Relevance of perceived childhood neglect, 5-HTT gene variants and hypothalamus-pituitary-adrenal axis dysregulation to substance abuse susceptibility.

The hypotheses of (1) gene x environment interaction in the susceptibility to experiment with drugs and (2) hypothalamus-pituitary-adrenal (HPA) axis involvement in mediating the effects of early adverse experiences and gene variants affecting serotonin function on substance abuse vulnerability were tested by investigating in 187 healthy adolescents the possible relevance of 5-HTT "S" polymorphism, childhood parental neglect reported retrospectively and HPA axis function to the susceptibility to experiment with illicit drugs. Higher frequency of the 5-HTT SS genotype seems to be associated with an increased susceptibility to use illegal psychotropic drugs among the adolescents. At the same time, reduced maternal care perception was found to represent a key intermediate factor of the association between SS polymorphism and drug use, suggesting that genetic factors and parental behavior concur to drug use susceptibility. Our results also confirm the relationship between basal plasma levels of cortisol and adrenocorticotropic hormone (ACTH) on the one hand, and retrospective measures of neglect during childhood: the higher the mother and father neglect CECA-Q scores, the higher the plasma levels of the two HPA hormones. Such positive relationship has been proved to be particularly effective and important when associated to the S-allele, both in homozygote and heterozygote individuals. However, when tested together with genotype and parental neglect, the effect of HPA hormones such as cortisol and ACTH was not found to improve significantly the explanatory power of the risk model.

Childhood neglect and parental care perception in cocaine addicts: relation with psychiatric symptoms and biological correlates.

UNLABELLED: Childhood neglect and poor child-parent relationships have been reported to increase substance use disorders susceptibility. Stressful environmental factors, including emotional neglect, could affect individual personality traits and mental health, possibly inducing stable changes in hypothalamic-pituitary-adrenal (HPA) axis and brain mono-amine function, in turn involved in addictive behavior vulnerability. Therefore, we decided to investigate homovanillic (HVA) and prolactin (PRL) plasma levels, as expression of possible changes in dopamine function, ACTH and cortisol plasma levels, as measures of HPA axis function, and concomitant psychiatric symptoms profile in abstinent cocaine addicts, in relationship to their childhood history of neglect and poor parental care perception. METHODS: Fifty abstinent cocaine dependent patients, and 44 normal controls, matched for age and sex, were submitted to a detailed psychiatric assessment (DSM IV criteria). All patients and controls completed the Symptoms Check List-90 (SCL-90) and the Buss Durkee Hostility Inventory (BDHI), to evaluate psychiatric symptoms frequency and aggressiveness levels. The Childhood Experience of Care and Abuse-Questionnaire (CECA-Q) and Parental Bonding Instrument (PBI) have been used to retrospectively investigate parent-child relationships. Blood samples were collected to determine HVA, PRL, ACTH and cortisol basal plasma levels. RESULTS: Cocaine addicted individuals in general showed significantly lower HVA, and higher PRL, ACTH and cortisol basal levels respect to controls. In particular, neuroendocrine changes characterized cocaine addicts with childhood history of neglect and low perception of parental care. Obsessive-compulsive, depression and aggressiveness symptoms have been found related to poor parenting, inversely associated to HVA levels and directly associated to PRL, ACTH and cortisol levels. CONCLUSIONS: These findings suggest the possibility that childhood experience of neglect and poor parent-child attachment may partially contribute to a complex neurobiological derangement including HPA axis and dopamine system dysfunctions, playing a crucial role in addictive and affective disorders susceptibility.

Effects of olanzapine on aggressiveness in heroin dependent patients.

