Effects of the NMDA antagonist MK-801 on radial maze performance in histidine-deficient rats

We examined the effects of a histidine-deficient diet on brain histamine contents as well as on learning and memory using the eight-arm radial maze in rats. A significant decrease in histamine content in the hippocampus was observed after long-term feeding of rats with a histidine-deficient diet. At the same time, significant enhancement of the acquisition process in radial maze performance was also observed. Pyrilamine did not show a significant effect on radial maze performance in histidine-deficient rats. On the other hand, pyrilamine caused a significant spatial memory deficit in control rats. Scopolamine was effective in inhibiting spatial memory in both histidine-deficient and control rats. MK-801 caused spatial memory deficits more potently in histidine-deficient rats than in controls. Brain glycine contents showed a significant increase in the hippocampus in histidine-deficient rats. These results indicated that the spatial memory deficits induced by MK-801 in histidine-deficient rats are closely related to increased glycine levels and activation of NMDA receptors.     

Ultrastructural studies on the epididymal spermatozoa in the rhesus monkey

Ultrastructural studies on the spermatozoa in different regions of the epididymis of the rhesus monkey have shown that the process of sperm maturation is associated with the caudad migration of the cytoplastmic droplet, a reduction in the volume of the cytoplasmic droplet, and an obvious wrinkling of the plasma membrane surrounding the head of the spermatozoa. These changes are completed by the time the spermatozoa reach the distal-middle segment of the epididymis. The present studies also indicate that spermatozoa are incorporated into the intraepithelial cells in the epidymis. This finding suggests that spermiophagy is a normal occurrence in the epidymis of rhesus monkey.     

MK801对大鼠脑缺血再灌注后海马CA1区c-fos基因表达及神经元凋亡的影响

目的:研究MK801对大鼠脑缺血再灌注后海马CA1区c-fos基因表达及神经元凋亡的影响。方法:将大鼠随机分为正常对照组、脑缺血再灌注模型组和脑缺血用药后再灌注组,用药组在再灌注前经腹腔注射MK801(0.5mg/kg);分别于再灌注后2、6、24和48 h,采用免疫组化法和Western印迹观察海马CA1区c-fos基因的表达情况。结果:c-fos基因的表达在脑缺血再灌注后2 h即开始增强,至再灌注后6 h达到高峰,24 h表达降低,至48 h又至高峰,但较再灌注6 h后较低。用药组海马CA1区c-fos基因的表达均较模型组的相应时间段降低,具有显著性差异(P<0.01)。结论:海马CA1区c-fos基因在脑缺血再灌注后表达升高,MK801可降低脑缺血再灌注后c-fos基因的表达,对缺血再灌注后的脑组织具有保护作用。     

Morris water maze: a versatile and pertinent tool for assessing spatial learning and memory

Since its development about 40 years ago (1981–2021), Morris water maze has turned into a very popular tool for assessing spatial learning and memory. Its many advantages have ensured its pertinence to date. These include its effectiveness in evaluating hippocampal-dependent learning and memory, exemption from motivational differences across diverse experimental manipulations, reliability in various cross-species studies, and adaptability to many experimental conditions with various test protocols. Nonetheless, throughout its establishment, several experimental and analysis loopholes have galvanized researchers to assess ways in which it could be improved and adapted to fill this gap. Therefore, in this review, we briefly summarize these developments since the early years of its establishment through to the most recent advancements in computerized analysis, offering more comprehensive analysis paradigms. In addition, we discuss the adaptability of the Morris water maze across different test versions and analysis paradigms, providing suggestions with regard to the best paradigms for particular experimental conditions. Hence, the proper selection of the experimental protocols, analysis paradigms, and consideration of the assay’s limitations should be carefully considered. Given that appropriate measures are taken, with various adaptations made, the Morris water maze will likely remain a relevant tool to assess the mechanisms of spatial learning and memory.     

