Total sleep deprivation increases extracellular serotonin in the rat hippocampus

Sleep deprivation exerts antidepressant effects after only one night of deprivation, demonstrating that a rapid antidepressant response is possible. In this report we tested the hypothesis that total sleep deprivation induces an increase in extracellular serotonin (5-HT) levels in the hippocampus, a structure that has been proposed repeatedly to play a role in the pathophysiology of depression. Sleep deprivation was performed using the disk-over-water method. Extracellular levels of 5-HT were determined in 3 h periods with microdialysis and measured by high performance liquid chromatography coupled with electrochemical detection. Sleep deprivation induced an increase in 5-HT levels during the sleep deprivation day. During an additional sleep recovery day, 5-HT remained elevated even though rats displayed normal amounts of sleep. Stimulus control rats, which had been allowed to sleep, did not experience a significant increased in 5-HT levels, though they were exposed to a stressful situation similar to slee-deprived rats. These results are consistent with a role of 5-HT in the antidepressant effects of sleep deprivation.

CYP2D6 polymorphism in a Mexican American population

BACKGROUND

Pharmacogenetic data are largely unavailable for Mexican Americans, despite being one of the largest populations in America.

METHODS

The CYP2D6 genotype (n = 349) and dextromethorphan hydroxylation phenotype (n = 285) were studied in 380 Mexican American subjects from Los Angeles County.

RESULTS

The allelic frequency was 22.8% for CYP2D6*2, 10.3% for CYP2D6*4, 7.4% for CYP2D6*10, 2.3% for CYP2D6*5, 1% for CYP2D6*XN (duplication), and <1% for CYP2D6*3 and CYP2D6*17. By using the published antimode for Caucasians, we identified nine subjects as poor metabolizers, an incidence of 3.2%. Of the eight poor metabolizers who were also genotyped, five either were homozygous for the CYP2D6*4 allele (4 cases) or had a combination of CYP2D6*4 and CYP2D6*5 alleles. The mean log(10) dextromethorphan/dextrorphan ratio was -2.47 for those classified as extensive metabolizers. The number of functional alleles among the extensive metabolizers correlated strongly with the phenotype, suggesting a gene-dose effect.

CONCLUSION

Compared with previous reports on Caucasian populations, studies show that Mexican Americans appear to possess a lower rate of CYP2D6*4. Frequencies for the other alleles appear to be less divergent between the two groups. This genotypic pattern might be responsible for the lower rate for the poor metabolizer status, as well as for the faster enzyme activity in the extensive metabolizer subjects that was also reflected in our data.

Analysis of the CYP2D6 gene polymorphism and enzyme activity in African-Americans in southern California

Despite its importance in drug metabolism and disease susceptibility, CYP2D6 activity and genetic polymorphism have rarely been investigated in African-American populations. In order to bridge this gap, we examined the genotype and phenotype of the enzyme in 154 African-American (AA) and 143 Caucasian (C) normal volunteers. AAs are significantly more likely to possess *17 and *5, but less likely to have *4. Overall, the two groups were similar in their CYP2D6 activity as measured with dextromethorphan as the probe (metabolic ratio 2.21 +/- 0.78 for AAs; 2.11 +/- 0.86 for Cs; t = 1.02, NS). Two of four AAs and six of seven Cs were classified as poor metabolizers and have two nonfunctioning alleles. CYP2D6 activity is determined by *17, *4, *5 and age in AAs (r2 = 0.33, f = 18.8, P < 0.001) and by *4 and *XN in Cs (r2 = 0.14, f = 10.8, P < 0.001). These results support previous findings demonstrating the importance of *17 in determining CYP2D6 activity in AAs.

Pharmacokinetics of reboxetine in healthy volunteers with different ethnic descents

RATIONALE

Ethnicity can affect the pharmacokinetics and pharmacodynamics of psychopharmacologic drugs.

OBJECTIVES

Reboxetine disposition differences among Asians, blacks, and Caucasians were examined.

METHODS

Healthy subjects (12 Asians, 12 blacks, 12 Caucasians) received a single oral dose of one 4-mg reboxetine tablet in an open label, parallel study design. Plasma concentrations of reboxetine enantiomers [R,R(-) reboxetine and predominantly active S,S(+) reboxetine] were quantified using HPLC-MS-MS. Plasma unbound fractions of reboxetine enantiomers were evaluated by equilibrium dialysis. Ethnic group effects on pharmacokinetic parameters were assessed by ANOVA.

RESULTS

Mean S,S(+) reboxetine CLPO for blacks was significantly greater, compared to Asians and Caucasians (154+/-82 ml/min, 101+/-19 ml/min and 101+/-18 ml/min, respectively). Mean S,S(+) reboxetine free fractions (fu) were significantly greater for Asians and blacks, compared to Caucasians (3.04+/-1.28%, 2.89+/-0.69%, and 1.99+/-0.58%, respectively). S,S(+) Reboxetine unbound clearance (CLu) was significantly less for Asians, compared to blacks and Caucasians (3742+/-1468 ml/min, 5187+/-2027 ml/min, and 5294+/-1163 ml/min, respectively). S,S(+) Reboxetine mean unbound AUC (AUCu) in these groups were 20.2+/-7.1 ng.h/ml, 14.6+/-5.1 ng.h/ml, and 13.2+/-3.2 ng.h/ml, respectively. AUCu was significantly greater for Asians. CLu and AUCu did not differ significantly between blacks and Caucasians. Ethnic effects of R,R(-) reboxetine were similar to those observed for S,S(+) reboxetine.

CONCLUSIONS

The AUCu difference between Asian and black and Caucasian subjects was modest. Tolerability differences among groups were not observed. No dosage adjustment is necessary for Asians or blacks.

Brain proton magnetic resonance spectroscopy and imaging in children exposed to cocaine in utero

OBJECTIVE

The effects of prenatal cocaine exposure have been examined using neurobehavioral and brain structural evaluations; however, no study has examined the effects of prenatal cocaine on brain metabolism. Proton magnetic resonance spectroscopy ((1)H-MRS) is a noninvasive method to examine the biochemistry of various brain regions. The purpose of this study was to examine the possible neurotoxic effects of prenatal cocaine exposure on the developing brain using (1)H-MRS.

