千金藤啶碱对大鼠脑内单胺代谢的影响

1-千金藤啶碱(1-SPD 15～120 mg/kg)能增加大鼠纹状体和边缘区的多巴胺代谢物DOPAC和HVA(+150～300%),并有剂量相关关系。此作用于给药后60 min达峰值,给药后4 h虽有恢复趋势,但仍明显高于对照值。SPD还能中等度地降低上述两个脑区的DA和NA(-18～48%)。DA转换率(表现为代谢物增加)的升高支持SPD为DA受体阻断剂。但DA和NA下降表明,除有受体阻断作用外,不能排除药物对单胺递质的贮存、释放或再摄取的影响。纹状体内的5-HIAA含量亦有明显升高。     

千金藤啶碱对大鼠脑内单胺代谢的影响

1-千金藤啶碱(1-SPD 15～120 mg/kg)能增加大鼠纹状体和边缘区的多巴胺代谢物DOPAC和HVA(+150～300%),并有剂量相关关系。此作用于给药后60 min达峰值,给药后4 h虽有恢复趋势,但仍明显高于对照值。SPD还能中等度地降低上述两个脑区的DA和NA(-18～48%)。DA转换率(表现为代谢物增加)的升高支持SPD为DA受体阻断剂。但DA和NA下降表明,除有受体阻断作用外,不能排除药物对单胺递质的贮存、释放或再摄取的影响。纹状体内的5-HIAA含量亦有明显升高。     

高效液相色谱法测定苦参素分散片的含量

目的 建立高效液相色谱法测定苦参素分散片含量的方法。方法 以Phenomenex C₁₈柱为固定相;流动相0.02mol·L^-1磷酸二氢钠溶液(pH3.5)-甲醇(90∶10);流量1.0ml·min^-1;检测波长220nm。结果 氧化苦参碱与氧化槐果碱分离良好,氧化苦参碱在0.04～0.16mg·ml^-1浓度范围内呈良好的直线关系,平均回收率为99.4%,RSD为0.78%(n=9)。结论 该方法简便、灵敏、准确、重复性好,可用于该制剂的质量控制。     

槐定碱的气相色谱测定法及其在兔体内的药代动力学

兔血浆中槐定碱的气相色谱测定条件:氮气、氢气和空气的流速分别为60,40和380ml/min。填充柱、进样室和检测室温度分别为190,280和300℃。内标物为槐胺碱,血浆中槐定碱浓度为3.0和10.0μg/ml时,测得回收率分别为103.6±2.4%(CV=2.34%)和101.5±6.5%(CV=6.35%)。线性范围为1～15/μg/ml。槐定碱在兔体内的药代动力学按二房室拟合,其混合参数值:α.0.0864 min^-1;β.0.00932 min^-1;Vc.1.19 L/kg;V_area.2.07 L/kg;V_dvv.1.99L/kg;Cl.19.3 ml/min·kg;MRT.103min。     

HPLC-MS法同时测定大鼠血浆中苦参碱、氧化苦参碱和氧化槐果碱的浓度及其药代动力学

建立同时测定大鼠灌胃给予三物黄芩汤后血浆中苦参碱、氧化苦参碱和氧化槐果碱含量的HPLC-MS分析方法，并计算了3种生物碱在大鼠体内的药代动力学参数。血浆样品经氯仿液-液萃取后，以乙腈-0.1%甲酸水溶液(10∶90)为流动相，用Kromasil C₁₈色谱柱(4.6 mm×150 mm， 5 μm)分离， 采用电喷雾离子化源(ESI)单重四极杆串联质谱， 以选择离子检测(SIM)方式进行检测。苦参碱、 氧化苦参碱和氧化槐果碱分别在10～5 000 ng·mL^-1、 2～1 000 ng·mL^-1和2～1 000 ng·mL^-1呈良好线性关系，提取回收率分别为89.1%～93.5%、83.9%～91.3 %、85.4%～88.0%。日内及日间精密度均<15%。该法快速，灵敏，专属，适用于同时测定生物样本中苦参碱、氧化苦参碱和氧化槐果碱的血药浓度。     

