喜树碱前体多相脂体的药理学研究

本文报道了对喜树碱前体(A-CPT)及喜树碱前体多相脂质体(A-CPT-pl)的药理学研究结果。结果表明,A-CPT腹腔注射给药(ip)及经口腔给药(PO),寇氏法求得小鼠的LD50分别为159.3mg/kg及33.7mg/kg,较喜树碱钠盐(CTP-Na)的毒性降低,按最大允许给药容量(0.5ml/10g)ip或PO A-CPT-pl 50mg/kg,在观察期间未见死亡。抑瘤试验结果表明,A-CPT-pl对S180及HepS的抑制率可达74%及82%,可使荷EAC小鼠的生命延长126%;A-CPT对S180及HepS的抑制率可达52%及53%,可使荷EAc小鼠的生命延长54%。肿瘤相伴免疫试验结果表明,每日ip,A-CPT-pl 0.5mg/kg,连续9天,对小鼠肿瘤相伴免疫没有明显影响。     

在体和离体心肌TTC染色的对比研究

比较在体和离体2,3,5-氯化三苯基四氮唑（TTC）染色方式对心肌梗死面积的效果。A组：TTC下腔静脉直接注射染色;B组：心脏切片后染色,染色后计算心肌梗死面积。A组和B组均能较好地标记梗死心肌,且两组梗死面积差异无统计学意义,（44.50±3.10）%VS（46.29±3.2）6%,（P〉0.05）;经下腔静脉直接注射TTC染色法较心脏切片后染色法节省时间和用量,染色效果更好。     

离体和在体大鼠心肌细胞凋亡模型的建立

目的建立离体和在体心肌细胞凋亡模型。方法离体模型:原代培养大鼠心肌细胞进行饥饿处理24 h后,培养液换成Hank's平衡液,同时进行缺氧处理,30 min后恢复到正常氧状态再培养2 h,固定,TUNEL染色,计数凋亡细胞;细胞总DNA抽提,agrose凝胶电泳,观察DNA ladder的产生。在体模型:150 g左右的WKY大鼠麻醉,固定,气管插管,开胸,冠状动脉左前降支结扎30 min,再灌注2 h后,心脏取出,冰冻切片,进行TUNEL染色,观察危险区细胞凋亡。结果原代培养大鼠心肌细胞缺氧/复氧处理引起大量心肌细胞凋亡,TUNEL染色阳性,DNA电泳有明显梯状条带,在体大鼠心脏冠状动脉左前降支结扎/再灌注造成心肌梗死,梗死周边危险区有大量凋亡细胞产生。结论离体细胞缺氧/复氧处理和在体大鼠心脏冠状动脉左前降支结扎/再灌注都能导致心肌细胞发生凋亡,这两种凋亡模型具有操作简单、成功率高等特点,可以用于心肌梗死机制的研究以及保护心肌药物的筛选。     

阿司匹林对在体及离体气管平滑肌的影响

目的 研究阿司匹林对在体及离体气管平滑肌的影响.方法 本次研究对象为2013年~2016年之间接受治疗的80例患者,随机分成观察组(n=25)、实验组(n=25)和对照组(n=30),采用不同剂量的阿司匹林进行治疗,即对照组使用剂量为100mg,观察组使用剂量为200mg,试验组使用剂量为300mg,比较不同剂量的阿司匹林对在体及离体气管平滑肌的影响.结果 对照组与观察组和实验组哮喘持续时间比较呈逐渐缩短趋势,差异有统计学意义P<0.05;对照组与观察组和实验组哮喘恢复时间比较呈逐渐延长趋势,差异有统计学意义P<0.05.对照组与观察组和实验组的张力值比较呈逐渐增长趋势,差异有统计学意义P<0.05;对照组与观察组和实验组的抑制率比较呈逐渐下降趋势,差异有统计学意义P<0.05.阿司匹林的剂量增加,对抗气管平滑肌收缩的作用随之减弱.结论 较为适量的阿司匹林对气管平滑肌的扩张具有较好的作用功效.     

