Protective Effects of Diallyl Sulfide, a Garlic Constituent, on the Warm Hepatic Ischemia–Reperfusion Injury in a Rat Model

PURPOSE: The aim of this study is to evaluate the effects of diallyl sulfide (DAS) on the warm hepatic ischemia-reperfusion (IR) injury in a rat model. METHODS: Rats (n = 8-10/group) were subjected to sham operation or warm ischemia (1 h)-reperfusion (3 h) preceded by a single intraperitoneal dose (1.75 mmol/kg) of DAS or vehicle, and relevant biochemical parameters were monitored. RESULTS: Warm IR injury caused a significant increase in the plasma markers of liver injury, which was attenuated by DAS. The hepatoprotective effects of DAS were associated with significant reductions in lipid peroxidation markers and in situ generation of superoxide in the liver and increases in the glutathione levels of the liver and bile, suggestive of an antioxidant effect for DAS. Additionally, DAS caused an almost twofold increase in the protein expression of the liver heme oxygenase-1, an enzyme that confers cytoprotection against oxidative stress. Whereas the total cytochrome P450 remained unchanged, the protein levels and activity of CYP2E1, which plays an important role in the generation of reactive oxygen species, significantly decreased by DAS pretreatment. CONCLUSIONS: DAS protects the liver from warm IR injury by reducing oxidative stress through, at least in part, induction of heme oxygenase-1 and inhibition of CYP2E1.     

The Protective Effect of Radicicol Against Renal Ischemia–Reperfusion Injury in Mice

Overexpression of heat shock protein 70 kDa (HSP70) is known to confer cellular protection against ischemia–reperfusion (I/R) injury. Radicicol, a HSP90 inhibitor, has been reported to induce the expression of HSP70 protein. Here we studied whether radicicol attenuated renal I/R injury in vivo. Treatment of mice with radicicol ameliorated renal I/R injury and increased renal HSP70 mRNA and protein. Administration of radicicol with quercetin, an inhibitor of HSP70 induction, eliminated the renoprotective effect of radicicol. Our results suggest that the up-regulation of renal HSP70 protein by radicicol leads to a novel drug therapy against renal I/R injury.     

Plasma Pharmacokinetics and Tissue Disposition of Novel Dextran–Methylprednisolone Conjugates With Peptide Linkers in Rats

The plasma and tissue disposition of two novel dextran prodrugs of methylprednisolone (MP) containing one (DMP‐1) or five (DMP‐5) amino acids as linkers were studied in rats. Single 5‐mg/kg doses (MP equivalent) of each prodrug or MP were administered intravenously, and blood and tissue samples were collected. Prodrug and drug concentrations were quantitated using HPLC, and noncompartmental pharmacokinetic parameters were estimated. Whereas conjugation of MP with dextran in both prodrugs substantially decreased the clearance of the drug by ～200‐fold, the accumulations of the drug in the liver, spleen, and kidneys were significantly increased by conjugation. However, the extent of accumulation of DMP‐1 in these tissues was substantially greater than that for DMP‐5. Substantial amounts of MP were regenerated from both prodrugs in the liver and spleen, with the rate of release from DMP‐5 being twice as fast as that from DMP‐1. However, the AUCs of MP regenerated from DMP‐1 in the liver and spleen were substantially higher than those after DMP‐5. In contrast, in the kidneys, the AUC of MP regenerated from DMP‐5 was higher than that after DMP‐1 administration. These data suggest that DMP‐1 may be more suitable than DMP‐5 for targeting immunosuppression to the liver and spleen. © 2009 Wiley‐Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 1626–1637, 2010     

Histological Protection by Donepezil Against Neurodegeneration Induced by Ischemia–Reperfusion in the Rat Retina

Although a blockade of acetylcholine esterase has been reported to suppress neuronal cell death induced by exogenous glutamate and β-amyloid, information is still limited regarding the neuroprotective effects of the acetylcholine esterase inhibitor donepezil. We histologically examined the effects of donepezil on neuronal injury induced by ischemia–reperfusion. Intravenous and intravitreous treatment with donepezil 15 min prior to ischemia dramatically reduced the retinal damage. The protective effect of donepezil in the ganglion cell layer was not affected by mecamylamine, a nicotinic acetylcholine-receptor antagonist, nor scopolamine, a muscarinic acetylcholine-receptor antagonist. The protective effect of donepezil in the inner plexiform layer was reduced not by mecamylamine, but by scopolamine. Neostigmine, a choline-esterase inhibitor, and pilocarpine, a muscarinic acetylcholine-receptor agonist, have protective effects in the inner plexiform layer and the inner nuclear layer. These results suggest that not only the activation of acetylcholine receptors but also a mechanism unrelated to acetylcholine-esterase inhibition contribute to the protective effect of donepezil on the ganglion cells in the ischemic–reperfused rat retina. Donepezil may be useful as a therapeutic drug against retinal diseases that cause neuronal cell death such as glaucoma with high intraocular pressure.     

