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J D Higley

Publications and source records attributed to J D Higley.

At least 55 records · Page 3Linked to original sources
PubMed1997

Behavioral and physiological characteristics of Indian and Chinese-Indian hybrid rhesus macaque infants.

Strain differences in temperament and physiology have been reported for several animal species, but nonhuman primates have not been well studied in this regard. We assessed behavioral and physiology in Chinese-Indian hybrid (n = 13) and Indian-origin (n = 29) nursery-reared rhesus monkey infants. Previous data indicate that Chinese-origin and Chinese-Indian hybrid rhesus exhibit more aggression directed toward humans and conspecifics and are more irritable in response to neonatal assessment procedures than are Indian-derived rhesus. In addition, in rhesus adults, low levels of cerebrospinal fluid 5-HIAA have been correlated with impulsivity, aggressive behavior, and diminished social competence. We therefore hypothesized that hybrid infants would exhibit more behavioral and adrenocortical reactivity in the home cage and during social separations, would be less sociable in their peer groups, and would exhibit lower CSF 5-HIAA levels than Indian-derived monkeys. Blood and cerebrospinal fluid samples were obtained on Days, 14, 30, 60, 90, 120, and 150 of life, and prior to and during social separations at 6 months of age. Behavioral observations were conducted in the home cage and during the separation condition. No differences in behavior were observed between hybrid and Indian-derived animals in the home cage. Indian-derived and hybrid infants exhibited diverging patterns of behavioral reactivity across the 4 weeks of the repetitive social-separation procedure, and during reunion periods. Although plasma cortisol levels were sensitive to the testing conditions, no group differences were observed. CSF 5-HIAA declined over time for all monkeys, and hybrid animals exhibited significantly lower 5-HIAA levels than Indian monkeys beginning at 6 months of age. These findings are consistent with the known behavioral and physiological characteristics of Chinese-origin adult rhesus.

Analysis of Variance↗
PubMed1996

CSF testosterone and 5-HIAA correlate with different types of aggressive behaviors.

We studied the potential roles of testosterone and serotonin in various forms of aggressive and violent behaviors by measuring each biochemical and behaviour in free-ranging adolescent male nonhuman primates. Our results showed that (1) CSF free testosterone concentrations were positively correlated with overall aggressiveness, but not with measures of impulsivity. (2) CSF 5-HIAA concentrations were negatively correlated with impulsive behavior, and severe, unrestrained aggression, but not with overall rates of aggression. High rates of impulsive behavior were positively correlated with severe, unrestrained aggression, but not overall rates of aggression. (3) Dimensional analyses showed that while subjects with low CSF 5-HIAA exhibited high rates of aggression, high CSF testosterone further augmented rates and intensity of aggression in subjects with low CSF 5-HIAA. We conclude that high CSF free testosterone concentrations are associated with competitive aggression, while low CSF 5-HIAA concentrations are associated with severe aggression which results from impaired impulse control, and perseverance.

Aggression↗
PubMed1996

Tympanic temperature asymmetry and stress behavior in rhesus macaques and children.

OBJECTIVES: To examine left-to-right tympanic membrane temperature asymmetries and their possible association with biobehavioral stress responses in rhesus macaques and children. SUBJECTS AND DESIGN: Infrared tympanic membrane thermometry was completed bilaterally in 19 two-year-old rhesus macaques and 18 eight-year-old children in a cross-sectional, laboratory-based study. Unidirectional temperature gradients were calculated as the mean of two left-sided measurements minus the mean of two right-sided measurements. Biobehavioral stress responses were assessed in monkeys as agitated motor activity and adrenocortical activation after separation from the social group, and in children as parent-reported resilience to psychological stress and child behavior problems. RESULTS: Significant asymmetry was detected in tympanic membrane temperatures in both monkey and child samples, with left-sided temperatures measuring slightly but significantly higher than those from the right tympanic membrane. Higher-magnitude left-to-right temperature gradients were associated with stress-related locomotion in macaques and with lower resilience and more behavior problems in children. CONCLUSIONS: There are small but reliable asymmetries in the tympanic membrane temperatures of young human and nonhuman primates. Tympanic membrane temperature gradients reflect important individual differences in biologically derived responses to psychological stressors.

Adaptation, Psychological↗
PubMed1996

Excessive mortality in young free-ranging male nonhuman primates with low cerebrospinal fluid 5-hydroxyindoleacetic acid concentrations.