METHODS

Cocaine-exposed children (n = 14) and age-matched unexposed control participants (n = 12) were evaluated with MRI and localized (1)H-MRS. Metabolite concentrations of N-acetyl-containing compounds (NA), total creatine (Cr), choline-containing compounds, myoinositol, and glutamate + glutamine were measured in the frontal white matter and striatum.

RESULTS

Despite an absence of structural abnormalities in either group, children exposed to cocaine in utero had significantly higher Cr (+13%) in the frontal white matter. NA, primarily a measure of N-acetyl aspartate and neuronal content, was normal in both regions examined by (1)H-MRS. Normal NA suggests no significant neuronal loss or damage in the 2 brain regions examined in children exposed to cocaine prenatally.

CONCLUSIONS

Consistent with findings in abstinent adult cocaine users, we found increased Cr in the frontal white matter, with normal NA in children exposed to cocaine. These findings suggest the need to investigate further possible abnormalities of energy metabolism in the brain of children exposed to cocaine in utero. In addition, this study demonstrates the feasibility of using (1)H-MRS to investigate the effects of prenatal drug exposure on the developing brain.

Effect of cigarette smoking on coumarin metabolism in humans

Extant data, mostly from studies in vitro, suggest that coumarin and nicotine are both metabolized by CYP2A6, a cytochrome P450 isozyme. In order to investigate this issue further, the activity of this enzyme in vivo was measured in 37 non-smokers and 37 smokers using coumarin (2.0 mg, PO) as the metabolic probe. The percentage of coumarin metabolized to 7-hydroxycoumarin in 8 h was measured in urine by high-pressure liquid chromatography. There was more than 10-fold variability in coumarin metabolism in both groups. Coumarin metabolism was significantly reduced in smokers (46.6 +/- 4.4%) as compared to non-smokers (66.4 +/- 3.5%; p < or = .001). The results support previous in vitro findings that both coumarin and nicotine are metabolized, at least in part, by a common pathway, which most likely is CYP2A6.

Contribution of development to buspirone effects on REM sleep: a preliminary report

In order to assess whether development influences the regulation of rapid eye movement (REM) sleep by serotonergic (5-HT) systems, the REM sleep responses to the partial 5-HT(1A) agonist, buspirone, were assessed in 14 normal adolescent and adult volunteers. Subjects were studied on three separate sessions for three consecutive nights. On the second night of each session, subjects received placebo or one of two doses of buspirone (0.14 mg/kg and 0.28 mg/kg, orally). Night 3 was considered the "recovery" night. In adolescents, both doses of buspirone significantly delayed REM latency. In contrast, low-dose buspirone had no effect on REM latency in the adults, and there was only a tendency for prolongation of REM latency with the higher dose. Other measures of REM sleep on nights 2 and 3 were comparable between the two groups. These preliminary results suggest that post-synaptic 5-HT(1A) acceptor-coupled REM sleep responses, particularly REM latency, may be relatively greater in youngsters than in adults, possibly due to reduced presynaptic input. The findings are discussed in relation to the age-dependent expression of REM sleep changes associated with depression.

Effect of ecstasy [3,4-methylenedioxymethamphetamine (MDMA)] on cerebral blood flow: a co-registered SPECT and MRI study

3,4-methylenedioxymethamphetamine (MDMA), an illicit recreational drug, damages serotonergic nerve endings. Since the cerebrovasculature is regulated partly by the serotonergic system, MDMA may affect cerebral blood flow (CBF) in humans. We evaluated 21 abstinent recreational MDMA users and 21 age- and gender-matched healthy subjects with brain SPECT and MRI. Ten of the MDMA subjects also had repeat SPECT and MRI after receiving two doses of MDMA. Abstinent MDMA users showed no significantly different global or regional CBF (rCBF) compared to the control subjects. However, within 3 weeks after MDMA administration, rCBF remained decreased in the visual cortex, the caudate, the superior parietal and dorsolateral frontal regions compared to baseline rCBF. The decreased rCBF tended to be more pronounced in subjects who received the higher dosage of MDMA. Two subjects who were scanned at 2-3 months after MDMA administration showed increased rather than decreased rCBF. Low-dose recreational MDMA use does not cause detectable persistent rCBF changes in humans. The lack of long-term rCBF changes may be due to a non-significant effect of serotonergic deficits on rCBF, or regeneration of serotonergic nerve terminals. The subacute decrease in rCBF after MDMA administration may be due to the direct effect of MDMA on the serotonergic system or the indirect effects of its metabolites on the dopaminergic system; the preliminary data suggest these effects may be transient.

Comparison of noncontingent versus contingent cocaine administration on plasma corticosterone levels in rats

The purpose of the present study was to compare the effects of contingent and noncontingent cocaine administration on plasma levels of corticosterone in rats. Male rats were trained to self-administer cocaine under a fixed-ratio 5 schedule. The rats were yoked such that the delivery of cocaine (0.25 mg/kg/infusion) to one rat (contingent cocaine) produced the simultaneous noncontingent delivery of the same dose of cocaine (noncontingent cocaine) or saline (noncontingent saline) to other rats. Although saline administration had no effect, plasma corticosterone levels were significantly higher in rat receiving contingent cocaine compared to those receiving noncontingent cocaine. These results demonstrate that the active vs. passive administration of cocaine can differentially affect this neuroendocrine response.

Age-related effects of scopolamine on REM sleep regulation in normal control subjects: relationship to sleep abnormalities in depression

In order to assess the influence of development on the regulation of rapid eye movement (REM) sleep by cholinergic systems, the REM sleep responses to scopolamine were assessed in five normal adolescent and seven adult control subjects in this preliminary investigation. Subjects were studied on two separate occasions for three consecutive nights. Subjects received placebo or scopolamine (1.5 ug/kg, i.m.) on night 2; night 3 was considered the "recovery" night. As expected, scopolamine delayed REM latency and suppressed REM sleep on night 2 in both the adolescents and adults. Subtle developmental differences occurred, with scopolamine having a tendency to suppress REM sleep less effectively in younger subjects. On night 3, REM latency was shortened and REM sleep was increased to comparable extent in both the adolescents and adults. The comparable REM sleep responses to scopolamine between normal adolescents and adults, particularly on night 3, are discussed in relation to the age-related expression of REM sleep abnormalities in depression.