Effects of Diazepam,Phenobarbital,Propranolol,and Cimetidine on Diazepam Oxidizing Isoenzymes in Rat Liver Microsomes

研究地西泮、苯巴比妥、普萘洛尔和西咪替丁对地西泮氧化代谢的影响及其药酶蛋白的初步分析，应用ＨＰＬＣ，ＳＤＳ聚丙烯酰胺凝胶电泳和薄层扫描测定地西泮及其代谢物，并对大鼠肝微粒体和酶蛋白进行分离和含量测定。结果表明地西泮、普萘洛尔和西咪替丁使肝微粒体中Ｐ４５０含量明显降低。地西泮和普萘洛尔明显抑制地西泮Ｃ３羟化活性，大剂量普萘洛尔尚能抑制地西泮Ｎ脱甲基。苯巴比妥明显诱导Ｐ４５０生成，增强地西泮Ｎ脱甲基和Ｃ３羟化酶活性及分子量为５１，０００和５９，０００的电泳蛋白带，而地西泮、普萘洛尔则呈抑制作用。并发现，地西泮Ｎ脱甲基酶活性和分子量为５９，０００蛋白含量呈线性相关（Ｐ＜０．０５），而Ｃ３羟化酶活性则与５１，０００蛋白含量呈线性相关（Ｐ＜０．０１）。因此地西泮Ｃ３羟化代谢可能与５１，０００的Ｐ４５０酶蛋白有关，而Ｎ脱甲基代谢则可能与５９，０００的Ｐ４５０酶蛋白有关。     

Effects of Insulin-Mimetic Vanadyl-Poly(γ-Glutamic Acid) Complex on Diabetic Rat Model

Poly-g-glutamic acid (g-PGA) prepared by fermentation of microbe was used as drug carrier for vanadium sulfate to obtain vanadyl-poly-g-glutamic acid (VO-γ-PGA) complex. The FI-IR spectrum of the complex demonstrated that the expected VO-γ-PGA complex is formed by the coordination of VO^2 + through the side chain carboxylic groups of the γ-PGA. Studies of the complex in treating type I diabetes were carried out on alloxan induced diabetes rats. The results of treating the rats in 2 weeks and then stopping administration for 10 days showed that VO-γ-PGA can effectively lower blood glucose levels of diabetic rats during administration. But after ceasing treatment there were no differences between groups in blood glucose level and water intake. The results of oral glucose tolerance and some serum parameters also demonstrated that VO-γ-PGA was more effective than vanadium sulfate in treating diabetic rats. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99:3041-3047, 2010 Keywords: vanadium; vanadyl sulfate; poly-γ-glutamic acid; vanadyl-poly-γ-glutamic acid; diabetes     

Contribution of TRPV1 Receptor–Expressing Fibers to Spinal Ventral Root After-Discharges and Mechanical Hyperalgesia in a Spared Nerve Injury (SNI) Rat Model

Neuropathic pain induces allodynia and hyperalgesia. In the spared nerve injury (SNI) model, marked mechanical hyperalgesia is manifested as prolongation of the duration of paw withdrawal after pin stimulation. We have previously reported that spinal ventral root discharges (after-discharges) after cessation of noxious mechanical stimulation applied to the corresponding hindpaw were prolonged in anesthetized spinalized rats. Since these after-discharges occurred through transient receptor potential (TRP) V1–positive fibers, these fibers could contribute to mechanical hyperalgesia. Therefore, we examined whether selective deletion of TRPV1-positive fibers by resiniferatoxin, an ultrapotent TRPV1 agonist, would affect the behavioral changes and ventral root discharges in SNI rats. Mechanical allodynia in the von Frey test, mechanical hyperalgesia after pin stimulation, and enhancement of ventral root discharges, but not thermal hyperalgesia in the plantar test, appeared in Wistar rats with SNI. Mechanical hyperalgesia was abolished by treatment with resiniferatoxin, whereas mechanical allodynia was not affected. Moreover, resiniferatoxin eliminated after-discharges completely. These results show that TRPV1-positive fibers do not participate in the mechanical allodynia caused by sensitization of Aβ-fibers, but contribute to the enhancement of after-discharges and mechanical hyperalgesia following SNI. It is suggested that the mechanisms responsible for generating mechanical allodynia differ from those for prolongation of mechanical hyperalgesia.     