BACKGROUND: The purpose of this study was to assess the impact of central serotonin turnover rate on survival to adulthood among nonhuman primates living in a large, free-ranging colony. METHODS: The rate of mortality was ascertained over a 4-year period after obtaining blood and cisternal cerebrospinal fluid (CSF) samples from 49 free-ranging, 2-year-old prepubertal male rhesus monkeys. Cerebrospinal fluid was assayed for 5-hydroxyindoleacetic acid (5-HIAA), norepinephrine, 3-methoxy-4-hydroxyphenylgycol, and homovanillic acid. Blood plasma was assayed for adrenocorticotropic hormone, cortisol, and testosterone. Following the sampling of body fluids, records of scars and wounds and aggressive encounters were used to rank the subjects from low to high in aggressiveness. Direct observations of aggressive behavior were collected from 27 of the subjects over a 3-month period. RESULTS: Four years later, 6 of the 49 subjects were known to be dead and an additional 5 had been missing for more than 2 years and were presumed dead. The CSF 5-HIAA concentrations were predictive of which subjects died, with 46% of the subjects with low CSF 5-HIAA concentrations dead or presumed dead. None of the subjects from the highest CSF 5-HIAA concentration quartile were dead or missing. Indeed, 91% of the dead subjects came from the 2 lowest quartiles of CSF 5-HIAA concentrations. Direct observations of aggressive behavior showed that dead or missing subjects had initiated escalated aggression, a measure of unrestrained aggression that has a high probability of trauma or injury, at a higher rate than subjects that were known to be alive. The cause of death could be ascertained for 6 of the 11 missing subjects. The 4 subjects that were known to die as a consequence of aggressive encounters came from the lowest quartile of CSF 5-HIAA concentrations and had been rated as more aggressive during their initial capture. Subjects captured more than once possessed lower CSF 5-HIAA concentrations, were rated as more aggressive, and were more likely to suffer early death than those captured only once. CONCLUSION: These findings suggest that low CSF 5-HIAA concentrations quantified early in life is a powerful biological predictor of future excessive aggression, risk taking, and premature death among nonhuman primate males.

Aggression↗
PubMed1996

Stability of interindividual differences in serotonin function and its relationship to severe aggression and competent social behavior in rhesus macaque females.

Few studies have investigated longitudinally interindividual stability of cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) concentrations in adult nonhuman primates across time and between baseline and stressful conditions. Furthermore, whereas studies with male macaques consistently have reported a significant, negative correlation between CSF 5-HIAA and rates of spontaneous aggression, wounding, and severe aggression, very few studies have examined this relationship in adult female nonhuman primates. Even fewer studies have investigated correlations between CSF 5-HIAA and competent social behavior, such as social dominance, in female monkeys. In the present study, two social groups of adult rhesus monkeys (Macaca mulatta) were formed by placing 16 females (aged 42 to 180 months, mean age: 68 months) in one of two indoor-outdoor enclosures with one or two adult males. CSF norepinephrine (NE), monoamine metabolites, and behavioral data were collected systematically over a 24-week period. In week 5 of the study, one additional female, not familiar to any of the other subjects, was added to each social group. Thereafter the groups were left undisturbed, and data characterizing spontaneous aggressive wounding and severe wound injuries in the females were collected for an additional year. The results showed that both group introduction and the addition of a new subject into each group resulted in increased monoamine turnover in the animals within the social groups. Interindividual differences in CSF concentrations of each of the monoamine metabolites and NE were highly stable from the baseline period to the stress samplings, and between stress samplings. Females with low CSF 5-HIAA exhibited higher rates of spontaneous aggressive wounding, and they were more likely to be removed from their social groups for aggressive wounding and/or treatment of injuries. CSF NE concentrations also were negatively correlated with rates of spontaneous aggression. In contrast, competitive aggression, i.e. noninjurious aggression used to maintain social dominance ranking, was not correlated with CSF 5-HIAA or NE. Females with above average CSF 5-HIAA prior to and following group formation were more likely to attain and maintain a high social dominance ranking within their social group than females with below average CSF 5-HIAA. The present findings indicate that CNS monoamine functioning in adult female rhesus macaques is traitlike, showing a high degree of interindividual stability across time and setting. These findings also suggest a role for serotonin in controlling impulses that regulate aggression and that competent social behavior among nonhuman primates may require average or above average serotonin functioning.

Aggression↗
PubMed1996

A nonhuman primate model of type II excessive alcohol consumption? Part 1. Low cerebrospinal fluid 5-hydroxyindoleacetic acid concentrations and diminished social competence correlate with excessive alcohol consumption.