Effect of sugar type on the survival of frozen-thawed rhesus monkey (Macaca mulatta) sperm

Sperm-freezing extenders supplemented with sugar or a combination of different sugars are widely used for the cryopreservation of nonhuman primate spermatozoa. Understanding which sugar or combination of sugars offers the highest level of cryoprotection would be beneficial for the development of sperm-freezing extenders. In the present study we aimed to investigate the effect of glucose, lactose, and raffinose separately or in combination on the cryosurvival of rhesus monkey spermatozoa. Toward that end, we prepared eight extenders by adding various types of sugars to a basic medium (BM): G-BM (0.3 M glucose), L-BM (0.3 M lactose), R-BM (0.3 M raffinose), LG-BM (0.15 M lactose+0.15 M glucose), RG-BM (0.15 M raffinose+0.15 M glucose), LR-BM (0.15 M lactose+0.15 M raffinose), and LRG-BM (0.1 M lactose+0.1 M raffinsoe+0.1 M glucose). A saline control (0.157 M sodium chloride) was also used. The results showed no significant difference in post-thaw motility when spermatozoa were frozen with G-BM, L-BM, LG-BM, RG-BM, and LRG-BM, but the post-thaw motility was significantly lower when it was frozen with R-BM, LR-BM, and the saline control. The highest plasma membrane integrity was achieved when spermatozoa were frozen with G-BM, L-BM, LG-BM, RG-BM, and LRG-BM, and the highest acrosome integrity was achieved with G-BM, L-BM, LG-BM, RG-BM, LRG-BM, and the saline control. The results indicate that the various sugars offered different protective effects. For the cryopreservation of rhesus monkey spermatozoa, glucose (monosaccharide) and lactose (disaccharide) were shown to be more suitable than raffinose (trisaccharide) for preserving spermatozoal motility, plasma membrane, and acrosome. Specifically, raffinose was detrimental to sperm acrosome integrity.     

猕猴精浆纤溶酶原激活因子的来源及在精子获能中的作用

我们的前期工作表明,不育症人精液中纤溶酶原激活因子（plasminogen activator;PA）活性明显升高;给成年办和猕猴注射长效睾酮诱发无精过程中,精液PA含量也伴随上升,为进一步查明PA的来源和对精子的作用,原位杂交检测组织型PA（tPA）,尿激酶型PA（uPA）及PA抑制因子－1（PAI-1)泊mRNAs在成年健康猕附睾、前列腺和精囊中的表达。体外培养猕猴精子,培液中加入uPA、tPA及其底物纤溶酶原（plasminogen）,测试PA对精子活力、顶体反应及激活卵子的影响。结果表明,猕猴附睾、前列腺和精囊均表达tPA、uPA和PAI-1 mRNAs。加入uPA能维持精子的活力,使精子产生超激活运动,诱导顶体反应的发生,并使精子获得激活卵子的能力,这说明猕猴精浆PA除来源于睾丸外,可能主要来源于附睾及附性腺;在体外,uPA,而不是tPA,可能诱导精子获能。     

Isolation and morphologic differentiation in vitro of villous cytotrophoblast cells from rhesus monkey placenta

Summary Trophoblast is the major functional cell type of the placenta. The purpose of this study was to devise a means to isolate trophoblast cells from the monkey placenta and to examine their capacity to differentiate in vitro. Methods originally devised for the isolation of human cytotrophoblast cells produced poor yields and a low degree of purity when applied to the near-term rhesus monkey placenta. However, a procedure has been developed which allows the isolation of a cell population consisting of more than 95% cytotrophoblast based on intermediate filament immunocytochemistry. The cells sedimented between densities of 1.040 and 1.053 g/ml on continuous Percoll density gradient centrifugation. When maintained in culture the cells adhered and formed aggregates of mononuclear cells by 24 h. By 5 d in culture, immunofluorescent staining using antidesmoplakin and antinuclear antibodies revealed that most colonies consisted of large multinucleated masses similar to syncytiotrophoblast. These results demonstrate trophoblast cells from monkey placental villi can be isolated with a high degree of purity and undergo morphologic, differentiation in vitro. This preparation should enable investigators to study many functional characteristics of these cells throughout gestation. This work was supported by grants HD11658 and RR00169 from the National Institutes of Health, Bethesda, MD.     

Ultrastractural features of the principal cell in the epididymis of the rhesus monkey

The ultrastructural features of the principal cell in the epididymal epithelium of the monkey epididymis are suggestive of the cell carrying out a dual function of absorption and secretion. Both these functions occur on the luminal surface of the cell as well as on the lateral and basal aspects of the cell which face the intercellular spaces. Transmision Electron Microscopic studies of epididymal tissues following their impregnation with lanthanum nitrate indicated that the intercellular spaces are effectively sealed-off from the luminal space by the apically situated tight junctions between adjoining principal cells. The intercellular spaces are contiguous with the perivascular spaces of the subepithelial blood capillaries. It is suggested that the absorptive and secretory functions occuring on the apical surface of cells may be related to the creation of an appropriate intraluminal milieu for the maturation of spermatozoa while the occurrence of these functions in the intercellular spaces may represent an exchange of substances between the principal cells and the subepithelial capillaries.     

