Predictors of social status in cynomolgus monkeys (Macaca fascicularis) after group formation

The purpose of the present study was to determine whether various behavioral and hormonal markers obtained in individually housed monkeys would be predictive of social rank following group housing. Body weight, serum cortisol and testosterone levels, and locomotor activity in an open-field apparatus were examined in 20 experimentally naive male cynomolgus monkeys (Macaca fascicularis) while they were individually housed. It was hypothesized that eventual subordinate monkeys would have higher cortisol levels and increased locomotor activity scores. These monkeys were then placed in social groups of four (five pens of four monkeys), and social rank was determined based on outcomes of dyadic agonistic encounters. Body weight correlated significantly with eventual social rank. In general, the heavier the monkey the higher the social rank. Locomotor activity in an open-field apparatus following administration of a low dose of cocaine (0.01 mg/kg, i.v.), which has been shown to increase CNS dopamine, correlated with eventual social rank such that individually housed monkeys with high levels of locomotion were more likely to become subordinate. Serum cortisol and testosterone levels failed to correlate with eventual social rank. Hypothalamic-pituitary feedback sensitivity and adrenal responsiveness were examined by measuring cortisol levels after administration of dexamethasone and following ACTH challenge. Cortisol responses in these tests were not associated with eventual social rank. These results suggest that, in addition to body weight, the level of reactivity in a novel environment after administration of a low dose of cocaine is a potential trait marker for social rank. This trait is apparently not associated with hormone levels, but may involve other CNS mechanisms.     

The effects of ketamine anesthesia on hematological and serum biochemical values in female cynomolgus monkeys (Macaca fascicularis)

The effects of ketamine anesthesia (15 mg/kg body weight) on hematological and serum biochemical values were examined in six female cynomolgus monkeys (Macaca fascicularis) who were born in the wild. As control, another six female cynomolgus monkeys of the same origin were injected with physiological saline. The white blood cell count, total protein concentration, albumin concentration and calcium concentration decreased after the injection of ketamine, whereas the red blood cell count, hematocrit value, hemoglobin concentration, total cholesterol concentration, free cholesterol concentration, triglyceride concentration, transaminase activities (GOT, GPT) and alkaline phosphatase activity were not affected. A transient increase of the serum glucose level was observed within 10 minutes after ketamine injection. The relationship between these effects of ketamine anesthesia and serum cortisol levels measured by radioimmunoassay was discussed.     

De novo lipogenesis and lipolysis activities in normal (Dw) and dwarf (dw) White Leghorn laying hens

1. In vitro activities of glucose oxidation, de novo lipogenesis and lipolysis were compared in normal (Dw) and dwarf (dw) laying hens. 2. Dwarfism reduced the hepatic glucose oxidation while de novo lipogenesis was not altered. As liver weight was depressed, total liver lipogenesis capacity was probably reduced by dwarfism. 3. As compared to normal hens, de novo lipogenesis and basal or stimulated lipolysis were lower in dwarf adipose tissue while its lipid content was enhanced in dwarfs. 4. Results suggest that in laying hens dwarfism reduces the adipose tissue lipid mobilization but probably also the liver de novo lipogenesis.     

Trigonella foenum graecum (fenugreek) seed powder improves glucose homeostasis in alloxan diabetic rat tissues by reversing the altered glycolytic,gluconeogenic and lipogenic enzymes

Trigonella foenum graecum (fenugreek) seed powder has been suggested to have potential antidiabetic effects. The effect of oral administration of Trigonella whole seed powder (5% in the diet) for 21 days on glycolytic, gluconeogenic and NADPlinked lipogenic enzymes were studied in liver and kidney tissues of alloxan-induced diabetic Wistar rats. Diabetic rats were characterised by a 4fold higher blood glucose level and a 0.7fold lower body weight compared to normal controls. The activities of the glycolytic enzymes were significantly lower in the diabetic liver and higher in the diabetic kidney. The activities of gluconeogenic enzymes were higher in both liver and kidney during diabetes, however the activities of the lipogenic enzymes were decreased in both tissues during diabetes. Trigonella seed powder treatment to diabetic rats for 21 days brought down the elevated fasting blood glucose levels to control levels. The altered enzyme activities were significantly restored to control values in both the liver and kidney after Trigonella seed powder treatment. The therapeutic role of Trigonella seed powder in type1 diabetes as exemplified in this study can be attributed to the change of glucose and lipid metabolising enzyme activities to normal values, thus stabilizing glucose homeostasis in the liver and kidney. These biochemical effects exerted by Trigonella seeds make it a possible new therapeutic in type1 diabetes.     