红色牙胶尖充填根管致牙体变色的离体观察

目的：观察红色牙胶尖充填根管后对牙体变色情况的影响。 方法：选择近期拔除的离体恒前牙80颗,随机分为4组。一组充白色牙胶尖作对照组;另三组为实验组,充红色牙胶尖,分别从根管上口以上、根管口以下挖断多余牙胶尖和充填前髓室内涂光固化粘结剂,并从根管口以上挖断多余牙胶尖。结果：实验组发生明显牙体变色（P＜0．001）,不同方法处理的实验组之间牙颈部和牙冠变色情况有明显差异（P＜0．001）,其中从根管口以上挖断多余牙胶而充填前涂光固化粘结剂一组冠颈部变色尤为明显。结论：红色牙胶尖充填根管可致牙体变色,充填前随室内涂布光固化粘结剂能有效防止牙冠变色,提示临床医生充填前牙根管时慎用此类红色牙胶尖或采取防范措施。     

牙体缺损中全冠修复的牙体预备体会

牙体缺损是指各种牙体硬组织不同程度的质地和生理解剖外形的损坏,它常表现为正常牙体形态、咬合及邻接关系的破坏。牙体缺损的修复是用人工制作的修复体恢复缺损牙的形态、外观和功能。用于牙体缺损修复治疗的修复体是人造全冠、部分冠和嵌体。其中,以全冠修复所占比例较大。     

布洛芬离体肝代谢中对映体间的相互作用

目的研究布洛芬离体肝代谢中对映体之间的相互作用。方法用家兔肝匀浆质与单纯的R(- ) 或S(+) 布洛芬以及两对映体以不同比例的混合物 ,加入必要的辅助因子进行离体肝手性转化代谢试验 ,利用立体选择性HPLC法测定各对映体以及中间产物硫酯的质量浓度。结果布洛芬手性转化代谢由R(- ) 型向S(+) 型单向进行 ,在S(+) 布洛芬的存在下 ,R(- ) 布洛芬的转化量减少 ,中间产物硫酯的生成量减少。结论S(+) 布洛芬在一定程度上抑制手性转化的进行     

甾体甲基化转移酶的研究——有关甾体衍生物的合成

目的：研究甾体甲基化转移酶。方法：从γ－ｏｒｙｚａｎｉｏｌ提取的ｃｙｃｌｏａｒｔｅｎｏｌ和２４（２８）－ｍｅｔｈｙｌｅｎｅｃｙｃｌｏａｒｔｅｎｏｌ为初始原料合成目标化合物。结果：成功地合成了１１个甾体衍生物。结论：目标化合物均经ＨＰＬＣ纯化;结构均经ＮＭＲ和ＧＣ／ＭＳ确证,方法简便易行。     

木脂体的生物活性

木脂体广泛分布于植物界,这类化合物已有两百多种。其生物活性直至近来才进行评述,较大的兴趣集中在它们作为抗肿瘤剂的效应上。这方面的研究已显示出它们能调节哺乳动物细胞生长的几种作用方式。木脂体在人体内的各种药理作用是明显的,虽然这些重要作用复杂而不易研究。最近从人体尿液和血液中检出了木脂体,提示需要了解它们在人体生理中可能起的作用。抗肿瘤活性     

四乙铵和4—氨基吡啶增强5—HT3受体介异的离体豚鼠回肠收缩

目的：研究四乙铵（ＴＥＡ）、４－氨基吡啶（４－ＡＰ）对５－ＨＴ３受体介导的豚鼠回肠收缩的影响。方法：等长换能器记录回肠收缩；［＾３Ｈ］ＧＲ６５６３０结合试验测定５－ＨＴ３受体结合特性。结果：ＴＥＡ、４－ＡＰ引起回肠收缩并增强自发活动，被阿托品或ＭＤＬ７２２２阻断，ＴＥＡ、４－ＡＰ增强２－甲基－５－ＨＴ和５－ＨＴ引起的收缩；逆转托烷司琼或Ｂｅｎｅｓｅｔｒｏｎ的抑制作用；不影响卡巴胆碱引起的收缩。ＴＥ     

Rabbit isolated renal artery contractions by some tryptamine derivatives, including 2-methyl-5-HT, are mediated by a 5-HT1-like receptor.