Effects of age,lactation, and repeated cycles on rhesus monkey copulatory intervals

Young, sexually mature female rhesus monkeys copulate on more days prior to conception than do older females, and this prolonged discrete mating period is associated with an earlier rise in serum estradiol prior to the first ovulation of the breeding season. The influence of repeated ovulatory cycles and the presence of a suckling infant on the copulatory patterns were examined in two separate analyses. Extending previous work, young, nulliparous females copulated on more days at the first ovulation of the breeding season than did older, multiparous females. However, the duration of the copulatory period at the second ovulation of the breeding season was similar and significantly shorter for both age groups. Furthermore, the presence of a suckling infant did not influence the duration of the mating periods in adult, multiparous females. The onset of copulatory behavior for all females was associated with serum estradiol concentrations of approximately 90 pg/ml, indicating that the age and cycle differences in the duration of the copulatory periods are due to the time course of serum estradiol prior to ovulation. A separate, longitudinal analysis of the duration of the mating period associated with the first ovulation of three successive breeding seasons indicated that females copulated on more days during their first ovulatory cycle of their first breeding season. These data indicate that the copulatory interval is longer for females during the first ovulation of the breeding season, and this pattern is accentuated in young, sexually mature animals.     

A description of the upper thoracic autonomic nervous system in the rhesus monkey (Macaca mulatta)

The purpose of this study was to describe the autonomic innervation of the carotid sinus and heart in the rhesus monkey. Nine male rhesus monkeys (Macaca mulatta) and one male crab-eating macaque (M. fascicularis) were carefully dissected from the origin of the vagus nerves and superior cervical ganglia to the level of the fourth thoracic ganglion. The specimens were either freshly killed or obtained no later than 24 hours post mortem. The macaque monkeys were found to possess an innervation pattern that displayed features common to dog (connections between the vagus nerves and middle cervical ganglia), baboon (distinct cervical sympathetic and cervical vagal nerve trunks), and man (nerves projecting from the middle cervical and stellate ganglia to the heart). Distinct inferior cervical and first thoracic ganglia were never seen, but rather, large and well defined stellate ganglia were found. The macaque innervation pattern, when considered as a whole, most closely resembled the baboon.     

Influence of kinship and spatial density on reconciliation and grooming in rhesus monkeys

Some cercopithecine primates direct disproportionate amounts of grooming, huddling, and agonistic support toward maternal kin. Disproportionate amounts of aggression are also directed toward maternal kin, however, suggesting that mechanisms that restore relationships damaged by aggression, such as reconciliation, might be biased toward these preferred social partners. Studies investigating kinship effects and reconciliation are inconsistent, however, perhaps because of differences in the environmental conditions under which behavior was observed. In order to test the effects of kinship and spatial density on affiliative and reconciliation behavior, we conducted focal and scan sampling on a group of rhesus monkeys (Macaca mulatta) living in an outdoor corral under low spatial density conditions. We then compared this data to previously published data on a group of the same species living under higher spatial density conditions. Neither overall grooming nor reconciliation were affected by spatial density once correction procedures were applied. Grooming was kin biased at both study sites, whereas reconciliation was kin biased only in the low-density group. Although data failed to support a Coping Model according to which grooming and reconciliation should go up under higher densities, we suggest that coping may be reflected not so much in overall rates of behavior but in strategic partner choices, such as the increased importance monkeys under crowded conditions appear to attach to nonkin partners. © 1996 Wiley-Liss, Inc.     

Placental transfer of synthetic and endogenous estrogen conjugates in the rhesus monkey (Macaca mulatta)

The placental transfer of conjugated and nonconjugated estrogens was compared in the pregnant rhesus monkey. Placement of catheters in the maternal and fetal circulation allowed for the sampling of blood after the administration of radiolabeled naturally occurring and synthetic estrogens to mother or fetus. In all cases, nonconjugated-estrogen placental transfer was greater than conjugated-estrogen transfer. Comparison of the conjugated estrogens suggested that diethylstilbestrol-monoglucuronide (DESG) was transferred less efficiently than the estrone-sulfate (E, S). High-performance liquid chromatog-raphy (HPLC) of selected plasma samples revealed that 50–90% of the E, S observed in the maternal circulation was cleaved after fetal administration. In contrast, HPLC of maternal or fetal plasma samples after DESG administration revealed only intact DESG. These results emphasize differences in the placental transfer of the synthetic and naturally occurring estrogen hormones.     

