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

Effect of tianeptine on the hypothalamic control of the corticotropic response to stress

Stress-induced stimulation of corticotropic function involves the activation of hypothalamic corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP), which can be measured by improved methods of neuroendocrine investigation. The antiserotoninergic tricyclic antidepressant, tianeptine, reduces the corticotropic response to stress, as shown by a reduction in hypothalamo-hypophyseal portal CRH and AVP levels.

Effect of the antidepressant tianeptine on the activity of the hypothalamo-pituitary-adrenal axis

The effect of the antidepressant agent, tianeptine, on the hypothalamo-pituitary-adrenal (HPA) axis was studied in adult male rats under basal and stressed conditions. Chronic treatment with tianeptine (10 mg/kg; 2 weeks; twice a day) induced a significant decrease of hypothalamic CRF (–12%) and pituitary ACTH concentrations (–21%), suggesting that tianeptine reduces the activity of hypothalamic CRF neurons and pituitary corticotrophs. The possible effect of tianeptine in the neuroendocrine response to stress was thus investigated. Rats were submitted to restraint stress for 30 min; under these conditions ACTH and corticosterone levels were considerably increased. A single injection of tianeptine was found to significantly reduce stress-evoked elevations of plasma ACTH and corticosterone. Time-course experiments, consisting of administering tianeptine 1–3 h before immobilization stress, revealed that the maximum inhibitory effect of tianeptine occurs about 2 h after injection of the antidepressant. Administration of various doses of tianeptine (from 2.5 to 20 mg/kg) showed that the effect of the drug was dose-dependent; the maximum effective dose being 10 mg/kg. Taken together, these data indicate that tianeptine may exert original ‘anti-stress’ activity.

Effects of tianeptine on behavioural and neurochemical responses to immobilization stress

The novel antidepressant drug tianeptine had an antidepressant-like effect on a rat model of depression based on the deficit in open field activity observed on the day after 2 h immobilization. Thus, tianeptine (10 mg/kg ip) given 2 h after the end of the immobilization period led to the deficit being opposed. Similar results were obtained using rats previously given 10 mg/kg of the drug per day for 13 days and a final dose 2 h after the end of immobilization. Other workers have found that tianeptine attenuates stress-induced activation of the hypothalamo-pituitary-adrenal axis. Possible relationships between these findings are discussed together with the paradoxical co-existence of the antidepressant properties of tianeptine with its ability to decrease the availability of 5-HT to receptors.

Maternal separation induces long-term changes in mineralocorticoid receptor in rats subjected to chronic stress and treated with tianeptine

PURPOSE

The aim of this study was to analyze whether early maternal separation would result in long-term, persistent alterations in stress response in adulthood, altering mineralocorticoid receptor immunoreactivity (MR-ir) in the dorsal hippocampal areas [CA1, CA2, CA3 and dentate gyrus (DG)], paraventricular nucleus of the hypothalamus and medial and central nucleus of the amygdala, key structures involved in stress response regulation. We also analyzed whether chronic treatment with the antidepressant tianeptine reverses these possible changes.

MATERIAL AND METHODS

Male Wistar rats were subjected to daily maternal separation for 4.5 h during 3 weeks or left undisturbed. As adults, they were exposed to chronic stress during 24 days or left undisturbed, and they were also daily treated with tianeptine (10 mg/kg i.p.) or isotonic solution.

RESULTS

In the CA2 and DG areas of the dorsal hippocampus, there was an increase in MR-ir in non-maternally separated and chronic stressed groups. Tianeptine raised MR-ir in the CA3. In the DG, control and maternally separated + chronic stress groups treated with tianeptine showed more MR-ir than their respective vehicle groups. In the paraventricular nucleus, tianeptine decreased MR-ir in non-separated groups, but not in maternally separated rats.

CONCLUSIONS

Our results support findings that early-life events induce long-term changes in stress response regulation, persistent into adulthood, which are manifested during challenges in later life, and that treatment with tianeptine, which tends to attenuate the hypothalamus-pituitary-adrenal axis dysregulation, depends on the individual experience of each rat.

How does early maternal separation and chronic stress in adult rats affect the immunoreactivity of serotonergic neurons within the dorsal raphe nucleus?

Vulnerability to emotional disorders like depression derives from interactions between early and late environments, including stressful conditions. The serotonin (5HT) system is strongly affected by stress and chronic unpredictable stress can alter the 5HT system. We evaluated the distribution of active serotonergic neurons in the dorsal raphe nucleus (DR) through immunohistochemistry in maternally separated and chronically stressed rats treated with an antidepressant, tianeptine, whose mechanism of action is still under review. Male Wistar rats were subjected to daily maternal separation (MS) for 4.5 h between postnatal days (PND) 1-21, or to animal facility rearing (AFR). Between (PND) days 50-74, rats were exposed to chronic unpredictable stress and were treated daily with tianeptine (10 mg/kg) or vehicle. We found an interaction between the effects of MS and chronic unpredictable stress on Fos-5HT immunoreactive cells at mid-caudal level of the DR. MS-chronically stressed rats showed an increase of Fos-5HT immunoreactive cells compared with AFR-chronically stressed rats. The ventrolateral (DRL/VLPAG) and dorsal (DRD) subdivisions of the DR were significantly more active than the ventral part (DRV). At the rostral level of the DR, tianeptine decreased the number of Fos-5HT cells in DR in the AFR groups, both unstressed and stressed. Overall, our results support the idea of a match in phenotype exhibited when the early and the adult environment correspond.

Maternal separation in early life modifies anxious behavior and Fos and glucocorticoid receptor expression in limbic neurons after chronic stress in rats: effects of tianeptine

Early-life adversity can lead to long-term consequence persisting into adulthood. Here, we assess the implications of an adverse early environment on vulnerability to stress during adulthood. We hypothesized that the interplay between early and late stress would result in a differential phenotype regarding the number of neurons immunoreactive for glucocorticoid receptor (GR-ir) and neuronal activity as assessed by Fos immunoreactivity (Fos-ir) in brain areas related to stress responses and anxiety-like behavior. We also expected that the antidepressant tianeptine could correct some of the alterations induced in our model. Male Wistar rats were subjected to daily maternal separation (MS) for 4.5 h during the first 3 weeks of life. As adults, the rats were exposed to chronic stress for 24 d and they were treated daily with tianeptine (10 mg/kg intraperitoneal) or vehicle (isotonic saline). Fos-ir was increased by MS in all structures analyzed. Chronic stress reduced Fos-ir in the hippocampus, but increased it in the paraventricular nucleus. Furthermore, chronic stress increased GR-ir in hippocampus (CA1) and amygdala in control non-MS rats. By contrast, when MS and chronic stress were combined, GR-ir was decreased in these structures. Additionally, whereas tianeptine did not affect Fos-ir, it regulated GR-ir in a region-dependent manner, in hippocampus and amygdala opposing in some cases the stress or MS effects. Furthermore, tianeptine reversed the MS- or stress-induced anxious behavior. The interplay between MS and chronic stress observed indicates that MS rats have a modified phenotype, which is expressed when they are challenged by stress in later life.