1. Despite the fact that 5-hydroxytryptamine (5-HT)-induced contractions of the rabbit isolated renal artery are mediated by a receptor belonging to the heterogeneous 5-HT1-like category, we observed that the so-called selective 5-HT3 receptor agonist, 2-methyl-5-HT, caused a concentration-dependent contraction of this vessel. This study was therefore undertaken to analyze the effects of 2-methyl-5-HT in the renal artery segments, either quiescent or precontracted with U46619 (10(-7) M). alpha-Methyl-5-HT and 5-methoxytryptamine, which have high affinities for 5-HT2 and 5-HT4 receptors, respectively, were used for comparison. 2. In the precontracted vessel segments, the maximum contractile responses obtained with 2-methyl-5-HT, alpha-methyl-5-HT, 5-methoxytryptamine and 5-HT were similar to those in the quiescent segments. However the pD2 values were higher in the precontracted segments, making them about 4-100 fold more sensitive. 3. Neither MDL 72222 (10(-6) M) nor tropisetron (3 x 10(-6) M) suppressed renal artery contractions elicited by 5-HT, 2-methyl-5-HT, alpha-methyl-5-HT or 5-methoxytryptamine, thus ruling out the involvement of 5-HT3 as well as 5-HT4 receptors. 4. On the other hand, both methiothepin (10(-8) and 10(-7) M) and ketanserin (10(-7) and 10(-6) M) caused a rightward shift of agonist concentration-effect curves.(ABSTRACT TRUNCATED AT 250 WORDS)     

Characterization of the 5-hydroxytryptamine receptor type involved in inhibition of spontaneous activity of human isolated colonic circular muscle.

1. Experiments were carried out to characterize pharmacologically the 5-hydroxytryptamine (5-HT) receptor types which mediate inhibition of spontaneous contractions of the intertaenial circular muscle in human isolated colon. 2. 5-HT caused a reproducible concentration-dependent inhibition of spontaneous contractions of the circular muscle of human colon in vitro with a mean EC50 value of 0.2 microM and 95% confidence limits of 0.1-0.5 microM. No evidence for a contractile action of 5-HT was found. Tetrodotoxin (TTX, 1.5 microM) caused a rightward shift of the concentration-response curve of 5-HT with a concentration-ratio of 2.9. 3. The inhibitory response to 5-HT was mimicked by several indoles with the rank order of potency 5-HT > 5-methoxytryptamine = alpha-methyl-5-HT > 5-carboxamidotryptamine >> 2-methyl-5-HT. 5-Hydroxyindalpine was inactive. 4. The substituted benzamides were agonists with the following rank order of potency, 5-HT > renzapride > zacopride > metoclopramide > cisapride. 5. The inhibitory responses to 5-HT were not inhibited by methysergide (10 microM) or methiothepin (1 microM), which are antagonists selective for 5-HT1-like and 5-HT2 receptors, nor by ondansetron (10 microM) which is an antagonist at 5-HT3 receptors. 6. The inhibitory responses induced by 5-HT and 5-methoxytryptamine were competitively antagonized by a weak 5-HT4 receptor antagonist, tropisetron, with pKB values of approximately 6. Tropisetron had no significant effect on the inhibitory response curve produced by isoprenaline (0.01-100 microM).(ABSTRACT TRUNCATED AT 250 WORDS)     

Investigation into the 5-hydroxytryptamine-induced atropine-resistant neurogenic contraction of guinea-pig proximal colon.