Temporal and spatial expression of MMP-2,-9,-14 and their inhibitors TIMP-1,-2,-3 in the corpus luteum of the cycling rhesus monkey

The corpus luteum (CL) is a transient endocrine organ that secretes progesterone to support early pregnancy. If implantation is unsuccessful, luteolysis is initiated. Extensive tissue remodeling occurs during CL formation and luteolysis. In this study, we have studied the possible involvement of MMP-2,-9,-14, and their inhibitors, TIMP-1,-2,-3 in the CL of cycling rhesus monkey at various stages by in situ hybridization, immunohistochemistry and microscopic assessment. The results showed that the MMP-2 mRNA and protein were mainly expressed in the endothelial cells at the early and middle stages of the CL development, while their expressions were observed in the luteal cells at the late stage during luteal regression. MMP-9 protein was detected in the CL at the early and middle stages, and obviously increased at the late stage. The expressions of MMP-14 and TIMP-1 mRNA were high at the early and late stages, and low at the middle stage. TIMP-2 mRNA was high throughout all the stages, the highest level could be observed at the late stage. The TIMP-3 production was detected throughout all the stages, but obviously declined during CL regression. MMP-9,-14 and TIMP-1,-2,-3 were mainly localized in the cytoplasm of the steroidogenic cells. The results suggest that the MMP/TIMP system is involved in regulation of CL development in the primate, and the coordinated expression of MMP-2,-14 and TIMP-1,-3 may have a potential role in the CL formation and the functional maintaining, while the interaction of MMP-2,-9,-14 and TIMP-1,-2,-3 might also play a role in CL regression at the late stage of CL development in the primate.     

Effect of glycerol and dimethyl sulfoxide on cryopreservation of rhesus monkey (Macaca mulatta) sperm

Glycerol and dimethyl sulfoxide (DMSO) are widely used as penetrating cryoprotectants in the freezing of sperm, and various concentrations are applied in different species and laboratories. The present study aimed to examine the effect of these two cryoprotectants at different concentrations (2%, 5%, 10%, and 15% glycerol or DMSO) on rhesus monkey sperm cryopreservation. The results showed that the highest recovery of post-thaw sperm motility, and plasma membrane and acrosome integrity was achieved when the sperm was frozen with 5% glycerol. Spermatozoa cryopreserved with 15% DMSO showed the lowest post-thaw sperm motility, and spermatozoa cryopreserved with 15% glycerol and 15% DMSO showed the lowest plasma membrane integrity among the eight groups. The results achieved with 5% glycerol were significantly better for all parameters than those obtained with 5% DMSO. The functional cryosurvival of sperm frozen with 5% glycerol was further assessed by in vitro fertilization (IVF). Overall, 85.7% of the oocytes were successfully fertilized, and 51.4% and 5.7% of the resulting zygotes developed into morulae and blastocysts, respectively. The results indicate that the type and concentration of the penetrating cryoprotectant used can greatly affect the survival of rhesus monkey sperm after it is frozen and thawed. The suitable glycerol level for rhesus monkey sperm freezing is 5%, and DMSO is not suitable for rhesus monkey sperm cryopreservation.     

Laboratory assessment of temperament and environmental enrichment in rhesus monkey infants (Macaca mulatta)

This study investigated the combined effects of early temperamental characteristics and environmental enrichment on a variety of developmental measures in nursery-reared rhesus monkey infants. Twenty-three infants, reared in either standard laboratory cages or enriched environments, were tested during the 1st month of life for interactive, motor, and temperamental capabilities and characteristics. At 8 months of age, all subjects were assessed on a second series of tests designed to measure their problem-solving skills, motor capabilities, and temperamental responses under challenge. Results indicated that enrichment was associated with higher scores on subsequent problem-solving and motor tests. However, such effects were found to combine with early temperament ratings. Specifically, individuals performing best on the 8-month tests had not only been reared in enriched environments, but also had been rated low on fearfulness during the early assessment. In addition, individuals scoring poorest had been rated as fearful initially in addition to being reared without enrichment. Results indicated that while high ratings on early laboratory assessments of fearfulness may be predictive of poorer problem-solving performance under challenging conditions, these adverse effects may be partially attenuated by environmental enrichment.     