The hippocampus and TNF: Common links between chronic pain and depression

Major depression and chronic pain are significant health problems that seriously impact the quality of life of affected individuals. These diseases that individually are difficult to treat often co-exist, thereby compounding the patient's disability and impairment as well as the challenge of successful treatment. The development of efficacious treatments for these comorbid disorders requires a more comprehensive understanding of their linked associations through common neuromodulators, such as tumor necrosis factor-α (TNFα), and various neurotransmitters, as well as common neuroanatomical pathways and structures, including the hippocampal brain region. This review discusses the interaction between depression and chronic pain, emphasizing the fundamental role of the hippocampus in the development and maintenance of both disorders. The focus of this review addresses the hypothesis that hippocampal expressed TNFα serves as a therapeutic target for management of chronic pain and major depressive disorder (MDD).

Swimming exercise ameliorates depression-like behaviors induced by prenatal exposure to glucocorticoids in rats

Prenatal exposure to glucocorticoids (GCs) leads to affective dysfunction in adulthood, which may be associated with the alterations in hypothalamic-pituitary-adrenal (HPA) axis. Physical exercise has been shown to ameliorate depressive symptoms. The objectives of present study were to investigate whether prenatal exposure to GCs induces depression-like behaviors in adult offspring rats, and determine whether swimming exercise alleviates the depression-like behaviors induced by this paradigm. Pregnant rats received dexamethasone (DEX) (0.1mg/kg/day) in the last third of pregnancy or vehicle. DEX treatment reduced body weight in 1, 3, 6, 9-week old male offspring, and 3, 6, 9-week old female offspring. DEX treatment resulted in an elevated level of serum corticosterone in adult offspring (9weeks). Female and male adult offspring rats exhibited decreased number of poking into holes and rearing and decreased central distance traveled in open field test (OFT), and reduced sucrose consumption, suggesting prenatal DEX exposure increase depression-like behaviors in the adult offspring rats. Four-week swimming exercise reduced serum corticosterone levels, and alleviated the depressive behavior by reversing the decreased number of poking into holes and rearing as well as decreased central distance traveled, and reversing the reduced sucrose consumption in male and female adult offspring. These findings suggested prenatal exposure to GCs increase the activity of HPA axis and depression-like behaviors of adult offsprings. Swimming exercise decreases HPA activity and ameliorates depression in rats exposed to DEX prenatally.

Mifepristone decreases depression-like behavior and modulates neuroendocrine and central hypothalamic-pituitary-adrenocortical axis responsiveness to stress

Glucocorticoid dyshomeostasis is observed in a proportion of depressed individuals. As a result, glucocorticoid receptor (GR) antagonists are currently being tested as potential anti-depressants. The current study was designed to test the efficacy of mifepristone, a GR antagonist, in mitigating behavioral, neuroendocrine and central nervous system (CNS) responses to an acute stressor. Adult male rats were treated for 5 days with mifepristone (10 mg/kg) and then exposed to the forced swim test (FST). Treatment with mifepristone decreased immobility and increased swimming (but not climbing) behavior in the FST, consistent with anti-depressant action. In addition, mifepristone dampened the ACTH response to FST exposure. In the CNS, mifepristone increased c-Fos expression in all subdivisions of the medial prefrontal cortex (mPFC) and decreased neuronal activity in some subdivisions of the hippocampus including the CA2, CA3, and hilus region of the dentate gyrus in animals exposed to FST. In contrast, mifepristone increased neuronal activity in the ventral subiculum (output region of the hippocampus) and decreased c-Fos expression in the central amygdala (CeA) in animals exposed to FST. These data suggest that anti-depressant efficacy and perhaps HPA dampening properties of RU486 are related to alterations in key limbic circuits mediating CNS stress responses, resulting in enhanced stress inhibition (via the mPFC and ventral subiculum) as well as decreased stress excitation (central amygdala). Overall the data suggest that drugs targeting the glucocorticoid receptor may ameliorate stress dysfunction associated with depressive illness.

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.

The immobility produced by intermittent swim stress is not mediated by serotonin

Exposure to uncontrollable stressors such as intermittent swim stress (ISS) produces a behavioral syndrome that resembles behavioral depression including immobility in a Forced Swim Test (FST) and escape learning deficits. The results of previous studies suggest that stress causes a temporary sensitization of the brain serotonin (5-HT) system that is necessary and sufficient for producing behavioral depression. If this hypothesis is true in the ISS paradigm, then enhancing or inhibiting 5-HT transmission during stress should exacerbate or block the development of behavioral depression, respectively. The selective 5-HT uptake inhibitor fluoxetine (FLX) was administered prior to ISS or confinement; 24 h later the FST was used to detect behavioral immobility. ISS, but not FLX, significantly increased immobility in the FST. The purported 5-HT uptake enhancer tianeptine (TPT) was administered in place of FLX. Again ISS increased immobility in the FST, but TPT had no effect. These results suggested that 5-HT is not a critical mediator of ISS induced behavioral depression. However, some authors have raised concern that TPT does not act directly on 5-HT. Therefore, the 5-HT synthesis inhibitor, para-chlorophenylaline (PCPA) was administered to deplete central 5-HT before stress. PCPA did not alter immobility in the FST. Finally, a sub-chronic regimen of FLX given after ISS, but before the FST, was without effect on reversing the ISS-induced immobility. Taken together, these experiments indicate that ISS produces a significant behavioral depression manifested as increased immobility but offer no support of the hypothesis that 5-HT is a critical mediator of these effects.

Long-term voluntary exercise and the mouse hypothalamic-pituitary-adrenocortical axis: impact of concurrent treatment with the antidepressant drug tianeptine

We investigated whether voluntary exercise and concurrent antidepressant treatment (tianeptine; 20 mg/kg/day; 4 weeks) exert synergistic effects on the mouse hypothalamic-pituitary-adrenocortical (HPA) axis. Animals had access to a running wheel, were treated with the antidepressant, or received both conditions combined. Control mice received no running wheel and no drug treatment. Exercise resulted in asymmetric changes in the adrenal glands. Whereas sedentary mice had larger left adrenals than right ones, this situation was abolished in exercising animals, mainly due to enlargement of the right adrenal cortex. However, antidepressant treatment alone was ineffective whereas the combination of antidepressant treatment and exercise resulted in an enlargement of both adrenal cortices. In these respective conditions, the levels of tyrosine hydroxylase (TH) mRNA expression in the left and right adrenal medullas varied greatly in parallel to the changes observed in the adrenal cortex sizes. TH mRNA expression in the locus coeruleus of exercising mice was significantly increased irrespective of concomitant tianeptine treatment. Corticotrophin-releasing factor mRNA levels in the hypothalamic paraventricular nucleus were decreased after voluntary exercise but were unaffected by tianeptine. Exercise, particularly in combination with tianeptine treatment, resulted in decreased early morning baseline plasma levels of corticosterone. If animals were exposed to novelty (i.e. a mild psychological stressor), a decreased response in plasma corticosterone levels was observed in the exercising mice. By contrast, after restraint, a mixed physical and psychological stressor, exercising mice showed an enhanced response in plasma corticosterone compared to the controls; a response which was even further boosted in exercising mice concomitantly treated with tianeptine. Under either condition, plasma adrenocorticotrophic hormone levels were not different between groups. Thus, voluntary exercise impacts substantially on HPA axis regulation. Concurrent tianeptine treatment results in synergistic actions, mainly at the adrenal level, affecting both its structure and function.