This study compared the anti-aggressiveness effects of the atypical anti-psychotic olanzapine with that of selective serotonin reuptake inhibitors (SSRI) and benzodiazepines (BZD) among patients with heroin dependence submitted to opioid-agonists substitution treatment. Sixty-seven (67) patients who met the DSM-IV criteria for heroin dependence and showed aggressive personality traits, not affected by comorbid schizophrenia or bipolar disorder, accepted to participate in a 12-week prospective, observational trial. Patients were included into two subgroups in relationship with treatment, for the evaluation of the endpoints at week 12: group 1: substitution treatment in combination with OLA (32 patients); group 2: substitution treatment in combination with fluoxetine/paroxetine and clonazepam (35 patients). Efficacy measures were Buss Durkee Hostility Inventory (BDHI), Symptoms Check List-90 (SCL 90) anger--hostility scores, incidence rates of aggressive incidents and attacks. The rates of patients who remained in treatment at week 12 in group 1, treated with OLA, and group 2, treated with SSRI and BDZ, were not significantly different (17 = 53.1% vs 16 = 45.7%). BDHI total, direct aggressiveness, verbal aggressiveness scores, SCL 90 aggressiveness scores and aggressive incidents rates showed a significantly more consistent decrease from baseline in group 1 than in group 2 subjects, in the patients who completed the treatment (p < 0.001; p < 0.01; p < 0.05; p < 0.01; p < 0.001). Among the completers, 69.3% achieved early full substance abuse remission, while 30.7% achieved partial substance abuse remission, with no significant difference between 1 and 2 treatment subgroups. Although obtained by an observational--open clinical study, with multiple limitations, our findings suggest that OLA may be useful as an adjunctive agent in reducing aggressive/hostile behaviour in heroin addicted individuals during maintenance substitution treatment. Otherwise, atypical anti-psychotic OLA seems to be unable to improve the outcome in terms of addictive behavior and relapse risk in the addicted patients not affected by overt psychotic disorders.

Naltrexone and buprenorphine combination in the treatment of opioid dependence.

Naltrexone treatment has demonstrated some advantages for special populations of heroin addicted individuals, but patients' compliance seems to be very poor, with a low adherence and low retention rate. Kappa-opioid system overdrive seems to contribute to opioid protracted abstinence syndrome, with dysphoria and psychosomatic symptoms during naltrexone treatment. The objective of this observational study was to determine the effectiveness of a functional k antagonist in improving naltrexone treatment outcome. A partial mu agonist/kappa antagonist (buprenorphine) and a mu antagonist (naltrexone) were combined during a 12 weeks protocol, theoretically leaving k antagonism as the major medication effect. Sixty patients were submitted to outpatient rapid detoxification utilizing buprenorphine and opioid antagonists. Starting on the fifth day, 30 patients (group A) received naltrexone alone. Alternatively, 30 patients (group B) received naltrexone (50mg oral dose) plus buprenorphine (4 mg sublingual) for the 12 weeks of the observational study. The endpoints of the study were: retention in treatment, negative urinalyses, changes in psychological symptoms (Symptom Checklist-90 Revised: SCL-90) and craving scores (visual analysis scale (VAS)). Thirty-four subjects (56.67%) completed the 12 weeks study. Twenty-one patients (35.0%) had all urine samples negative for opiates and cocaine. nine subjects (15.0%) had urine samples negative for cocaine and opiates for the last 4 weeks of the study. five subjects (8.3%) continued to use cocaine during the 12 weeks of the study. No significant change in pupillary diameter after buprenorphine administration was evidenced during clinical observations from baseline across the weekly measurements. Retention rates in group A (naltrexone) and group B (naltrexone + buprenorphine) at week 12 were respectively 40% (12 patients) and 73.33% (22 patients), with a significant difference in favour of group B (p= 0.018). Patients treated with naltrexone in combination with buprenorphine (B patients) showed a significantly lower rate of positive urines for morphine (4.45%) and cocaine metabolites (9.09%) than those treated with naltrexone alone (A) (25%, morphine; 33.33% cocaine) (p< 0.05; p< 0.05). Irritability, depression, tiredness, psychosomatic symptoms and craving scores decreased significantly less in Group A patients than in group B patients. The dysfunction of opioid system with kappa receptors hyper-activation provoked by heroin exposure, probably underlying dysphoric and psychosomatic symptoms during naltrexone treatment, seems to be counteracted, at least in part, by buprenorphine. The combination of buprenorphine and naltrexone may significantly improve the outcome of opioid antagonists treatment in terms of retention, negative urinalyses, and reduced dysphoria, mood symptoms and craving.