REM sleep in depression is influenced by ethnicity

The influence of ethnicity on the manifestation of EEG sleep changes in depression was studied in 95 patients (21 African-Americans [AA], 17 Asians [AS], 37 Caucasians [C] and 20 Hispanics [H]) with unipolar major depression. Subjects were studied twice for 2 consecutive nights. On the second night of each 2-night session, placebo or scopolamine (1.5 microg/kg, IM, at 23.00 h) was administered. On the baseline (placebo) night, sleep architecture, sleep continuity and rapid eye movement (REM) sleep variables were generally comparable among the groups. However, REM sleep was less in AA and AS subjects than in C and H subjects. Furthermore, the distribution of REM sleep over the course of the night in AA and AS subjects differed significantly from that in the C and H groups. Although scopolamine significantly affected sleep continuity and REM sleep measures, no significant differential effects of scopolamine were observed. Because many antidepressants suppress REM sleep, the differences in baseline REM sleep observed might be related to the greater sensitivity of some ethnic-minority depressed patients to pharmacotherapy.

Cerebral (1)H MRS alterations in recreational 3, 4-methylenedioxymethamphetamine (MDMA, "ecstasy") users

3,4-methylenedioxymethamphetamine (MDMA) is an illicit drug that has been associated with serotonergic axonal degeneration in animals. This study evaluates neurochemical abnormalities in recreational MDMA users. Twenty-two MDMA users and 37 normal subjects were evaluated with magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy ((1)H MRS) in the mid-frontal, mid-occipital, and parietal brain regions. (1)H MRS showed normal N-acetyl (NA) compounds in all brain regions. The myo-inositol (MI) concentration (+16.3%, P = 0.04) and the MI to creatine (CR) ratio (+14.1%, P = 0. 01) were increased in the parietal white matter of MDMA users. The cumulative lifetime MDMA dose showed significant effects on [MI] in the parietal white matter and the occipital cortex. The normal NA concentration suggests a lack of significant neuronal injury in recreational MDMA users. However, the usage-related increase in MI suggests that exposure to MDMA, even at recreational doses, may cause increased glial content. J. Magn. Reson. Imaging 1999;10:521-526.

Relationship between ethnicity and sleep patterns in normal controls: implications for psychopathology and treatment

The purpose of the study was to examine ethnic influences on sleep regulation. Seventy-three normal volunteers from four ethnic groups (17 African-Americans, 10 Asians, 30 Caucasians and 16 Hispanics) were studied for two consecutive nights with sleep polysomnography recordings in the laboratory. The subjects were in good physical and psychological health, and were asymptomatic with respect to sleep/wake complaints or sleep disorders. With the exception of minor differences, sleep continuity, sleep architecture and rapid eye movement (REM) sleep patterns were comparable among the four groups. African-Americans had evidence of more stages 1 and 2 and diminished stage 4 sleep, whereas the Hispanics had higher REM density. These preliminary findings suggest that sleep patterns are remarkably similar across cultures. There are, however, important cross-ethnic differences, specifically in the depth of sleep and in phasic REM measures. Because sleep disturbances are common symptoms of emotional disorders and since many psychoactive agents affect sleep, cross-ethnic differences in sleep patterns may have potential implications for the treatment and prevention of psychiatric disorders.

Genetic polymorphism of CYP2E1, ADH2, and ALDH2 in Mexican-Americans

The major enzymes involved in the metabolism of ethanol are alcohol dehydrogenases (ADH) and aldehyde dehydrogenase (ALDH). Some of the isozymes of ADH are expressed polymorphically. Studies investigating a causal link between ADH expression and alcoholic liver disease (ALD) have so far produced conflicting results. The cytochrome P450 2E1 (CYP2E1) represents a second enzyme that can metabolize ethanol. Although normally a minor route of metabolism, its role in chronic alcoholics may be proportionately greater than in nonalcoholics because CYP2E1 is inducible by ethanol. An Rsa I restriction fragment length polymorphism (RFLP) in the 5'-flanking region of the CYP2E1 gene has been identified. Studies have shown that the mutant allele demonstrates greater transcriptional rate, protein level, and enzyme activity when compared with the wild-type allele. The association between the Rsa I site polymorphism and ALD has been reported. In this report, we examined the genotypes of ADH2(2), ALDH2(2), and CYP2E1 in a group of healthy subjects of Mexican-American descent. The ADH2(2) and ALDH2(2) frequencies are 6% and 0%, respectively, which are similar to those which have been reported for Caucasians. In contrast, the Rsa I allele frequency of the CYP2E1 gene is 16%, which is significantly higher than in Caucasians. The high RsaI allele frequency found in Mexican-Americans suggests that it might play a role in the development of ALD in this rapidly growing minority population where ALD is common.

Prenatal stress is associated with depression-related electroencephalographic sleep changes in adult male rats: a preliminary report

1. Prenatal stress in rats has been shown to produce long-term behavioral, neuroendocrine and neurochemical changes. These changes may model aspects of human depressive illness. 2. In this pilot investigation, adult male offspring exposed to stress in utero and non-stressed controls were studied using 24-hour electroencephalographic sleep recordings. 3. Prenatally stressed animals demonstrated reduced latency to the onset of rapid eye movement (REM) sleep, prolongation of the first REM episode, and diminished slow-wave sleep. 4. Although preliminary, the observed changes parallel those seen in studies of human depression. These data further support the face validity of the prenatal stress model as a potential tool for future studies on the pathophysiology of depressive disorder.