1. The aim of this study was to characterize the receptors mediating the atropine-resistant neurogenic contraction to 5-hydroxytryptamine (5-HT) in the longitudinal muscle of the guinea-pig proximal colon and to determine the type of tachykinin receptors involved in the contractile response to 5-HT by the use of selective antagonists. 2. In the presence of atropine (0.3 microM), guanethidine (5 microM), hexamethonium (100 microM), ketanserin (0.1 microM) and indomethacin (3 microM), 5-HT (0.01-3 microM) produced concentration-dependent neurogenic contractions of colonic strips and at 0.3 microM produced a maximal effect (pEC50 = 7.39 +/- 0.09, n = 18). The 5-HT4 receptor stimulant, 5-methoxytryptamine (5-MeOT, 0.03-10 microM) also produced neurogenic contractions with similar maximum effect to those of 5-HT (pEC50 = 6.89 +/- 0.16). 3. The 5-HT4 receptor antagonist, DAU 6285 (3 microM) shifted the concentration-response curves to both 5-HT and 5-MeOT to the right without significant depression of the maximum, but the 5-HT1/5-HT2 receptor antagonist, metitepine (0.1 microM) and the 5-HT3 receptor antagonist, ondansetron (0.3 microM) had no effect on the control curves to 5-HT and 5-MeOT. 4. The selective NK1 receptor antagonist, FK 888 (1 microM) markedly attenuated the contractions to 5-HT and 5-MeOT. In contrast, the selective NK2 receptor antagonist, SR 48968 (10 nM) and the selective NK3 receptor antagonist, SR 142801 (10 nM) had no effect on the contractions to 5-HT and 5-MeOT. 5. These results indicate that the 5-HT-induced atropine-resistant neurogenic contraction of guinea-pig proximal colon is due to activation of 5-HT4 receptors, presumably located on excitatory motor neurones, innervating the longitudinal muscle. The contraction evoked by activation of the 5-HT4 receptors is mediated primarily via NK1 receptors but not NK2 or NK3, suggesting that the 5-HT4 receptor-mediated contraction is evoked indirectly via tachykinin release from tachykinin-releasing excitatory neurones.     

5-HT3 receptors augment neuronal, cholinergic contractions in guinea pig trachea European Journal of Pharmacology, 234 (1993) 109–112

Serotonin (5-HT) and the selective 5-HT₃ receptor agonist, 2-methyl-5-hydroxytryptamine enhanced electrical field stimulated contractions of the isolated guinea pig trachea. 5-HT (EC₅₀ = 3.5 μM) was twice as potent as 2-methyl-5-hydroxytryptamine (EC₅₀ = 7.4 μM). The effects of 5-HT and 2-methyl-5-hydroxytryptamine were antagonized by the selective 5-HT₃ receptor antagonist, zacopride (apparent pA₂ = 7.60 against 2-methyl-5-hydroxytryptamine). 2-Methyl-5-hydroxytryptamine (10 μM) had no effect on contractile responses to exogenous acetylcholine. Furthermore, the increase in electrical field stimulated contraction by 2-methyl-5-hydroxytryptamine was unchanged by hexamethonium (100 μM) but contractions were blocked by atropine (1 μM). These results suggest that excitatory 5-HT₃ receptors exist on postganglionic cholinergic nerves in the isolated guinea pig trachea.     

5-HT3 receptor antagonists injected into the area postrema inhibit cisplatin-induced emesis in the ferret.

1. The purpose of the present study was to identify and investigate the role of 5-hydroxytryptamine3 (5-HT3) receptors in the area postrema in the control of cisplatin-induced emesis in the ferret. 2. Homogenate binding and autoradiography experiments using the high affinity 5-HT3 receptor ligand, [3H]-GR65630, identified the presence of a high concentration of 5-HT3 receptors in the area postrema of the ferret. 3. Intraperitoneal injection of the 5-HT3 receptor antagonists, GR38032F, GR65630A and MDL72222, at doses of 1, 0.1 and 1 mg kg-1 respectively, inhibited emesis induced by cisplatin, 9 mg kg-1 i.p. 4. Discrete injection of low doses of the 5-HT3 receptor antagonists directly into the area postrema region also inhibited cisplatin-induced (9 mg kg-1 i.p.) emesis. The dose ranges used were: GR38032F, 0.01-1 microgram; GR65630A, 0.001-0.1 microgram; MDL72222, 0.1-10 micrograms. 5. Cisplatin-induced emesis was not inhibited by discrete injection of ketanserin (30 micrograms) or methiothepin (30 micrograms) into the area postrema. Injection of the 5-HT3 receptor agonist, 2-methyl-5-HT, directly into the area postrema produced an incomplete emetic response. 6. These results confirm a role of 5-HT, and in particular 5-HT3 receptors, in the control of cisplatin-induced emesis, and show that at least one functional site for these receptors in modulating the emetic response is the area postrema, the locus of the chemoreceptor trigger zone.     