Developmental, biochemical, and behavioral concomitants of excessive alcohol consumption were investigated using a nonhuman primate model. The variables of interest were: (1) interindividual stability of cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) from infancy to adulthood, (2) effect of parental deprivation early in life on adult CSF 5-HIAA concentrations; (3) correlations between CSF 5-HIAA and 3-methoxy-4-hydroxyphenylglycol (MHPG) concentrations and alcohol consumption; and (4) correlation between the frequency of competent social behaviors and alcohol consumption. Twenty-nine rhesus macaques were reared for their first 6 months either with their mothers or without adults in peer-only conditions. At 6 and 50 months of age, each subject underwent a series of four, 4-day social separations. Cisternal CSF was sampled before and during the first and last separations; concomitantly, observational data were collected on social dominance behavior in the home-cage. When they reached 50 months of age, the monkeys were provided free access to a palatable alcohol solution daily for 1-hr periods before, during, and after the social separations. Before and after the 50-month separations, data were collected on all types of social behavior in the home-cage. Results showed that peer-reared subjects consumed more alcohol than mother-reared subjects during baseline conditions. Mother-reared subjects, however, increased their rates of consumption to equal peer-reared subjects' rates of consumption during the conditions of a social separation stressor. Peer-reared subjects also exhibited lower CSF 5-HIAA concentrations in infancy and adulthood than their mother-reared counterparts. With rearing condition held constant, interindividual differences in CSF 5-HIAA, MHPG, and homovanillic acid were stable from infancy to adulthood, and high rates of alcohol were consumed by the young adult monkeys with low CSF 5-HIAA and MHPG concentrations, particularly when the CSF was obtained during the social separations. High rates of alcohol consumption were also observed in subjects with infrequent social interactions and less competent social behaviors. In contrast to the human data, we found no gender differences in rates of alcohol consumption, nor in the correlations between alcohol consumption and the other variables. With some exceptions, findings from the study are generally consistent with predictions from Cloninger's type II model of excessive alcohol consumption in men with low CSF 5-HIAA, who also exhibit impaired impulse control and violent and antisocial behaviors.

Adult↗
PubMed1996

A nonhuman primate model of type II alcoholism? Part 2. Diminished social competence and excessive aggression correlates with low cerebrospinal fluid 5-hydroxyindoleacetic acid concentrations.

The purpose of this study was to develop an animal model for behavioral features of type II, early-onset alcohol abuse. To perform this research, cerebrospinal fluid (CSF) monoamine metabolite concentrations and home-cage social behaviors of 29 rhesus macaque subjects were examined in a 4-year longitudinal study. Half of the monkeys were reared for their first 6 months with their mothers, and the other half were reared without adults, instead with access only to monkeys of similar age. When the subjects were 6 months old, and again when they were 50 months old, they underwent a series of four, 4-day social separations. We obtained cisternal CSF before and during the first and last separation of each series to quantify 5-hydroxyindoleacetic acid (5-HIAA), 3-methoxy-4-hydroxyphenylgycol (MHPG), and homovanillic acid concentrations. After the 6-month separations, subjects were placed into social groups, and social dominance rankings were assessed. Before and after the 50-month separations, social dominance rankings were evaluated again, and home-cage aggression and social behavior data were collected. Over the 3 1/2 years between CSF samplings, records were maintained of subjects' removal from their social groups for excessive aggression or treatment for wounding. Our results showed that among infants, reduced CSF 5-HIAA was correlated with low social dominance. As young adults, subjects from both rearing groups with low CSF 5-HIAA and MHPG concentrations exhibited reduced rates of social interaction and low social dominance rankings. In addition, peer-reared subjects with low CSF 5-HIAA concentrations exhibited inept social behaviors, and were frequently removed from their social groups for excessive aggression and deviant social behaviors. From these results, we conclude that the peer-rearing paradigm aggravates the untoward social consequences associated with low CSF 5-HIAA concentrations over and beyond reducing CSF 5-HIAA concentrations, suggesting that early experiences may contribute to CNS serotonin changes that increase the disposition to type II-related behaviors.

Adult↗
PubMed1995

Cerebral glucose metabolism, CSF 5-HIAA levels, and aggressive behavior in rhesus monkeys.