Mechanisms of Inhibitory Effects of Breviscapine on Lipid Peroxidation in Rat Brain Mitochondria

本文研究了灯盏花素抑制脂质过氧化的作用机制。大鼠脑线粒体脂质过氧化物用硫代巴比妥酸比色法测定。灯盏花素与铁的螯合活性用差示光谱法测定。黄嘌呤黄嘌呤氧化酶（ＸａｎＸＯ）体系产生的超氧阴离子自由基（Ｏ２）及ＦｅＳＯ４Ｈ２Ｏ２体系产生的羟自由基（·ＯＨ）用比色法测定。结果表明：灯盏花素能有效地抑制ＸａｎＸＯ和ＦｅＳＯ４Ｈ２Ｏ２诱导的脑线粒体脂质过氧化反应，其ＩＣ５０分别为９３０１和６２１８μｍｏｌ·Ｌ－１。灯盏花素也能清除ＸａｎＸＯ体系产生的Ｏ２和ＦｅＳＯ４Ｈ２Ｏ２体系产生的·ＯＨ，其ＩＣ５０分别为３２６３和２０２２μｍｏｌ·Ｌ－１。灯盏花素还具有螯合Ｆｅ２＋的活性。由此可见，灯盏花素是在氧自由基与线粒体膜的反应中（１）·ＯＨ的形成（通过与Ｆｅ２＋螯合）（２）脂质过氧化的启动（通过清除Ｏ２和·ＯＨ）两个环节抑制脂质过氧化反应的。清除氧自由基和与Ｆｅ２＋螯合是灯盏花素抑制脑线粒体脂质过氧化的作用机制     

Protective Effect of Tetrandrine and Fructose-1,6-diphos phate on the Model of Focal Cerebral Ischemia in Rats

以大鼠大脑中动脉阻塞２４小时后的梗塞面积和体积为指标，试验了汉防己碱和１，６┐二磷酸果糖对大鼠局部脑缺血的保护作用。在大脑中动脉阻塞后，汉防己碱７．５，１２．０和１５．０ｍｇ·ｋｇ┐１以及１，６┐二磷酸果糖２００和３５０ｍｇ·ｋｇ┐１分别立即腹腔给药，以剂量依赖方式明显减少大鼠脑的梗塞面积和体积。ＭＫ８０１２．０ｍｇ·ｋｇ┐１亦能减少梗塞面积和体积。汉防己碱和１，６┐二磷酸果糖联合用药所产生的保护作用比任何一药物单用时的保护作用都好，提示汉防己碱和１，６┐二磷酸果糖有协同作用。在大脑中动脉阻塞后１小时和２小时给药，汉防己碱和１，６┐二磷酸果糖仍有脑缺血保护作用，但在梗塞后３小时给药则未见任何保护作用。提示中风或脑缺血后，既非５分钟即不可救药，但亦应尽早用药。实验结果表明汉防己碱和１，６┐二磷酸果糖可能是有希望的脑缺血保护剂。     

Effects of Hepatic Ischemia-Reperfusion Injury on the P-Glycoprotein Activity at the Liver Canalicular Membrane and Blood–Brain Barrier Determined by In Vivo Administration of Rhodamine 123 in Rats

Purpose

To investigate the effects of normothermic hepatic ischemia-reperfusion (IR) injury on the activity of P-glycoprotein (P-gp) in the liver and at the blood–brain barrier (BBB) of rats using rhodamine 123 (RH-123) as an in vivo marker.

Methods

Rats were subjected to 90 min of partial ischemia or sham surgery, followed by 12 or 24 h of reperfusion. Following intravenous injection, the concentrations of RH-123 in blood, bile, brain, and liver were used for pharmacokinetic calculations. The protein levels of P-gp and some other transporters in the liver and brain were also determined by Western blot analysis.

Results

P-gp protein levels at the liver canalicular membrane were increased by twofold after 24 h of reperfusion. However, the biliary excretion of RH-123 was reduced in these rats by 26%, presumably due to IR-induced reductions in the liver uptake of the marker and hepatic ATP concentrations. At the BBB, a 24% overexpression of P-gp in the 24-h IR animals was associated with a 30% decrease in the apparent brain uptake clearance of RH-123. The pharmacokinetics or brain distribution of RH-123 was not affected by the 12-h IR injury.