The stress system in the human brain in depression and neurodegeneration

Corticotropin-releasing hormone (CRH) plays a central role in the regulation of the hypothalamic-pituitary-adrenal (HPA)-axis, i.e., the final common pathway in the stress response. The action of CRH on ACTH release is strongly potentiated by vasopressin, that is co-produced in increasing amounts when the hypothalamic paraventricular neurons are chronically activated. Whereas vasopressin stimulates ACTH release in humans, oxytocin inhibits it. ACTH release results in the release of corticosteroids from the adrenal that, subsequently, through mineralocorticoid and glucocorticoid receptors, exert negative feedback on, among other things, the hippocampus, the pituitary and the hypothalamus. The most important glucocorticoid in humans is cortisol, present in higher levels in women than in men. During aging, the activation of the CRH neurons is modest compared to the extra activation observed in Alzheimer's disease (AD) and the even stronger increase in major depression. The HPA-axis is hyperactive in depression, due to genetic factors or due to aversive stimuli that may occur during early development or adult life. At least five interacting hypothalamic peptidergic systems are involved in the symptoms of major depression. Increased production of vasopressin in depression does not only occur in neurons that colocalize CRH, but also in neurons of the supraoptic nucleus (SON), which may lead to increased plasma levels of vasopressin, that have been related to an enhanced suicide risk. The increased activity of oxytocin neurons in the paraventricular nucleus (PVN) may be related to the eating disorders in depression. The suprachiasmatic nucleus (SCN), i.e., the biological clock of the brain, shows lower vasopressin production and a smaller circadian amplitude in depression, which may explain the sleeping problems in this disorder and may contribute to the strong CRH activation. The hypothalamo-pituitary thyroid (HPT)-axis is inhibited in depression. These hypothalamic peptidergic systems, i.e., the HPA-axis, the SCN, the SON and the HPT-axis, have many interactions with aminergic systems that are also implicated in depression. CRH neurons are strongly activated in depressed patients, and so is their HPA-axis, at all levels, but the individual variability is large. It is hypothesized that particularly a subgroup of CRH neurons that projects into the brain is activated in depression and induces the symptoms of this disorder. On the other hand, there is also a lot of evidence for a direct involvement of glucocorticoids in the etiology and symptoms of depression. Although there is a close association between cerebrospinal fluid (CSF) levels of CRH and alterations in the HPA-axis in depression, much of the CRH in CSF is likely to be derived from sources other than the PVN. Furthermore, a close interaction between the HPA-axis and the hypothalamic-pituitary-gonadal (HPG)-axis exists. Organizing effects during fetal life as well as activating effects of sex hormones on the HPA-axis have been reported. Such mechanisms may be a basis for the higher prevalence of mood disorders in women as compared to men. In addition, the stress system is affected by changing levels of sex hormones, as found, e.g., in the premenstrual period, ante- and postpartum, during the transition phase to the menopause and during the use of oral contraceptives. In depressed women, plasma levels of estrogen are usually lower and plasma levels of androgens are increased, while testosterone levels are decreased in depressed men. This is explained by the fact that both in depressed males and females the HPA-axis is increased in activity, parallel to a diminished HPG-axis, while the major source of androgens in women is the adrenal, whereas in men it is the testes. It is speculated, however, that in the etiology of depression the relative levels of sex hormones play a more important role than their absolute levels. Sex hormone replacement therapy indeed seems to improve mood in elderly people and AD patients. Studies of rats have shown that high levels of cumulative corticosteroid exposure and rather extreme chronic stress induce neuronal damage that selectively affects hippocampal structure. Studies performed under less extreme circumstances have so far provided conflicting data. The corticosteroid neurotoxicity hypothesis that evolved as a result of these initial observations is, however, not supported by clinical and experimental observations. In a few recent postmortem studies in patients treated with corticosteroids and patients who had been seriously and chronically depressed no indications for AD neuropathology, massive cell loss, or loss of plasticity could be found, while the incidence of apoptosis was extremely rare and only seen outside regions expected to be at risk for steroid overexposure. In addition, various recent experimental studies using good stereological methods failed to find massive cell loss in the hippocampus following exposure to stress or steroids, but rather showed adaptive and reversible changes in structural parameters after stress. Thus, the HPA-axis in AD is only moderately activated, possibly due to the initial (primary) hippocampal degeneration in this condition. There are no convincing arguments to presume a causal, primary role for cortisol in the pathogenesis of AD. Although cortisol and CRH may well be causally involved in the signs and symptoms of depression, there is so far no evidence for any major irreversible damage in the human hippocampus in this disorder.

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.

Do antidepressants regulate how cortisol affects the brain?

Although the effects of antidepressants on glucocorticoid hormones and their receptors are relevant for the therapeutic action of these drugs, the molecular mechanisms underlying these effects are unclear. Studies in depressed patients, animals and cellular models have demonstrated that antidepressants increase glucocorticoid receptor (GR) and mineralocorticoid receptor (MR) expression and function; this, in turn, is associated with enhanced negative feedback by endogenous glucocorticoids, and thus with reduced resting and stimulated hypothalamic-pituitary-adrenal (HPA) axis activity. In a series of studies conducted over the last few years, we have shown that antidepressants modulate GR function in vitro by inhibiting membrane steroid transporters that regulate the intracellular concentration of glucocorticoids. In this paper, we will review the effects of membrane steroid transporters and antidepressants on corticosteroid receptors. We will then present our unpublished data on GR live microscopy in vitro, showing that ligand-induced translocation of the GR starts within 30 seconds and is completed within minutes. Furthermore, we will present our new data using an in situ brain perfusion model in anaesthetised guinea-pigs, showing that entry of cortisol to the brain of these animals is limited at the blood-brain barrier (BBB). Finally, we will present a comprehensive discussion of our published findings on the effects of chemically unrelated antidepressants on membrane steroid transporters, in mouse fibroblasts and rat cortical neurones. We propose that antidepressants in humans could inhibit steroid transporters localised on the BBB and in neurones, like the multidrug resistance p-glycoprotein, and thus increase the access of cortisol to the brain and the glucocorticoid-mediated negative feedback on the HPA axis. Enhanced cortisol action in the brain might prove to be a successful approach to maximise therapeutic antidepressant effects.

The effects of paroxetine and tianeptine on peripheral biochemical markers in major depression

Depression is related to the alterations of the central serotonergic system and some antidepressants achieve their therapeutic effects through alteration of serotonin (5-HT) (re)uptake. Peripheral biochemical markers, platelet and serum 5-HT concentrations, platelet monoamine oxidase (MAO) activity, plasma levels of cortisol and prolactin (PRL), were investigated in patients with major depression before and after 4 weeks of treatment with paroxetine (an inhibitor of 5-HT uptake) or tianeptine (a stimulator of 5-HT uptake). Study was open, single center and included female depressed patients, 21 treated with tianeptine (37.5 mg/day) and 15 treated with paroxetine (20 mg/day), and 11 drug-free healthy women (controls). Before treatment, depressed patients as a group had significantly higher serum 5-HT and cortisol concentrations than healthy controls. There were no differences in the other biochemical markers. Response to antidepressant treatment was estimated according to the 50% fall in the initial scores of Hamilton Depression Rating Scale (HAMD) after 4 weeks of treatment. Good therapeutic response was observed in 47% and 45% patients treated with paroxetine and tianeptine, respectively. Paroxetine treatment induced significant decrease in platelet 5-HT concentrations in both responders and nonresponders, while no alterations in platelet 5-HT values were found in tianeptine-treated patients. There was a subgroup of depressed patients in paroxetine-treated group with high pretreatment platelet 5-HT concentration and later poor therapeutic response to paroxetine treatment. Serum 5-HT values, platelet MAO activity or plasma cortisol or PRL levels were unchanged after both treatments. The results suggest that pretreatment platelet 5-HT levels, but not other peripheral biochemical markers, might predict therapeutic outcome at least in paroxetine-treated patients.