OBJECTIVE: Considerable evidence suggests that low concentrations of 5-hydroxyindoleacetic acid (5-HIAA) in CSF are associated with a history of aggressive behavior in both human and nonhuman primates. The purpose of this investigation was to examine the relationships among CSF 5-HIAA concentration, history of aggressive behavior, and cerebral glucose metabolism in a group of nonhuman primates whose CSF 5-HIAA had been sampled several times over the preceding 2 years and whose social behavior had been observed since birth. METHOD: The subjects were nine adult male rhesus monkeys studied under isoflurane anesthesia. Cerebral glucose utilization was measured by [18F]fluorodeoxyglucose positron emission tomography. Aggressiveness ratings were made by a primatologist who had had frequent contact with the animals over several years. RESULTS: There was a significant negative correlation between ratings of aggressive behavior and CSF 5-HIAA concentrations. There was also a negative correlation between the dose of pentobarbital required to induce anesthesia and level of CSF 5-HIAA. Moreover, there were significant negative correlations between CSF 5-HIAA levels and both whole brain glucose utilization and regional glucose utilization in the orbital-frontal cortex. CONCLUSIONS: These results suggest that both increased aggressiveness and low concentrations of CSF 5-HIAA are associated with higher brain glucose metabolism in rhesus monkeys under standardized anesthesia. Aggressive nonhuman primates with low CSF 5-HIAA concentrations may have "innate" tolerance toward functional gamma-aminobutyric acid A receptor agonists such as pentobarbital, isoflurane, and possibly alcohol.

Aggression↗
PubMed1995

Correlation of CSF 5-HIAA concentration with sociality and the timing of emigration in free-ranging primates.

OBJECTIVE: The purpose of this study was to examine the relationship between behavior and serotonin in nonhuman primates. METHOD: During a routine capture and medical examination, 26 adolescent male rhesus macaques (Macaca mulatta) were selected as subjects from a free-ranging population of 4,500 rhesus monkeys inhabiting a 475-acre sea island. Blood samples (N = 23) and CSF samples (N = 22) were obtained, and each subject was fitted with a radio transmitter collar for rapid location. The subjects were released into their social groups, and quantitative behavioral observations were made over a 3-month period. RESULTS: CSF 5-hydroxyindoleacetic acid (5-HIAA) concentration was positively correlated with three measures of sociality: 1) total time spent grooming others, 2) total time spent in close proximity to other group members, and 3) mean number of neighbors within a 5-m radius. In addition, CSF 5-HIAA concentration was positively correlated with age at emigration from the natal group (in months). CONCLUSIONS: In adolescent male rhesus macaques living in naturalistic settings, CSF 5-HIAA concentration is positively correlated with affiliative sociality. Rhesus males with low CSF 5-HIAA concentrations exhibit less social competence and emigrate from their social groups at a younger age than do males with higher concentrations of CSF 5-HIAA.

Age Factors↗
PubMed1994

Serotonin, violent behavior and alcohol.

At the NIAAA intramural research program, in collaboration with investigators at the Department of Psychiatry, University of Helsinki, we have mounted an extensive research program on early onset male alcoholism. A central serotonergic deficit is common among these patients. This finding has led to behavioral, biochemical, physiological and molecular genetic studies on the serotonin system in early onset, antisocial and violent male alcoholics and in appropriate control populations. The results of the studies completed by the fall of 1993 are summarized in this communication.

Age Factors↗
PubMed1994

Low CSF 5-HIAA concentrations and severe aggression and impaired impulse control in nonhuman primates.

OBJECTIVE: The purpose of this study was to examine the relationship between behavior and serotonin by using a nonhuman primate model of aggression and impulse control. METHOD: During a routine capture and medical examination, 26 adolescent male rhesus macaques (Macaca mulatta) were selected as subjects from a free-ranging population of 4,500 rhesus monkeys inhabiting a 475-acre sea island. Physiological data were obtained from 22-23 of the subjects. Blood and CSF samples were obtained, and each subject was fitted with a radio transmitter collar for rapid location. The subjects were released into their social groups, and quantitative behavioral observations were made over a 3-month period. RESULTS: CSF 5-hydroxyindoleacetic acid (5-HIAA) concentrations were inversely correlated with "escalated" aggression, i.e., a measure of more intense or severe aggression as defined by the ratio of chases and physical assaults to all aggressive acts. CSF 5-HIAA concentrations were significantly lower in those subjects who showed evidence of physical wounding than in subjects with no wounds. Low CSF 5-HIAA concentrations were also correlated with greater risk-taking as determined by an analysis of leaping behaviors in the forest canopy. The ratio of long leaps (leaps that traversed the longest distances at dangerous heights) to all leaps was negatively correlated with CSF 5-HIAA concentrations. CONCLUSIONS: Adolescent male rhesus macaques with low CSF 5-HIAA concentrations are at risk for 1) exhibiting more violent forms of aggressive behavior and 2) loss of impulse control as evidenced by greater risk taking during movement through the forest canopy.

