calcium ionophore (A(23187))-induced leukotriene (LT) D4 release from the lung tissue of non-sensitized guinea pigs in a concentration-dependent manner with an IC50 (95 % CI) of 50 (36 - 69) microg/mL. These results indicate that Perilla seed oil may improve lung function in asthma by controlling eicosanoid production and suppressing LT generation.     

In vitro and in vivo effects of SCA40 on guinea pig airways

SCA40 (6-bromo-8-methylaminoimidazo[1,2-a]- pyrazine-2-carbonitrile), a compound which had been described as an opener of Ca²⁺-dependent large conductance potassium channels (BK_Ca channels), was investigated in comparison with salbutamol for in vitro and in vivo bronchospasmolytic effects and for the ability to reverse airways hyperreactivity in guinea pigs. SCA40 reduced the spontaneous tone of isolated guinea pig tracheal rings with a biphasic concentration-response curve (first phase: pD₂ = 8.0, E_Max = 29.7% of maximal effect; second phase: pD₂ = 6.4, E_Max = 72.6%). The salbutamol curve was monophasic (pD₂ = 8.0, E_Max = 100%). Total lung resistance (R_L) was determined in anaesthetized, ventilated guinea pigs. Bronchoconstriction, measured as an increase in R_L, was elicited in normoreactive animals by i.v. infusion of bombesin (100 ng/kg/min) or by i.v. injection of histamine (1.8–5.6 μg/kg). Airways hyperreactivity was induced by acute i.v. administration of pre-formed immune complexes. Intravenous bolus injections of histamine (2.4 μg/kg) were used to define the sensitivity of the airways prior to and after the exposure to immune complex. Following intratracheal (i.t.) administration, SCA40 reversed bombesin-induced bronchoconstriction with an ED₅₀ of 43 μg/kg (E_Max = 57%). The ED₅₀ for salbutamol was 0.8 μg/kg i.t. (E_Max = 78%). Histamine-induced bronchoconstriction in hyperreactive guinea pigs was inhibited by SCA40 with an ED₅₀ of 13 μg/kg i.t. (E_Max = 82%). Salbutamol completely inhibited histamine-induced bronchospasm with an ED₅₀ of 9 ng/kg i.t. In normoreactive guinea pigs, SCA40 prevented histamine-induced bronchoconstriction with an ED₅₀ of 100 μg/kg i.t.; for salbutamol the ED₅₀ in this test was 0.48 μg/kg i.t. Thus, for both SCA40 and salbutamol, the effects obtained at low doses in hyperreactive guinea pigs represent a true reversal of airways hyperreactivity, whereas at higher doses, anti-hyperreactive and bronchospasmolytic properties may account for the observed effects. In conclusion, SCA40 relaxes guinea pig airways smooth muscle in vitro and in vivo, and it partly reverses airways hyperreactivity. With respect to both potency and efficacy, SCA40 is markedly less active than the β-adrenoceptor agonist salbutamol. Received: 23 August 1996 / Accepted: 11 October 1996