Cortisol response to surgery and postoperative confusion in depressed patients under general anesthesia with fentanyl

The purpose of this study was to investigate the relationship between postoperative confusion and plasma cortisol response to surgery in depressed patients. We studied 80 depressed patients and 40 control patients who had undergone orthopedic surgery and perioperatively measured plasma cortisol and adrenocorticotropin levels. Postoperative confusion in the first 3 postoperative days occurred in 5 (13%) depressed patients given fentanyl during anesthesia, 13 (33%) patients without fentanyl and 1 (3%) control patients. Plasma cortisol concentration (19.7 +/- 6.9 and 19.2 +/- 8.0 microg dl(-1)) 15 min after skin incision and 60 min after the end of surgery in depressed patients with fentanyl was significantly lower than that (24.2 +/- 7.2 and 23.5 +/- 8.1 microg dl(-1)) of depressed patients without fentanyl. Plasma cortisol levels during and after surgery in depressed patients with postoperative confusion were higher than those of depressed patients without postoperative confusion. We conclude that the occurrence of postoperative confusion in depressed patients is associated with an increase in plasma cortisol levels during and after surgery. The incidence of postoperative confusion in depressed patients with fentanyl was significantly lower than that of depressed patients without fentanyl.

Tianeptine: a review of its use in depressive disorders

Tianeptine is an antidepressant agent with a novel neurochemical profile. It increases serotonin (5-hydroxytryptamine; 5-HT) uptake in the brain (in contrast with most antidepressant agents) and reduces stress-induced atrophy of neuronal dendrites. Like the selective serotonin reuptake inhibitors (SSRIs) and in contrast with most tricyclic antidepressant agents, tianeptine does not appear to be associated with adverse cognitive, psychomotor, sleep, cardiovascular or bodyweight effects and has a low propensity for abuse. Tianeptine has a comparatively favourable pharmacokinetic profile. It is not subject to first-pass hepatic metabolism, has high bioavailability and limited distribution, and is rapidly eliminated. While this offers advantages for tianeptine over the tricyclic antidepressant agents in terms of dose titration, treatment changes and potential drug interactions, its rapid elimination makes adherence to dosage schedules more important. Tianeptine differs from most antidepressants in that it is not primarily metabolised by the hepatic cytochrome P450 system, indicating less likelihood of drug-drug interactions; this is of particular interest for elderly patients. Tianeptine, in dosages of 25 to 50 mg/day, has been investigated in patients with major depression, depressed bipolar disorder, dysthymia or adjustment disorder. It has equivalent antidepressant efficacy to several classical antidepressant agents (amitriptyline, clomipramine, imipramine, mianserin) and the SSRIs fluoxetine (in most patients), paroxetine and sertraline. Comparison with maprotiline indicated superior efficacy for tianeptine but dothiepin appeared superior in another study. Extended treatment with tianeptine decreases the incidence of relapse/recurrence of depression. Tianeptine appears to be as effective as fluoxetine, sertraline, amitriptyline, clomipramine and mianserin and more effective than maprotiline in improving associated anxiety in patients with depressive disorders. Depression and anxiety symptoms in alcohol dependant patients also respond well to tianeptine. The adverse effects associated with tianeptine are similar in many respects to those of the SSRIs and minimal in comparison with the tricyclic antidepressants. The most common adverse effects are nausea, constipation, abdominal pain, headache, dizziness and changes in dreaming. Anticholinergic effects occur less often with tianeptine than with tricyclic agents. Hepatoxicity is rare. The dosage should be decreased in elderly patients and those with severe renal failure, but adjustment is not necessary in patients with alcoholism or hepatic impairment, or those undergoing haemodialysis.

CONCLUSIONS

The antidepressant efficacy and favourable tolerability and pharmacokinetic profiles of tianeptine in patients with depression, including those with associated anxiety, have been proven; the data indicate that it may have additional potential in specific subgroups of depressed patients such as the elderly and those with chronic alcoholism.

Glucocorticoid receptors in major depression: relevance to pathophysiology and treatment

Hyperactivity of the hypothalamic--pituitary--adrenal (HPA) axis has been reliably observed in patients with major depression. One of the primary features of this HPA axis hyperactivity is reduced sensitivity to the inhibitory effects of the glucocorticoid dexamethasone on the production of adrenocorticotropic hormone and cortisol during the dexamethasone suppression test and, more recently, the dexamethasone--corticotropin-releasing hormone test. Because the effects of glucocorticoids are mediated by intracellular receptors including, most notably, the glucocorticoid receptor (GR), a number of studies have considered the possibility that the number and/or function of GRs are reduced in depressed patients. Moreover, whether antidepressants act by reversing these putative GR changes has been examined. The extant literature on GR receptors in major depression was reviewed along with studies examining the impact of antidepressants on the GR. The data support the hypothesis that the function of the GR is reduced in major depression in the absence of clear evidence of decreased GR expression. The data also indicate that some antidepressants have direct effects on the GR, leading to enhanced GR function and increased GR expression. Hypotheses regarding the mechanism of these receptor changes involve relevant second messenger pathways that regulate GR function. The findings indicate that the GR is an important molecular target in major depression. Further elucidation of the biochemical and molecular mechanisms involved in GR changes in major depression is an exciting frontier that will no doubt lead to new insights into the pathophysiology and treatment of affective disorders.

Cellular mechanisms in the vulnerability to depression and response to antidepressants

As a testable heuristic, the concept of stress response and adaptation is highly appealing, and the support for the concept is strong. This explanatory model of depression may account for hitherto apparently discordant facts--contradictory symptoms, antidepressant drugs that act on differing systems, facilitation of antidepressant response by augmentation, and response to psychotherapy and pharmacotherapy. This article has focused narrowly on specific cellular elements of the stress-adaptational mechanisms, including the AC-PKA and PLC-PKC transductional cascades, together with specific response elements, such as the HPA axis, BDNF, and NMDA receptors; however, other important mechanisms, including specific receptor subtypes (e.g., 5-HT1A and NE alpha 2), transmitter systems (e.g., acetylcholine and depamine), and hormones (e.g., thyroid and growth hormones and prolactin), which may be important, have not been discussed. As the complex interactions of these systems gradually yield to investigation, not only will new treatments be developed, but better matching of treatment to patient may become an achievable goal.

Inhibition of the cortisol response to surgical stress in chronically depressed patients

STUDY OBJECTIVE

To evaluate whether the pituitary-adrenal and catecholamine response to surgical stress is modified in chronically depressed patients.

DESIGN

Prospective, controlled study.

PATIENTS

25 ASA physical status I and II depressed patients taking chronic antidepressant therapy and 25 control patients undergoing orthopedic surgery of the extremities.

INTERVENTIONS

All patients received anesthesia induction with thiopental 5 mg/kg and suxamethonium 1 mg/kg intravenously (IV) and were maintained with 1.5% to 2.0% isoflurane in nitrous oxide (70%) and oxygen (30%).

MEASUREMENTS AND MAIN RESULTS

Plasma cortisol concentration (27.7 +/- 3.6 microg/dL) in chronic depressed patients at 60 minutes after the skin incision was not significantly higher than that (23.9 +/- 2.7 microg/dL) before the induction, although plasma cortisol concentration in the control group significantly increased. Plasma norepinephrine concentration at 60 min after the skin incision in depressed patients with more symptoms of depression was significantly higher than that of patients with less symptoms of depression.