Aggression↗
PubMed1993

Paternal and maternal genetic and environmental contributions to cerebrospinal fluid monoamine metabolites in rhesus monkeys (Macaca mulatta).

BACKGROUND: To study genetic and environmental contributions to cerebrospinal fluid (CSF) monoamine concentrations, 55 young rhesus monkeys (Macaca mulatta) were reared apart from their 10 fathers to perform a paternal half-sibling analysis. METHODS: To study maternal genetic contributions, 23 infants were reared with their mothers, 23 infants were removed from their mothers at birth and fostered to unrelated lactating female monkeys, and 24 infants were removed from their mothers at birth and reared with age-matched peers. When the monkeys reached age 6 months, CSF samples were obtained via cisternal puncture prior to and during a series of social separations. RESULTS: When the results were statistically pooled according to the biological father, comparisons using analysis of variance indicated that both CSF 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) concentrations showed significant heritable (h2) effects (h2 > 0.5) for both sons and daughters, whereas 3-methoxy-4-hydroxyphenylglycol (MHPG) showed a nearly significant paternal genetic effect only for sons (h2 > 0.5). In addition, there were substantial maternal genetic influences on the young monkeys' CSF MHPG and 5-HIAA (h2 > 0.5) levels. Structural equation analyses indicated a maternal genetic contribution without a maternal environmental contribution to CSF 5-HIAA concentration; on the other hand, there was both a maternal genetic and environmental contribution to MHPG. CONCLUSIONS: These findings suggest that a significant portion of the variance in the turnover of the monoamine neurotransmitters is determined by genetic mechanisms.

Animals↗
PubMed1992

A longitudinal assessment of CSF monoamine metabolite and plasma cortisol concentrations in young rhesus monkeys.

Twenty-two rhesus macaques were studied longitudinally from infancy to early adolescence in order to assess the effects of developmental change, experimental history, gender, and individual variation on the response of the catecholaminergic, serotonergic, and adrenocortical systems to separation-induced stress. Experimental effects were assessed by comparing subjects reared for the first 6 months of life either with their mothers or in peer groups. Developmental changes in response to repeated separation stress were assessed by subjecting the monkeys to four sequential 4-day social separations when they were 6 and 18 months old. At both ages, prior to, and on the last day of the first and fourth separations, cerebrospinal fluid (CSF) was obtained from the cisterna magna to assess monoamine metabolite concentrations, and blood samples were collected to assess plasma cortisol concentrations. Blood samples were also obtained on the first day of each separation at each age. Age-related declines were found in both homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) concentrations for all subjects. Social separation consistently increased CSF 3-methoxy-4-hydroxyphenolglycol (MHPG) over baseline levels, but decreased HVA concentrations, whereas 5-HIAA levels increased following the first, but not the fourth separation. Plasma cortisol increased rapidly immediately after separation and remained higher than baseline on day 4 of both the first and fourth separation. Independent of age and experimental condition, peer-rearing increased CSF MHPG and plasma cortisol concentrations. During year 1, peer-rearing also produced diminished CSF 5-HIAA concentrations in female monkeys relative to female mother-reared monkeys, but increased male peer-reared monkeys' concentrations relative to mother-reared males. Interindividual differences were highly stable, with significant correlations both within and between years for each of the three metabolites and cortisol.

Animals↗
PubMed1992

Cerebrospinal fluid monoamine and adrenal correlates of aggression in free-ranging rhesus monkeys.

Clinical and preclinical studies involving several different mammalian species and research paradigms suggest a negative correlation between aggression and central serotonin activity. To test the generalizability of laboratory findings in rhesus monkeys that show a negative correlation between cerebrospinal fluid 5-hydroxyindoleacetic acid concentrations and aggression, we obtained cisternal cerebrospinal fluid and blood plasma samples from monkeys living in naturalistic conditions. During a semiannual trapping, 28 juvenile and adolescent male rhesus monkeys were chosen from a population of 4200 provisioned, free-ranging rhesus monkeys living on Morgan Island, a sea island located off the coast of South Carolina. Based on direct observations of participation or avoidance of aggressive behavior and examinations of apparent fight wounds, 18 monkeys were selected for cerebrospinal fluid taps and blood samples. The remaining 10 monkeys were selected at random. Descriptions of aggressive behavior and the number of old scars and recent wounds were carefully transcribed, and a photograph showing wounds and scars was obtained for each animal. Using the transcriptions and photographs, researchers experienced in rhesus monkey behavior, but blind to the subjects' monoamine and hormone concentrations, were asked to rank the monkeys from the most to the least aggressive. The results showed a significant negative correlation between high rankings for aggression and cerebrospinal fluid 5-hydroxyindoleacetic acid concentrations. There was evidence that aggression was associated with stress, in that cerebrospinal fluid, norepinephrine, and plasma corticotropin and cortisol concentrations were positively correlated with high rankings of aggression.