Pharmacokinetics of Hoasca alkaloids in healthy humans

N,N-Dimethyltryptamine (DMT), harmine, harmaline and tetrahydroharmine (THH) are the characteristic alkaloids found in Amazonian sacraments known as hoasca, ayahuasca, and yajè. Such beverages are characterized by the presence of these three harmala alkaloids, where harmine and harmaline reversibly inhibit monoamine oxidase A (MAO-A) while tetrahydroharmine weakly inhibits the uptake of serotonin. Together, both actions increase central and peripheral serotonergic activity while facilitating the psychoactivity of DMT. Though the use of such 'teas' has be known to western science for over 100 years, little is known of their pharmacokinetics. In this study, hoasca was prepared and administered in a ceremonial context. All four alkaloids were measured in the tea and in the plasma of 15 volunteers, subsequent to the ingestion of 2 ml hoasca/kg body weight, using gas (GC) and high pressure liquid chromatographic (HPLC) methods. Pharmacokinetic parameters were calculated and peak times of psychoactivity coincided with high alkaloid concentrations, particularly DMT which had an average Tmax of 107.5 +/- 32.5 min. While DMT parameters correlated with those of harmine, THH showed a pharmacokinetic profile relatively independent of harmine's.

Brain N-acetyl aspartate concentrations measured by H MRS are reduced in adult male rats subjected to perinatal stress: preliminary observations and hypothetical implications for neurodevelopmental disorders

The present study was undertaken to determine if the concentration of brain N-acetyl-aspartate (NAA), a putative neuronal marker, is reduced in adult rats subjected to stress during the perinatal period. As the prenatal stressor, pregnant rats were subjected to restraint stress for one hour twice daily from days 14-21 of gestation; stressed offspring were reared by normal dams and studied as adults. As the postnatal stressor, normal pups were reared by prenatally 'stressed' dams and studied as adults. As compared to non-stressed controls (n=6), NAA concentrations were significantly reduced 21 and 25% in left frontal cortex from the prenatal (n=4) and postnatal (n=6) stress groups. respectively. The data suggest that in perinatally stressed adult offspring permanent neuronal damage or loss has occurred. While no direct causal associations between perinatal stress and the developmental of particular disorders can be inferred from these limited data, the effects of perinatal stress on subsequent brain neuropathology are reviewed. particularly in relation to NAA. For hypothesis-generating purposes, the possible relevance of stress and NAA to the neurodevelopmental hypothesis of schizophrenia is discussed in greater detail.

Proton spectroscopy in myotonic dystrophy: correlations with CTG repeats

OBJECTIVES

To seek cerebral metabolite abnormalities in patients with myotonic dystrophy and to determine whether the degree of cerebral abnormalities (measured by proton magnetic resonance spectroscopy) correlates with severity of the genetic defect (measured by trinucleotide repeats).

DESIGN

Fourteen patients with myotonic dystrophy were compared with 24 healthy control subjects.

SETTING

A university-affiliated medical center.

RESULTS

Compared with healthy subjects, patients with myotonic dystrophy had elevated levels of myoinositol (+19% in the occipital region and +12.9% in the temporoparietal region), total creatine (+7.6% and +6.8%), and choline-containing compounds (+21% and +7.7%). Furthermore, the creatine and myoinositol peak areas correlated with the number of trinucleotide cytosine-thymine-guanine(n) (CTG)n repeats from leukocytes, especially in the temporoparietal brain region (r=0.76; P=.004).

CONCLUSIONS

Neurochemical alterations observed with proton magnetic resonance spectroscopy are proportional to the cytosine-thymine-guanine repeat size. Increases in myoinositol and creatine concentrations may be caused by increased glial content, while elevated levels of choline-containing compounds are most likely caused by increased glial content and cell membrane abnormalities. Proton magnetic resonance spectroscopy is a powerful noninvasive tool to study brain biochemistry, which may reflect the extent of neuropathological involvement in patients with myotonic dystrophy.

Sleep electroencephalographic abnormalities in adolescent depressives: effects of scopolamine

In contrast to sleep studies of adult depressives that have consistently demonstrated abnormalities of sleep continuity, slow-wave sleep, and REM sleep, existing studies of depressed children and adolescents have been conflicting. Furthermore, only one study has explored the cholinergic regulation of sleep in early-onset depressives. In the present study, the electroencephalographic sleep of 20 adolescent outpatients with major depressive episodes and 13 normal control adolescents was obtained on two separate 2-night sessions, 1 night incorporating challenge with scopolamine. Depressed adolescents showed increased baseline phasic REM sleep measures, increased arousals, a trend toward reduced slow-wave sleep, and a greater difference in the change of first REM period density on the scopolamine night versus placebo night compared to controls. These findings support the continuity of some sleep abnormalities of depression into adolescence, and suggest that adolescent depression may be associated with alterations of cholinergic neurotransmission in some patients.

Abnormal ACTH and prolactin responses to fenfluramine in rats exposed to single and multiple doses of MDMA

The present study examined the persistent functional consequences associated with exposure to single and multiple doses of (+/-) 3,4-methylenedioxymethamphetamine (MDMA) as reflected by the neuroendocrine responses to d,l-fenfluramine (FEN). Adult male rats were administered a single dose of MDMA (20 mg/kg, s.c.) and challenged 2 weeks later with saline or FEN (2, 4, 6 and 8 mg/kg, s.c.). The corticotropin (ACTH) response to FEN (6 and 8 mg/kg) was blunted and the prolactin response to FEN (4 and 6 mg/kg) was enhanced in MDMA pre-treated rats. The ACTH and prolactin responses to FEN (6 mg/kg, s.c.) were then evaluated 4, 8 and 12 months after exposure to single and multiple doses MDMA (20 mg/kg, s.c. and 20 mg/kg, s.c., bid, x 4 days, respectively). The ACTH response to FEN was significantly reduced at 4 and 8 months in both MDMA treatment groups, and at 12 months in the multiple dose group only. In contrast, the prolactin response to FEN was enhanced in both groups of MDMA treated rats at 4 months, but only in the multiple dose group at 8 months. By 12 months, the prolactin response to FEN had normalized. Following multiple doses of MDMA, 5-HT concentrations were reduced significantly in the frontal cortex at 4 and 12 months. The results indicate that exposure to single or multiple doses of MDMA can produce functional alterations which can persist for months, whereas the biochemical sequelae were less robust and shorter lived.