CONCLUSION

The cortisol response to surgical stress in depressed patients was inhibited and norepinephrine response to surgical stress was increased in depressed patients with more symptoms of depression.

Hypothalamic pituitary adrenocortical and sympathetic nervous system responses to the cold pressor test in Alzheimer's disease

BACKGROUND

Increased basal activity of the hypothalamic-pituitary-adrenocortical (HPA) axis has been repeatedly demonstrated in Alzheimer's disease (AD), and some studies suggest increased basal activity of the sympathetic nervous system (SNS) in this disorder; however, the effects of AD on HPA axis or SNS responses to a standardized aversive stressor have not been examined. The neuroendocrine response to aversive stress may be relevant to the pathophysiology of AD.

METHODS

Plasma adrenocorticotropic hormone (ACTH), cortisol, norepinephrine (NE), and epinephrine responses to a 1-min cold pressor test (CPT) were measured in nine medically healthy AD outpatients (age 76 +/- 2 years) and nine age- and gender-matched medically healthy cognitively normal older subjects (age 76 +/- 1 year).

RESULTS

The cortisol response to CPT was increased in the AD group but the ACTH response did not differ between groups. Basal NE concentrations were higher in the AD group. Although NE responses to CPT did not differ between groups, the blood pressure response to CPT was higher in the AD subjects.

CONCLUSIONS

These results suggest increased HPA axis responsiveness to CPT at the level of the adrenal cortex in AD. The results also suggest increased basal sympathoneural activity and increased cardiovascular responsiveness to sympathoneural stimulation in AD under the conditions of this experimental protocol. Increased SNS stimulatory modulation of the adrenal cortex is a possible mechanism contributing to the observed enhanced cortisol response to CPT in these AD subjects.

The psychiatric side effects of corticosteroids

LEARNING OBJECTIVES

Readers will learn the importance of psychiatric symptomatology with corticosteroid drug therapy, especially when combined with other medications.

DATA SOURCES

A brief history of corticosteroid use over the last five decades was complied utilizing MEDLINE and PSYCHOINFO as sources of information which include peer-reviewed research articles, case studies, and relevant reviews in English.

CONCLUSION

Corticosteroids are routinely prescribed for a variety of allergic and immunologic illnesses. Psychiatric side effects from corticosteroids include mania, depression and mood disturbances. Psychiatric symptoms usually occur within the first two weeks of corticosteroid therapy and seem to be dose related. Treatment with lithium or antipsychotics may be helpful. Physicians should carefully monitor patients for psychiatric and cognitive side effects of corticosteroid use.

Glucocorticoids and depression

Depression has been associated with impaired mineralocorticoid receptor function, restrained glucocorticoid receptor feedback at the level of the hypothalamic-pituitary-adrenal (HPA) axis, raised cortisol level and increased corticotropin-releasing factor activity, which may act in concert to induce the signs and symptoms of the disorder. Pre-clinical and clinical evidence suggests that both genetic and environmental factors contribute to the development of these HPA axis abnormalities in depressed patients. Support for this view derives from models using genetically modified animals and/or chronic stress exposure at different developmental stages, although all of the current approaches have to be viewed within their limitations to model the disease. However, both animal and human studies challenging the HPA system show at least some neuroendocrine and behavioural changes comparable to those seen in depression, suggesting that some of the depressive symptoms can be attributed to HPA axis hyperactivity. Moreover, normalization of the neuroendocrine function following chronic antidepressant drug treatment seems to be a prerequisite for stable remission of depressive psychopathology, i.e. that normalization of HPA function is critical for relief of the clinical symptomatology of this disorder.

Effects of antidepressants and benzodiazepine treatments on the dendritic structure of CA3 pyramidal neurons after chronic stress

Both repeated stress and corticosterone administration induce remodeling of apical dendrites of hippocampal CA3 pyramidal neurons. Circulating glucocorticoids are involved in the mechanism that produces atrophy, along with excitatory amino acids and serotonin (5-hydroxytryptamine, 5-HT). We used 5-HT-related antidepressants and a benzodiazepine in order to explore indirectly the role of serotonin and GABA(A)-benzodiazepine receptors in the stress-induced structural changes visualized by the Golgi impregnation of the rat hippocampus. The 5-HT reuptake enhancer (+/-)-tianeptine prevented the dendritic atrophy caused by repeated restraint stress in a non-stereoselective fashion and two 5-HT reuptake antagonists, fluoxetine and fluvoxamine, failed to block dendritic atrophy. Tianeptine also functions as a therapeutic tool since it reversed the already established hippocampal atrophy caused by treatment with corticosterone for 3 weeks. Finally, the benzodiazepine agonist adinazolam was effective in preventing the stress-induced dendritic atrophy. These findings suggest that the synaptic availability of 5-HT is involved in the mechanism leading to stress-induced dendritic remodeling and supports the idea that the hippocampal inhibitory GABAergic tone may play a regulatory role.

Stress and hippocampal plasticity

The hippocampus is a target of stress hormones, and it is an especially plastic and vulnerable region of the brain. It also responds to gonadal, thyroid, and adrenal hormones, which modulate changes in synapse formation and dendritic structure and regulate dentate gyrus volume during development and in adult life. Two forms of structural plasticity are affected by stress: Repeated stress causes atrophy of dendrites in the CA3 region, and both acute and chronic stress suppresses neurogenesis of dentate gyrus granule neurons. Besides glucocorticoids, excitatory amino acids and N-methyl-D-aspartate (NMDA) receptors are involved in these two forms of plasticity as well as in neuronal death that is caused in pyramidal neurons by seizures and by ischemia. The two forms of hippocampal structural plasticity are relevant to the human hippocampus, which undergoes a selective atrophy in a number of disorders, accompanied by deficits in declarative episodic, spatial, and contextual memory performance. It is important, from a therapeutic standpoint, to distinguish between a permanent loss of cells and a reversible atrophy.

The human hypothalamo-neurohypophysial system in health and disease

The present paper reviews the changes observed in the human supraoptic (SON) and paraventricular (PVN) nuclei, and their projections to the neurohypophysis, median eminence and to other brain areas in health and disease.

The serotonin uptake-enhancing drug tianeptine suppresses asthmatic symptoms in children: a double-blind, crossover, placebo-controlled study

Studies have shown that levels of free serotonin in plasma are increased in symptomatic patients with asthma. In addition, the concentration of free serotonin in symptomatic patients with asthma correlates positively with clinical status and negatively with pulmonary function. Thus, reducing the concentration of free serotonin in plasma might be useful in treating patients with asthma. We studied the effectiveness of tianeptine in treating patients with asthma. Tianeptine is the only drug known to be able to reduce levels of free serotonin in plasma and to enhance uptake by platelets. In this study, 69 children with asthma were assigned in randomized fashion to receive tianeptine and/or placebo in a double-blind crossover trial that lasted 52 weeks. Tianeptine provoked a dramatic and sudden decrease in both clinical rating and free serotonin plasma levels and an increase in pulmonary function.

Neuropharmacologic treatment of bronchial asthma with the antidepressant tianeptine: a double-blind, crossover placebo-controlled study

Studies have shown the levels of free serotonin in plasma are increased in symptomatic patients with asthma. In addition, the concentration of free serotonin in symptomatic children with asthma correlates positively with clinical status and negatively with pulmonary function (forced expiratory volume in 1 second [FEV1]). Thus, reducing the concentration of free serotonin in plasma may be useful in treating children with asthma. We studied the effectiveness of tianeptine in treating these patients. Tianeptine is the only drug known to be able to reduce the level of free serotonin in plasma and to enhance the uptake by platelets. Sixty-nine of the 82 children with asthma initially enrolled participated in this study. Children were randomized to receive tianeptine or placebo or both in a double-blind crossover trial. The trial lasted 52 weeks. Tianeptine provoked a dramatic and sudden decrease of both clinical rating and free serotonin plasma levels and an increase in pulmonary function.

