Effects of psychotropic drugs (desimipramine, chlorimipramine, sulpiride and diazepam) on the human HPA axis

Psychotropic Drug Effects on Steroid Stress Hormone Release and Possible Mechanisms Involved

There is no doubt that chronic stress accompanied by adrenocortical stress hormone release affects the development and treatment outcome of several mental disorders. Less attention has been paid to the effects of psychotropic drugs on adrenocortical steroids, particularly in clinical studies. This review focuses on the knowledge related to the possible modulation of cortisol and aldosterone secretion under non-stress and stress conditions by antipsychotic drugs, which are being used in the treatment of several psychotic and affective disorders. The molecular mechanisms by which antipsychotic drugs may influence steroid stress hormones include the modulation of central and/or adrenocortical dopamine and serotonin receptors, modulation of inflammatory cytokines, influence on regulatory mechanisms in the central part of the hypothalamic-pituitary axis, inhibition of corticotropin-releasing hormone gene promoters, influencing glucocorticoid receptor-mediated gene transcription, indirect effects via prolactin release, alteration of signaling pathways of glucocorticoid and mineralocorticoid actions. Clinical studies performed in healthy subjects, patients with psychosis, and patients with bipolar disorder suggest that single and repeated antipsychotic treatments either reduce cortisol concentrations or do not affect its secretion. A single and potentially long-term treatment with dopamine receptor antagonists, including antipsychotics, has a stimulatory action on aldosterone release.

Effects of antipsychotics on circadian rhythms in humans: a systematic review and meta-analysis

Antipsychotics are widely used to treat psychiatric illness and insomnia. However, the etiology of insomnia is multifactorial, including disrupted circadian rhythms. Several studies show that antipsychotics might modulate even healthy circadian rhythms. The purpose of this systematic review is to integrate current knowledge about the effects of antipsychotics on the circadian rhythms in humans, and to conduct a meta- analysis with the available data. Nine electronic databases were searched. We followed the PRISMA guidelines and included randomized controlled trials (RCTs), non-RCTs, case-control studies, case series, and case reports. Of 7,217 articles, 70 were included. The available data was mainly from healthy individuals, or patients having schizophrenia, but the findings showed a transdiagnostic impact on circadian parameters. This was consistently seen as decreased amplitude of cortisol, melatonin, and body temperature. Particularly, a meta-analysis of 16 RCTs measuring cortisol rhythm showed that antipsychotics, especially atypical antipsychotics, decreased the cortisol area under the curve and morning cortisol level, compared to placebo. The data with melatonin or actigraphy was limited. Overall, this evidence about the circadian effect of antipsychotics showed a need for longitudinal, real-time monitoring of specific circadian markers to differentiate a change in amplitude from a shift in phasing, and for knowledge about optimal timing of administration of antipsychotics, according to individual baseline circadian parameters. Standardizing selection criteria and outcome methods could facilitate good quality intervention studies and evidence-based treatment guidelines. This is relevant considering the accumulating evidence of the high prevalence and unfavorable impact of disrupted circadian rhythms in psychiatric disorders.

Changes in Cortisol but Not in Brain-Derived Neurotrophic Factor Modulate the Association Between Sleep Disturbances and Major Depression

Sleep disturbance is a symptom consistently found in major depression and is associated with a longer course of illness, reduced response to treatment, increased risk of relapse and recurrence. Chronic insomnia has been associated with changes in cortisol and serum brain-derived neurotrophic factor (BDNF) levels, which in turn are also changed in major depression. Here, we evaluated the relationship between sleep quality, salivary cortisol awakening response (CAR), and serum BDNF levels in patients with sleep disturbance and treatment-resistant major depression (n = 18), and in a control group of healthy subjects with good (n = 21) and poor (n = 18) sleep quality. We observed that the patients had the lowest CAR and sleep duration of all three groups and a higher latency to sleep than the healthy volunteers with a good sleep profile. Besides, low CAR was correlated with more severe depressive symptoms and worse sleep quality. There was no difference in serum BDNF levels between groups with distinct sleep quality. Taken together, our results showed a relationship between changes in CAR and in sleep quality in patients with treatment-resistant depression, which were correlated with the severity of disease, suggesting that cortisol could be a physiological link between sleep disturbance and major depression.

Cortisol and Major Depressive Disorder-Translating Findings From Humans to Animal Models and Back

Major depressive disorder (MDD) is a global problem for which current pharmacotherapies are not completely effective. Hypothalamic-pituitary-adrenal (HPA) axis dysfunction has long been associated with MDD; however, the value of assessing cortisol as a biological benchmark of the pathophysiology or treatment of MDD is still debated. In this review, we critically evaluate the relationship between HPA axis dysfunction and cortisol level in relation to MDD subtype, stress, gender and treatment regime, as well as in rodent models. We find that an elevated cortisol response to stress is associated with acute and severe, but not mild or atypical, forms of MDD. Furthermore, the increased incidence of MDD in females is associated with greater cortisol response variability rather than higher baseline levels of cortisol. Despite almost all current MDD treatments influencing cortisol levels, we could find no convincing relationship between cortisol level and therapeutic response in either a clinical or preclinical setting. Thus, we argue that the absolute level of cortisol is unreliable for predicting the efficacy of antidepressant treatment. We propose that future preclinical models should reliably produce exaggerated HPA axis responses to acute or chronic stress a priori, which may, or may not, alter baseline cortisol levels, while also modelling the core symptoms of MDD that can be targeted for reversal. Combining genetic and environmental risk factors in such a model, together with the interrogation of the resultant molecular, cellular, and behavioral changes, promises a new mechanistic understanding of MDD and focused therapeutic strategies.

Psychosocial Stress-Induced Analgesia: An Examination of Effects on Heat Pain Threshold and Tolerance and of Neuroendocrine Mediation

Stress-induced analgesia (SIA) is an adaptive response of reduced nociception following demanding acute internal and external stressors. Although a psychobiological understanding of this phenomenon is of importance for stress-related psychiatric and pain conditions, comparably little is known about the psychobiological mechanisms of SIA in humans. The aim of this study was to investigate the effects of acute psychosocial stress on heat pain perception and its possible neuroendocrine mediation by salivary cortisol levels and α-amylase activity in healthy men. Employing an intra-individual assessment of heat pain parameters, acute psychosocial stress did not influence heat pain threshold but significantly, albeit slightly, increased heat pain tolerance. Using linear mixed-model analysis, this effect of psychosocial stress on heat pain tolerance was not mediated by increases of salivary cortisol and state anxiety levels or by the activity of α-amylase. These results show that while psychosocial stress is selectively analgesic for heat pain tolerance, this observed effect is not mediated by stress-induced increases of salivary cortisol and α-amylase activity, as proxies of both the hypothalamus-pituitary-adrenal axis and the autonomic nervous system activation.

Impact of alprazolam in allostatic load and neurocognition of patients with anxiety disorders and chronic stress (GEMA): observational study protocol

INTRODUCTION

The allostatic load model explains the additive effects of multiple biological processes that accelerate pathophysiology related to stress, particularly in the central nervous system. Stress-related mental conditions such as anxiety disorders and neuroticism (a well-known stress vulnerability factor), have been linked to disturbances of hypothalamo-pituitary-adrenal with cognitive implications. Nevertheless, there are controversial results in the literature and there is a need to determine the impact of the psychopharmacological treatment on allostatic load parameters and in cognitive functions. Gador study of Estres Modulation by Alprazolam, aims to determine the impact of medication on neurobiochemical variables related to chronic stress, metabolic syndrome, neurocognition and quality of life in patients with anxiety, allostatic load and neuroticism.

