肌萎灵注射液对大鼠原代培养运动神经元生长的影响

为了观察中药制剂肌萎灵注射液对大鼠原代培养脊髓运动神经元生长的影响,本研究采用MTT方法观察神经元活力,并通过免疫组织化学技术进行NF 200染色后图像分析测定突起长度。结果表明:浓度为0. 5% ~5%的肌萎灵注射液能增加培养神经元活力,浓度为0. 5% ~1%的肌萎灵能促进神经元突起生长。本研究结果提示:肌萎灵注射液对培养的大鼠脊髓运动神经元生长有促进作用。     

Effect of Dehydroepiandrosterone on Avoidance Behavior of Adult Male Rats

We studied the effect of repeated intraperitoneal treatment with dehydroepiandrosterone in doses of 0.1 and 0.7 mg/kg on conditioned-response activity and behavior of adult male rats. The effect of dehydroepiandrosterone on learning was estimated in conditioned active and passive avoidance response paradigms. Chronic administration of dehydroepiandrosterone in low and high doses had no effect on retention of conditioned passive avoidance response in adult male rats 24 h after learning. However, chronic administration of dehydroepiandrosterone in low dose impaired acquisition of the conditioned active avoidance response. It should be emphasized that chronic administration of dehydroepiandrosterone in high dose did not modulate acquisition and retention of this reaction.     

Effects of melanotan II,a melanocortin agonist,on grooming and exploration in rats after repeated restraint/immobilization

2 mg/kg melanotan II (MTII, administered i.p.), a cyclic peptide analog of α-melanocyte stimulating hormone, at a single dose increased grooming in naive rats placed in an unfamiliar open-field device without changing locomotion or rearing. Male rats exposed to restraint/immobilization stress (IS) for 1 h on three consecutive days displayed increased grooming after the second stressor exposure, compared to pre-stress levels. MTII, administered to the rats after IS, enhanced the grooming response compared both to the pre- and post-stress values. The increase was greatest after the first dose and declined over the following two applications. As to the locomotion of rats in the entire experimental space, IS reduced the distance moved only after the first two stressor exposures; MTII did not influence these alterations. Locomotion in the central part of arena was not reduced by the stressor or by MTII, on the contrary, there was an increase in both groups after the third intervention. The only observed change in rearing was an increase in the MTII group after the third restraint exposure. Thus, MTII selectively increased grooming without markedly affecting the spatio-temporal structure of locomotor behavior in the open-field. The decline of MTII enhanced grooming over the three test days may be interpreted in terms of adaptation to the stressor and of the developing tolerance to the peptide.     

Administration of ciprofibrate to lactating mothers induces PPARα-signaling pathway in the liver and kidney of suckling rats

It is well known that the hypolipidemic drug ciprofibrate induces peroxisome proliferation in rodent liver, which in turn leads to the oxidative stress, and modifies some parameters related to cell proliferation and apoptosis. The administration of ciprofibrate to rats during the lactating period determined in their pups significant modifications in hepatic peroxisome enzyme activities, induction of the PPARalpha-target gene, Cyp4a10, and perturbation in cell proliferation and apoptosis, which affected the size of the liver. Moreover, this modification was associated to about two-fold induction of mRNA-PPARalpha. On the contrary, in the kidney, although a similar two-fold up-regulation of PPARalpha was detected, the induction of both peroxisomal enzyme activities and Cyp4a10 were weak, and no alterations were detected, neither in cell cycle nor in the size of the tissue. Our results indicate that the response to ciprofibrate is stronger in the liver than in the kidney of newborn rats.     