Differential response of rapid eye movement sleep to cholinergic blockade by scopolamine in currently depressed, remitted, and normal control subjects

The degree of cholinergic dysregulation of sleep in adult depression was evaluated using scopolamine. On separate sessions, placebo and scopolamine (4.5 micrograms/kg, IM) were administered to 14 patients with unipolar major depression, 16 recovered/remitted patients, and 18 normal controls. Scopolamine increased rapid eye movement (REM) latency (RL), reduced REM activity (RA), REM density (RD), and REM duration, and increased the percentage of stage 4 sleep in all groups. There was a differential effect of scopolamine on RL, RA, and REM duration for the first REM period, and on percentage of stage 4 sleep. Whereas a primary cholinergic hyperactivity could account for the RA and RD responses, the response profile for RL was more compatible with reduced aminergic tone as the proximal cause of the cholinergic hyperactivity. Whether the sleep abnormalities observed in remitted patients reflect an underlying vulnerability for development or recurrence of depression, and/or a scar, remains to be determined.

The pharmacokinetics and pharmacodynamics of adinazolam: multi-ethnic comparisons

The pharmacokinetics and pharmacodynamics of adinazolam and N-demethyladinazolam (NDMAD), its major active metabolite, were compared in 39 healthy male volunteers (13 Asian, 12 Caucasian and 14 African-American). In a four-way, double-blind crossover design, subjects were administered (1) 30 mg oral adinazolam mesylate SR tablets, (2) 10 mg parenteral (i.v.) adinazolam mesylate, (3) 30 mg i.v. NDMAD and (4) placebo. Venous blood samples were collected at specific time intervals after drug administration and assayed for adinazolam and NDMAD concentrations. Sedation was rated at the time of each blood draw according to the Nurse-Rated Sedation Scale, and the digit-symbol substitution test was administered to evaluate psychomotor performance. After i.v. administration of adinazolam, Asians manifested significantly higher Cmax, larger AUC and lower CL of both adinazolam and NDMAD than their Caucasian and African-American counterparts. Likewise, after i.v. NDMAD Asians had significantly higher NDMAD Cmax and AUC than Caucasians and African-Americans. Most of these differences remained statistically significant after controlling for body surface area. With PO adinazolam, Asians also manifested substantially higher Cmax, larger AUC and lower CL for both adinazolam and NDMAD; however, with the exception of Cmax, these differences did not reach statistical significance. These results are in accordance with previous observations for ethnic-related differences in drug pharmacokinetics. In contrast, pharmacodynamic differences were not noted among the three study groups.

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.

In vivo proton magnetic resonance spectroscopy of the normal aging human brain

The effect of age on brain metabolite concentrations was evaluated using localized proton magnetic resonance spectroscopy. This technique allows in vivo measurements of N-acetyl compounds (NA), total creatine (CR), choline-containing compounds (CHO), myo-inositol (MI), glutamate and glutamine (GLX), as well as the percentage of cerebrospinal fluid (CSF) and the brain water content within the brain region studied. Frontal gray matter and frontal white matter brain regions were examined in 36 normal healthy volunteers (19-78 years of age). Using a rigorous absolute quantitation method, with an external reference and atrophy correction, we found relatively stable concentrations of NA, a neuronal marker. In contrast, CR, CHO, MI, and the percentage of CSF increased in the gray matter with age. However, the brain water content decreased significantly with age (r = -0.72; p < 0.0001). No significant age-related changes in metabolite concentrations, CSF or brain water content were observed in the white matter regions. These findings demonstrate that biochemical alterations are associated with aging in the frontal gray matter. There might be an increase in the brain density as indicated by increased metabolite concentrations and decreased brain water content with aging.

Psychobiologic effects of 3,4-methylenedioxymethamphetamine in humans: methodological considerations and preliminary observations

3,4-Methylenedioxymethamphetamine (MDMA) is a phenethylamine with potent effects on serotonergic neurotransmission which has been the object of controversy over its potential as a therapeutic adjunct versus its possible risks for causing neurotoxic injury. This paper discusses the background, methodology and preliminary findings of the first FDA approved Phase I study prospectively evaluating the effects of MDMA administration in humans. Six subjects with prior experience with MDMA were administered two different dosages of MDMA and an inactive placebo utilizing a randomized, double-blind methodologic design. Dosages from 0.25 to 1.0 mg/kg, p.o., were administered. All subjects tolerated the procedures without any overt evidence of physical discomfort or psychological distress. MDMA produced a modest increase in heart rate and blood pressure. The threshold dose for the stimulation of ACTH and prolactin appeared to be between 0.5 and 0.75 mg/kg, with the two higher doses clearly stimulating both ACTH and prolactin. Methodology for assessing MDMA's effects on serotonergic neurotransmission is discussed.

Prenatal stress prevents the desensitization of the corticosterone response to TFMPP by desmethylimipramine, but not by phenelzine, in adult male offspring

Gravid female rats were subjected to one hour of restraint stress twice daily or left undisturbed from days 14-21 of gestation. Adult 105-day old male non-stressed (NS) and stressed (S) offspring were treated once daily with saline, desipramine (DMI) (10 mg/kg, sc) or phenelzine (5.0 mg/kg, sc) for 14 days. Twenty-four hours after the last injection, animals were challenged with saline or 1-(m-trifluoromethylphenyl)piperazine (TFMPP) (5.0 mg/kg, sc), a serotonin1B/2C (5-HT1B/2C) agonist, and plasma prolactin and corticosterone concentrations were measured one hour later. As compared to acute saline administration, TFMPP significantly increased prolactin and corticosterone concentrations in all groups. In NS offspring, both DMI and phenelzine treatment augmented the prolactin response, but blunted the corticosterone response, to TFMPP. In S offspring, the prolactin response to TFMPP also was augmented by phenelzine or DMI treatment, whereas the corticosterone response to TFMPP was blunted during phenelzine treatment. However, DMI treatment was not able to desensitize the corticosterone response to TFMPP in the S rats. The results indicate the adaptive capacity of 5-HT systems to DMI administration was compromised in adult animals exposed to stress in utero.