METHODS/ANALYSIS

In this observational prospective phase IV study, highly sympthomatic patients with anxiety disorders (six or more points in the Hamilton-A scale), neuroticism (more than 18 points in the Neo five personality factor inventory (NEO-FFI) scale), an allostatic load (three positive clinical or biochemical items at Crimmins and Seeman criteria) will be included. Clinical variables of anxiety, neuroticism, allostatic load, neurobiochemical studies, neurocognition and quality of life will be determined prior and periodically (1, 2, 4, 8, and 12 weeks) after treatment (on demand of alprazolam from 0.75 mg/day to 3.0 mg/day). A sample of n=55/182 patients will be considered enough to detect variables higher than 25% (pretreatment vs post-treatment or significant correlations) with a 1-ß power of 0-80. t Test and/or non-parametric test, and Pearson's test for correlation analysis will be determined.

ETHICS AND DISSEMINATION

This study protocol was approved by an Independent Ethics Committee of FEFyM (Foundation for Pharmacological Studies and Drugs, Buenos Aires) and by regulatory authorities of Argentina (ANMAT, Dossier # 61 409-8 of 20 April 2009), following the law of Habeas Data and psychotherapeutic drug control.

TRIAL REGISTRATION NUMBER

GEMA 20811.

Hypothalamic-pituitary-adrenocortical axis: neuropsychiatric aspects

Evidence of aberrant hypothalamic-pituitary-adrenocortical (HPA) activity in many psychiatric disorders, although not universal, has sparked long-standing interest in HPA hormones as biomarkers of disease or treatment response. HPA activity may be chronically elevated in melancholic depression, panic disorder, obsessive-compulsive disorder, and schizophrenia. The HPA axis may be more reactive to stress in social anxiety disorder and autism spectrum disorders. In contrast, HPA activity is more likely to be low in PTSD and atypical depression. Antidepressants are widely considered to inhibit HPA activity, although inhibition is not unanimously reported in the literature. There is evidence, also uneven, that the mood stabilizers lithium and carbamazepine have the potential to augment HPA measures, while benzodiazepines, atypical antipsychotics, and to some extent, typical antipsychotics have the potential to inhibit HPA activity. Currently, the most reliable use of HPA measures in most disorders is to predict the likelihood of relapse, although changes in HPA activity have also been proposed to play a role in the clinical benefits of psychiatric treatments. Greater attention to patient heterogeneity and more consistent approaches to assessing treatment effects on HPA function may solidify the value of HPA measures in predicting treatment response or developing novel strategies to manage psychiatric disease.

Lithium monotherapy increases ACTH and cortisol response in the DEX/CRH test in unipolar depressed subjects. A study with 30 treatment-naive patients

BACKGROUND

Distorted activity of the hypothalamic-pituitary-adrenocortical (HPA) system is one of the most robustly documented biological abnormalities in major depression. Lithium is central to the treatment of affective disorders, but little is known about its effects on the HPA system of depressed subjects.

OBJECTIVE

To assess the effects of lithium monotherapy on the HPA system of patients with major depression by means of the combined DEX/CRH test.

METHOD

Thirty drug-naive outpatients with major depression (single episode or unipolar recurrent; SCID I- and II-confirmed) were treated with lithium monotherapy for four weeks. The DEX/CRH test was conducted directly before intake of the first lithium tablet and four weeks thereafter. Weekly ratings with the HDRS(21) were used to determine response (≥50% symptom reduction) and remission (HDRS ≤7).

RESULTS

Lithium levels within the therapeutic range were achieved rapidly. Tolerability was good; no patient terminated the treatment prematurely. Response and remission rates were 50% and 33% respectively. Compared to the DEX/CRH test before the start of the treatment, a considerable and significant increase in all CRH-stimulated ACTH and cortisol parameters could be detected in the second DEX/CRH test. When analysed with particular regard to responders and non-responders, that significant increase was only present in the responders.

CONCLUSIONS

We were able to demonstrate that lithium leads to a significant activation of the HPA system. This is possibly connected to stimulation of hypothalamic arginine vasoporessin (AVP), to direct intracellular effects of lithium on pituitary cells and to an induction of gene expression.

TRIAL REGISTRATION

drks-nue.uniklinik-freiburg.de DRKS00003185.

Long-term benzodiazepine use and salivary cortisol: the Netherlands Study of Depression and Anxiety (NESDA)

BACKGROUND

As benzodiazepines (BZDs) have anxiolytic effects, it is expected that they influence the stress system. During short-term treatment, BZD use was found to suppress cortisol levels. However, little research has been done on the effects of long-term BZD administration on the hypothalamic-pituitary-adrenal (HPA) axis.

METHODS

The association between long-term BZD use and cortisol levels was investigated in subjects of the Netherlands Study of Depression and Anxiety with a lifetime diagnosis of anxiety or depression (n = 1531). The subjects were categorized as "daily BZD users" (n = 96), "infrequent BZD users" (n = 172), and "nonusers" (n = 1263). Possible associations between characteristics of BZD use (dose, duration, and dependence) and salivary cortisol levels were analyzed.

MAIN OUTCOME MEASURE

Subjects provided 7 saliva samples, from which 4 cortisol indicators were calculated: the cortisol awakening response, diurnal slope, evening cortisol, and cortisol suppression after ingestion of 0.5 mg of dexamethasone.

RESULTS

Daily users used BZDs for a median duration of 26.5 months and had a median daily dosage of 6.0 mg as measured in diazepam equivalents. Evening cortisol levels were significantly lower in daily users (P = 0.004; effect size: d = 0.24) and infrequent users (P = 0.04; effect size: d = 0.12) compared to nonusers. We did not find significant differences in the cortisol awakening response, diurnal slope, or in the dexamethasone suppression test.

CONCLUSIONS

Despite the finding of slightly lower evening cortisol levels in daily and infrequent BZD users compared to nonusers, results indicate that long-term BZD use is not convincingly associated with HPA axis alterations.

Suppressive effect of mirtazapine on the HPA system in acutely depressed women seems to be transient and not related to antidepressant action

Impaired regulation of the hypothalamus-pituitary-adrenocortical (HPA) system is a consistent finding among patients with depression, which can be most sensitively detected with the combined dexamethasone (dex)/corticotrophin releasing hormone (CRH) test. The majority of patients with acute depression shows an exaggerated plasma corticotrophin (ACTH) and cortisol response to this test that normalizes gradually during successful antidepressant therapy. In contrast, persistently high HPA-responses to this challenge are prognostically less favorable. It has been recently questioned, whether this observation applies also to treatment with the atypical antidepressant mirtazapine, as patients treated with this drug showed a distinct attenuation of the endocrine response to the dex/CRH test already after 1 week of treatment. In the present study, we investigated whether the attenuating effect of mirtazapine on the HPA system is an acute pharmacological reaction disappearing after physiological adaptation or whether this effect is related to the antidepressant action of the drug. We examined plasma ACTH and cortisol responses to the dex/CRH test in acutely depressed inpatients treated either with mirtazapine (n=55) or a monoamine reuptake inhibitor (n=105) according to doctor's choice and compared the test results with healthy controls (n=40). Patients treated with monoamine reuptake inhibitors received either selective serotonin reuptake inhibitors (SSRI), tricyclic antidepressants (TCA) or the combined serotonin and noradrenalin reuptake inhibitor venlafaxine. We found increased plasma ACTH and cortisol responses to the dex/CRH test in depressed patients compared with healthy controls, but also significantly (p=.017) attenuated plasma cortisol secretion in the mirtazapine group compared to the group of monoamine reuptake inhibitor treated patients. This effect was not significant in male patients. Furthermore this effect was independent of the psychopathological state, but depended on treatment duration. Patient treatment with mirtazapine for up to 7 days resulted in dex/CRH test outcome that was indistinguishable from controls. This effect, however waned as it was not observable in patients treated for a longer period. These results suggest that short-term administration of mirtazapine has immediate but only transient suppressive effects on the HPA system predominantly in women. Our results confirm that dex/CRH tests can be used as predictors of clinical course also under mirtazapine treatment.