Seasonal weight changes in male rhesus monkeys (Macaca mulatta)

Adult male rhesus monkeys lose weight during the breeding season and regain it during the nonbreeding season. The annual pattern of maximum weight gain just prior to the onset of breeding resembles the seasonal “fattening” seen in squirrel monkeys, but the period of weight gain is less discrete. The magnitude of weight change is less in younger males, in that sexually immature males gain weight in both seasons, but significantly less during the breeding season. Females do not lose weight during the breeding season. Post hoc analyses revealed no significant correlations between male testosterone levels, dominance ranks, weights, or weight changes. The heaviest animals as juveniles were predictably the heaviest as adolescents. The timing of seasonal changes in testosterone did not correlate with the timing of changes in weight; weight losses followed the rise in testosterone, and weight gains continued until early in the breeding season after testosterone levels had already begun to rise. It is suggested that seasonal hormonal changes may influence activities in individuals and that changes in the activities of particular group members may alter the activity patterns of other group members. This alteration of activity patterns due to group influences on individuals as well as individual influences on the group may explain why hormonal regulation of seasonal weight appears to be indirect and why individuals (juveniles) experiencing no seasonal hormonal changes nonetheless show differences in activity patterns and seasonal weight changes.     

Decreased Hepatic Insulin Extraction Precedes Overt Noninsulin Dependent (Type II) Diabetes in Obese Monkeys

Many obese middle-aged rhesus monkeys (Macaca mulatta) spontaneously develop noninsulin dependent diabetes mellitus (NIDDM). Basal hyperinsulinemia and increased stimulated plasma insulin levels are associated with this obesity and precede the onset of overt diabetes. The present studies sought to determine the relative contributions of enhanced insulin secretion and of reduced insulin clearance to this early obesity-associated hyperinsulinemia. Direct simultaneous measurement of portal and jugular vein insulin levels in two normal monkeys showed a constant rate of hepatic insulin extraction of 56±3% over the range of peripheral insulin levels from 351±113 to 625±118 pmol/L. In 33 additional monkeys ranging from normal to diabetic, basal C-peptide levels were examined as an indicator of β-cell secretion and the molar ratio of plasma C-peptide to insulin (C/I ratio) under basal steady state conditions calculated as an index of hepatic insulin extraction. Well in advance of overt diabetes, there was a progressive decline of 67% in the apparent hepatic insulin extraction rate in association with increased obesity and plasma insulin levels. Basal insulin levels and hepatic insulin extraction returned toward normal in monkeys with impaired glucose tolerance and in those with overt diabetes. We conclude that reduced insulin disposal, probably due to reduced hepatic extraction of insulin, in addition to increased β-cell activity, contributes to the development of basal hyperinsulinemia in obese rhesus monkeys progressing toward NIDDM. In addition, in overt diabetes, normal hepatic insulin extraction in the presence of limited β-cell secretion may exacerbate the hypoinsulinemic state. (OBESITY RESEARCH 1993; 1:252–260)     

Moonstruck Primates: Owl Monkeys (Aotus) Need Moonlight for Nocturnal Activity in Their Natural Environment