槐果碱对HERG钾通道电生理功能的影响

HERG(human ether-a-go-go-related gene)钾通道在心律失常的发生及治疗中具有重要作用， 因此已成为近些年来的研究热点。本研究应用全细胞膜片钳技术记录在HEK(human embryonic kidney) 293细胞上稳定表达的HERG钾通道的电流和动力学曲线(激活、 失活、 复活和去活化)来研究不同浓度槐果碱对HERG电流及动力学曲线的影响， 以了解槐果碱抗心律失常的作用机制。结果表明， 槐果碱浓度依赖性地抑制HERG时间依赖性电流(I_step)及其尾电流(I_tail)。在0 mV时， 10、 30、 100及300 μmol·L^-1槐果碱对I_step的抑制率分别为(10.7±2.8)%、 (11.3±5.5)%、 (47.0±2.3)%及(53.7±2.5)%， 对I_tail的抑制率分别为(1.1±3.0)%、 (17.1±3.3)%、 (32.7±1.9)%(P<0.05， n=12)及(56.0±2.4)%(P<0.05， n=13)。100 μmol·L^-1槐果碱作用后失活时间常数减小， 失活速率变快；复活时间常数在大部分指令电压下明显减小(P<0.01， n=12)，复活速度加快；瞬时失活时间常数减小(P<0.05， n=12)；稳态激活、去活化无明显改变。由此可看出，槐果碱通过影响通道的失活过程抑制HERG钾电流，使得心肌细胞复极时间延长，改善快速性心律失常。     

用在体脑微透析技术研究大鼠纹状体中单胺递质的释放和代谢

采用脑微透析技术与高效液相色谱-电化学检测器联用测定了清醒自由活动大鼠纹状体细胞外液中多巴胺(DA)及其酸性代谢物3,4-二羟苯乙酸(DOPAC)和高香草酸(HVA)以及5-羟色胺代谢物5-羟吲哚乙酸(5-HIAA)的含量.透析液中DA为0.44 pmol/40μl,DOPAC和HVA含量较DA高约80倍.右旋苯丙胺2 mg/kg,ip使纹状体DA释放显著增加,DOPAC和HVA含量明显下降.     

苦参碱类生物碱的镇痛作用研究进展

苦参碱类生物碱（包括有苦参碱、氧化苦参碱、氧化槐定碱、槐果碱、氧化槐果碱等）具有镇痛作用,镇痛特征是以中枢性为主、无成瘾性和耐药性,综述其镇痛作用及作用机制研究进展。苦参碱类生物碱的中枢性镇痛作用机制可能是：激活大麻素受体-2和上调电压门控钙离子N-型通道表达,促进抑制性神经递质（γ-氨基丁酸、甘氨酸）合成和释放,下调GAT-1表达,使突触间隙γ-氨基丁酸浓度升高以及上调γ-氨基丁酸-A受体表达,从而增强γ-氨基丁酸能神经功能。γ-氨基丁酸能神经功能的增强可抑制兴奋性神经递质谷氨酸过度表达并下调NMDA受体和蛋白激酶Cγ表达,降低NMDA受体对谷氨酸的兴奋性,从而下调电压门控钙离子L-型通道的表达,抑制钙离子内流,阻滞CaMKⅡ/CREB通路,减轻炎症反应和产生镇痛作用。     

DL-四氢巴马汀对大鼠单胺的排空作用

DL-四氢巴马汀(THP)是中药延胡索的有效成分,具有镇静、安定、镇痛和温和降压等作用。本文用高压色谱并用电化学检测器法研究了THP对大鼠单胺代谢的影响。THP60mg/kg能降低三种单胺介质的含量:DA(-70%),NA(-50%),5-HT(-30%)。它们的酸性或中性代谢物HVA,DOPAC,MHPG-SO₄和5-HIAA含量显著升高(+200～300%)。而DA的甲基化代谢物3-甲氧基酪胺(3-MT)含量明显减少。DA酸性代谢物的升高和DA被COMT甲基化的代谢物3-MT的降低,皆表示DA被排空和导致DA能系统功能的低落。可以得出结论,THP是一个短效单胺排空剂。     