Adrenocorticotropic Hormone↗
PubMed1991

Nonhuman primate model of alcohol abuse: effects of early experience, personality, and stress on alcohol consumption.

Twenty-two 50-month-old rhesus monkeys were provided concurrent free access to an aspartame-sweetened 7% ethanol solution and an aspartame-sweetened vehicle before, during, and after social separation. Subjects had been reared for their first 6 months of life either without access to adults but with constant access to age mates (peer reared), a condition producing reduced exploration and increased fear-related behaviors, or as controls with their mothers; thereafter, all subjects received identical treatment. During home-cage periods, for 1 hr each day, 4 days a week, when the ethanol solution and vehicle were freely available, peer-reared subjects consumed significantly more alcohol than mother-reared subjects. When stress was increased via social separation, mother-reared animals increased their alcohol consumption to a level nearly as high as that of peer-reared monkeys. Average individual differences in alcohol consumption were markedly stable over time. In addition, there were strong positive correlations between alcohol consumption and distress behaviors. Biological indices of increased stress, such as plasma cortisol and corticotropin, were higher in peer-reared subjects. Within the peer- and mother-reared groups, these indices were positively correlated with alcohol consumption. The results suggest that early rearing experiences that predispose monkeys to increased fear-related behaviors produce excessive alcohol consumption under normal living conditions. Furthermore, a major challenge such as social separation increases alcohol consumption to levels producing intoxication even in monkeys not particularly vulnerable to stress.

Alcohol Drinking↗
PubMed1991

CSF monoamine metabolite concentrations vary according to age, rearing, and sex, and are influenced by the stressor of social separation in rhesus monkeys.

In humans, CSF monoamine metabolite concentrations have been shown to vary as a complex function of age, sex, psychiatric diagnosis, and stress. To test for such relationships in rhesus monkeys, 28 subjects, reared either in anxiety producing peer-only groups or in mother-infant dyads, were studied at 6, 18 or 50 months of age. Each monkey underwent a series of four 4-day social separations, each followed by 3 days of reunion. Prior to and during the first and fourth separations, CSF was obtained from the cisterna magna and assayed for the serotonin metabolite 5-HIAA, the dopamine metabolite HVA, and the norepinephrine metabolite MHPG. CSF 5-HIAA showed an age-related decline which was greater in the mother-reared subjects. Peer-only-reared males had an increased 5-HIAA concentration relative to females, and higher 5-HIAA levels than mother-reared males. MHPG was also higher in peer-only-reared monkeys than in mother-reared subjects at all ages. In both groups HVA declined across the three ages, and MHPG increased from the 18- to the 50-month measurements. Both MHPG and 5-HIAA concentrations increased during the initial social separation, although only MHPG remained elevated across the repeated separations; HVA, on the other hand declined during social separation. These results are discussed in terms of established anxiety and aggression differences between peer-only and mother-reared monkeys.

Aging↗
PubMed1989

Pituitary--adrenal response to capture in Cayo Santiago--derived group M rhesus monkeys.

113 rhesus monkeys, representing 4 age classes, 3 matrilines, and immigrant adult males in a 161-member Cayo Santiago-derived troop living in a 2-acre enclosure, were sampled for levels of plasma ACTH and cortisol during a period of capture and brief cage confinement for routine veterinary examination. ACTH levels showed significant decreases over initially high values following capture in all subjects except infants, whereas cortisol levels remained elevated throughout the sampling period. Members of the lowest-ranking matriline had significantly higher ACTH levels than members of the other matrilines and immigrant males. Infants and juveniles exhibited higher cortisol levels than adolescent and adult monkeys. The overall pattern of results was generally consistent with previous findings from laboratory studies, providing not only evidence of generality across conditions and subject populations but also the basis for more detailed subsequent analyses of the relationship between pituitary-adrenocortical responsiveness, behavioral response to challenge, and age-sex-dominance status in wild-born rhesus monkeys.

Academies and Institutes↗