Ethnicity and psychopharmacology. Bridging the gap

Taken together, the literature reviewed clearly indicates that the disposition and effect of a large number of psychotropic agents are influenced substantially by ethnicity and culture. Recent advances in the realm of pharmacokinetics, pharmacogenetics, and pharmacodynamics have led to a greater understanding of some of the mechanisms responsible for such differences. In comparison, much less currently is known regarding how various psychosocial factors impinge on drug responses in different cultural settings. Progress in research in this area is important for clinical reasons, as psychiatric clinicians will increasingly be confronted with patients with divergent ethnic and cultural backgrounds. In addition, knowledge derived from such research will contribute significantly to a better understanding of how the effects of psychotropic agents are mediated, and also should be valuable for the drug development industry that will have to take into account the increasingly diversifying domestic and international markets.

Relationship of 24-hour urinary free cortisol to 4-hour salivary morning and afternoon cortisol and cortisone as measured by a time-integrated oral diffusion sink

The relationship between salivary corticosteroids integrated over 4-hour periods and urinary free cortisol collected over 24 hours was investigated in normal controls. Twenty-one normal volunteers wore "oral diffusion sink" sampling devices in their mouths for two 4-hour periods (08:00-12:00 hours and 13:00-17:00 hours) and on the same day collected a 24-hour urine specimen. Time-integrated salivary corticosteroid concentrations were determined from the sample devices and urinary free cortisol was measured. Salivary corticosteroids were not consistently higher in the morning than in the afternoon period and did not differ between men and women. Urinary free cortisol levels were higher in women. No salivary corticosteroids measure was significantly correlated with urinary free cortisol. We conclude that time-integrated salivary corticosteroids do not reflect urinary free cortisol levels in normal controls.

Pretreatment with MK-801 inhibits pemoline-induced self-biting behavior in prepubertal rats

The indirect dopamine agonist, pemoline (120-300 mg/kg s.c.), can induce self-biting behavior in the rat. The present study demonstrates that the non-competitive N-methyl-D-aspartate (NMDA) antagonist, dizocilpine (MK-801, 0.2 mg/kg s.c.), significantly attenuates pemoline-induced self-biting behavior, while simultaneously increasing locomotor activity. When animals received a fixed dose of MK-801 with increasing doses of pemoline, a competitive relationship emerged such that high-dose pemoline surmounted the antagonistic effect of MK-801. In contrast to spiperone, delayed administration of MK-801 was ineffective in blocking the subsequent expression of self-biting behavior, suggesting that dizocilpine exerts its protective effect early in the cascade of events which eventually leads to self-biting behavior in this paradigm.

Exposure to threshold doses of nicotine in utero: II. Neuroendocrine response to nicotine in adult male offspring

Groups of gravid female rats were injected subcutaneously with saline (SAL), a low-dose of nicotine (LN) (0.05 mg/kg, bid) or a high-dose of nicotine (HN) (3.0 mg/kg, bid) from day 4 to day 20 of gestation, or were left undisturbed. In adult 120-day-old male offspring, the ACTH and prolactin responses to acute nicotine challenge were evaluated. The experiment was performed on three separate occasions. Based upon dose-response and time-course studies with nicotine in normal animals, the neuroendocrine responses to nicotine (0.75 and 1.0 mg/kg, sc) were measured 7.5 min after nicotine administration, the peak response-time for both hormones. The ACTH response to acute nicotine administration was blunted significantly in the HN rats, but normal in the LN rats, for all three experiments. In two experiments, the prolactin response to acute nicotine administration was blunted significantly in the HN rats, but enhanced significantly in the LN offspring. The results indicate that prenatal nicotine administration can produce long-term neuroendocrine effects involving nicotinic-receptor coupled circuits, with long-term functional sequelae produced by dosages of nicotine considerably smaller than previously shown to be pharmacologically/toxicologically active.

Neuroendocrine responses produced by enantiomeric pairs of drugs that interact with phencyclidine and sigma receptors

The present study characterized the response of the hypothalamo-pituitary-adrenal axis after the acute administration of enantiomeric pairs of drugs that bind to phencyclidine (PCP) and sigma receptors. Rats were injected with the enantiomers of 1-(1-phenylcyclohexyl)-3-methylpiperidine (PCMP), N-allylnormetazocine (SKF 10,047), dioxadrol (dexoxadrol and levoxadrol) or pentazocine, and plasma levels of adrenocorticotropin (ACTH) and corticosterone were determined by radioimmunoassay. The effects of the enantiomers of PCMP and dioxadrol showed stereospecificity as both (+)-PCMP and dexoxadrol increased plasma levels of ACTH and corticosterone but (-)-PCMP and levoxadrol had no effect. Whereas (-)-pentazocine produced greater responses than (+)-pentazocine, the two enantiomers of SKF 10,047 did not show stereoselectivity. Although the potency of the enantiomers of PCMP and dioxadrol parallel their affinity for binding to PCP receptors, the potency of the enantiomers of pentazocine did not. These results suggest that although the stimulation of the hypothalamo-pituitary-adrenal axis by PCP and drugs with PCP-like activity might be due to interactions with PCP receptors, the effects of pentazocine also involve interactions at other sites.

Dissociation between plasma bioactive and immunoactive ACTH concentrations in depressed patients