Effects of acute or 3-day treatments of Hypericum caprifoliatum Cham. & Schltdt. (Guttiferae) extract or of two established antidepressants on basal and stress-induced increase in serum and brain corticosterone levels

Since depressive patients present alterations in the hypothalamo-pituitary-adrenal (HPA) axis that are normalised by antidepressants, this HPA axis has been considered as a target of their actions. We have investigated the mechanism of action of a cyclohexane extract of Hypericum caprifoliatum (HCP), which displays antidepressant like activity, by studying, in mice, the influence of HCP and of two established antidepressant drugs, imipramine and bupropion, administered either acutely or semi-chronically (once a day, three consecutive days), on serum and brain cortex corticosterone levels, either in basal conditions or shortly after a forced-swimming session (FSS). Administered acutely, imipramine (20 mg/kg, per os (p.o.)), bupropion (30 mg/kg, p.o.) and HCP (360 mg/kg, p.o.) significantly reduced the immobility time and had no effects on FSS-induced increase of serum and cortical corticosterone levels. Conversely, 3 days repeated treatment with imipramine or bupropion resulted in a significant reduction of immobility time and FSS-induced increase of serum and cortical corticosterone levels. In a different way, repeated treatment with HCP significantly reduced the immobility time and only cortical corticosterone levels in stressed mice. These results indicate that short-term treatments with antidepressants are sufficient to induce modifications in the HPA axis reactivity to stress; and that apparently HCP has an influence on corticosterone levels by a mechanism diverse from the other tested antidepressants.

Drugs and HPA axis

This paper outlines the interferences of the most widely used drugs with hypothalamo-pituitary-adrenal function and the related laboratory parameters, with the purpose of providing practical help to clinicians during testing for hypo- or hypercortisolemic states.

Are compounds acting at metabotropic glutamate receptors the answer to treating depression?

Numerous studies over the last few years have suggested that modulating the glutamatergic system may be an efficient method to achieve an antidepressant effect. Data suggest that metabotropic glutamate receptors (mGlu receptors), related to long-term, modulatory effects on glutamatergic neurotransmission, may be a good target for the development of new, effective and safe therapeutic drugs to treat several CNS disorders including depression and anxiety. Several potent, selective and systemically active orthosteric and allosteric ligands of specific mGlu receptor subtypes have been discovered and these have been tested as potential antidepressants in models of depression in rodents. The mGluR5 antagonists and group II mGlu receptor antagonists seem to be the most promising compounds with potential antidepressant-like activity; however, the efficacy of mGlu receptor ligands in the clinical setting is still an unanswered question.

Hypersensitivity of the corticotropic axis to the serotoninergic agent clomipramine in obese women

Serotoninergic control of food intake has been shown to be abnormal in obese persons with a decrease in serotoninergic tone. The neuroendocrine effects of intravenous I.V. administration of clomipramine (CMI), a serotonin uptake inhibitor, were studied in normal-weight (n=7) and obese subjects before (n=12) and after (n=6) dietary restriction. Under double-blind, placebo-controlled conditions, a single 12.5 mg dose of CMI was administered. There was no difference in baseline values of prolactin (PRL), corticotropin (ACTH) and cortisol in non-obese controls, obese before and obese after weight loss. CMI led to significant increases of PRL, ACTH, and cortisol concentrations in the controls as well as the obese group. The ACTH and cortisol responses to CMI in obese subjects were somewhat greater than the responses in normal-weight subjects. The area under the curve AUC for ACTH after clomipramine was 6202 +/- 976 pg/ml x 150 minutes for tile obese before weight loss and 3274 +/- 512 pg/ml x 150 minutes for the controls and the difference was significant at the level of p=0.052. The cortisol peak value after clomipramine was 163.71 +/- 14.31 ng/ml in the non-obese and 214.66 +/- 12.59 ng/ml in the obese (p=0.025). However, there was no difference in the obese subjects before and after weight loss. These data support the assumption that obese women have an abnormal sensitivity to the serotoninergic control of the hypothalamic pituitary adrenal axis (HPA), and that a mild weight loss does not significantly modify their serotoninergic tone.

The atypical antipsychotics olanzapine and quetiapine, but not haloperidol, reduce ACTH and cortisol secretion in healthy subjects

RATIONALE

Increased activity of the hypothalamic-pituitary-adrenal (HPA) axis is an important aspect of the pathophysiology of major depression and schizophrenia. Despite the usefulness of atypical antipsychotics in the treatment of depression and their positive influence on cognitive functioning possibly related to their impact on cortisol, little is known about their effect on HPA axis function.

OBJECTIVE

Therefore, this double-blind, placebo-controlled, randomized cross-over study investigated the influence of the atypical antipsychotics quetiapine and olanzapine in comparison with haloperidol and placebo on plasma adrenocorticotropic hormone (ACTH), cortisol, and prolactin levels. Eleven healthy male volunteers were studied during four sessions one week apart, orally receiving placebo, quetiapine (50 mg), olanzapine (5 mg), or haloperidol (3 mg). Blood samples were taken at hourly intervals from 0900 until 1700 hours. For ACTH, cortisol, and prolactin a significant effect of treatment condition (p < or = 0.005; p < or = 0.035; p < or = 0.0001, respectively) for area under the curve (AUC) was found. In comparison to placebo, quetiapine and olanzapine significantly reduced ACTH (p < or = 0.002; p < or = 0.05, respectively) and cortisol (p < or = 0.005; p < or = 0.03, respectively). No effect of haloperidol on AUC of ACTH or cortisol levels was observed. In comparison with placebo, haloperidol (p < or = 0.0001) and olanzapine (p < or = 0.0001) elevated AUC of prolactin plasma levels, whereas no significant effect was observed for quetiapine as a main effect of treatment condition. The atypical antipsychotics' strong influence on HPA-function with pronounced ACTH and cortisol lowering is possibly related to the atypicals' blockade of serotonergic receptors, but blockade of adrenergic or histaminergic receptors may play a role as well. The observed HPA-axis down-regulation may be clinically important for the atypicals' effects on depressive symptomatology and cognitive functioning.

Cortisol response to diazepam: its relationship to age, dose, duration of treatment, and presence of generalized anxiety disorder

OBJECTIVE

Acute diazepam administration has been shown to decrease plasma cortisol levels consistent with decreased activity of the hypothalamic-pituitary-adrenal axis, especially in individuals experiencing stress. However, the effects of chronic diazepam treatment on cortisol have been less studied, and the relationship to age, anxiety, duration of treatment, and dose are not well understood.