5-Hydroxytryptamine receptors that facilitate excitatory neuromuscular transmission in the guinea-pig isolated detrusor muscle.

1. In isolated detrusor strips from the guinea-pig urinary bladder, contractile responses to electrical field stimulation were mostly mediated by neurally released acetylcholine (ACh) and adenosine 5'-triphosphate (ATP). 2. 5-Hydroxytryptamine (5-HT) produced a concentration-dependent increase in the amplitude of stimulated detrusor strip contractions. The 5-HT concentration-response curve showed a biphasic profile: the high potency phase was obtained at sub-micromolar concentrations (10-300 nM), while the low potency phase in the range 1-30 microM. The maximum response of the first phase was 30% of the total 5-HT response. 3. Like 5-HT, the 5-HT3 receptor agonist, 2-methyl-5-hydroxytryptamine (2-methyl-5-HT: 0.3-100 microM), the 5-HT2 receptor agonist, (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI: 30 nM-3 microM) and the 5-HT4 receptor agonist, 5-methoxytryptamine (5-MeOT: 0.1-30 microM) potentiated, though with lower potency, detrusor contractions. The resulting concentration-response curves were monophasic in nature. 2-Methyl-5-HT had a maximum effect comparable to that of 5-HT. By contrast, the maximal effects of DOI and 5-MeOT were only 20% and 30% of that elicited by 30 microM 5-HT, respectively. 4. The 5-HT3 receptor antagonist, granisetron (0.3 microM) had no effect on the high potency phase, but caused a rightward parallel shift of the low potency phase of the 5-HT curve (pKB = 7.3).(ABSTRACT TRUNCATED AT 250 WORDS)     

PHARMACOLOGICAL ANALYSIS OF 5-HYDROXYTRYPTAMINE EFFECTS ON HUMAN ISOLATED URETER

5-Hydroxytryptamine (5-HT) induced concentration-dependent contractions in human isolated ureteral strips in vivo. On the basis of available selective 5-HT agonists and antagonists, we have further investigated the receptors involved. At concentrations from 10 n m to 1 m m, 5-HT induced concentration-dependent contractions. Significant contractions were not observed with 5-HT1Aagonist 8-OH-DPAT (10(-9)-10(-4)m), 5-HT1Dalphaagonist sumatriptan (10(-9)-10(-4)m), 5-HT2agonist DOI (10(-9)-10(-4)m), 5-HT3agonist 2-methyl 5-HT (10(-9)-10(-3)m) and 5-HT4agonist renzapride (10(-9)-10(-3)m) on the human isolated ureter. On the other side, a 5-HT1-likeagonist 5-CT (10(-9)-10(-3)m) produced contractions on the isolated samples. The Emaxdeveloped by 5-CT was significantly smaller than that of the 5-HT (29% of 5-HT). Methithepin, the less selective 5-HT1/2antagonist (10(-9)-10(-6)m), 5-HT3antagonist, ondansetron (10(-9)-10(-5)m) and 5-HT4antagonist DAU 6285 (10(-8)-10(-6)m) did not antagonise the contractile responses to 5-HT. 10(-7)m ketanserin antagonised 5-HT induced contractile responses in ureteral strips. Additionally, combined administration of 5-HT4antagonist DAU 6285 (10(-6)m) and 5-HT1/2antagonist methithepin (10(-6)m) caused a rightward shift of the CRC of 5-HT yielding pEC50values of 4.68+/-0.15. 5-HT-induced contractile responses that were not abolished by TTX and atropine, thus supporting the suggestion that in the human, the contractile responses to cumulative addition of 5-HT of the ureter are not mediated by excitation of cholinergic neurons. In the present study the receptor mediating the contractile response to 5-HT in the human upper ureter could not be clearly designated 5-HT1-like, 5-HT2, 5-HT3or 5-HT4. This study suggests that contractile response to 5-HT in the upper segments of the human ureter appear to be mediated by an atypical 5-HT receptor subtype.     