Primates show activity patterns ranging from nocturnality to diurnality, with a few species showing activity both during day and night. Among anthropoids (monkeys, apes and humans), nocturnality is only present in the Central and South American owl monkey genus Aotus. Unlike other tropical Aotus species, the Azara''s owl monkeys (A. azarai) of the subtropics have switched their activity pattern from strict nocturnality to one that also includes regular diurnal activity. Harsher climate, food availability, and the lack of predators or diurnal competitors, have all been proposed as factors favoring evolutionary switches in primate activity patterns. However, the observational nature of most field studies has limited an understanding of the mechanisms responsible for this switch in activity patterns. The goal of our study was to evaluate the hypothesis that masking, namely the stimulatory and/or inhibitory/disinhibitory effects of environmental factors on synchronized circadian locomotor activity, is a key determinant of the unusual activity pattern of Azara''s owl monkeys. We use continuous long-term (6–18 months) 5-min-binned activity records obtained with actimeter collars fitted to wild owl monkeys (n = 10 individuals) to show that this different pattern results from strong masking of activity by the inhibiting and enhancing effects of ambient luminance and temperature. Conclusive evidence for the direct masking effect of light is provided by data showing that locomotor activity was almost completely inhibited when moonlight was shadowed during three lunar eclipses. Temperature also negatively masked locomotor activity, and this masking was manifested even under optimal light conditions. Our results highlight the importance of the masking of circadian rhythmicity as a determinant of nocturnality in wild owl monkeys and suggest that the stimulatory effects of dim light in nocturnal primates may have been selected as an adaptive response to moonlight. Furthermore, our data indicate that changes in sensitivity to specific environmental stimuli may have been an essential key for evolutionary switches between diurnal and nocturnal habits in primates.     

Physical activity of adult female rhesus monkeys (Macaca mulatta) across the menstrual cycle

Physical activity is an important physiological variable impacting on a number of systems in the body. In rodents and several species of domestic animals, levels of physical activity have been reported to vary across the estrous cycle; however, it is unclear whether such changes in activity occur in women and other primates across the menstrual cycle. To determine whether significant changes in activity occur over the menstrual cycle, we continuously measured physical activity in seven adult female rhesus monkeys by accelerometry over the course of one menstrual cycle. Monkeys were checked daily for menses, and daily blood samples were collected for measurement of reproductive hormones. All monkeys displayed ovulatory menstrual cycles, ranging from 23 to 31 days in length. There was a significant increase in estradiol from the early follicular phase to the day of ovulation (F(1.005,5.023) = 40.060, P = 0.001). However, there was no significant change in physical activity across the menstrual cycle (F(2,12) = 0.225, P = 0.802), with activity levels being similar in the early follicular phase, on the day of the preovulatory rise in estradiol and during the midluteal phase. Moreover, the physical activity of these monkeys was not outside the range of physical activity that we measured in 15 ovariectomized monkeys. We conclude that, in primates, physical activity does not change across the menstrual cycle and is not influenced by physiological changes in circulating estradiol. This finding will allow investigators to record physical activity in female primates without the concern of controlling for the phase of the menstrual cycle.     

Individual differences in physical activity are closely associated with changes in body weight in adult female rhesus monkeys (Macaca mulatta)

The increased prevalence of overweight adults has serious health consequences. Epidemiological studies suggest an association between low activity and being overweight; however, few studies have objectively measured activity during a period of weight gain, so it is unknown whether low activity is a cause or consequence of being overweight. To determine whether individual differences in adult weight gain are linked to an individual's activity level, we measured activity, via accelerometry, over a prolonged period (9 mo) in 18 adult female rhesus monkeys. Weight, food intake, metabolic rate, and activity were first monitored over a 3-mo period. During this period, there was mild but significant weight gain (5.5 +/- 0.88%; t =-6.3, df = 17, P < 0.0001), whereas caloric intake and activity remained stable. Metabolic rate increased, as expected, with weight gain. Activity level correlated with weight gain (r = -0.52, P = 0.04), and the most active monkeys gained less weight than the least active monkeys (t = -2.74, df = 8, P = 0.03). Moreover, there was an eightfold difference in activity between the most and least active monkeys, and initial activity of each monkey was highly correlated with their activity after 9 mo (r = 0.85, P < 0.0001). In contrast, food intake did not correlate with weight gain, and there was no difference in weight gain between monkeys with the highest vs. lowest caloric intake, total metabolic rate, or basal metabolic rate. We conclude that physical activity is a particularly important factor contributing to weight change in adulthood and that there are large, but stable, differences in physical activity among individuals.     