Determination of homovanillic acid (HVA) in human plasma by HPLC with coulometric detection and a new SPE procedure.

A sensitive high-performance liquid chromatographic method has been developed for the determination of homovanillic acid (HVA), the main metabolite of dopamine, in human plasma. Analyses were carried out on a reversed-phase column (C8, 250 mm x 4.6 mm i.d., 5 microm) using a mobile phase composed of 10% methanol and 90% aqueous citrate buffer, containing octanesulfonic acid and EDTA at pH 4.8. Coulometric detection was used, setting the guard cell at +0.100 V, the first analytical cell at -0.200 V and the second analytical cell at +0.500 V. A careful solid-phase extraction procedure, based on strong anion exchange (SAX) cartridges (100 mg, 1 mL), was implemented for the pre-treatment of plasma samples. Extraction yield was satisfactory, being the mean value 98.0%. The calibration curve was linear over the concentration range of 0.2-25.0 ng mL(-1) of homovanillic acid. The limit of quantitation (LOQ) was 0.2 ng mL(-1) and the limit of detection (LOD) was 0.1 ng mL(-1). The method was successfully applied to plasma samples from former alcohol, cocaine and heroin addicts. Results were satisfactory in terms of precision and accuracy. Hence, the method is suitable for the determination of homovanillic acid in human plasma.

Long-lasting effects of (+/-)3,4-methylenedioxymethamphetamine (ecstasy) on serotonin system function in humans.

BACKGROUND: Fifteen (+/-)3,4-Methylenedioxymethamphetamine (MDMA) users, who did not show other drug dependencies or prolonged alcohol abuse, and 15 control subjects were included in the study. METHODS: Prolactin (PRL) and cortisol (CORT) responses to the serotonergic agonist d-fenfluramine (D-fen), clinical psychobehavioral changes, and psychometric measures were evaluated 3 weeks and then 12 months after MDMA discontinuation. RESULTS: MDMA users showed significantly reduced PRL and CORT responses in comparison with control subjects at 3 weeks (respectively, p < .001; p < .005). The responses of PRL to D-fen were unmodified at 12 months after prolonged abstinence and were significantly reduced in comparison with controls (p < .001). In contrast, CORT responses in MDMA users were restored after 12 months of abstinence, with significantly higher responses to D-fen, in comparison with 3-week responses (p < .05). MDMA users' high scores on the Novelty Seeking (NS) scale on the Tridimensional Personality Questionnaire (TPQ) appeared unchanged by long-term abstinence. In contrast, Buss Durkee Hostility Inventory (BDHI) (Buss and Durkee 1957) direct and guilt scores decreased significantly after 12 months of abstinence. PRL AUCs at 12 months were inversely correlated with the measures of MDMA exposure (r = -.538). CONCLUSIONS: Our data indicate long-lasting 5-HT system impairment in abstinent MDMA users although the hypothesis of serotonergic changes attributable to a premorbid condition cannot be excluded. CORT restored responses to D-fen at 12 months, and the correlation of neuroendocrine changes with MDMA exposure suggest that the neuroendocrine impairment may be due to a partially reversible neurotoxic action of MDMA on the human brain.

Neuroendocrine correlates of temperamental traits in humans.