Previous studies have reported dissociations between plasma cortisol and immunoactive adrenocorticotropic hormone (ACTH) concentrations in both normal controls and in patients with major depression. In order to investigate this issue further, placebo and dexamethasone (DEX) were administered to normal controls and depressed patients at 11 PM, and plasma cortisol and ACTH were measured the following morning at 7 AM. Plasma ACTH concentrations were quantitated by both immunoassay (I-ACTH) and by bioassay (B-ACTH). In 10 normal controls, DEX (0.25, 0.5, and 1.0 mg, PO, elixir) produced a dose-related suppression of cortisol, I-ACTH and B-ACTH, with all three hormones significantly suppressed by DEX (0.5 and 1.0 mg) (p < or = 0.01). In 20 depressed patients, 7 AM plasma ACTH and cortisol concentrations were assessed following a single dose of DEX (0.5 mg). Fifteen patients were classified as suppressors and five as escapers, as reflected by mean (+/- SEM) cortisol concentration of 19.9 +/- 3.0 ng/ml and 81.2 +/- 7.0 ng/ml, respectively. Mean I-ACTH concentrations were comparable in both the escapers (8.6 +/- 1.6 pg/ml) and in the suppressors (7.0 +/- 1.0 pg/ml). In contrast, the mean B-ACTH concentration was more than two-fold higher in the escapers (4.5 +/- 0.5 pg/ml) than in the suppressors (2.2 +/- 0.3 pg/ml) (p < or = 0.001). Eleven of the 20 patients received both placebo and DEX (0.5 mg) on two separate occasions. Although DEX significantly suppressed both cortisol (p < or = 0.0001) and B-ACTH (p < or = 0.01) concentrations, I-ACTH was not significantly reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Exposure to threshold doses of nicotine in utero: I. Neuroendocrine response to restraint stress in adult male offspring

Gravid female rats were injected subcutaneously with saline or nicotine (3.0 mg/kg and 0.05 mg/kg, bid) from day 4 to day 20 of gestation or were left undisturbed. In adult 120-day old male offspring, the ACTH, corticosterone and prolactin concentrations before, during (15, 30, 45 and 60 minutes) and after (30, 60, 90 and 120 minutes) one hour of restraint stress were studied. Baseline (non-stress) concentrations of each hormone were comparable among the groups. As compared to saline controls, ACTH concentrations were significantly higher during stress at 30 and 60 minutes in the high-dose nicotine (HN) animals, with the average ACTH concentration during stress also being significantly higher in the HN rats. Neither nicotine regimen affected the corticosterone response to stress at any time-point. The prolactin response to stress was significantly reduced in the HN group at 45 and 60 minutes as compared to saline controls, with the average prolactin concentration also reduced during stress. During recovery, average ACTH concentrations were significantly higher in the HN group, and significantly lower in the LN group, with no differences found for either corticosterone or prolactin. The results indicate that exposure to a high-dose of nicotine during gestation, and to a very low-dose as well, produced functional alterations in adult male offspring as manifested by abnormal neuroendocrine responses to restraint stress. However, the differences between the nicotine and saline controls were sometimes as great as between the non-injected controls and the saline controls. Thus, any conclusions drawn about the long-term effects of prenatal nicotine on neuroendocrine responsivity to stress must be tempered by the influence of the repeated injection procedure.

CSF biochemistries, glucose metabolism, and diurnal activity rhythms in alcoholic, violent offenders, fire setters, and healthy volunteers

BACKGROUND

There is an extensive literature describing a central serotonin deficit in alcoholic, impulsive, violent offenders and fire setters. In the present study, we investigated biochemical concomitants of impulsivity and aggressiveness, and the physiological consequences of reduced central serotonin turnover.

METHODS

Forty-three impulsive and 15 nonimpulsive alcoholic offenders and 21 healthy volunteers were studied in the forensic psychiatry ward of a university psychiatric department. The subjects underwent lumbar punctures and oral glucose and aspartame challenges, and their diurnal activity rhythm was measured with physical activity monitors. Discriminant function analyses were used to investigate psychophysiological and biochemical concomitants of aggressive and impulsive behaviors.

RESULTS

Alcoholic, impulsive offenders with antisocial personality disorder had low mean cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) and corticotropin levels and high mean CSF testosterone concentrations. Compared with healthy volunteers, they showed increased physical activity during the daytime. Alcoholic, impulsive offenders with intermittent explosive disorder had a low mean CSF 5-HIAA concentration and blood glucose nadir after an oral glucose challenge, and desynchronized diurnal activity rhythm. Healthy volunteers had mean CSF 5-HIAA concentrations that were intermediate between those of alcoholic, impulsive and nonimpulsive offenders. Alcoholic, nonimpulsive offenders had a significantly higher mean CSF 5-HIAA concentration than all the other groups, including healthy volunteers.

CONCLUSIONS

In the present sample, a low CSF 5-HIAA concentration was primarily associated with impulsivity and high CSF testosterone concentration, with aggressiveness or interpersonal violence.

Personality profiles and state aggressiveness in Finnish alcoholic, violent offenders, fire setters, and healthy volunteers

BACKGROUND

Based on clinical observations in a series of studies on Finnish alcoholic, violent offenders, we asserted that the impulsive offenders represented an extreme group of type 2 alcoholics. We also observed that these subjects were vulnerable to hypoglycemia after the administration of oral glucose load. Furthermore, we believe that while being hypoglycemic, the impulsive offenders are particularly irritable and aggressive. In the present study, we addressed these issues by studying psychological trait and state variables in a new group of violent offenders and fire setters, and age- and sex-matched healthy volunteers.

METHODS

Fifty-eight alcoholic, violent offenders and impulsive fire setters and 21 healthy volunteers were administered the Karolinska scales of personality and the Rosenzweig picture frustration test after an oral aspartame and glucose challenge.

RESULTS

The psychological test results and the criminal histories of the offenders, together with biochemical measurements, suggest that a low 5-hydroxyindoleacetic acid concentration in cerebrospinal fluid in the alcoholic offenders is associated with irritability and impaired impulse control, and a high free testosterone concentration in cerebrospinal fluid is associated with increased aggressiveness, monotony avoidance, sensation seeking, suspiciousness, and reduced socialization.

CONCLUSION

Finnish alcoholic, impulsive offenders have personality profiles characteristic of Scandinavian early-onset male alcoholics with antisocial traits, who have been also referred to as type 2 alcoholics.