饲料脂肪水平对吉富罗非鱼生产性能、营养物质消化及血液生化指标的影响

为探讨吉富罗非鱼对脂肪的适宜需求量,将630尾(2.63±0.16)g吉富罗非鱼随机分成6个脂肪组的饲料组(1.73%、3.71%、5.69%、7.67%、9.64%和16.55%),每组设置3个重复,每个重复35尾,第1组为对照组,投喂基础日粮(含脂肪1.73%),另外5组为试验组,在基础日粮中分别添加2%、4%、6%、8%、15%的鱼油,饲养90d后测定生长、饵料系数、营养物质表观消化率及血液常规生化指标。结果显示,随着饲料脂肪水平提高,增重率和特定生长率呈现一个先上升后下降的趋势(P＜0.05),蛋白质效率极显著地提高(P＜0.01),饵料系数极显著地下降(P＜0.01)。增重率与饲料脂肪水平的二次多项式回归分析显示,吉富罗非鱼获得最高增长所需饲料的最佳脂肪水平为9.34%。饲料脂肪水平对粗蛋白表观消化率和饲料干物质表观消化率无显著影响(P>0.05),饲料脂肪水平增加显著提高了粗脂肪和磷的表观消化率(P＜0.05)。未添加鱼油的1.73%组血液中白蛋白和白球比均显著高于其他组(P＜0.05),随着饲料脂肪水平的提高,胆固醇的浓度及碱性磷酸酶的活性极显著地上升(P＜0.01)。饲料脂肪水平对血糖浓度有显著影响(P＜0.05),对甘油三酯浓度、谷丙和谷草转氨酶的活性无显著影响(P>0.05)。结果表明,饲料中的脂肪水平可以促进吉富罗非鱼对脂肪和磷的表观消化率,但是脂肪水平过高会对鱼体增重及血液生化参数产生负作用,从生产上来说吉富罗非鱼鱼种对脂肪的适宜需求量为7.67%-9.34%。       

An experimental study of vocal communication between mother and infant monkeys (Macaca nemestrina)

Vocal communication was studied in six feral-born mother monkeys (Macaca nemestrina) and their three- to four-month-old infants in tests which employed two sound-shielded rooms equipped with microphones and speakers. The mothers' locomotor activity levels were measured as activity counts, and vocalizations of mothers and infants were recorded under three conditions: mothers in two-way auditory communication with their own infants, in two-way auditory communication with other infants of matched sex and age, and without communication. Mothers' vocalizations and activity counts during auditory access were correlated with the number of infants' vocalizations in the same tests. Mothers' activity counts were higher with auditory access to an infant. However, neither activity counts nor vocalizations of mothers differed when in communication with their own infants from the same measures when in communication with matched infants. Neither mothers nor infants vocalized differently, either qualitatively or quantitatively, in the three conditions.     

Spontaneous diabetes mellitus in cynomolgus monkeys (Macaca fascicularis)

Glucose tolerance tests were performed with fourteen cynomolgus monkeys. They were divided into two groups with regard to the serum glucose level at the time of routine health-examination. Nine of them had normal glucose level (below 123 mg/dl, the normal group) and the other five monkeys exhibited hyperglycemia (the abnormal group). Fifty per cent glucose solution was administered into the saphenous vein at a dose of 4 ml/head. Blood samples were taken just before and 5, 10, 20, 30, 60 and 120 minutes after the glucose administration. K-value (K = 0.693/t 1/2 X 100) as the decreasing rate of serum glucose during from 5 to 60 minutes after the administration was calculated. Average K-value for eight monkeys of the normal group was 3.12 +/- 0.48. Both immunoreactive insulin level (IRI) and C-peptide immunoreactivity (CPR) increased just after the glucose administration and began to decrease 5 to 30 minutes after the administration in all the eight animals. Remaining one animal (No. 009) of the normal group showed 1.03 in K-value. For the abnormal group, K-value averaged 0.75 +/- 0.25. IRI was slightly higher in this group than in the 8 monkeys of the normal group. Furthermore, the abnormal group did not show any definite change of a certain trend in IRI and CPR. In conclusion, the former 8 monkeys were judged to be normal in the function of pancreatic beta-cells, and the latter 5 monkeys and No. 009 monkey were judged to be suffering from type II (noninsulin dependent) diabetes mellitus at different stages of the disease.     