Prevention of stress-induced morphological and cognitive consequences

Atrophy and dysfunction of the human hippocampus is a feature of aging in some individuals, and this dysfunction predicts later dementia. There is reason to believe that adrenal glucocorticoids may contribute to these changes, since the elevations of glucocorticoids in Cushing's syndrome and during normal aging are associated with atrophy of the entire hippocampal formation in humans and are linked to deficits in short-term verbal memory. We have developed a model of stress-induced atrophy of the hippocampus of rats at the cellular level, and we have been investigating underlying mechanisms in search of agents that will block the atrophy. Repeated restraint stress in rats for 3 weeks causes changes in the hippocampal formation that include suppression of 5-HT1A receptor binding and atrophy of dendrites of CA3 pyramidal neurons, as well as impairment of initial learning of a radial arm maze task. Because serotonin is released by stressors and may play a role in the actions of stress on nerve cells, we investigated the actions of agents that facilitate or inhibit serotonin reuptake. Tianeptine is known to enhance serotonin uptake, and we compared it with fluoxetine, an inhibitor of 5-HT reuptake, as well as with desipramine. Tianeptine treatment (10 mg/kg/day) prevented the stress-induced atrophy of dendrites of CA3 pycamidal neurons, whereas neither fluoxetine (10 mg/kg/day) nor desipramine (10 mg/kg/day) had any effect. Tianeptine treatment also prevented the stress-induced impairment of radial maze learning. Because corticosterone- and stress-induced atrophy of CA3 dendrites is also blocked by phenytoin, an inhibitor of excitatory amino acid release and actions, these results suggest that serotonin released by stress or corticosterone may interact pre- or post-synaptically with glutamate released by stress or corticosterone, and that the final common path may involve interactive effects between serotonin and glutamate receptors on the dendrites of CA3 neurons innervated by mossy fibers from the dentate gyrus. We discuss the implications of these findings for treating cognitive impairments and the risk for dementia in the elderly.

Dexamethasone, but not stress, induce measurable changes of mitochondrial benzodiazepine receptor mRNA levels in rats

The expression of the mitochondrial benzodiazepine receptor gene was assayed by a semi-quantitative non-radioactive reverse transcriptase polymerase chain reaction (RT-PCR) assay. The level of amplified mitochondrial benzodiazepine receptor mRNA was expressed as a ratio of either glyceraldehyde-3-phosphate dehydrogenase (GAPDH) or beta-actin mRNA co-amplified in the same RT-PCR assay. The relative amounts of mitochondrial benzodiazepine receptor RNA in several rat tissues were found to be similar to the previously reported relative amount of mitochondrial benzodiazepine receptor binding sites. The level of these binding sites has also been reported to be altered by stress stimuli. In this study we specifically measured the effect of stress on the mRNA levels of the mitochondrial benzodiazepine receptor as an alternative method to the binding assay in an attempt to understand the mechanism by which stress alters binding. Sprague-Dawley male rats were either forced to swim for 15 min in 18 degrees C water or restrained in a plastic cylinder for 45 min either once, or twice daily for 7 days. Neither the swim stress, nor acute or chronic restraint stress, caused a measurable statistically significant relative change in mitochondrial benzodiazepine receptor mRNA in the adrenal gland, kidney, testis and olfactory bulb. However, daily treatment of rats for 7 days with 4 mg/kg of dexamethasone caused a significant decrease in mitochondrial benzodiazepine receptor gene expression in adrenal glands. This finding and the measurement of the relative levels of mitochondrial benzodiazepine receptor mRNA in the various tissues indicate that mitochondrial benzodiazepine receptor density is regulated to some extent at the gene expression level. However, the lack of detectable stress-induced changes in mRNA levels for this receptor seem to indicate that either mRNA changes were below detectable levels or that other mechanisms may be involved in the previously reported stress-induced changes of mitochondrial benzodiazepine receptor density. Because the focus of this work was on the regulation of mitochondrial benzodiazepine receptor gene expression, ligand binding studies to determine changes in receptor densities were not performed.

Stress effects on morphology and function of the hippocampus

The hippocampal formation, which contains high levels of adrenal steroid receptors, is vulnerable to insults such as stroke, seizures, and head trauma, and it is also sensitive and vulnerable to the effects of stress. We have discovered that the hippocampus of rodents and tree shrews shows atrophy of pyramidal neurons in the CA3 region. Psychosocial stress and restraint stress produce atrophy over approximately 3-4 weeks. Atrophy is blocked by inhibiting adrenal steroid formation and by blocking the actions of excitatory amino acids using Dilantin or NMDA receptor inhibitors. Glucocorticoid administration also blocks CA3 atrophy, but Dilantin administration blocks this as well, indicating that excitatory amino acid release mediates the atrophy, which likely involves disassembly of the dendritic cytoskeleton. Studies with in vivo microdialysis in several laboratories have shown that glutamate release in the hippocampus increases in stress and that stress-induced glutamate release is reduced by adrenalectomy. Recent electron microscopy of mossy fiber terminals on CA3 neurons has revealed a depletion of synaptic vesicles as a result of repeated stress. The mossy fiber terminals appear to be responsible for driving atrophy of CA3 neurons, which involves principally atrophy of the apical dendrites. These results are discussed in relation to data from MRI showing atrophy of the whole human hippocampus in Cushing's disease, recurrent depressive illness, PTSD, and normal aging as well as dementia.

Stress versus depression

1. Exhaustive evidence is quoted showing that uncontrollable (uncoping) stress provoked in experimental mammals leads to depletion of central noradrenergic activity+ adrenomedullary-cortical gland hyperactivity. These physiological disorders cause the typical neuroendocrine peripheral profile: a) raised catecholamines (CA) in plasma [noradrenaline (NA)+adrenaline (Ad)+dopamine (DA), b) reduced NA/Ad ratio in plasma and c) raised plasma cortisol. 2. Exhaustive evidence is quoted which indicates that severely ill humans show peripheral neuroendocrine profile similar to that found in mammals submitted to uncontrollable stress situation. Further, the NA/Ad ratio does not increase but decreases during orthostasis and exercise stress challenges, as well as oral glucose stress (tolerance) test. 3. Exhaustive evidence is quoted which indicates that endogenous depressed subjects show a neuroendocrine profile opposite to that observed in stressed mammals and severely ill humans. This profile consists of central NA (neural sympathetic) hyperactivity+ adrenomedullary glands hyporresponsivity. These disorders are reflected in a three to ten fold increase of the NA/Ad ratio in plasma. 4. Exhaustive evidence is also quoted showing that dysthymic depressed patients show low plasma catecholamines+low NA/Ad plasma ratio (< 2) during supine-resting condition, it is normalized at orthostasis and exercise periods. 5. It is quoted evidence showing that whereas platelet serotonin is increased in dysthymics, the same is reduced in both endogenous depressed and stressed mammals as well as severely ill humans. 6. It is quoted evidence showing that free serotonin in plasma is greatly raised in uncoping stressed mammals and severely ill humans. The same parameter is normal or slightly increased in dysthymic and endogenous depressed humans. These findings are consistent with the increased platelet aggregability observed in "uncontrollable" stressed mammals and in severely ill, but not depressed patients. 7. It is also quoted evidence showing that whereas parasympathetic activity is absent in uncontrollable stressed mammals and severely ill humans, the same is increased in both types of depressed humans. 8. According to the above, the authors postulate the existence of 3 distinct central+ peripheral neuroendocrine profiles for endogenous depression, dysthymic depression and maladaptation to stress syndrome. These different profiles should lead researchers to attempt different therapeutical approach. 9. In view of the fact that the authors found much clinical overlap among the three syndromes (endogenous depression, dysthymic depression and severely ill patients), they believe that a differential diagnosis should be based on neurochemical, neuroendocrine, physiologic, metabolic and neuropharmacological grounds. 10. The experimentally induced uncontrollable stress (behavioral despair) syndrome in mammals should not be used as a valid model of human depressive syndrome.