Studies investigating temperament traits in humans and their biological correlates have found high levels of novelty seeking (NS) linked with dopaminergic system changes, and particularly a deficit of dopamine transporter. Harm avoidance and reward dependence, on the other hand, appeared to be associated, respectively with serotonin and noradrenaline changes. In the present study, we have investigated the dopaminergic (DA), serotonergic (5-HT), and noradrenergic (NE) functions in healthy volunteers by challenging the monoamine systems with the DA agonist bromocriptine, the 5-HT agonist D-fenfluramine, and the NE agonist clonidine, respectively. Parallel to this investigation, we examined the temperament traits of our subjects by measuring NS, harm avoidance (HA) and reward dependence (RD) using the 'Three-dimensional Personality Questionnaire' (TPQ). The aims of the study were to see whether or not the monoamine functions were correlated with temperament traits. Bromocriptine challenge induced a significant GH increase and a significant suppression of PRL. D-fenfluramine test significantly increased PRL and cortisol plasma levels and Clonidine test induced a significant rise in GH values. NS scores showed a significant direct correlation with brom-stimulated GH values (r=0.426, P<0.05) and a significant inverse correlation with brom-inhibited PRL values (r=-0.498, P<0.01). HA scores correlated significantly with D-fen-stimulated PRL and CORT AUCs, (PRL: r=0.424, P<0.05; CORT: r=0. 595, P<0.005). RD scores correlated positively with clon-stimulated GH values (r=0.55; F=8.6; P<0.01) and negatively with brom-inhibited-PRL AUCs (r=-0.439, P<0.05). Our data support Cloninger theory concerning the biological correlates of temperamental traits, and evidence the link between the neuroendocrine responses to dynamic challenges and stable temperament features.

Neuroendocrine responses to experimentally-induced psychological stress in healthy humans.

Previous studies of hormonal and neurophysiological changes in response to psychological stress in humans have produced contrasting findings due to differing experimental procedures and consistent individual variability. Habituation effects, which influence physiological coping in response to exposure to repeated stress, need to be investigated more extensively. In the present study, twenty healthy male subjects were each exposed twice to the same psychosocial stressor (Stroop Color Word Interference task, public speaking and mental arithmetic in front of an audience) during a first session (day 1) and a second session (day 8). Plasma concentrations of norepinephrine (NE), epinephrine (EPI), adrenocorticotropic hormone (ACTH), cortisol (CORT) and prolactin (PRL) were measured immediately before the beginning of the tests and at their end, 30 min later, on both experimental days. For the total group, NE, EPI, ACTH, and CORT levels were significantly elevated, and PRL levels were significantly decreased, after stress exposure on day 1. ACTH and CORT levels showed less significant increases after stress on day 8. In contrast, NE and EPI responses to stress were not significantly blunted, and PRL response was unchanged on day 8. Cluster analysis revealed two groups of subjects who showed different habituation patterns for ACTH and CORT. The first group (n=12) of subjects showed a reduction of ACTH and CORT responses to stress on day 8. The subjects of the second group (n=8) displayed a significant increase of ACTH and cortisol in response to stress on day 8, without any habituation effect. These results increase the evidence concerning the involvement of the HPA axis and catecholamines in response to psychological stress, and suggest that possible individual differences in the neuroendocrine coping mechanisms may affect mood regulation and the state of health.

Pivagabine effects on neuroendocrine responses to experimentally-induced psychological stress in humans.

Neuroendocrinology of chronic stress seems to be characterized by HPA axis hyperactivity and early childhood stressors have been hypothesized to predispose individuals to adult onset depression by means of dysregulation of the HPA axis. Pivagabine (PVG), a hydrophobic 4-aminobutyric acid derivative, has been used experimentally recently in the treatment of different disorders related to stress-maladaptation, because of its possible inhibitory action on corticotrophin releasing factor secretion and HPA axis function. In the present study, 20 healthy male subjects were each exposed twice to the same psychosocial stressor (stroop color-word interference task, public speaking and mental arithmetic in front of an audience) during a first session (day 1) and a second session (day 8). Plasma concentrations of norepinephrine (NE), epinephrine (EPI), adrenocorticotropic hormone (ACTH) and cortisol (CORT), heart rate (HR) and systolic blood pressure (SBP) were measured immediately before the beginning of the tests and at their end, 30 min later, on both experimental days. Utilizing a double blind schedule, the subjects received pivagabine (900 mg, twice a day)(PVG group: nine subjects) or placebo (PBO group: 11 subjects) during the 7 days between the two stress sessions. NE, EPI, ACTH, and CORT levels were significantly elevated after stress exposure on day 1 and day 8 in PBO group subjects. After PVG treatment, on day 8, ACTH, CORT, NE and EPI responses to stress were significantly blunted, together with HR and SBP, in PVG group subjects. These results add to the evidence concerning PVG capacity to inhibit the HPA axis in humans, in response to stressful stimuli, and suggest that the action of PVG may be mediated not only by GABAergic receptors, but also by the suppression of catecholamines response. PVG treatment could modulate HPA hyper-responsiveness to stress in subjects with negative affectivity and depressive traits.