Lipoic acid decreases lipid peroxidation and protein glycosylation and increases (Na(+) + K(+))- and Ca(++)-ATPase activities in high glucose-treated human erythrocytes

Lipoic acid supplementation has been found to be beneficial in preventing neurovascular abnormalities in diabetic neuropathy. Insufficient (Na(+) + K(+))-ATPase activity has been suggested as a contributing factor in the development of diabetic neuropathy. This study was undertaken to test the hypothesis that lipoic acid reduces lipid peroxidation and glycosylation and can increase the (Na(+) + K(+))- and Ca(++)-ATPase activities in high glucose-exposed red blood cells (RBC). Washed normal human RBC were treated with normal (6 mM) and high glucose concentrations (45 mM) with 0-0.2 mM lipoic acid (mixture of S and R sterioisomers) in a shaking water bath at 37 degrees C for 24 h. There was a significant stimulation of glucose consumption by RBC in the presence of lipoic acid both in normal and high glucose-treated RBC. Lipoic acid significantly lowered the level of glycated hemoglobin (GHb) and lipid peroxidation in RBC exposed to high glucose concentrations. High glucose treatment significantly lowered the activities of (Na(+) + K(+))- and Ca(++)-ATPases of RBC membranes. Lipoic acid addition significantly blocked the reduction in activities of (Na(+) + K(+))- and Ca(++)-ATPases in high glucose- treated RBC. There were no differences in lipid peroxidation, GHb and (Na(+) + K(+))- and Ca(++)-ATPase activity levels in normal glucose-treated RBC with and without lipoic acid. Thus, lipoic acid can lower lipid peroxidation and protein glycosylation, and increase (Na(+) + K(+))- and Ca(++)-ATPase activities in high-glucose exposed RBC, which provides a potential mechanism by which lipoic acid may delay or inhibit the development of neuropathy in diabetes.     

Effects of chronic mild stress on the oxidative parameters in the rat brain

Major depression is characterized for symptoms at the psychological, behavioral and physiological levels. The chronic mild stress model has been used as an animal model of depression. The consumption of sweet food, locomotor activity, body weight, lipid and protein oxidation levels and superoxide dismutase and catalase activities in the rat hippocampus, prefrontal cortex and cortex were assessed in rats exposed to chronic mild stress. Our findings demonstrated a decrease on sweet food intake, no effect on locomotor activity, lack of body weight gain, increase in protein (prefrontal, hippocampus, striatum and cortex) and lipidic peroxidation (cerebellum and striatum), and an increase in catalase (cerebellum, hippocampus, striatum, cortex) and a decrease in superoxide dismutase activity (prefrontal, hippocampus, striatum and cortex) in stressed rats. In conclusion, our results support the idea that stress produces oxidants and an imbalance between superoxide dismutase and catalase activities that contributes to stress-related diseases, such as depression.     

In situ studies on heart rate and locomotor activity in the freshwater crayfish, Astacus astacus (L.) in relation to natural fluctuations in temperature and light intensity