砂生槐子总生物碱水剂和生物黏附片的pH转换两步溶出实验及药动学研究

目的 比较砂生槐子总生物碱水剂和片剂的体内外性质。方法 将砂生槐子制备成总生物碱浸膏,再用生理盐水稀释成水剂;通过体外黏附力考察筛选出生物黏附材料海藻酸钠、卡波姆的最佳比例,制备砂生槐子总生物碱生物黏附片。采用体外pH转换两步（pH值分别为1.4、6.5）溶出实验评价砂生槐子总生物碱水剂和片剂在胃肠道中的扩散行为。将20只SD大鼠随机分为2组,每组10只,分别ig给予砂生槐子总生物碱片剂和水剂,给药剂量均为7 mg·kg⁻¹,于给药后0.25、0.50、1.00、2.00、3.00、4.00、5.00、6.00、8.00、10.00、12.00、24.00、36.00、48.00 h取血200～400 μL于EDTA-Na₂制备好的离心管中,分离血浆,超高效液相色谱（UHPLC）法检测苦参碱、氧化苦参碱、槐定碱的质量浓度。结果 海藻酸钠与卡波姆的比例为2∶1时,离体肠组织的黏附力最大,为（563.43±20.38）N。体外pH转换溶出实验显示水剂进入模拟胃液后迅速扩散;片剂在模拟胃液（pH＝1.4）中几乎不溶解,模拟肠液（pH＝6.5）中迅速溶解释放,1 h的累积溶出率在75%以上。药动学实验表明,水剂组的苦参碱、氧化苦参碱、槐定碱的峰浓度（C_max）分别是片剂组的2.2、1.9、2.4倍;水剂组各生物碱的达峰时间（t_max）均显著小于片剂组（P＜0.05）;水剂组氧化苦参碱的血药浓度-时间曲线下面积AUC_0-∞是片剂组的2.5倍、槐定碱的AUC_0-∞是片剂组的3.5倍。结论 砂生槐子生物碱水剂体外迅速扩散,体内生物利用度优于片剂。     

Formation of deaminated metabolites of dopamine in noradrenaline neurons

Summary The deaminated monoamine metabolites 3-methoxy-4-hydroxyphenylethyleneglycol (MOPEG), 3,4-di-hydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were determined electrochemically following organic solvent extraction and reverse-phase, high performance, liquid chromatography in four regions of the mouse brain. In the noradrenaline (NA)-predominant regions (hemispheres, brain stem), the ratio of the concentrations of DOPAC plus HVA to NA plus dopamine (DA) was approximately the same as in the DA-predominant regions (corpus striatum, limbic system). Yohimbine and reserpine elevated the concentrations of DOPAC and HVA both in the NA-and the DA-predominant regions. The effect of yohimbine was somewhat enhanced by the ₁-receptor blocking agent prazosin in the NA-predominant regions. The concentration of MOPEG was increased by yohimbine and decreased by reserpine.The concentrations of DOPAC and HVA were lowered by clonidine, but not by apomorphine in the NA-predominant regions of reserpine-treated mice. In, the DA-predominant regions, apomorphine, but not clonidine, reduced the concentrations of DOPAC and HVA. The effects of clonidine and apomorphine were reversed by yohimbine and haloperidol, respectively.The results indicate that the concentrations of the acid DA metabolites DOPAC and HVA in the NA-predominant regions reflect the rate of synthesis of DA in the NA neurons.     