Neurotransmitter and endocrine modulation of aggressive behavior and its components in normal humans.

Correlations between aggressiveness and its components and plasma concentrations of norepinephrine (NE), epinephrine (EPI), testosterone (T), cortisol (Cort) and prolactin (Prl) were studied in 158 physically and psychologically healthy male volunteers. Global aggressiveness, examined directly in the probands by the Buss-Durkee Hostility Inventory (BDHI), was not correlated with any of the biochemical parameters investigated, but reports by first-degree relatives and spouses showed positive correlations between global aggressiveness and NE and T levels. The BDHI scores for 'irritability' and 'resentment' were positively correlated with NE, T and Cort.

Hostility in heroin abusers subtypes: fluoxetine and naltrexone treatment.

1. Substance abusers subtypes have been identified considering underlying psychobiological disorder, familial factors, age of onset, legal problems and drug of choice. 2. In the present study the authors submitted 98 male heroin addicted individuals (age 19-28 y) to the Buss Durkee Hostility Inventory (Italian version) and a structured interview concerning social and clinical history; legal problems, age of onset of drug abuse, drug of choice. 3. Serotonergic system sensitivity was evaluated with fenfluramine challenge for PRL assay. 4. Thirty two patients (group A) showed high score for resentment and guilt at BDHI (hostility in), low rate of legal problems, late age of onset, preference for heroin and alcohol. Twenty nine patients (group B) showed high score for assault and irritability at BDHI (hostility out), high rate of legal problems, early age of onset, preference for heroin and cocaine. The other 37 patients (group C) showed aggression score in the normal range at BDHI, no legal problems, late onset of substance abuse, preference for heroin only. 5. PRL responses was blunted in group A (p < 0.001) and significantly decreased in group B (p < 0.05). PRL plasma levels were inversely correlated with HRSD scores. 6. All the patients were included in a treatment protocol with fluoxetine and naltrexone or placebo and naltrexone for 6 months. 7. The treatment was effective in group A with a significant improvement of BDHI results and decrease of craving score, lower level of drop out, lower level of positive urine controls. No significant differences between fluoxetine and placebo effects have been evidenced in patients of group B and C. The present findings suggest that psychopharmacological approach to addiction needs a diagnostic screening for specific subtypes.

Buprenorphine versus methadone for opioid dependence: predictor variables for treatment outcome.

The present study compared in a clinical non-experimental setting the efficacy of buprenorphine (BUP) and methadone (METH) in the treatment of opioid dependence: all the subjects included in the study showed severe long-lasting heroin addiction. Participants (154) were applicants to a 12 weeks treatment program, who were assigned to either METH (78) (mean doses 81.5 +/- 36.4 mg) or BUP (76) (mean doses 9.2 +/- 3.4 mg) treatment. Aim of the study was to evaluate patient/treatment variables possibly influencing retention rate, abstinence from illicit drugs and mood changes. METH patients showed a higher retention rate at week 4 (78.2 versus 65.8) (P < 0.05), but BUP and METH were equally effective in sustaining retention in treatment and compliance with medication at week 12 (61.5 versus 59.2). Retention rate was influenced by dose, psychosocial functioning and not by psychiatric comorbidity in METH patients. In contrast, BUP maintained patients who completed the observational period showed a significantly higher rate of depression than those who dropped out (P < 0.01) and the intention to treat sample (P < 0.05). No relationship between retention and dose, or retention and psychosocial functioning was evidenced for BUP patients. The risk of positive urine testing was similar between METH and BUP, as expression of illicit drug use in general. At week 12, the patients treated with METH showed more risk of illicit opioid use than those treated with BUP (32.1% versus 25.6%) (P < 0.05). Negative urines were associated with higher doses in both METH and BUP patients. As evidenced for retention, substance abuse history and psychosocial functioning appear unable to influence urinalyses results in BUP patients. Buprenorphine maintained patients who showed negative urines presented a significantly higher rate of depression than those with positive urines (P < 0.05). Alternatively, psychiatric comorbidity was found unrelated to urinalyses results in METH patients. Our data need to be interpreted with caution because of the observational clinical methodology and non-random procedure. The present findings provide further support for the utility of BUP in the treatment of opioid dependency and demonstrate efficacy equivalent to that of METH during a clinical procedure. BUP seems to be more effective than METH in patients affected by depressive traits and dysphoria, probably due to antagonist action on kappa-opioid receptors. Psychosocial functioning and addiction severity cannot be used as valuable predictors of BUP treatment outcome. High doses appear to predict a better outcome, in term of negative urines, for both METH and BUP, but not in term of retention for BUP patients.