METHOD

This double-blind placebo-controlled study examined acute and chronic effects of diazepam on plasma cortisol levels in young (19-35 years) and elderly (60-79 years) individuals with and without generalized anxiety disorder (GAD). Subjects received single oral challenges of placebo or diazepam (2.5 mg or 10 mg) in a placebo-controlled cross-over design, followed by 3 weeks of chronic daily treatment with 2.5 mg or 10 mg diazepam or placebo taken at 10 p.m., and then by a final acute challenge with a single oral dose of the same study medication received during chronic treatment.

RESULTS

The elderly experienced significant reductions in plasma cortisol levels compared to placebo both in the initial challenge and during chronic treatment, but the young did not. However, cortisol response to drug was comparable in both groups. Final challenge did not produce any significant cortisol effects in either group and the cortisol response in the elderly was significantly reduced compared to the initial challenge. GAD status was not a factor in plasma cortisol responses to diazepam.

CONCLUSIONS

Diazepam reduced cortisol both acutely and during chronic treatment, but not during final challenge, consistent with some tolerance development. This effect was most apparent in the elderly compared with the young adults and was not modulated by GAD status or dosage, and was not related to drug effects on performance and on self-ratings of sedation and tension.

Four days of citalopram increase suppression of cortisol secretion by prednisolone in healthy volunteers

RATIONALE

Chronic antidepressant treatment increases glucocorticoid-mediated negative feedback on the hypothalamic-pituitary-adrenal (HPA) axis, and thus reduces HPA axis activity, in depressed patients and healthy controls. In contrast, acute antidepressant treatment induces an activation of basal HPA axis activity.

OBJECTIVES

We examined the effects of 4 days of treatment with the selective serotonin reuptake inhibitor, citalopram, on basal salivary cortisol and on suppression of salivary cortisol by prednisolone.

METHODS

We used a single-blind, placebo-controlled, repeated-measure design. Salivary cortisol was measured from 0900 to 1700 hours. In the first phase of the study, basal salivary cortisol secretion was measured on 2 study days, before and after 4 days of treatment with citalopram (orally, 20 mg/day). In the second phase, salivary cortisol secretion after suppression by prednisolone (5 mg, given at 2200 hours the night before) was measured on 2 study days, again before and after 4 days of treatment with citalopram (orally, 20 mg/day). Eight volunteers participated to the study.

RESULTS

Citalopram increased basal salivary cortisol in the morning (0900-1100 hours) by approximately 47% (P=0.003). Moreover, citalopram increased suppression by prednisolone in the morning (0900-1100 hours): suppression was approximately 22% before citalopram and 45% after citalopram (P=0.05).

CONCLUSIONS

Citalopram increases glucocorticoid-mediated negative feedback on the HPA axis after as little as 4 days of treatment. This effect could be due to an increased function of the corticosteroid receptors. Our findings further support the notion that one of the mechanisms by which antidepressants exert their therapeutic effects is by normalizing HPA axis hyperactivity in depressed patients.

Quetiapine reduces nocturnal urinary cortisol excretion in healthy subjects

RATIONALE

Hypothalamic-pituitary-adrenal (HPA) axis dysfunction is a frequent finding in psychiatric disorders, including psychotic depression and schizophrenia. Conflicting results exist concerning the influence of antipsychotics on the HPA-axis.

OBJECTIVE

Therefore, this double-blind, placebo-controlled, randomized cross-over study investigated the effect of quetiapine on nocturnal urinary cortisol and melatonin excretion in 13 healthy male subjects under conditions of undisturbed and experimentally disturbed sleep.

METHODS

Volunteers were studied 3 times for 3 consecutive nights (N0, adaptation; N1, standard sleep conditions; N2, acoustic stress) 4 days apart. Placebo, quetiapine 25 mg or quetiapine 100 mg was administered orally 1 h before bedtime on nights 1 and 2. Urine produced during the 8-h bedtime period was collected for later determination of cortisol and melatonin concentrations by standard radioimmunoassays.

RESULTS

MANOVA showed a significant effect for N1 vs. N2 with elevated total amount of cortisol ( p<0.005) and melatonin ( p<0.05) excretion after acoustic stress. Both quetiapine 25 mg and 100 mg significantly ( p<0.0005) reduced the total amount of cortisol excretion in comparison to placebo. No interaction effect of stress condition was observed. There was no effect of quetiapine on melatonin levels.

CONCLUSION

The significant reduction of nocturnal cortisol excretion following quetiapine reflects a decreased activity of the HPA-axis in healthy subjects. This finding may be an important aspect in quetiapine's mode of action in different patient populations.

Interdose elevation in plasma cortisol during chronic treatment with alprazolam but not lorazepam in the elderly

Benzodiazepines (BZPs) have been shown to reduce hypothalamic-pituitary-adrenal (HPA) axis activity acutely in normal humans. In contrast, the effects of chronic BZP treatment on the HPA axis have not been well studied, especially in the geriatric population. This study examined the acute and chronic effects (3 weeks) of alprazolam and lorazepam on plasma cortisol in 68 subjects (60-83 years) who received 0.25 or 0.50 mg b.i.d. alprazolam, or 0.50 or 1.0 mg b.i.d. lorazepam, or placebo orally according to a randomized, double-blind, placebo-controlled parallel design. Memory assessment and blood samples for plasma cortisol were obtained prior to the morning dose on days 0, 7, 14, and 21, and at 1, 2.5, and 5 h postdrug on days 0 and 21. Assessments of anxiety and depression were carried out at days 0, 7, 14, and 21 before drug administration. Plasma cortisol was affected compared to placebo only by the 0.5 mg alprazolam dose. During the first and the last day of treatment, there was a significant drop in cortisol at 2.5 h after alprazolam compared to placebo. The predose cortisol levels increased significantly during chronic alprazolam treatment, and correlations were found between these cortisol changes and changes in depression, anxiety, and memory scores. These findings suggest that even a short period of chronic treatment with alprazolam, but not lorazepam, may result in interdose HPA axis activation in the elderly, consistent with drug withdrawal. If confirmed, this effect may contribute to an increased risk for drug escalation and dependence during chronic alprazolam treatment.

The sleep-improving effects of doxepin are paralleled by a normalized plasma cortisol secretion in primary insomnia. A placebo-controlled, double-blind, randomized, cross-over study followed by an open treatment over 3 weeks

RATIONALE

In primary care, sedating antidepressants are often used for treating insomnia, although their underlying sleep-promoting mechanisms are only incompletely understood. Since enhanced evening and nocturnal plasma cortisol levels are supposed to maintain insomniac sleep complaints, a functional link between sleep and cortisol secretion in the mode of action of antidepressants in insomnia might be suspected.

OBJECTIVES

We therefore investigated the effects of the tricyclic antidepressant doxepin on nocturnal sleep and plasma cortisol concentration in ten patients (age 41.3+/-9.5 years) with chronic primary insomnia between 1700 hours and 0800 hours.

METHODS

Single infusions of placebo and 25 mg doxepin were applied following a double-blind, randomized cross-over design. Afterward, all patients received 25 mg doxepin p.o. for 3 weeks in an open-study design.

RESULTS

Both doxepin application forms improved sleep significantly and reduced mean cortisol levels from 9.0+/-1.7 microg/l (single placebo i.v.) to 7.5+/-1.6 microg/l (single doxepin i.v.) or 7.6+/-2.0 microg/l (subchronic doxepin p.o.). The duration of the quiescent period of the cortisol rhythm was significantly prolonged following both doxepin administrations compared with placebo.