Time course of bromocriptine induced excitation in the rat: behavioural and biochemical studies

The aim of the present study was to further investigate the behavioural and biochemical pharmacology of the directly acting dopamine (DA) receptor agonist bromocriptine (BRC).BRC produced an initial depression of locomotion followed after about an hour by a weak but significant locomotor stimulation. The stimulation was potentiated by concomitant administration of the D₁ agonist SKF38393.Ex vivo biochemical determinations indicated that reductions in dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) levels occurred in the striatum after BRC injection without a significant change in DA levels, indicating a reduced DA turnover. An increase in 5-hydroxytryptamine (5HT) and 5-hydroxyindoleacetic acid (5HIAA) levels occurred in the striatum leading to a significant increase in turnover (i.e. ratio of 5HIAA to 5HT). Noradrenaline concentrations increased in the striatum. In the cortex, sharp falls in HVA and DOPAC levels without a corresponding change in DA were observed. While there was no significant change in noradrenaline levels in this brain region, an increase in 5HIAA, but not in 5HT, levels occurred. These changes indicate an increase in 5HT turnover (ratio of 5HIAA to 5HT).In vivo dialysis indicated that extracellular levels of DA, DOPAC and HVA in the striata of freely moving rats were sharply reduced for at least 6 h after injection.In vitro binding studies showed that BRC exhibited high (K_i values in low nanomolar range) affinities for DA D_2A, D_2B, D₃, ₁ and ₂ adrenergic receptors together with unexpectedly high affinity (about 1 nM) for 5HT_1A receptors.The data indicate that the initial behavioural depression and later locomotor stimulation induced by BRC are accompanied by a sharp monophasic fall in striatal extracellular DA levels as indicated by dialysis studies. Since the behavioural stimulation was augmented by concomitant D₁ receptor stimulation, the data suggest that the reduced DA turnover is influencing the amount of DA available to stimulate postsynaptic D₁ receptors. However, the biochemical studies indicated that BRC has a high affinity for 5HT_1A receptors and affects the turnover of 5HT in the brain. Thus, the behavioural effects of BRC may depend not only on effects on the DA system but also on 5HT systems.[/p]     

Effect of S-adenosyl-L-methionine on cerebral monoamine turnover after hypoxia in rats

The effects of S-Adenosyl-L-methionine (SAMe) on cerebral monoamine turnover at 60 min of reoxygenation after hypoxia (PaO2, 31-35 mmHg) for 15 min were studied in 44 rats anesthetized with nitrous oxide. The accumulations of monoamine metabolites: 3-methoxy 4-hydroxyphenylglycol (MHPG), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were determined after probenecid. The accumulations of noradrenaline (NA) and dopamine (DA) were also determined after pargyline. In the non-treated group, there was an impairment of degradation of NA to MHPG and of DA to DOPAC or HVA in the control group (no hypoxia). These changes were accompanied by higher levels of NA and DA in the cerebral cortex, hypothalamus and striatum than those of the control group. In the group treated with 100 mg/kg SAMe plus 38 mg/kg mannitol 3 min after the start of reoxygenation, there were no significant changes in these metabolites and amines. Mannitol alone did not cause significant changes. There were no changes in serotonin and 5-HIAA in any of the groups studied. The effects of SAMe were studied in an additional 16 awake rats. MHPG in all regions measured after probenecid in the rats treated with SAMe was higher than that without SAMe. It appears that SAMe ameliorates perturbation of cerebral catecholamine turnover produced by reoxygenation after hypoxia.     

Postmortem instability of dopamine and its metabolites in rat striatum and limbic forebrain.

The level of dopamine (DA) and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 3-methoxytyramine (3-MT) were determined in the brains of rats kept 24 h after death at two different temperatures, 4 degrees C and 22 degrees C. The estimations were carried out in the striatum and limbic forebrain containing: nucleus accumbens, septum, limbic cortex, amygdala, tuberculum olfactorium. Brain tissue of control rats was dissected immediately after decapitation, frozen over solid CO2 and stored at -70 degrees C until assayed. DA and its metabolites were measured, using high-performance liquid chromatography (HPLC) with electrochemical detection. The levels of DA, DOPAC and HVA in the striatum were significantly decreased (from 50% to 80%) when rats were kept 24 h after death. The changes were more pronounced at 22 degrees C than at 4 degrees C. As the decrease in DA concentration was stronger than that of its final metabolite HVA, the ratio of HVA/DA concentration measured as an index of the rate of DA metabolism was even increased (from 8 to 11). Different changes occurred in the limbic region, where the levels of DA and HVA did not change neither at 4 degrees C nor 22 degrees C. The level of intraneuronally formed DA metabolite-DOPAC was elevated (by about 60%). The level of 3-MT, extraneuronally formed DA metabolite, was significantly increased both in the striatum (200%) and limbic DA structures (500%). These data demonstrate regional postmortal differences in stability of DA and its metabolite levels, which are in the striatum temperature-, time-, and storage-dependent. That implicates a careful assessment of postmortem studies when measuring the neurotransmitter dynamics in human necropsy material.     