Aggressive responding of male heroin addicts under methadone treatment: psychometric and neuroendocrine correlates.

Objective measures of experimentally-induced aggressiveness were evaluated in 20 methadone-treated heroin addicts, in comparison to 20 normal healthy male subjects. All the subjects were submitted to preliminary DSM IV interviews, Buss Durkee Hostility Inventory (BDHI) and Minnesota Multiphasic Personality Inventory (MMPI II). During a laboratory task, the point subtraction aggression paradigm (PSAP), subjects earned monetary reinforcers with repeated button presses, and were provoked by the subtraction of money, which was attributed to a fictitious other participants. Subjects could respond by ostensibly subtracting money from the fictitious subject (the aggressive response), or protecting their counter (escape response). Money-earning responses were significantly lower (t=4.38, P<0.001) and aggressive responses significantly higher (t=5.45; P<0.001) in methadone patients in comparison to controls. During the experimentally-induced aggressiveness, plasma adrenocorticotropic hormone (ACTH), cortisol (CORT) and growth hormone (GH) concentrations increased significantly less and norepinephrine (NE) and epinephrine (EPI) levels, together with heart rate (HR), significantly more in methadone subjects than in healthy subjects. PSAP aggressive responses positively correlated with catecholamines changes, BDHI 'direct' and 'irritability' scores, MMPI 'psychopathic deviate' scores both in methadone subjects and controls, and with CORT responses only in healthy subjects. No correlation was found between methadone doses, or exposure extent, and aggressiveness levels. Our findings suggest that heroin dependent patients have higher outward-directed aggressiveness than healthy subjects, in relationship with monoamines hyper-reactivity, also under methadone medication. Aggressiveness in methadone patients seems to be related more to the personality traits than to drug effects. Hypothalamus-pituitary-adrenal (HPA) axis responses, unexpectedly dissociated from catecholamines rise among methadone patients, could be due to a long-lasting inhibitory action exerted by opiates on pro-opio-melanocortin (POMC), or to a premorbid psychobiological condition that exhausted hormonal reactivity.

Neuroendocrine responses to experimentally-induced emotions among abstinent opioid-dependent subjects.

The present study investigated neuroendocrine and cardiovascular changes during experimentally-induced affective states in abstinent heroin-dependent subjects and healthy controls. The procedure for eliciting emotions in all subjects used pleasant and unpleasant stimuli that did not differ in subjective arousal properties. We investigated whether the valence of the stimuli differentially affected neuroendocrine responses by comparing neutral, pleasant and unpleasant pictures on heart rate (HR), systolic (SBP) and diastolic blood pressure (DBP), methyl-OH-phenyl-glycol (MHPG), norepinephrine (NE), epinephrine (EPI), adrenocorticotrophic hormone (ACTH) and cortisol (CORT) plasma levels. Twelve abstinent heroin-dependent subjects, in comparison with 12 control subjects, were submitted to three experimental sessions, each on one of three experimental days a week apart, in counterbalanced order: day 1=unpleasant pictures, day 2=pleasant pictures, day 3=neutral pictures. In the rating of subjective arousal pleasant and unpleasant stimuli received the same high score in comparison with neutral stimuli; a different cardiovascular and neuroendocrine pattern was obtained in healthy subjects: unpleasant stimuli elicited increases in HR, SBP, MHPG, NE, ACTH, CORT, whereas neutral and pleasant stimuli did not induce any significant response in hormonal levels. In contrast, in heroin addicts, despite increased perceptions of unpleasantness, HR, SBP, MHPG and NE levels did not increase after disliked stimuli; these subjects also reported increased arousal during exposure to neutral stimuli. In comparison with controls, addicted individuals showed higher CORT and ACTH basal levels, and a consequent lack of response to unpleasant stimuli. The results indicate that neuroendocrine and cardiovascular systems respond selectively to affective, motivationally relevant stimuli, and that substance use disorders may be associated with dysregulation of emotion-processing mechanisms.

