Urinary excretion of 5-hydroxyindoleacetic acid--no relationship to the level in cerebrospinal fluid

Low central nervous system serotonergic activity is traitlike and correlates with impulsive behavior. A nonhuman primate model investigating genetic and environmental influences on neurotransmission

We have used nonhuman primates to examine developmental and behavioral correlates of CNS serotonergic activity, as measured by concentrations of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid (CSF). These studies show that interindividual differences in CNS serotonin turnover rate exhibit traitlike qualities and are stable across time and settings, with interindividual differences in CSF 5-HIAA concentrations showing positive correlations across repeated sampling. Primates with low CNS serotonergic activity exhibit behaviors indicative of impaired impulse control, unrestrained aggression, social isolation, and low social dominance. Maternal and paternal genetic influences play major roles in producing low CNS serotonin functioning, beginning early in life. These genetic influences on serotonin functioning are further influenced by early rearing experiences, particularly parental deprivation.

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.

Interrelationships of neurochemicals, estrogen, and recurring headache

Recurring headache syndromes, such as migraine, are common problems for women throughout their adult lives. Headache symptoms often fluctuate over the years that they are present and, for most headache sufferers, these changes seem to occur randomly. For many women, however, chronic headache changes in predictable patterns in relation to alterations in hormonal states. Clinically, headache is often modified during menses, pregnancy, and menopause. Although sex hormones are changing with these clinical events, this paper will present the more important link between altered sex hormones and changes in neurochemicals believed to be responsible for recurring headache syndromes according to the neurobiological theory of migraine.

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.

Determination of urinary 5-hydroxyindole-3-acetic acid by high-performance liquid chromatography with electrochemical detection and direct sample injection

A method for the routine quantitative determination of the major serotonin metabolite 5-hydroxyindole-3-acetic acid (5-HIAA) in urine is described. 5-HIAA was analyzed without prior sample cleanup, using an automated high-performance liquid chromatography system with isocratic elution and electrochemical detection (+0.60 V versus a Ag/AgCl reference electrode). The urine samples were mixed with a solution of the internal standard (5-hydroxyindole-3-propionic acid) and centrifuged. The supernatant was transferred to sealed glass vials, and a 2-microliters aliquot was injected directly onto a C18 reversed-phase analytical column, using an automatic sample injector. Samples of urine could be stored for several months at -80 or at +7 degrees C for 2 days without loss of 5-HIAA. However, a gradual decline with time occurred in crude samples stored at room temperature or above, as well as in urine samples diluted with the mobile phase. The detector response was linear in the range of 0-65 mumol/l 5-HIAA, and the intra- and interassay coefficients of variation were about 5 and 7%, respectively (n = 10).

Urinary monoamine metabolites as indices of mental stress in healthy males and females

Concentrations of the serotonin metabolite 5-hydroxyindole acetic acid (5-HIAA), the dopamine metabolite homovanillic acid (HVA) and the noradrenaline metabolite 4-hydroxy-3-methoxyphenyl glycol (HMPG) were determined in urine samples from healthy male and female students by mass fragmentography. Urine samples were obtained after a demanding examination (mental stress) and a day of ordinary school work (control condition). Self-ratings were obtained of feelings induced by the examination, and of habitual psychosomatic symptoms. The results for both sexes showed that the examination stress induced a significant increase of HVA and HMPG excretion, but not of 5-HIAA. The males excreted significantly more of each of the metabolites than the females. The pattern of correlations between metabolite levels and psychological and psychosomatic variables were strikingly different for the two sexes.

Concentrations of 5-hydroxyindoleacetic acid and homovanillic acid in the cerebrospinal fluid of chronic therapy-resistant schizophrenics before and after hemodialysis therapy

The concentrations of the monoamine metabolites 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) have been determined by high-performance liquid chromatography in samples of lumbar cerebrospinal fluid from chronic therapy-resistant schizophrenics, both before and after either inactive or active hemodialysis for 10 weeks. A reasonable test-retest reliability was found for 5-HIAA during the inactive dialysis, but this was not found during active dialysis.