In vivo effects of some histamine H1-receptor antagonists on monoamine metabolism in the mouse brain

Summary The in vivo effects of four Hr-antagonists, diphenhydramine, chlorpheniramine, mepyramine, and promethazine, on the metabolism of noradrenaline (NA), dopamine (DA), and 5-hydroxytryptamine (5-HT) were investigated in the whole mouse brain. Diphenhydramine and chlorpheniramine had no significant effect on levels of NA, 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG), DA, and 5-HT, but they significantly decreased levels of 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA). In particular chlorpheniramine markedly decreased 5-HIAA levels at doses as low as 1 mg/kg, i. p. Mepyramine significantly decreased 5-HIAA levels but not those of other substances. High doses of promethazine significantly decreased NA levels but markedly increased those of MHPG, DOPAC, HVA, 5-HT, and 5-HIAA. The DA reduction induced by -methyl-p-tyrosine (-MT) was significantly inhibited by diphenhydramine, chlorpheniramine, and promethazine, but the -MT-induced NA decrease was significantly enhanced by promethazine. The 5-HIAA accumulations induced by probenecid were significantly inhibited by chlorpheniramine and mepyramine. These results suggest: (1) Diphenhydramine and chlorpheniramine inhibit the turnover of both DA and 5-HT by blocking their neuronal uptake. (2) Promethazine and mepyramine inhibit DA and 5-HT turnover, respectively, as a result of the inhibition of the uptake mechanism. (3) Promethazine increases NA turnover by enhancing NA release. The discriminative effects of these drugs on the monoamine systems may be related to some differences in their CNS actions. Send offprint requests to K. Saeki at the above address     

Effects of DM-9384, a pyrrolidone derivative, on ischemia-induced changes in the central monoamine systems.

Alterations in brain tissue levels of monoamines and monoamine metabolites were studied in gerbils 60 min after cerebral ischemia induced by 10 min carotid ligation after pretreatment with the antiischemic drug DM-9384 (1, 3, 10, 30 mg/kg, PO). The DA levels decreased in striatum after the ischemia, while cortical and hippocampal DA levels increased. The DOPAC levels increased in cortex, but were essentially unaffected in other regions. The HVA levels increased in all forebrain regions studied. NA levels decreased in hippocampus and superior colliculus, while a general increase in MHPG levels was seen. Decreases in 5-HT levels were seen in all forebrain regions except cortex. The 10 mg/kg and 30 mg/kg doses of DM-9384 counteracted the decrease in striatal 5-HT and hypothalamic MHPG/NA ratio, respectively. Thus pretreatment with DM-9384 exerted minor protective effects on the alterations induced in monoamine systems by transient forebrain ischemia.     

Role of the dopaminergic system in the cataleptogenic action of bulbocapnine

Time courses of the behavioural and biochemical effects of a cataleptogenic dose (50mgkg^?1 i.p.) of bulbocapnine have been studied in the rat. Catalepsy ensues immediately after administration of the drug and lasts 1 h. Concomitant with the onset of catalepsy there is a rise in HVA and DOPAC concentrations in whole and discrete parts of the brain (striatum, limbic system). Dopamine content does not change in whole brain but it decreases in the striatum and increases in the cortex and hippocampus. No significant effects on NA, 5-HT and 5 HIAA concentrations were observed.