Comparative pharmacodynamic studies with the novel serotonin uptake-enhancing tianeptine and -inhibiting fluvoxamine utilizing EEG mapping and psychometry

In a double-blind, placebo-controlled study, the encephalotropic and psychotropic effects of tianeptine (TIA)--a new tricyclic antidepressant, enhancing serotonin reuptake--were investigated as compared with the serotonin reuptake inhibiting antidepressant, fluvoxamine (FLU), utilizing EEG mapping, psychometric and psychophysiological measures. 16 healthy volunteers (8 males, 8 females) aged 21-35 (man 27) years received randomized and at weekly intervals single oral doses of placebo, 12.5 and 25 mg TIA and 50 mg FLU. EEG recordings, psychometric and psychophysiological tests and evaluation of pulse, blood pressure and side effects were carried out at 0, 2, 4, 6 and 8 hours; blood sampling, in addition, at hour 1. TIA plasma levels rose fast to peaks at 1-2 hours and declined rapidly as well, while the MC5 metabolite peaked in the 4th hour and declined more slowly. EEG mapping demonstrated that both TIA and FLU induced significant changes in brain function between the 1st and 8th hour, which, however, differed in their time course. 12.5 mg TIA exhibited, as compared with placebo, slight activating properties in the EEG (decrease of delta and theta, increase of alpha and beta, acceleration of the centroid), parallelled by thymopsychic improvement (mood elevation). 25 mg TIA showed EEG activation up to the 4th hour, later EEG sedation, accompanied by an initial thymopsychic improvement and differential changes thereafter (improved mood, decreased vigility), with the noopsyche improving at all times (attention, Pauli test). 50 mg FLU induced initially sedation and thereafter activation, accompanied by thymopsychic deterioration and subsequent improvement, the latter also being observed in the noopsyche (attention, memory). In pupillary and skin conductance measures, generally a slight activation occurred after placebo, which was attenuated by 25 mg TIA. Correlation maps between plasma levels and EEG changes demonstrated: the higher the TIA plasma levels, the more absolute and relative beta power, the less alpha power and the faster the centroid of the total power spectrum, reflecting CNS-activation. Topographically, the correlations were mostly seen over both fronto-temporal regions. In the latter, dominant frequency signalled desactivation in the right and activation in the left hemiphere after both antidepressants which, thereby induced changes in brain function opposite to those observed in depression. Both drugs were well tolerated.

Tianeptine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic efficacy in depression and coexisting anxiety and depression

Tianeptine is a novel antidepressant agent, both structurally (modified tricyclic) and in terms of its pharmacodynamic profile. Unlike other antidepressant agents, tianeptine stimulates the uptake of serotonin (5-hydroxytryptamine; 5-HT) in rat brain synaptosomes and rat and human platelets, increases 5-hydroxyindoleacetic acid (5-HIAA) levels in cerebral tissue and plasma, and reduces serotonergic-induced behaviour. Tianeptine reduces the hypothalamic-pituitary-adrenal response to stress, antagonises stress-induced behavioural deficits and prevents changes in cerebral morphology. The antidepressant efficacy of tianeptine, as shown in 2 trials of patients with major depression or depressed bipolar disorder with or without melancholia, is greater than that of placebo. In patients with major depression without melancholia or psychotic features, depressed bipolar disorder or dysthymic disorder, the antidepressant efficacy of short term (4 weeks to 3 months) tianeptine therapy appears to be similar to that of amitriptyline, imipramine and fluoxetine and may be superior to that of maprotiline in patients with coexisting depression and anxiety. However, submaximal dosages of amitriptyline and maprotiline were used in these studies. Preliminary evidence suggests that tianeptine may also be effective in patients with endogenous depression. Progressive therapeutic improvements have been observed with up to 1 year of tianeptine treatment, and long term therapy may reduce the rate of relapse or recurrence. Tianeptine is effective in the treatment of depression in elderly and post-alcohol-withdrawal patient subgroups. Tianeptine was more effective in reducing psychic anxiety than placebo in patients with major depression or depressed bipolar disorder with or without melancholia. The overall anxiolytic properties of tianeptine in patients with coexisting depression and anxiety appear to be similar to those of amitriptyline, imipramine and fluoxetine and may be superior to those of maprotiline, although submaximal dosages of amitriptyline and maprotiline were used. Studies of tianeptine in patients with primary anxiety have not been conducted. Tianeptine is well tolerated in the short (3 months) and long (up to 1 year) term. The incidence of dry mouth (38 vs 20%), constipation (19 vs 15%), dizziness/syncope (23 vs 13%), drowsiness (17 vs 10%) and postural hypotension (8 vs 3%) are greater with amitriptyline than with tianeptine. Insomnia and nightmares occur in more tianeptine than amitriptyline recipients (20 vs 7%). The relative lack of sedative, anticholinergic and cardiovascular adverse effects with tianeptine makes it particularly suitable for use in the elderly and in patients following alcohol withdrawal; these patients are known to have increased sensitivity to the adverse effects associated with psychotropic drugs.(ABSTRACT TRUNCATED AT 400 WORDS)

Restraint stress in biomedical research: an update

Since the publication of our initial review of restraint stress in 1986, much work has continued with this technique, either as a tool for the investigation of other pharmacological, physiological, or pathologic phenomena or with restraint stress itself serving as the object of the study. As we noted in 1986, the major use of restraint has been for the induction of stress responses in animals and, more specifically, for the investigation of drug effects, particularly as they affect typical stress-related pathology--gastrointestinal, neuroendocrine, and immunological agents have been extensively studied. In compiling this update on restraint stress and its effects, we noted an increasing emphasis on central nervous system mechanisms in peripheral disease, especially gastrointestinal disease. In particular, many CNS-active agents have been tested for their effects on gastric and duodenal lesion formation and gastric secretion, including antidepressants, antipsychotics, anxiolytics, noradrenergic, serotonergic, dopaminergic, and peptidergic compounds. Some of these agents are especially active in the gastrointestinal tract even when administered centrally, further solidifying the concept of a brain-gut axis. The present update includes studies of: methods and procedures, pre-restraint manipulations, post-restraint/healing effects, and drug effects. In addition, a current bibliography of reports that have employed restraint is included.