Conclusions

Hepatic IR injury may alter the peripheral pharmacokinetics and brain distribution of drugs that are transported by P-gp and possibly other transporters.     

Effects of prednisolone on behavior and hypothalamic–pituitary–interrenal axis activity in zebrafish

Prednisolone is a synthetic glucocorticoid used clinically for treating allergies, inflammation, and autoimmune diseases. Long-term prednisolone use has been shown to have negative effects on physiology and mood. We aimed to study the pharmacology and toxicology of glucocorticoid-like drugs by investigating behavioral and hypothalamic–pituitary–interrenal (HPI) axis effects in a zebrafish model. Zebrafish embryos 24 h post fertilization were exposed to 25 μM prednisolone. Their behavior was investigated 5 days post fertilization (dpf), and their HPI axis-related activity and related neurotransmitter levels were investigated 3, 4, 5, and 6 dpf. The behavior results showed that exposure to prednisolone resulted in decreased autonomic activity and low sensitivity to light. qRT-PCR and ELISA results showed decreased activity of the HPI axis and increased secretion of dopamine and serotonin after exposure to prednisolone. This study provides us with new insights into understanding the effects of glucocorticoids on the HPI axis.     

Application of a Combined “Effect Compartment/Indirect Response Model” to the Central Nervous System Effects of Tiagabine in the Rat

Pharmacological inhibition of GABA uptake transporters provides a mechanism for increasing GABAergic transmission, which may be useful in the treatment of various neurological disorders. The purpose of our investigations was to develop an integrated pharmacokinetic–pharmacodynamic (PK/PD) model for the characterization of the pharmacological effect of tiagabine, R-N-(4,4-di-(3-methylthien-2-yl)but-3-enyl)nipecotic acid, in individual rats in vivo. The tiagabine-induced increase in the amplitude of the EEG 11.5–30 Hz frequency band (), was used as pharmacodynamic endpoint. Chronically instrumented male Wistar rats were randomly allocated to four groups which received an infusion of 3, 10, or 30 mg kg ^–1 ml min ^-1 kg^–1, 1.50.1 L kg^–1 and 200.2 min.A time delay was observed between the occurrence of maximum plasma drug concentrations and maximal response. A physiological PK/PD model has been used to account for this time delay, in which a biophase was postulated to account for tiagabine available to the GABA uptake carriers in the synaptic cleft and the increase in EEG effect was considered an indirect response due to inhibition of GABA uptake carriers. The population values for the pharmacodynamic parameters characterizing the delay in pharmacological response relative to plasma concentrations were k_eo=0.030 min ^–1 and k_out=81 min^–1, respectively. Because of the large difference in these values the PK/PD model was simplified to the effect compartment model. Population estimates were E₀=155 6 V, E_max=100 5 V, EC₅₀=287 7 ng ml^–1, Hill factor=1.8 0.2 and k_eo=0.030 0.002 min ^–1. The results of this analysis show that for tiagabine the combined effect compartment-indirect response model can be simplified to the classical effect compartment model.     

Effects of Aspirin and Mefenamic Acid on Soman Poisoning–Induced Neuropathology in Mice

The efficacy of aspirin and mefenamic acid to counteract soman-induced brain damage was investigated in mice. Neuronal damage was evaluated in the hippocampus and amygdala by performing ω3 receptor density measurements and hemalun–phloxin staining. The effect of both drugs on the proliferation of neural progenitors after soman exposure was also assessed. Mefenamic acid aggravated the soman-induced hippocampal neuropathology. On the other hand, aspirin recorded a weak neuroprotective effect in the amygdala. However, this drug also diminished the proliferation of neural precursor cells. The possible neurochemical mechanisms underlying such differences in the efficacy of the two drugs are also reviewed.     

Enhanced Therapeutic Effect of Cytidine-5′ -Diphosphate Choline when Associated with GM1 Containing Small Liposomes as Demonstrated in a Rat Ischemia Model

Purpose. Cytidine-5-diphosphate choline (CDPc) was encapsulated in long-circulating unilamellar vesicles (SUVs) to improve the drug's biological effectiveness. Methods. SUVs made up of diaplmitoylphosphatidylcholine/diaplmitoylphosphatidylserine/ cholesterol (7:4:7 molar ratio) and 8 mol % of ganglioside G_Ml were prepared by extrusion through polycarbonate filters (mean diameter 50 nm). The formulation effectiveness was evaluated by an in vivo model of cerebral ischemia on Wistar rats. Results. The enhanced delivery of CDPc into the brain improved the therapeutic effectiveness of the drug. CDPc-loaded SUVs improved the survival rate of ischemized and reperfused Wistar rats (320-350 g) by -66% compared with the free drug. Liposome formulation was also able to effectively protect the brain against peroxidative damage caused by post-ischemic reperfusion. SUVs lowered the conjugated diene levels of the cerebral cortex. The liposomal delivery system did not alter the distribution patterns in the various cerebral lipid fractions of the drug, radiolabeled with ¹⁴C-CDPc. Conclusions. CDPc-loaded SUVs were able to protect the brain against damage induced by ischemia. A possible clinical application is envisaged.     