Functional vulnerability of developing central nervous system to maternal thiamine deficiencies in the rat

Thiamine deficiency (B1 vitamin) was induced during three periods of rat central nervous system (CNS) ontogenesis. Females were fed a thiamine deficient diet such that developing offspring were exposed either to pre-, peri-, or postnatal thiamine deficiency. To control the effects of undernourishment generated by different thiamine deficiencies, every treatment group had its own pair-fed control pup from a non drug-treated but undernourished dam. Seven different developmental abilities (exploratory activity, emotional reaction, hind paws lifting reflex, wire grasping times, crawling and leap execution latencies, and nociception) were recorded in the offspring from the 10th to the 45th postnatal day. The vulnerability of developing brain to the specific lack of B1 vitamin increases from prenatal (28%) to perinatal (43%) and postnatal periods (57%).     

Effects of a diet rich in Q-3 fatty acids on left ventricular geometry and dynamics in spontaneously hypertensive rats

Summary The aim of the present study was to investigate the chronic effects of a dietetic antihypertensive treatment on blood pressure, ventricular dynamics and geometry of the pressure loaded heart. Spontaneously hypertensive rats (SHR) received a standard diet enriched with 10% mackerel oil, containing 30% polyunsaturated Q-3 fatty acids, over a period of 70 days. As described previously the diet reduced blood pressure permanently by 40-50 mm Hg. Despite this reduction, the degree of left ventricular hypertrophy was only slightly (statistically insignificantly) reduced. This was probably a result of an increase in sympathetic tone as indicated by a raised pulse rate. On the other hand, the treatment prevented the development of eccentric hypertrophy, typical to the SHR, without changing the elastic material properties of the myocardium. Since the age-matched controls did not show significant degenerative alterations, protective effects at the level of myocardial tissue could not be demonstrated. Furthermore, future investigations need to investigate why myocardial contractility of the treated animals diminishes as observed in this study.     

Developmental changes in the behavioral and autonomic effects of kappa opioid receptor stimulation of the midbrain periaqueductal gray

Kappa opioid receptors stimulation with U50,488 is known to modulate behaviors during the early postnatal period, but the specific neuroanatomical locus of many of these effects is unexplored. In the present study, we infused U50,488 into the midbrain periaqueductal gray (PAG) and investigated the effects of this drug on behavior and heart rate of 1-, 2-, and 3-week-old rats. U50,488 increased activity most potently in 1- and 2-week-old subjects. Ultrasonic vocalization (USV) production was increased in 1-week-old subjects, but not in 2- or 3-week-old pups. Heart rate changes were similarly seen in younger aged subjects. At 1 week, U50,488 decreased heart rate, but at 2 weeks it increased heart rate. There was no effect of this drug on heart rate at 3 weeks. At 1 week, USVs were more potently elicited from dorsal than lateral PAG infusion sites. No other site-specific effects within the PAG were seen. The age-related decline in behavioral effects elicited by U50,488 is consistent with other published reports, and to the extent that kappa receptor activity mediates infant separation responses, implicates the PAG as a modulator of those responses.     

维生素A阻抑大鼠实验性肝纤维化的病理研究

利用光镜、电镜、免疫组化和形态学定量技术动态研究维生素A对大鼠四氯化碳肝纤维化的抑制作用。结果表明,维生素A可减少四氯化碳中毒大鼠肝内纤维连接蛋白和Ⅰ、Ⅲ型胶原沉积,抑制贮脂细胞向成纤维细胞转化,并可明显地减轻肝纤维化程度。本文还对维生素A抑制肝纤维化的机理及意义作了初步探讨。     

Changes in Hemodynamics and Respiration in Rats with Different Resistance to Acute Hypoxia

Effects of acute hypoxia on hemodynamics and respiration were studied in acute experiments on narcotized rats. The animals were divided into groups characterized by high, low-, and medium- resistance to hypoxia by the time of respiration arrest during inhalation of gas mixture containing 3% O2. Hemodynamic parameters of highly resistant animals were higher than in low-resistant rats throughout the entire hypoxic period. The development of a rare (with prolonged inspiratory phase) respiratory rhythm in highly resistant rats is an adaptive reaction, which allows them longer tolerate hypoxia compared to low-resistant animals.