CONCLUSIONS

The results implicate that the sleep-improving effects of doxepin are mediated at least in part by a normalization of hypothalamic-pituitary-adrenal axis functions. Although in some patients rebound insomnia and specific side effects must be considered, our findings give a further rationale for the use of antidepressants in the treatment of primary insomnia.

Serotonin and the neuroendocrine regulation of the hypothalamic--pituitary-adrenal axis in health and disease

Serotonin (5-hydroxytryptamine, 5-HT)-containing neurons in the midbrain directly innervate corticotropin-releasing hormone (CRH)-containing cells located in paraventricular nucleus of the hypothalamus. Serotonergic inputs into the paraventricular nucleus mediate the release of CRH, leading to the release of adrenocorticotropin, which triggers glucocorticoid secretion from the adrenal cortex. 5-HT1A and 5-HT2A receptors are the main receptors mediating the serotonergic stimulation of the hypothalamic-pituitary-adrenal axis. In turn, both CRH and glucocorticoids have multiple and complex effects on the serotonergic neurons. Therefore, these two systems are interwoven and communicate closely. The intimate relationship between serotonin and the hypothalamic-pituitary-adrenal axis is of great importance in normal physiology such as circadian rhythm and stress, as well as pathophysiological disorders such as depression, anxiety, eating disorders, and chronic fatigue.

Effects of autoshaping procedures on 3H-8-OH-DPAT-labeled 5-HT1a binding and 125I-LSD-labeled 5-HT2a binding in rat brain

Effects of experience with Pavlovian autoshaping procedures on lever-press autoshaping conditioned response (CR) performance and 3H-8-OH-DPAT-labeled binding of 5-HT(1a) receptors as well as 125I-LSD-labeled binding of 5-HT(2a) receptors were evaluated in four groups of male Long-Evans hooded rats. Two groups of rats (Group Paired High CR and Group Paired Low CR) received Pavlovian autoshaping procedures wherein the presentation of a lever (conditioned stimulus, CS) was followed by the response-independent presentation of food (unconditioned stimulus, US). Rats in Group Paired High CR (n=12) showed more rapid CR acquisition and higher asymptotic levels of lever-press autoshaping CR performance relative to rats in Group Low CR (n=12). Group Omission (n=9) received autoshaping with an omission contingency, such that performing the lever-press autoshaping CR resulted in the cancellation the food US, while Group Random (n=9) received presentations of lever CS and food US randomly with respect to one another. Though Groups Omission and Random did not differ in lever-press autoshaping CR performance, Group Omission showed significantly lower levels of 3H-8-OH-DPAT-labeled 5-HT(1a) binding in post-synaptic areas (frontal cortex, septum, caudate putamen), as well as significantly higher plasma corticosterone levels than Group Random. In addition, Group Random showed higher levels of 3H-8-OH-DPAT-labeled 5-HT(1a) binding in pre-synaptic somatodendritic autoreceptors on dorsal raphe nucleus relative to each of the other three groups. Autoradiographic analysis of 125I-LSD-labeled 5-HT(2a) receptor binding revealed no significant differences between Groups Paired High CR and Paired Low CR or between Groups Omission and Random in any brain regions.

Dexamethasone-induced effects on lymphocyte distribution and expression of adhesion molecules in treatment-resistant depression

Alterations in immune function are associated with major depression and have been related to changes in endocrine function. We investigated whether alterations in immune function were associated with altered basal hypothalamic-pituitary-adrenal (HPA) function (salivary cortisol) and lymphocyte sensitivity to dexamethasone (DEX) intake (1 mg PO). The latter was explored by comparing the impact of DEX-induced changes on peripheral lymphocyte redistribution and expression of adhesion molecules (beta2 integrins and L-selectin). The study included 36 inpatients with treatment-resistant major depression (unipolar subtype) and 31 matched healthy controls. The dexamethasone suppression test (DST) was carried out and used to classify 10 patients as HPA axis non-suppressors. The latter presented significantly higher post-DEX salivary cortisol levels than DST suppressors, 82.0 vs. 8.9 nM l(-1) h(-1). No differences in basal salivary cortisol levels were found between patients and controls. Changes in cell redistribution (CD4(+), CD8(+), CD19(+), CD56(+) and HLADR(+) cells) after DEX administration were more prominent in controls than in patients, but the effects of DEX varied dependent on whether patients exhibited DEX-induced suppression of cortisol secretion. Glucocorticoid-induced suppression of adhesion molecule expression was also generally less marked in patients than controls. Our data indicate that alterations in immune function and steroid regulation associated with depression are not related to elevated basal levels of cortisol and further suggest that lymphocyte steroid resistance is associated with drug-resistant depression.

Benzodiazepines and anterior pituitary function

Benzodiazepines (BDZ) are one of the most prescribed classes of drugs because of their marked anxiolytic, anticonvulsant, muscle relaxant and hypnotic effects. The pharmacological actions of BDZ depend on the activation of 2 specific receptors. The central BDZ receptor, present in several areas of the central nervous system (CNS), is a component of the GABA-A receptor, the activation of which increases GABAergic neurotransmission and is followed by remarkable neuroendocrine effects. The peripheral benzodiazepine receptors (PBR), structurally and functionally different from the GABA-A receptor, have been shown in peripheral tissues but also in the CNS, in both neurones and glial cells, and in the pituitary gland. BDZ receptors bind to a family of natural peptides called endozepines, firstly isolated from neurons and glial cells in the brain and then in several peripheral tissues as well. Endozepines modulate several central and peripheral biological activities, including some neuroendocrine functions and synthetic BDZ are likely to mimic them, at least partially. BZD, especially alprazolam (AL), possess a clear inhibitory influence on the activity of the HPA axis in both animals and humans. This effect seems to be mediated at the hypothalamic and/or suprahypothalamic level via suppression of CRH. The strong negative influence of AL on hypothalamicpituitary-adrenal (HPA) axis agrees with its peculiar efficacy in the treatment of panic disorders and depression. BZD have also been shown to increase GH secretion via mechanisms mediated at the hypothalamic or supra-hypothalamic level, though a pituitary action cannot be ruled out. Besides the impact on HPA and somatotrope function, BDZ also significantly affect the secretion of other pituitary hormones, such as gonadotropins and PRL, probably acting through GABAergic mediation in the hypothalamus and/or in the pituitary gland. In all, BDZ are likely to represent a useful tool to investigate GABAergic activity and clarify its role in the neuroendocrine control of anterior pituitary function; their usefulness probably overrides what had been supposed before.

Chronic antidepressant treatments decrease pro-opiomelanocortin mRNA expression in the pituitary gland: effects of acute stress and 5-HT(1A) receptor activation

Consistent findings in depressed patients are hyperactivity in the hypothalamic-pituitary-adrenal (HPA) axis with high plasma concentrations of adrenocorticotropic hormone and cortisol. Long-term antidepressant treatments seem to normalize this hyperactivity, suggesting a link between the HPA axis and the action of antidepressant treatments. The present study was carried out to study the effects of antidepressant treatments on pro-opiomelanocortin (POMC) mRNA expression, with a focus on interaction with acute stress and 5-HT(1A) receptor activation. Male rats were treated for 21 days with saline, citalopram, fluoxetine, moclobemide or desipramine, and the expression of POMC mRNA in the anterior pituitary was analysed by semi-quantitative in situ hybridization. All antidepressants, but not saline, cocaine and haloperidol, reduced POMC mRNA expression. The decrease in POMC mRNA was not observed until 9 days of citalopram treatment. Decreased POMC mRNA levels were also observed after 14 days of repeated electroconvulsive stimulation. The decreased POMC mRNA levels did not affect the stress-induced POMC mRNA increase, measured following swim stress and restraint stress. Finally, using Fos as a marker for neural activity, we showed attenuation of 8-OH-DPAT-stimulated activity in the paraventricular nucleus following 21 days of citalopram treatment. In conclusion, antidepressant treatments decrease basal POMC mRNA expression without affecting the acute stress response, and the reduced POMC mRNA may be related to reduced 5-HT(1A)-stimulated hypothalamic output.

