微量失血对左肝外叶切除+ 定容失血性休克大鼠生存率的影响

目的:观察在大鼠左肝外叶切除+定容失血性休克模型制作过程中微量失血对最终大鼠生存率的影响。方法:45只SD大鼠按不同的放血比例分为三组,以Wigger改良法建立左肝外叶切除+定容失血性休克模型,严格标化放血前的各项手术操作和观测指标,比较三组大鼠最终生存率的差异。结果:在分别按2.4ml/100g(A组)、2.5ml/100g(B组)、2.6ml/100g(C组)比例定容失血的大鼠模型中,各组大鼠生存率分别为:A组66.67%,B组42.86%,C组7.69%,A、B两组与C组大鼠的生存率相比较存在明显差异(P<0.05)。结论:即使是0.1ml/100g的微量失血对于该模型大鼠的生存率也是有显著影响的,这一点在大鼠的定容失血性休克模型实验中是不应被忽视的。     

Stimulus change dis-habituates operant responding supported by water reinforcers

The present experiment examined whether habituation contributes to within-session decreases in operant responding for water reinforcers. The experiment asked if this responding can be dishabituated, a fundamental property of habituated behavior. During baseline, rats’ lever pressing was reinforced by water on a variable interval 15-s schedule. During experimental conditions, rats responded on the same schedule and a new stimulus was introduced for 5 min at 15, 30 or 45 min into the 60-min session. The new stimulus was extinction, continuous reinforcement or flashing lights in different conditions. Rate of responding primarily decreased within the session during baseline. Introducing a new stimulus sometimes suppressed (extinction, continuous reinforcement) and sometimes increased (flashing lights) responding while it was in effect. The new stimulus increased responding after it ended and before it was presented in the session. The results are incompatible with the idea that non-habituation satiety factors (e.g., cellular hydration and blood volume) contributed to within-session changes in responding. These satiety factors should increase with increases in consumption, decrease with decreases in consumption and remain constant with constant consumption of water. Nevertheless, all stimulus changes increased operant responding for water. These results support the idea that habituation contributes to within-session decreases in responding for water reinforcers.     

The influence of NMDA, a potent agonist of glutamate receptor, on behavioral activity of rats with experimental hyperammonemia evoked by liver failure

Summary. The study was designed to investigate the effects of NMDA receptor agonist on the behavioral activity in rats with experimental hyperammonemia. The experiments were performed on adult male Wistar rats. Experimental hyperammonemia was induced by intraperitoneal injections of tioacetamide (TAA, 200mg/kg) for three consecutive days. Rats treated with saline (0.9%) served as control. Stimulation of the NMDA glutamatergic receptor was evoked by ip. injection of agonist N-methyl-D-aspartate acid (NMDA) in a dose of 30mg/kg thirty minutes before experiments. Memory motivated affectively was evaluated in the passive avoidance responses. The speculative influence of the treatment on anxiety and motor activity was tested in elevated plus-maze and in open field respectively.To show change of NMDA receptor function after various doses of agonist, the seizures evoked by N-methyl-D-aspartate acid was carried out. This experiment showed that with rise of dose of NMDA time to appear of convulsions was contracted in rats with hyperammonemia as well as in control rats. Dose of NMDA caused convulsions was three times as less in rats with hyperammonemia than dose in control. Time of duration of convulsions was proportional to applied dose of NMDA and it lengthened with rise of agonists dose in both groups of studied animals.Furthermore, we observed that NMDA increased motor activity of control rats in open field test, but not in rats with hyperammonemia (treated tioacetamide). Hyperammonemia did not have significant influence on motor activity and on a passive avoidance latency. The NMDA given in control and in hyperammonemia, increased acquisition, consolidation and recall of a passive avoidance responses. Moreover, NMDA had anxiogenic-like profile in elevated plus-maze.In rats with hyperammonemia NMDA had no influence on locomotor activity but it significantly increased memory in a passive avoidance responses. Furthermore, we observed that reactivity of NMDA glutamate receptor in rats with hyperammonemia was higher than in control rats.     

Oral administration of the biomimetic [Cr3O(O2CCH2CH3)6(H2O)3]+ increases insulin sensitivity and improves blood plasma variables in healthy and type 2 diabetic rats

The in vivo effects of gavage administration of the synthetic, functional biomimetic cation [Cr₃O(O₂CCH₂CH₃)₆(H₂O)₃]⁺ to healthy and type 2 diabetic model rats are described. After 24 weeks of treatment (0–1,000 g Cr/kg body mass) of healthy Sprague Dawley rats, the cation results in a lowering (P<0.05) of fasting blood plasma low-density lipoprotein (LDL) cholesterol, total cholesterol, triglycerides, and insulin levels and of 2-h plasma insulin and glucose concentrations after a glucose challenge. Zucker obese rats (a model of the early stages of type 2 diabetes) and Zucker diabetic fatty rats (a model for type 2 diabetes) after supplementation (1,000 g Cr/kg) have lower fasting plasma total, high-density lipoprotein, and LDL cholesterol, triglycerides, glycated hemoglobin, and insulin levels and lower 2-h plasma insulin levels in glucose tolerance tests. The lowering of plasma insulin concentrations with little effect on glucose concentrations suggests that the supplement increases insulin sensitivity. The cation after 12 and 22 or 24 weeks of administration lowers (P<0.05) fasting plasma glycated hemoglobin levels in the Zucker diabetic and Zucker obese rats, respectively, and thus can improve the glucose status of the diabetic models. The effects cannot be attributed to the propionate ligand.Supplementary material is available for this article at .An erratum to this article can be found at     