Neurotransmitter-hormonal responses to psychological stress in peripubertal subjects: relationship to aggressive behavior.

The relationship between different degrees of normal aggressiveness (low, medium, high) and neurotransmitter-neuroendocrine responses to the administration of psychologically stressful tests (Mental Arithmetic, Stroop Color Word Interference task, Trial Social Stress test) was examined in thirty male peripubertal junior school adolescents. Plasma concentrations of norepinephrine (NE), epinephrine (EPI), ACTH, cortisol (CORT), growth hormone (GH), prolactin (PRL) and testosterone (T) were measured immediately before the beginning of the tests and at their end, 30 min later. High-normal aggressiveness have been found associated with significantly higher basal concentrations of NE, ACTH, PRL, and T and with a significant increase of GH responses to the stressful stimuli.

Intravenous flumazenil following prolonged exposure to lormetazepam in humans: lack of precipitated withdrawal.

The capacity of flumazenil to reverse benzodiazepine agonist effects has been widely demonstrated. In contrast, the role of flumazenil in precipitating withdrawal symptoms is unclear in humans: the inability of RO 15-1788 to induce benzodiazepine withdrawal seems to be related to the duration of exposure to the GABAergic drugs. In the present experiment we evaluated the effects of intravenous flumazenil or placebo in 36 healthy volunteers pretreated with lormetazepam for 30 days (2 mg/day) and 18 lormetazepam-dependent subjects (6-8 mg/day). Measurements of a balance task, subject- and observer-rated symptoms showed a reversal of lormetazepam effects induced by flumazenil without any significant withdrawal symptoms. Slight anxiety, increase in heart rate and perspiration were observed in a few subjects. Independent of benzodiazepine doses, long-term treatment seems to be responsible for tolerance development with consistent changes in GABA-benzodiazepine receptor sensitivity. Flumazenil could be able to normalize benzodiazepine receptor sensitivity and exert its weak agonist activity.

Serotonergic function after (+/-)3,4-methylene-dioxymethamphetamine ('Ecstasy') in humans.

(+/-)3,4-Methylene-dioxymethamphetamine (MDMA, or 'Ecstasy') effects on serotonin system function and behaviour in humans are unclear. Fifteen MDMA users, who did not have other drug dependencies or alcohol abuse, and had not used other drugs for prolonged periods, and 15 control individuals were included in a study to assess the biological and psychological changes after chronic use of MDMA. Prolactin and cortisol responses to D-fenfluramine challenge, clinical psychobehavioural changes, personality characteristics, including mood, aggressiveness and temperamental aspects, were evaluated 3 weeks after MDMA discontinuation. MDMA users had significantly reduced prolactin and cortisol responses in comparison with control individuals (p < 0.001 and p < 0.005, respectively). Dysphoria and mood changes were exhibited in seven individuals, tiredness in five and sensation-seeking behaviour in twelve at the clinical evaluation. Significantly higher scores were found in MDMA individuals than in control individuals for Minnesota Multiphasic Personality Inventory subscale for Depression, for Buss Durkee Hostility Inventory direct and guilt subscales, for Hamilton Depression Rating Scale and for novelty-seeking Tridimensional Personality Questionnaire subscale. Prolactin responses to D-fenfluramine stimulation area under the curve among MDMA users were negatively correlated with direct aggressiveness scores for Buss Durkee Hostility Inventory; a negative correlation between prolactin responses and novelty-seeking scores was also evidenced among MDMA users. These data suggest an association between serotonin system impairment and MDMA use in humans; in interpretation of these results, the possibility that serotonin deficit in MDMA individuals was partially related to a premorbid condition, in relationship with novelty-seeking behaviour and mood disorders, can not be excluded.