Neuropharmacology of venlafaxine

Venlafaxine (Effexor) is an effective antidepressant and has also been approved for the treatment of generalized anxiety disorder. Venlafaxine was initially characterized as an inhibitor of both serotonin (5HT) and norepinephrine (NE) uptake and was therefore termed a "dual uptake inhibitor." This chapter reviews data from both in vitro and in vivo studies regarding its effects on 5HT and NE neurotransmission. In addition, the effects of venlafaxine on other systems that may play a role in its therapeutic efficacy effects are described. The data indicate that venlafaxine is a relatively weak inhibitor of NE transport in vitro. In vivo studies indicate that venlafaxine selectively inhibits 5HT uptake at low therapeutic doses and inhibits both 5HT and NE uptake at higher therapeutic doses. This chapter concludes with a discussion of the effects of venlafaxine on various aspects of physiology.

Biomarkers for the effects of antipsychotic drugs in healthy volunteers

Studies of novel antipsychotics in healthy volunteers are traditionally concerned with kinetics and tolerability, but useful information may also be obtained from biomarkers of clinical endpoints. A useful biomarker should meet the following requirements: a consistent response across studies and antipsychotics; a clear response of the biomarker to a therapeutic dose; a dose-response relationship; a plausible relationship between biomarker, pharmacology and pathogenesis. In the current review, all individual tests found in studies of neuroleptics in healthy volunteers since 1966 were progressively evaluated for compliance with these requirements. A MedLine search yielded 65 different studies, investigating the effects of 23 different neuroleptics on 101 different (variants of) neuropsychological tests, which could be clustered into seven neuropsychological domains. Subjective and objective measures of alertness, and of visual-visuomotor-auditory and motor skills were most sensitive to antipsychotics, although over half of all the studies failed to show statistically significant differences from placebo. The most consistent effects were observed using prolactin response and saccadic eye movements, where 96% and 83% of all studies resp. showed statistically significant effects. The prolactin inducing dose equivalencies relative to haloperidol of 19 different antipsychotic agents correlated with the lowest recommended daily maintenance dose (r(2) = 0.52). This relationship could reflect the clinical practice of aiming for maximum tolerated levels, or it could represent a common basis behind prolactin release and antipsychotic activity (probably D2-receptor antagonism). The number of tests used in human psychopharmacology appears to be excessive. Future studies should look for the most specific and sensitive test within each of the domains that are most susceptible to neuroleptics.

Predicting the development of posttraumatic stress disorder from the acute response to a traumatic event

Posttraumatic stress disorder (PTSD) is a psychiatric condition that is directly precipitated by an event that threatens a person's life or physical integrity and that invokes a response of fear, helplessness, or horror. In recent years it has become clear that only a proportion of those exposed to fear-producing events develop or sustain PTSD. Thus, it seems that an important challenge is to elucidate aberrations in the normal fear response that might precipitate trauma-related psychiatric disorder. This paper summarizes the findings from recent studies that examined the acute and longer term biological response to traumatic stress in people appearing to the emergency room immediately following trauma exposure. In the aggregate, these studies have demonstrated increased heart rate and lower cortisol levels at the time of the traumatic event in those who have PTSD at a follow-up time compared to those who do not. In contrast, certain features associated with PTSD, such as intrusive symptoms and exaggerated startle responses, are only manifest weeks after the trauma. The findings suggest that the development of PTSD may be facilitated by an atypical biological response in the immediate aftermath of a traumatic event, which in turn leads to a maladaptive psychological state.

Parenteral clomipramine challenge in depressed adolescents: mood and neuroendocrine response

BACKGROUND

Major depressive disorder (MDD) in the adolescent demonstrates a unique clinical profile, and pathogenic serotonergic dysregulation is hypothesized. Parenteral clomipramine (CMI) is known to distinguish adult MDD from control, but neurochallenge data are lacking in adolescent MDD.

METHODS

Thirteen drug-free outpatient adolescents who met DSM-III-R criteria for MDD were compared to adolescent controls by acute neuroendocrine and mood response to 12.5 mg of parenteral CMI.

RESULTS

Repeated measures analysis revealed significant changes from baseline for sadness (p < .01) between groups, with normal controls increasing sadness rating after CMI. Prolactin (PRL) maximum change score from baseline was decreased in MDD relative to controls (p < .05). Gender effects on PRL were evident in controls but not in MDD.

CONCLUSIONS

The findings of PRL blunting in adolescent MDD mirrors previous work in adults. A unique finding is the induction of sadness in normal adolescent controls after CMI infusion.

Intravenous clomipramine challenge in obsessive-compulsive disorder: predicting response to oral therapy at eight weeks

BACKGROUND

Challenge with intravenous clomipramine (CMI) is serotonin selective and has been reported to transiently exacerbate symptoms in obsessive-compulsive disorder (OCD) patients, and to predict subsequent response to oral CMI therapy.

METHODS

We administered CMI (12.5 mg, i.v.) to medication free OCD patients (N = 29) and normal controls (N = 22) to characterize neurohormonal response. A subset of OCD patients (26/29), was then treated with either pulse load i.v. or oral CMI followed by 8 weeks of oral CMI therapy.

RESULTS

In response to CMI challenge, OCD patients exhibit blunted cortisol and exaggerated growth hormone response relative to normal controls. OCD patients differ from controls in "sadness" ratings, with control exhibiting increased dysphoria in response to CMI. Growth hormone response to CMI challenge predicts treatment response (> or = 25% decreases YBOCS from baseline) to oral CMI at 8 weeks.

CONCLUSIONS

Growth hormone abnormalities associated with OCD in response to CMI challenge differentiates nonresponders after 8 weeks of oral CMI treatment from responders.

Nefazodone. A review of its pharmacology and clinical efficacy in the management of major depression

Nefazodone hydrochloride is a phenylpiperazine antidepressant with a mechanism of action that is distinct from those of other currently available drugs. It potently and selectively blocks postsynaptic serotonin (5-hydroxytryptamine; 5-HT) 5-HT2A receptors and moderately inhibits serotonin and noradrenaline (norepinephrine) reuptake. In short term clinical trials of 6 or 8 weeks' duration, nefazodone produced clinical improvements that were significantly greater than those with placebo and similar to those achieved with imipramine, and the selective serotonin reuptake inhibitors (SSRIs) fluoxetine, paroxetine and sertraline. The optimum therapeutic dosage of nefazodone appears to be between 300 and 600 mg/day. Limited long term data suggest that nefazodone is effective in preventing relapse of depression in patients treated for up to 1 year. Analyses of pooled clinical trial results indicate that nefazodone and imipramine produces similar and significant improvements on anxiety- and agitation-related rating scales compared with placebo in patients with major depression. Short term tolerability data indicate that nefazodone has a lower incidence of adverse anticholinergic, antihistaminergic and adrenergic effects than imipramine. Compared with SSRIs, nefazodone causes fewer activating symptoms, adverse gastrointestinal effects (nausea, diarrhoea, anorexia) and adverse effects on sexual function, but is associated with more dizziness, dry mouth, constipation, visual disturbances and confusion. Available data also suggest that nefazodone is not associated with abnormal weight gain, seizures, priapism or significant sleep disruption, and appears to be relatively safe in overdosage. Nefazodone inhibits the cytochrome P450 3A4 isoenzyme and thus has the potential to interact with a number of drugs. Further long term and comparative studies will provide a more accurate assessment of the relative place of nefazodone in the management of major depression. Nonetheless, available data suggest that nefazodone is a worthwhile treatment alternative to tricyclic antidepressants and SSRIs in patients with major depression.