1. By the aid of a computer technique, the in situ variations in heart rate and locomotor activity were recorded continuously for 7 days in sixteen individuals of the crayfish, Astacus astacus (Linnaeus 1758), in association with natural changes in water temperature and light intensity.
2. All sixteen crayfish investigated were found to express circadian rhythmicity in heart rate with a periodicity of ≈ 24 h. For 88% of the animals investigated, rhythmicity was significant ( P < 0.05). Ninety‐three per cent of the crayfish showed circadian rhythmicity in locomotor activity with a 24 ± 2 h periodicity and, for 67% of the animals, this rhythmicity was significant ( P < 0.05). In general, the expression of circadian rhythms was associated with nocturnal behaviour, heart rates and locomotor activity levels being higher at night than by day.
3. A positive correlation was observed between heart rate and locomotor activity. Temperature and light intensity exerted positive and negative influences on heart rate in A. astacus , respectively.
4. In the first experiment, 84% of the variation in heart rate could be explained by the changes in locomotor activity, temperature and light intensity. In the second experiment 35% of the variation in the heart rate was explained using these parameters.     

Protective effect of Withania somnifera Dunal on the behavioral and biochemical alterations in sleep-disturbed mice (Grid over water suspended method)

Sleep disruption involves extensive changes in physiological function, including EEG, motor, metabolic, autonomic processes physiological homeostasis and psychological balance that are necessary for physical health. Benzodiazepines are the most widely used drugs for the sleep related problems in spite of their limitations and side effects. Objective of the study was to investigate the protective effect of W. somnifera on the behavioral and biochemical alterations in sleep disturbed mice. Pretreatment with W. somnifera root extract (100. 200 mg/kg) and diazepam (0.5 mg/kg) significantly protected reduction in body weight, improved the reduced locomotor activity and anxiety levels in animals. Biochemical studies also revealed that W. somnifera (100 and 200 mg/kg) and diazepam (0.5 mg/kg) pretreatment for five days decreased significantly lipid peroxidation, nitrites levels and improved catalase, and reduced glutathione levels. Co-administration of W. somnifera (100 mg/kg) with diazepam (0.5 mg/kg) improved significantly all the biochemical parameters as compared to their effect per se. Preliminary results suggest that Withania root extract can be used in the management sleep loss and associated oxidative stress.     

Mandibular growth in the rhesus monkey (Macaca mulatta)

Mandibular growth of 42 rhesus monkeys (Macaca mulatta) was analyzed quantitatively and qualitatively. Four groups of animals were defined according to dentitional age (i.e., infant, juvenile, adolescent, young adult). At each age growth was observed for a 24 week period. Since some animals were observed at more than one stage of development, 57 periods of growth were studied. The growth incremental data were collected by superimposing serial cephalograms on mandibular implants. Growth and remodeling of both the skeletal and dento-alveolar components of the rhesus mandible were greatest in the infant monkeys and were less in successive age groups. Posterior relocation of the ramus was noted in all age groups while bone deposition on the anterior and inferior borders of the mandibular body was greatest in the younger animals. The most pronounced dental changes also occurred in the younger animals while the dentitions of the adolescent and adult animals were generally more stable. This study demonstrates that the rate and direction of normal mandibular growth varies with the age of the animal. Furthermore, mandibular growth is quantified at four defined maturational levels to provide a set of values illustrating normal mandibular growth. These values can also be used as control data for experimental studies.     

The hypothalamic arcuate nucleus: a key site for mediating leptin's effects on glucose homeostasis and locomotor activity

Leptin is required for normal energy and glucose homeostasis. The hypothalamic arcuate nucleus (ARH) has been proposed as an important site of leptin action. To assess the physiological significance of leptin signaling in the ARH, we used mice homozygous for a FLPe-reactivatable, leptin receptor null allele (Lepr(neo/neo) mice). Similar to Lepr(db/db) mice, these mice are obese, hyperglycemic, hyperinsulinemic, infertile, and hypoactive. To selectively restore leptin signaling in the ARH, we generated an adeno-associated virus expressing FLPe-recombinase, which was delivered unilaterally into the hypothalamus using stereotaxic injections. We found that unilateral restoration of leptin signaling in the ARH of Lepr(neo/neo) mice leads to a modest decrease in body weight and food intake. In contrast, unilateral reactivation markedly improved hyperinsulinemia and normalized blood glucose levels and locomotor activity. These data demonstrate that leptin signaling in the ARH is sufficient for mediating leptin's effects on glucose homeostasis and locomotor activity.