Naloxone and metergoline effects on growth hormone response to gamma-hydroxybutyric acid.

Gamma-hydroxybutyric acid (GHB) has been recently used in alcohol detoxification, but conflicting data are available concerning the central mechanism of action of this GABA catabolite. GHB ability to stimulate growth hormone (GH) secretion has been reported. Our previous studies revealed the ability of flumazenil (a benzodiazepine antagonist) to counteract GHB effects on GH secretion. Other hypotheses, including an opioid or serotonergic role of GHB, have been considered. In the present study we investigated GH responses to GHB with or without naloxone (an opiate receptor antagonist) or metergoline (a serotonin receptor antagonist) pretreatment. This study included 10 male healthy volunteers (aged 24.3 +/- 2.9 years) who were submitted to four tests in random order: (A) oral GHB administration; (B) oral GHB and i.v. naloxone administration; (C) oral GHB and oral metergoline administration; and (D) oral placebo and i.v. saline administration. Blood samples for GH assay were collected during the three tests at -15, 0, 15, 30, 45, 60 and 90 min. GHB induced a significant increase in GH plasma levels; naloxone pretreatment did not antagonize GHB action on GH secretion; metergoline significantly decreased GH response to GHB (p < 0.05). No changes were obtained with placebo and saline administration. The opioid system does not seem to be involved in GHB effects on GH-secreting pituitary cells; GHB effects on the serotonergic system influencing GH secretion, on the other hand, cannot be excluded.

Neuroendocrine correlates of depression in abstinent heroin-dependent subjects.

The functions of the central alpha-adrenergic, serotoninergic and dopaminergic systems were investigated in 28 heroin-dependent subjects 6-8 weeks after detoxification, and in 22 healthy control subjects (group C). Fourteen heroin-dependent subjects with depressive comorbidity (group A), and 14 heroin-dependent subjects without other Axis I and II pathologies (group B) were included among abstinent substance abusers. Norepinephrine (NE) function was evaluated by growth hormone (GH) responses to acute stimulation with clonidine (clon); serotonin (5-HT) function by prolactin (PRL) and cortisol (CORT) responses to acute stimulation with D-fenfluramine (D-fen) and dopamine (DA) function by GH and PRL responses to acute administration of bromocriptine (brom). Central NE activity, as measured by the GH-clon test, seems to be well preserved both in A and B subjects. PRL and CORT responses to D-fen were significantly blunted both in A subjects and in B subjects, in comparison with control subjects (C); the PRL response in A subjects was significantly lower than in B subjects. The DA system of B subjects was found unimpaired; in contrast, a significantly higher GH response to brom in A subjects (depressed) could express D2 post-synaptic receptor hypersensitivity and, therefore, decreased pre-synaptic DA release. In sum, the study of central monoamine function revealed an alteration only of the 5-HT system in detoxified heroin-dependent subjects without psychiatric comorbidity, which might be a trait character of these subjects, possibly involved in the pathogenesis of the disorder. A more significant impairment of 5-HT function and the hypersensitivity of post-synaptic DA receptors in A subjects suggests that specific biological correlates of psychiatric comorbidity may characterize substance abuser subtypes.

Neurotransmitter-neuroendocrine responses to experimentally induced aggression in humans: influence of personality variable.

Aggressiveness was experimentally induced in 30 psychophysically healthy male subjects, 18-19 years old, divided into 15 cases with low normal and 15 with high normal basal aggressivity. Plasma norepinephrine (NE), epinephrine (EPI), growth hormone (GH), prolactin (PRL), cortisol (CORT) and testosterone (Te) concentrations were measured in basal conditions and during experimentally induced aggressiveness. Basal Te and stimulated NE, GH and Cort levels were higher in subjects with high-normal than in those with low-normal aggressiveness, suggesting that the functional tonus of the NE system and of the NE-dependent hormonal axes might be a modulator of the behavioral parameter.