Behavioral and endocrine responses to clomipramine in panic disorder patients with or without alcoholism

Central nervous system serotonin functions may differ between certain subgroups of alcoholics, patients with panic disorder, and healthy volunteers. To investigate these possibilities we administered the serotonin uptake inhibitor, clomipramine (12.5 mg, i.v.), to patients with alcohol dependence, patients with panic disorder with or without alcohol dependence, and healthy volunteers. Alcoholics did not differ from healthy volunteers in their neuroendocrine or behavioral responses. In contrast, patients with panic disorder exhibited marked dysphoric reactions and/or panic attacks following low-dose i.v. clomipramine, whereas their neuroendocrine responses were similar to the other two groups. Patients with panic disorder may have super-sensitive postsynaptic serotonin receptors in areas of their central nervous system, which are important for mood regulation.

Effects of alprazolam on increases in hormonal and anxiety levels induced by meta-chlorophenylpiperazine

The effects of alprazolam, a triazolobenzodiazepine, on hormonal and behavioral responses induced by meta-chlorophenylpiperazine (MCPP), a serotonin receptor agonist, were investigated in 10 healthy men. Alprazolam (0.5 mg) or placebo was given 1 hour before MCPP (0.5 mg/kg) or placebo. Cortisol, prolactin, and growth hormone (GH) release, MCPP and alprazolam plasma levels, anxiety level, and panic symptoms were measured over 210 minutes. MCPP was found to increase cortisol, prolactin, GH, and anxiety levels. Alprazolam decreased cortisol and GH levels but had no effect on prolactin. When used in combination with MCPP, alprazolam blunted MCPP-induced cortisol and GH release, and it blocked the anxiogenic effects of MCPP.

Neuroendocrine and temperature effects of nefazodone in healthy volunteers

The effects of a novel antidepressant, nefazodone (50 mg, 100 mg, and 200 mg orally) on neuroendocrine function and temperature were assessed using a single-blind, crossover design in eight healthy male volunteers. Nefazodone significantly increased plasma levels of prolactin (PRL) and raised oral temperature. There was also a trend towards an increase in plasma cortisol. These results are consistent with an acute facilitatory effect of some aspects of 5-HT neurotransmission, perhaps mediated through nefazodone's metabolism to its major metabolite, m-chlorophenylpiperazine (mCPP).

Neuroendocrine probes of serotonergic function: a critical review

Neuroendocrine probes of serotonergic function are based on the premise that serotonin (5-HT) exhibits an excitory influence on the release of certain anterior pituitary hormones and that the extent of release of these hormones following a challenge with a 5-HT agonist would provide an index of central 5-HT activity. This paper critically reviews studies published to date on healthy volunteers to assess the validity of tests of serotonergic function. Using standardized criteria, it is concluded that although extensive data is available on 5-HT-neuroendocrine probes, there is no test that is currently available that would fulfil all the proposed requirements for a test to be acceptable, although ipsapirone, m-chlorophenylpiperazine (m-CPP), and possibly fenfluramine challenge tests come very close. The rapid development and availability of more specific and stereo-selective 5-HT agonists/antagonists seem to indicate that it will not be too long before a valid neuroendocrine test for the assessment of serotonergic function emerges.

Adrenocorticotropin hormone response to diazepam in healthy young men

The effects of diazepam (DZ) infusions on changes in adrenocorticotropin hormone (ACTH) are a source of debate. In this study, 66 healthy young adult men were evaluated for changes in plasma ACTH after intravenous infusions with placebo, 0.12 mg/kg and 0.20 mg/kg of DZ. After the higher DZ dose, 85% of the subjects demonstrated a decrease in ACTH of 20% or more, with the nadir occurring between 30 and 60 min postinfusion and values returning to baseline levels by 180 min. These results support the conclusion that at the clinically relevant doses used here, DZ infusions are associated with a significant decrease in ACTH.

ECT treatment does not enhance neuroendocrine responses to serotonergic challenge

We prospectively investigated the effects of a course of electroconvulsive therapy (ECT) on neuroendocrine responses to serotonergic challenge in five depressed patients. Low dose intravenous chlorimipramine (CMI) challenge produced a modest release of prolactin and significant increases in plasma adrenocorticotrophic hormone (ACTH) and cortisol. Interestingly, ECT did not alter the neuroendocrine responses to serotonergic challenge despite clinical response in four of the five patients. If anything, the modest prolactin (PRL) response to CMI, rather than being enhanced, appeared to be abolished following ECT. Using confidence intervals, we estimate that there is less than a 5% probability of a 78% increase in prolactin response to CMI after ECT. To detect this, a sample size of greater than 35 would be needed. These findings suggest that neither ECT nor the clinical response in severely depressed patients is likely to produce consistent changes in neuroendocrine response to the acute serotonergic effects of CMI infusion. The lack of effect of ECT on prolactin response to serotonergic challenge might be explained by simultaneous enhancement of both serotonergic and dopaminergic neurotransmission.

Oxaprotiline enantiomers stimulate ACTH and corticosterone secretion in the rat

The effect of oxaprotiline (OXA) enantiomers--of which (+)-OXA inhibits noradrenaline (NA) uptake, whereas (-)-OXA does not--on the secretion of adrenocorticotropin hormone (ACTH) and corticosterone was studied in rats. Both enantiomers dose-dependently and with a similar potency increased the plasma level of ACTH and corticosterone, the effect of (-)-OXA on corticosterone being of a longer duration. The stimulation of ACTH secretion and the inability of (+)- and (-)-OXA to increase the plasma corticosterone concentration in animals pretreated with dexamethasone indicate that secretion of the latter hormone results from the action of the enantiomers at a level superior to the adrenal cortex, i.e. the hypothalamus/pituitary. The corticosterone response to (+)- or (-)-OXA was not modified in rats with a selective lesion of NA nerve endings induced by the neurotoxin DSP-4, nor was it affected by the selective alpha 1-antagonist prazosin, the selective alpha 2-antagonist yohimbine, the mixed alpha 1/alpha 2-antagonist phentolamine, the selective dopamine (D2) receptor antagonist sulpiride and the non-selective 5-hydroxytryptamine (5-HT) receptor antagonist metergoline. These results indicate that neither the NA system nor D2 and 5-HT receptors are involved in the hormonal response to the OXA enantiomers. Although the (+)- and (-)-OXA-induced stimulation of corticosterone secretion was not antagonized by diazepam, ipsapirone, naloxone, or propranolol, it cannot be excluded that both these enantiomers act as non-specific stressors.