Tramacol- induced Physical Dependence and Its Effects on Behavioral Sensitization to Mthamphetamine in Mice

AIM:Tramado is a centrally acting,synthetic analgesic with opioid agonist properties and effects on monoaminergie transmission,It is the unique non-controlled analgesic for the treatment of moderately severe acute or chronic pain.In recent years,however,some epidmiological data indicate that tramadol possess relatively high poly-drug abuse potential.     

Effects of Rhynchophyline on L-type Calcium Channels in Isolated Rat Cortical Neurons During Acute Hypoxia

目的：研究钩藤碱对急性分离的Ｗｉｓｔａｒ大鼠大脑皮层神经元低氧状态下Ｌ型钙通道的作用。方法：细胞贴附膜片钳技术，从－４０ｍＶ去极化至０ｍＶ激活Ｌ型钙通道。结果：低氧可激活皮层神经元Ｌ型钙通道开放，使平均开放时间延长，平均关闭时间缩短，开放概率增加。钩藤碱（１５和３０μｍｏｌ·Ｌ－１）可浓度依赖性抑制低氧状态下此钙通道的激活，缩短其平均开放时间（从８８７ｍｓ缩至３０３ｍｓ和２２３ｍｓ，Ｐ＜０００１），延长其平均关闭时间（从９２３ｍｓ延至３８８４和５４４３ｍｓ，Ｐ＜０００１）并降低其开放概率（从０１４２降至００３１和００２５，Ｐ＜０００１）此作用与维拉帕米（１５μｍｏｌ·Ｌ－１）相似，但稍弱。结论：钩藤碱对低氧大鼠大脑皮层神经元Ｌ型钙通道有阻滞作用，从而降低细胞内钙超载，此为钩藤碱改善低氧性脑代谢紊乱的机制之一     

Effects of indometacin on joint damage in rat and rabbit

目的：研究吲哚美辛（Ｉｎｄ）对关节损伤的影响．方法：检测佐剂性关节炎大鼠（ＡＡ）非致炎侧后足爪容积，ＬＰＳ诱导腹腔巨噬细胞和关节滑膜细胞产生白细胞介素１（ＩＬ１），以及兔滑膜成纤维细胞增殖反应和软骨蛋白多糖的合成．结果：Ｉｎｄ２ｍｇ·ｋｇ－１·ｄ－１ｉｇ９ｄ，可抑制ＡＡ大鼠ｄ１８，ｄ２１，和ｄ２４继发炎症反应，但促进巨噬细胞和滑膜细胞分泌ＩＬ１．Ｉｎｄ１０μｍｏｌ·Ｌ－１体外分别促进ＩＬ１诱导兔滑膜成纤维细胞增殖反应以及抑制关节软骨蛋白多糖合成．结论：Ｉｎｄ不利于关节损伤的修复．     

Isomerization of Asp–Asp Motif in Model Peptides and a Monoclonal Antibody Fab Fragment

Isomerization of aspartyl (Asp or D) residues is a critical degradation route to consider for stable monoclonal antibody formulations. Among the known hotspot sequences, the DD motif is relatively understudied. To gain mechanistic insights, we used model hexapeptides, YADXFK, YADDXK, and DIDDDM, as surrogates for the hotspots in a Fab protein (YADDFK and DIDDDM), to characterize the rate-pH profile of Asp isomerization. Compared with the YADGFK peptide, isomerization of D3 (the first D in the DD pair) in YADDFK was highly pH dependent. Comparison of rate-pH profiles of YADDFK, YADNFK, and YADHFK revealed a charge effect of the n + 1 residue—isomerization rate is accelerated by the positive side chain and reduced by negative side chain at n + 1 residue. Studies on YADDFK, YADDAK, and YADDGK indicated a mutual impact of D3 and D4 on their respective isomerization rates through charge effect. Comparison of rate-pH profile of DIDDDM sequence in peptide models with that in the complementary determining region of the Fab showed a faster rate in the Fab than in peptides, presumably because of contribution from structural factors in the former. © 2012 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:947–959, 2013