Effect of tianeptine on the hypothalamic somatotropic axis in the conscious sheep

The action of serotonin on growth hormone (GH) secretion is controversial because of interspecies differences and lack of specificity of serotoninergic drugs. Serotonin (5-HT) appears to inhibit GH release in the sheep and in man. We have investigated the site of action of tianeptine, a 5-HT uptake enhancer, in sheep since it is possible to collect hypophysial portal blood for the simultaneous determination of growth hormone-releasing hormone (GHRH) and somatostatin in this species under conscious, unstressed conditions. Tianeptine injection (10 mg/kg i.v.) resulted in a significant, immediate and short-lasting (30 min) increase in peripheral GH (+750%; P < 0.01) and hypophysial portal GHRH (+180%; P < 0.01). No change in the secretion of somatostatin was recorded during the same time. These data suggest that serotoninergic inputs are inhibitory to GH secretion. Tianeptine acts centrally to stimulate GH secretion in the sheep and its effect is mediated through changes in GHRH but not somatostatin release into hypophysial portal blood.

Effect of chronic treatment with the antidepressant tianeptine on the hypothalamo-pituitary-adrenal axis

The effects of acute and chronic administration of tianeptine, a novel antidepressant agent, on the hypothalamo-pituitary-adrenal axis were studied in the adult male rat. A single injection of tianeptine did not alter the activity of the hypothalamo-pituitary-adrenal axis. In contrast, chronic administration of tianeptine (10 mg/kg twice a day for 15 days) induced a significant decrease in the concentration of corticotropin-releasing factor (CRF) in the hypothalamus and adrenocorticotropin (ACTH) in the anterior lobe of the pituitary. Chronic tianeptine treatment did not modify CRF levels in the cerebral cortex and hippocampus, and did not alter alpha-melanocyte-stimulating hormone and beta-endorphin levels in the neurointermediate lobe of the pituitary. Using the in situ hybridization technique, we observed that chronic administration of tianeptine did not modify CRF mRNA levels in the paraventricular nucleus of the hypothalamus. The effect of chronic tianeptine treatment on the neuroendocrine response to stress was also investigated. Tube restraint stress for 30 min induced a significant depletion of hypothalamic CRF and a substantial increase of plasma ACTH and corticosterone. Tianeptine abolished the stress-induced reduction of hypothalamic CRF concentration and markedly reduced the stress-induced increase in plasma ACTH and corticosterone levels. Taken together, these results suggest that tianeptine acts primarily at the level of the hypothalamus: (1) in unstressed rats, tianeptine reduces hypothalamic CRF and pituitary ACTH contents; (2) in stressed animals, tianeptine attenuates the activation of the hypothalamo-pituitary-adrenal axis.

Acute noise stress reduces [3H]5-hydroxytryptamine uptake in rat brain synaptosomes: protective effects of buspirone and tianeptine

Acute noise stress decreased [3H]5-hydroxytryptamine ([3H]5-HT) uptake in synaptosomes from rat hypothalamus, hippocampus and cerebral cortex. The decrease was due to the maximum rate of [3H]5-HT uptake, which peaked 30 min after stress and partly returned to resting values within 4 h, with no changes in affinity (Km values). No changes in [3H]paroxetine binding and basal [3H]5-HT release were found in stressed rats. Tianeptine, given at the dose of 10 mg/kg 1 h before stress, counteracted the noise-induced decrease of 5-HT uptake, since it increased [3H]5-HT uptake in both resting and stressed animals, but did not prevent the rise in plasma corticosterone of stressed rats. Buspirone pretreatment had no effect on [3H]5-HT uptake in resting rats but prevented the noise-induced decrease in [3H]-HT uptake. Diazepam did not modify either the basal or the noise-induced reduction in [3H]5-HT uptake. The evidence that treatments reducing extrasynaptic 5-HT, by increasing its reuptake (tianeptine) or reducing its release (buspirone) in innervated regions are able to modify the stress-induced decrease in 5-HT uptake, further confirms the importance of serotonin in the mechanisms mediating neurochemical responses to stress.

Corticosterone response to the serotonergic agonist D-fenfluramine may be independent from corticotropin-releasing factor (CRF)

This study was designed to assess the involvement of corticotropin-releasing factor (CRF) in the corticosterone response to the acute administration of the serotonergic indirect agonist D-fenfluramine in the rat. In addition to plasma corticosterone, D-fenfluramine-induced hyperglycemia (which is independent from the hypothalamo-pituitary-adrenal axis) was also analyzed. Acute i.v. injection of sheep anti-CRF antiserum (15 min beforehand) markedly diminished either stress-induced corticosterone release (but not ether stress-induced increases in plasma glucose levels), thereby indicating that passive immunization was efficient. Acute administration of D-fenfluramine (3 mg/kg i.v.) increased plasma corticosterone and glucose levels to similar extents in control rats (i.e. injected with normal sheep serum) and in anti-CRF antiserum-injected rats. These results indicate that, under our experimental conditions, D-fenfluramine-induced corticosterone elevation is of peripheral origin (through pituitary and/or adrenocortical pathways).

Tianeptine raises dopamine and blocks stress-induced noradrenaline release in the rat frontal cortex

The effects of various doses of tianeptine on extracellular concentrations of dopamine were studied in the frontal cortex and nucleus accumbens of the rat. At 5 and 10 mg/kg intraperitoneally, tianeptine raised extracellular dopamine in the nucleus accumbens but only the higher dose caused a significant increase in the frontal cortex. At 10 mg/kg tianeptine significantly raised the concentrations of dihydroxyphenylacetic acid and homovanillic acid in both brain regions. In another experiment, 10 and 20 mg/kg tianeptine did not modify the extracellular concentrations of noradrenaline in the frontal cortex but dose dependently blocked the increase in extracellular noradrenaline caused by restraint stress.

Physiopharmacological interactions between stress hormones and central serotonergic systems

The present review tries to delineate some mechanisms through which the sympathetic nervous system (SNS) and the hypothalamo-pituitary-adrenal (HPA) interact with central serotonergic systems. The recent progress in 5-hydroxytryptamine (5-HT) receptor pharmacology has helped to define the means by which central serotonergic activity may alter the respective activities of the SNS (sympathetic nerves and adrenomedulla) and of the HPA axis. These pharmacological findings have also helped to characterize the differential effects of central 5-HT upon different branches of the SNS and the numerous sites at which 5-HT exerts stimulatory influences upon the HPA axis. Although relevant to stress-related neuroendocrinology, the extent to which these interactions are involved in the antidepressant/anxiolytic properties of some serotonergic agents still remains to be clarified. Beside these findings, there is also abundant evidence for a tight control of central serotonergic systems by stress hormones. Activation of the SNS increases, by numerous means, central availability of tryptophan, whereas glucocorticoids exert differential actions upon the intra- and the extraneuronal regulation of 5-HT function. Actually, a significant number of these mechanisms is involved in the maintenance of homeostasis during stressful events, thereby conferring to these mechanisms a key role in adaptation processes.

Tianeptine attenuates stress-induced morphological changes in the hippocampus

Repeated 6-h daily restraint stress over 21 days reduces length and number of branch points of hippocampal CA3c pyramidal dendrites in the hippocampal formation of adult male rats. This effect is mimicked by daily injections of 40 mg/kg corticosterone. Daily treatment with tianeptine (15 mg/kg) prior to stress sessions or the corticosterone treatment prevented these effects of stress or corticosterone, respectively. Tianeptine treatment did not prevent the effects of stress to increase adrenal/body weight ratio, nor did it prevent the effects of stress to decrease body weight gain, indicating that its actions are not mediated solely by effects on stress-induced secretion of corticosterone. Because tianeptine is known to enhance neural uptake of serotonin, these results suggest that the serotonergic system may be involved in modulating stress and corticosterone effects on dendritic morphology.