The novel antidepressant, tianeptine, reduces stress-evoked stimulation of the hypothalamo-pituitary-adrenal axis

The possible effect of tianeptine, a novel antidepressant agent, on the neuroendocrine response to stress was investigated in adult male rats. Tube restraint stress for 30 min induced a marked increase of plasma ACTH and corticosterone. A single i.p. injection of tianeptine (10 mg/kg), 120 min before stress caused a significant decrease of ACTH and corticosterone levels. In order to investigate the kinetics of the effect of tianeptine, the drug was injected at various times (from 15 min to 12 h) before restraint stress. The inhibitory effect of tianeptine on stress-induced elevations of plasma ACTH and corticosterone occurred from 1 to 3 h after the injection. Administration of increasing doses of tianeptine revealed that only the highest doses (10 and 20 mg/kg) had a significant effect on stress-evoked stimulation of ACTH and corticosterone secretion. These results show that the antidepressant, tianeptine, reduces the activation of the hypothalamo-pituitary-adrenal (HPA) axis induced by restraint stress. Since depressed patients generally exhibit an elevated cortisol level, the present data suggest that part of the therapeutic properties of tianeptine could be accounted for by the effect of this antidepressant to modulate the activity of the HPA axis.

Acute effect of intravenous clomipramine upon sleep-related hormone secretion in depressed outpatients and healthy control subjects

Tricyclic antidepressants have been used frequently as pharmacological probes in neuroendocrine studies even though they appear to lack neurochemical specificity. Despite this, the hormonal responses to these drugs have been used to provide evidence that depressed patients have alterations in both noradrenergic and serotonergic tone within the central nervous system. Most studies have been conducted in the morning, which is not a time of high physiological neuroendocrine secretory activity. The present study has used the relatively specific serotonergic probe intravenous clomipramine given to depressed patients and healthy subjects immediately before sleep onset, which is a time of increased neuroendocrine activity. Under these conditions, 12.5 mg clomipramine stimulates the secretion of both cortisol and prolactin, but unlike studies conducted in the morning, clomipramine suppresses the secretion of growth hormone in both groups. These data suggest that serotonergic mechanisms are involved in the regulation of the secretion of these three hormones at the time of sleep onset.

Desipramine increases circulating growth hormone in elderly depressed patients: a pilot study

Serial blood samples were collected from 15 elderly depressed inpatients, ages 62 to 95 years, following random assignment to a 50 mg oral test dose of desmethylimipramine (DMI) or amitriptyline (AMI). Nine female and six male subjects began the 210-min study at 0800h. Serum growth hormone (hGH), cortisol, and prolactin (hPRL) were determined by radioimmunoassay. Baseline hormone concentrations were related to self and observer ratings of anxiety and depression. There was a trend for the hGH, cortisol, and hPRL concentrations to decline during the period of study. This trend for all three hormones reversed in those subjects receiving DMI, beginning approximately 90 min after drug ingestion. The DMI-induced increase of hGH reached statistical significance at the very end of the sampling period. There was an apparent latency in the DMI-induced effect for all three hormones. There was no stimulatory effect of AMI on hGH, cortisol, or hPRL. The female subjects had higher baseline hGH levels than the men. In addition, a significant negative correlation was found between baseline hPRL levels and self ratings of anxiety.

Effect of codeine and oxazepam on afternoon cortisol secretion in men

The objective of this study was to investigate the effects of oral codeine and oxazepam on afternoon cortisol secretion. Nine subjects received either oxazepam (30 mg) or codeine (30 mg) or placebo at 1700h on separate days in a counterbalanced design; the subjects were not aware of the sequence. Blood samples were collected with an indwelling intravenous catheter at 30-min intervals from 1500h to 1630h. Codeine, but not oxazepam, suppressed cortisol secretion. The trend of the declining cortisol values following codeine was significantly linear. These results are consistent with other evidence indicating the presence of an inhibitory opioid mechanism in the human hypothalamo-pituitary-adrenal (HPA) axis. The cortisol response to codeine may be a reliable and potentially useful paradigm for the study of the role of opioidergic mechanisms in HPA axis dysfunction.

Intravenous alprazolam challenge in normal subjects. Biochemical, cardiovascular, and behavioral effects

Alprazolam, a novel benzodiazepine derivative is thought to be effective in the treatment of anxiety, panic, and depressive disorders. There is considerable interest in alprazolam's mechanism of action, particularly whether its profile of actions might resemble that of the alpha 2 adrenoreceptor agonist, clonidine. The present study assessed the biochemical, cardiovascular, and behavioral responses of healthy volunteers to acute intravenous infusions of alprazolam and placebo. Alprazolam reduced ACTH and cortisol while increasing growth hormone. There was a transient reduction in plasma norepinephrine and only modest effects on cardiovascular parameters. Subjects became quite sedated after intravenous alprazolam. This pharmacodynamic profile resembles that previously reported for traditional benzodiazepines, although alprazolam may be a more potent stimulator of growth hormone release. Alprazolam's effects on growth hormone resemble those of clonidine, but unlike clonidine, alprazolam has relatively little effect on plasma catecholamine and cardiovascular parameters. This suggests that alpha 2 mechanisms do not play a primary role in alprazolam's mode of action. Since alprazolam infusion affects three different measures (ACTH/cortisol, growth hormone, and plasma norepinephrine) thought to be dysregulated in depression, challenge with intravenous alprazolam may prove to be a useful "probe" in affective disorders.

Lithium increases 5-HT-mediated prolactin release

The effects of short-term (3-4 days) lithium treatment on the prolactin responses to intravenous clomipramine (0.1 mg/kg), metoclopramide (5 micrograms/kg) and haloperidol (2.5-5 micrograms/kg) were assessed in male volunteers. Prolactin responses to clomipramine were significantly enhanced by lithium while those following administration of haloperidol and metoclopramide were not significantly altered. Lithium did not change the cortisol response to clomipramine. The results suggest that lithium may selectively enhance 5-HT mediated prolactin release. These data are consistent with the hypothesis that synergistic effects of lithium and clomipramine on brain 5-HT function may be involved in their therapeutic effect in resistant depression.

Afternoon plasma cortisol in relation to depression. A replication study

In 37 consecutive depressed inpatients afternoon plasma cortisol (1500-1520 h) was measured in 3 ways: 1) spontaneously; 2) 2 h after oral administration of 60 mg oxazepam; and 3) 16 h after oral administration of 2 mg dexamethasone. Both oxazepam and dexamethasone caused a significant suppression of cortisol secretion. Spontaneous and suppressed cortisol levels correlated significantly to stress/distress items on the Hamilton Rating Scale for Depression (sum of items 8, 9, 10 and 12), whereas no correlations to age, or type of depression were found. In an earlier similar study of 35 patients both spontaneous and suppressed cortisol levels correlated significantly with age, type and severity of depression as well as with the stress/distress items. Those patients were older, more depressed (HRSD-17) and had higher stress/distress scores compared with the present sample of 37 patients. The consistent finding of a correlation with the stress/distress items suggest that this factor is important in relation to the hypersecretion of cortisol during depression and this may explain the limited diagnostic power of spontaneous and suppressed cortisol levels.

Acute changes in sleep-related hormone secretion of depressed patients following oral imipramine

Tricyclic antidepressants have acute effects on hormone secretion when given either orally or parenterally in the morning. These drugs also have acute effects on the sleep electroencephalogram (EEG) when given immediately before sleep onset. In particular, imipramine significantly delays the REM-nREM cycle and increases the amount of delta wave activity. This study shows that an oral dose of 50 mg imipramine given at bedtime to depressed patients has little effect on the secretion of prolactin and melatonin, but acutely advances the secretion of growth hormone and cortisol. This suggests that sleep and hormone secretion may only be temporally related, as they can be dissociated pharmacologically.