Low-dose naltrexone inhibits pemoline-induced self-biting behavior in prepubertal rats

ABSTRACT Pemoline-induced self-biting behavior has been compared to similar self-injurious behavior (SIB) that occurs in the context of some mental retardation syndromes. The opiate antagonist, naltrexone, has been used successfully in the treatment of SIB in individuals with autism or mental retardation. This is the first report of the effect of naltrexone in an animal model of self-biting behavior. Naltrexone (0.01 mg/kg s.c.) significantly reduced the severity of self-biting behavior, but higher doses (0.10-10 mg/kg s.c.) had no such effect. Consistent with these results in the rat, a review of the clinical use of naltrexone in SIB is also suggestive of a relative loss of efficacy at higher doses (apparent therapeutic window). Naltrexone has higher affinity for mu receptors than other opioid receptor subtypes. Thus, the effect of naltrexone in treating SIB appears to be due to (mu-receptor interactions, with the loss of effect at higher doses due to supervening kappa receptor binding. Speculatively, one may ask if dosage reduction would convert naltrexone nonresponders to responders by lowering kappa receptor-mediated effects. Given the co-localization of opioids and dopamine inputs in some neurons, opioid-dopamine system interactions may also be important in pemoline-induced self-biting behavior.

Effects of low-dose dexamethasone on sleep EEG patterns, plasma cortisol, and the TSH response to TRH in major depression

Dexamethasone (DEX) (0.5 mg, P.O.) and placebo were administered at 2300 h in randomized design to 19 patients with major depression and the effects on the sleep electroencephalogram (EEG) were studied. In addition, the thyroid stimulating hormone (TSH) response to thyrotropin releasing hormone (TRH) and basal plasma cortisol concentrations were assessed the following morning. DEX did not affect sleep architecture or continuity variables, including rapid eye movement (REM) latency, REM activity and REM density. Similarly, DEX did not significantly influence the TSH response to TRH (delta max TSH). In contrast, plasma cortisol concentrations were significantly suppressed by DEX. The results indicate that, as opposed to higher dosages of glucocorticoids, 0.5 mg DEX had minimal effects on the sleep EEG or delta max TSH in depressed patients.

Haloperidol plasma levels and clinical response: a therapeutic window relationship

OBJECTIVE

The purpose of the study was to assess the relationship between plasma haloperidol and clinical response.

METHOD

Sixty-nine newly admitted drug-free schizophrenic men were randomly assigned to receive haloperidol, 5, 10, or 20 mg daily for 4 weeks, and clinical response was measured at the end of the fixed-dose period. Haloperidol was assayed by a sensitive and specific radioimmunoassay.

RESULTS

The authors found a curvilinear relationship between clinical response and plasma haloperidol during fixed-dose treatment, with an apparent optimum between 5 and 12 ng/ml. When plasma levels above 12 ng/ml were lowered to the 5-12 ng/ml range, all patients improved to varying degrees and no patient deteriorated. When plasma levels of nonresponders within this therapeutic window were raised above 12 ng/ml (as in routine practice), they, on balance, deteriorated in that they became more dysphoric. With the 20-mg dose, half the patients had plasma levels above 12 ng/ml.

CONCLUSIONS

In this sample of newly admitted schizophrenic men, optimal clinical response occurred with a plasma haloperidol range of 5-12 ng/ml.

Relationship between REM sleep latency and nocturnal cortisol concentrations in depressed patients

Due to conflicting reports on the possible association between shortening of rapid eye movement (REM) latency and increased cortisol secretion in patients with severe depression, this study examined the relationship between REM sleep latency and nocturnal cortisol concentration in 12 outpatients with major depression. The results showed a significant inverse correlation (r = -0.71, P < 0.01) between REM sleep latency and mean (23.00 hours-03.00 hours) plasma cortisol concentration. Age and severity of depression did not contribute to the inverse relationship. REM activity and density during the first REM period showed no significant correlations with the cortisol measures. A review of the literature suggests that this relationship might be unique to subjects with major depression, and again raises the possibility that these biological disruptions may have a common neurochemical basis.

Ethnicity and family involvement in the treatment of schizophrenic patients

In a cross-ethnic study of neuroleptic response, the level of family involvement with the treatment of 26 Asian and 26 Caucasian patients was evaluated. Asian family members were intimately involved, Caucasians much less so. These results quantitatively demonstrated the relatively greater importance of working with family members when treating Asian patients. They also indicate that relatively more effort is needed to increase involvement of Caucasian families in the treatment process.

Dose-dependent effects of scopolamine on nocturnal growth hormone secretion in normal adult men: relation to delta-sleep changes

To explore the sensitivity of nocturnal GH secretion to different degrees of cholinergic blockade, we investigated the effects of two doses of the muscarinic receptor antagonist scopolamine (SCOP; 3.0 and 6.0 micrograms/kg, im) and placebo, administered in a randomized fashion at 2300 h on three nights to eight normal male volunteers. Both doses of SCOP produced significant reductions in mean nocturnal GH concentration compared to the effects of the placebo; the higher dose of SCOP reduced GH to a greater degree than the lower dose, but this difference was not statistically significant (mean, 2.3 micrograms/L after 6 micrograms/kg vs. 3.0 micrograms/L after 3 micrograms/kg). Both SCOP doses significantly shifted GH secretion into later portions of the night, with a significantly greater delay observed after the larger dose. Similarly, a significant delay in the time of the GH rise was produced by SCOP. In contrast, the effects of both doses of SCOP on delta-sleep or sleep onset were small. These data confirm earlier reports demonstrating that cholinergic muscarinic input represents a potentially important source of regulation of nocturnal GH release and suggest that the magnitude of the reduction in GH and the extent of delay in the GH rise time may reflect quantitative differences in the degree of cholinergic blockade. These data are in agreement with recent studies suggesting that the timing of GH release need not be associated with delta-sleep per se.

Corticosterone and prolactin response to TFMPP in rats during repeated antidepressant administration

The corticosterone and prolactin response to acute administration of the 5-HT agonist 1-(m-trifluoromethylphenyl) piperazine (TFMPP) (10 mg kg-1) was assessed in rats treated for 10 days with either saline, amitriptyline (20 mg kg-1 day-1) or nialamide (40 mg kg-1 day-1). For all groups, TFMPP significantly increased both serum corticosterone and prolactin concentrations compared with control animals challenged with saline. However, the corticosterone response to TFMPP was attenuated significantly by nialamide pretreatment, while the prolactin response to TFMPP was enhanced significantly by amitriptyline pretreatment. These results support previous reports that antidepressants differentially affect 5-HT-ergic systems involved in the regulation of corticosterone and prolactin secretion.