Effects of maternal marginal zinc deficiency on myelin protein profiles in the suckling rat and infant rhesus monkey

In the current study, the effects of marginal Zn deficiency on myelin protein profiles in neonatal rats and rhesus monkeys were investigated. Following mating, rats were fed a Zn-adequate diet,ad libitum (50 μg Zn/g; 50 Zn AL), or a marginal Zn diet (10 μg Zn/g) from day 0 (10 Zn d0) or day 14 (10 Zn d14) of gestation to day 20 postnatal. An additional group of dams was restricted-fed the control diet to the food intake of the 10 Zn d0 group (50 Zn RF). Day 20 pup plasma and liver Zn concentrations in the 10 Zn groups were lower than in the 50 Zn groups. In a parallel experiment, rhesus monkeys were fed a Zn-adequatead libitum diet (100 μg Zn/g) or a marginal Zn diet (4 μg Zn/g diet; MZD) throughout gestation and lactation. Day 30 monkey infant plasma and liver Zn levels were similar in the MZD and control groups. Rat brain and monkey brain cortex weights were similar among the dietary groups. The amount of myelin recovered (mg protein/g brain) from day 20 rat pups from the 10 Zn groups was lower than that recovered from the 50 Zn rat pups. Myelin recovery from the MZD and control monkey infants was similar. When myelin protein profiles were characterized, it was found that the percentages of high-molecular-weight (HMW) proteins and Wolfgram protein were higher, whereas the percentages of small and large basic proteins were lower in myelin from the 10 Zn d0 and 50 Zn RF pups compared to the distribution in the 50 Zn AL rat pups. Results for the 10 Zn d0 and 10 Zn d14 pups were similar for all of the parameters studied. The percentage of HMW proteins was higher and that of basic protein lower in myelin from MZD monkey infants compared to the percentage of these proteins in myelin from controls. Although the interpretation of the rat data is complicated because of the anorexia associated with the Zn deficiency, the observed changes in monkey myelin protein profiles provide strong evidence that maternal Zn deficiency affects myelination in the offspring.     

MK—801降低炎性痛在鼠脊髓NOS表达和NO含量

用NADPH-d组织化学法,观察鞘内注射NMDA受体拮抗剂MK-801对大鼠右后掌皮下注射甲醛诱发的炎症性痛及痛过敏过程中脊髓后角一氧化氮合酶(NOS)表达的影响,同时测定一氧化氮(NO)代谢终产物     

Temporal and spatial expression of MMP-2,-9,-14 and their inhibitors TIMP-1,-2,-3 in the corpus luteum of the cycling rhesus monkey

A CL develops by extensive cellular reorganization and neovascularization of the remnants of the evacu-ated follicle following ovulation. In both rodent and primate, the development of CL is a rapid process with very high cellular turnover[1,2]. A CL is u…     

Perception of novel changes in a familiar environment by socially‐housed rhesus monkeys

Many animals appear to have a sophisticated spatial representation of their environment. The development of these representations depends on the joint abilities of discriminating novel objects and remembering their locations. Variations of a detection of novelty paradigm were used to determine the nature and limitations of these abilities in rhesus monkeys. Socially‐housed monkeys at two facilities (UMASS Primate Laboratory and the New England Regional Primate Research Center) were exposed to novelty detection tasks using a vertical object grid arranged on a mesh wall of the animals' pens. Monkeys rapidly responded with increased exploration to the replacement of one familiar object with a novel object, to the movement of a familiar object to a novel location, and to the swapping of two familiar objects. However, novelty of object was more salient than novelty of place. In these initial studies, monkeys were given continuous access to the grid, and only one or two changes occurred on a given day. In subsequent studies, the task difficulty was varied either by reducing the length of grid exposure or increasing the number of changed objects/session. Surprisingly, only a reduction in length of exposure markedly affected novelty detecting abilities. Rhesus monkeys clearly possessed the dual novelty detecting abilities. These skills were negatively affected only when monkeys' access to the grid was limited. The procedure employed here provided a convenient way to assess complex cognitive abilities in a group setting. It also relied on rhesus monkeys' inherent attraction to novelty and required only their species‐typical behavior for assessment. Am. J. Primatol. 47:117–131, 1999. © 1999 Wiley‐Liss, Inc.