Mode of action of gingerols and shogaols on 5-HT3 receptors: binding studies, cation uptake by the receptor channel and contraction of isolated guinea-pig ileum

Ginger (rhizomes of Zingiber officinale) has been shown to exert potent anti-emetic properties, but its mode of action has not yet been elucidated. Among its active constituents, [6]-, [8]- and [10]-gingerol as well as [6]-shogaol were shown in different in vivo studies to be at least partly responsible for the drug's anti-emetic properties. In an attempt to gain more insight into the mode of action of these compounds, three different in vitro models were used to investigate their effects on 5-HT(3) receptors (serotonin receptor subtype) in more detail: [(14)C]guanidinium influx into N1E-115 cells which express 5-HT(3) receptors, isotonic contractions of the isolated guinea-pig ileum and equilibrium competition binding studies using a radioactively labeled 5-HT(3) receptor antagonist ([(3)H]GR65630) (3-(5-methyl-1H-imidazol-4-yl)-1-(1-methyl-1H-indol-3-yl)-1-propanone). All four compounds inhibited the [(14)C]guanidinium influx through 5-HT(3) receptor channels as well as contractions of the guinea-pig ileum induced by SR57227A ((4-amino)-(6-chloro-2-pyridyl)l-piperidine hydrochloride), a highly selective 5-HT(3) receptor agonist. Both effects were concentration-dependent, with the following order of potency for both models: [6]-shogaol> or =[8]-gingerol>[10]-gingerol> or =[6]-gingerol. All compounds showed also weak anticholinergic and antineurokininergic activities in the guinea-pig ileum (acetylcholine and substance P are mediators of the 5-HT(3) receptor effect). The vanilloid receptor did not seem to be involved derived from experiments using capsazepine. None of the tested ginger substances, however, was able to displace [(3)H]GR65630 from its binding site (5-HT(3) receptor) neither on intact N1E-115 cells nor on the purified membranes of HEK-293 cells over-expressing the h5-HT(3) receptor. It may be concluded that [6]-, [8]-, [10]-gingerol and [6]-shogaol exert their anti-emetic effect at least partly by acting on the 5-HT(3) receptor ion-channel complex, probably by binding to a modulatory site distinct from the serotonin binding site. This may include indirect effects via receptors in the signal cascade behind the 5-HT(3) receptor channel complex such as substance P receptors and muscarinic receptors; this needs further investigation since ginger is effective against motion sickness which is cured by some vanilloids and by anticholinergics such as scopolamine.     

3H]zacopride: ligand for the identification of 5-HT3 recognition sites

[3H]Zacopride displayed saturable binding to homogenates of the rat entorhinal cortex as measured by the inclusion of the 5-HT3 receptor antagonist BRL43694 in the incubation media. Scatchard analysis indicated a single high affinity binding site (KD 0.76 +/- 0.08 nM, Bmax 77.5 +/- 6.5 fmol (mg protein)-1) with a Hill slope close to unity. Other 5-HT3 receptor antagonists (zacopride, ICS 205-930, GR38032F, GR65630, metoclopramide and cocaine) also competed for the binding site displacing 60% of the total [3H]zacopride binding. 5-HT and 2-methyl-5-HT also were competitive antagonists for [3H]zacopride binding whereas 5-HT1/5-HT2 agonists and antagonists, and agents acting on other neurotransmitter receptors had Ki values greater than 10(-5) M. It is concluded that [3H]zacopride may prove a useful ligand for the study of 5-HT3 recognition sites.