Investigating serum factors promoting erythrocytic growth of Plasmodium falciparum

The elucidation of factors inducing the growth of Plasmodium falciparum can provide critical information about the developmental mechanisms of this parasite and open the way to search for novel targets for malaria chemotherapy. The ability of components of a growth-promoting factor derived from bovine serum and various related substances to sustain growth of P. falciparum was characterized. A simple total lipid fraction (GFS-C) containing non-esterified fatty acids (NEFAs) as essential factors was noted to promote the parasite's growth. Various proteins from a variety of animals were tested, indicating the importance not only of GFS-C, but also of specific proteins, such as bovine and human albumin, in the parasite growth. Several combinations of the NEFAs tested sustained low parasite growth. Among various phospholipids and lysophospholipids tested, lysophosphatidylcholine containing C-18 unsaturated fatty acids was found to sustain the complete development of the parasite in the presence of bovine albumin. Several other lysophospholipids can partially support growth of P. falciparum.     

Modulatory role of testosterone in alarm pheromone release by male rats

An alarm pheromone released from stressed conspecifics evokes behavioral and autonomic responses in rats. We have previously reported that male Wistar rats show behavioral changes including increased sniffing, walking and rearing, and decreased resting as well as exaggerated response of body temperature to a novel environment [known as stress-induced hyperthermia (SIH)] when they are exposed to an alarm pheromone released from other male rats receiving foot shocks. The purpose of the present study was to examine the role of testosterone in the production and release of the alarm pheromone using these behavioral and autonomic responses in recipient rats. Three groups of alarm pheromone donors were presented, namely, intact males, castrated males, and testosterone-implanted castrated males. The effects of the alarm pheromone on the autonomic responses did not differ among the three groups, regardless of the donor's steroidal milieu, whereas behavioral responses were altered by castrating the donor males and the effects were restored by testosterone implantation. These results suggest that the alarm pheromone released from stressed male rats can be classified into at least two categories according to the androgen dependency of their production and/or release.     

Female-induced sexual arousal in male mice and rats: behavioral and testosterone response

Exposure of a male mouse to a female mouse separated from it by a holed partition induced specific behavior and an increase in blood testosterone in the male. The male made more approaches to the partition and spent more time at it. The time spent by the male mouse over the first 10 min at the partition, behind which an estrus female was placed, was increased sixfold compared to the time spent by a male mouse exposed to the vacant neighboring compartment; and 1.5-fold compared to that spent by a male mouse exposed to a nonreceptive female or a male. Increased blood testosterone level was detected at 20 min of exposure to a receptive female in winter and at 40 min in summer. No variation in blood testosterone levels in the male mouse exposed to a nonreceptive female or a male was observed. Similar response to a receptive female placed in the neighboring compartment was shown in a male rat. The time spent by the male rat at the partition was 12 times higher when there was an estrus female behind it than in control. Blood testosterone in the male rat increased in response to a female rat and did not change in response to a male rat indicating female-induced motivation. It was concluded that the partition time might serve as a quantitative measure of sexual motivation in the males and that the model of female-induced sexual arousal used was suitable for studying both motivational and hormonal components of sexual arousal in male mice and rats.     

Regulation of protein synthesis by branched-chain amino acids in vivo

Recent advances in the understanding of mRNA translation have facilitated molecular studies on the regulation of protein synthesis by nutrients and the interplay between nutrients and hormonal signals. Numerous reports have established that, in skeletal muscle, the branched-chain amino acids (BCAAs) have the unique ability to initiate signal transduction pathways that modulate translation initiation. Of the BCAAs, leucine is the most potent. Oral administration of leucine to food-deprived rats enhances muscle protein synthesis, in part, through activation of the mRNA binding step of translation initiation. Interestingly, leucine signaling in skeletal muscle differs from that in liver, suggesting that the responses may be tissue specific. The purpose of this paper was to briefly review the current knowledge of how BCAAs act as regulators of protein synthesis in physiologically important tissues, with particular focus on the mechanisms by which BCAAs regulate translation initiation.     

盐酸氨溴索联合布地奈德对致敏大鼠气道炎症及肺组织氧化应激水平的影响

目的观察盐酸氨溴索联合吸入布地奈德对致敏大鼠气道炎症及肺组织氧化应激水平的影响。方法32只雄性Wistar大鼠随机分为对照组、致敏组、布地奈德干预组（BUD）和氨溴索＋布地奈德干预组（AMB＋BUD）。测定各组大鼠支气管肺泡灌洗液（ABLF）细胞计数及分类;取部分肺组织行HE染色病理学观察;测定肺组织中活性氧（ROS）、谷胱甘肽（GSH）含量。结果BUD＋AMB组BALF中细胞总数、嗜酸粒细胞数、淋巴细胞数以及肺组织ROS含量均明显低于BUD组（P〈0.05,P〈0.01）,而肺组织GSH含量明显高于BUD组（P〈0.01）;同时BUD＋AMB组大鼠支气管壁炎症反应及病理损伤程度也较BUD组明显减轻。相关性分析显示：各组大鼠BALF中细胞总数、嗜酸性粒细胞数、淋巴细胞数与肺组织ROS含量之间均呈正相关（P〈0.05）。结论氧化应激在哮喘发病过程中发挥着重要作用。盐酸氨溴索通过其抗炎、抗氧化作用,与吸入糖皮质激素合用对哮喘急性发作有协同治疗效果。