The effects of tianeptine on wet-dog shakes, fore-paw treading and a flexor reflex in rats are consistent with enhancement of 5-hydroxytryptamine uptake

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.

Gpm6b deficiency impairs sensorimotor gating and modulates the behavioral response to a 5-HT2A/C receptor agonist

The neuronal tetraspan proteins, M6A (Gpm6a) and M6B (Gpm6b), belong to the family of proteolipids that are widely expressed in the brain. We recently reported Gpm6a deficiency as a monogenetic cause of claustrophobia in mice. Its homolog proteolipid, Gpm6b, is ubiquitously expressed in neurons and oligodendrocytes. Gpm6b is involved in neuronal differentiation and myelination. It interacts with the N-terminal domain of the serotonin transporter (SERT) and decreases cell-surface expression of SERT. In the present study, we employed Gpm6b null mutant mice (Gpm6b(-/-)) to search for behavioral functions of Gpm6b. We studied male and female Gpm6b(-/-) mice and their wild-type (WT, Gpm6b(+/+)) littermates in an extensive behavioral test battery. Additionally, we investigated whether Gpm6b(-/-) mice exhibit changes in the behavioral response to a 5-HT2A/C receptor agonist. We found that Gpm6b(-/-) mice display completely normal sensory and motor functions, cognition, as well as social and emotionality-like (anxiety, depression) behaviors. On top of this inconspicuous behavioral profile, Gpm6b(-/-) mice of both genders exhibit a selective impairment in prepulse inhibition of the acoustic startle response. Furthermore, in contrast to WT mice that show the typical locomotion suppression and increase in grooming activity after intraperitoneal administration of DOI [(±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride], Gpm6b(-/-) mice demonstrate a blunted behavioral response to this 5-HT2A/C receptor agonist. To conclude, Gpm6b deficiency impairs sensorimotor gating and modulates the behavioral response to a serotonergic challenge.

Animal models of the serotonin syndrome: a systematic review

The serotonin syndrome (SS) is a potentially life-threatening disorder in humans which is induced by ingestion of an overdose or by combination of two or more serotonin (5-HT)-enhancing drugs. In animals, acute administration of direct and indirect 5-HT agonists also leads to a set of behavioral and autonomic responses. In the current review, we provide an overview of the existing versions of the animal model of the SS. With a focus on studies in rats and mice, we analyze the frequency of behavioral and autonomic responses following administration of 5-HT-enhancing drugs and direct 5-HT agonists administered alone or in combination, and we briefly discuss the receptor mediation of these responses. Considering species differences, we identify a distinct set of behavioral and autonomic responses that are consistently observed following administration of direct and indirect 5-HT agonists. Finally, we discuss the importance of a standardized assessment of SS responses in rodents and the utility of animal models of the SS in translational studies, and provide suggestions for future research.

Acute and chronic tianeptine treatments attenuate ethanol withdrawal syndrome in rats

Effects of acute and chronic tianeptine treatments on ethanol withdrawal syndrome were investigated in rats. Ethanol (7.2% v/v) was given to adult male Wistar rats by a liquid diet for 30 days. Acute or chronic (twice daily) tianeptine (5, 10 and 20 mg/kg) and saline were administered to rats intraperitoneally. Acute and last chronic tianeptine injections and saline were done 30 min before ethanol withdrawal testing. After 2nd, 4th and 6th hours of ethanol withdrawal, rats were observed for 5 min, and withdrawal signs which included locomotor hyperactivity, agitation, tremor, wet dog shakes, stereotyped behavior and audiogenic seizures were recorded or rated. Locomotor activity in naive (no ethanol-dependent rats) was also tested after acute tianeptine treatments. Acute but not chronic tianeptine treatment attenuated locomotor hyperactivity and agitation in ethanol-dependent rats. Both acute and chronic tianeptine treatment produced some significant inhibitory effects on tremor, wet dog shakes, stereotyped behaviors and audiogenic seizures during the ethanol withdrawal. Our results suggest that acute or chronic tianeptine treatment attenuates ethanol withdrawal syndrome in ethanol-dependent rats and this drug may be useful for treatment of ethanol-type dependence.

The effects of tianeptine or paroxetine on 35% CO2 provoked panic in panic disorder

Antidepressants that inhibit the reuptake of serotonin (5-HT) are particularly effective in the treatment of panic disorder. Evidence suggests that increased 5-HT availability is important for the anti-panic effect of serotonergic drugs and in maintaining the response to selective serotonin reuptake inhibitors (SSRIs). Tianeptine is an antidepressant with 5-HT reuptake enhancing properties (i.e. the opposite pharmacological profile to that of SSRIs). Therefore, no effect would be expected in panic disorder. The aim of the present study was to compare the effect of tianeptine with that of paroxetine, a selective 5-HT reuptake inhibitor with demonstrated efficacy in panic disorder, on the vulnerability to a laboratory panic challenge in panic disorder patients. Twenty panic disorder patients were treated with either tianeptine or paroxetine for a period of 6 weeks, in a randomized, double-blind, separate group design. The reaction to a 35% CO(2) panic challenge was assessed at baseline and after treatment. Improvement on several clinical scales was also monitored. Tianeptine, as well as paroxetine, showed a significant reduction in vulnerability to the 35% CO(2) panic challenge. In spite of their opposite influence on 5-HT uptake, both tianeptine and paroxetine appeared to reduce the reaction to the panic challenge. These results raise questions about the necessity of 5-HT uptake for the therapeutic efficacy of anti-panic drugs.

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.

Effects of the (+) and (-) enantiomers of the antidepressant drug tianeptine on 5-HTP-induced behaviour

The effects of the (+) and (-) enantiomers of the antidepressant drug tianeptine (5, 10, 20 mg/kg, i.p.) on wet dog shakes (WDS) and faecal pellet production induced by concurrently administered 5-hydroxytryptophan (5-HTP, 100 mg/kg, i.p.) given 30 min after carbidopa (25 mg/kg, i.p.) were investigated in rats. WDS scores peaked approximately 1 hr after giving 5-HTP and gradually declined over the next 2 hr. (-)-Tianeptine dose-dependently and significantly inhibited WDS. Inhibition became less marked with time after administration, but remained significant over the 3 hr period after the 10 and 20 mg/kg doses and during the first 40 min after the 5 mg/kg dose. (+)-Tianeptine caused slight inhibition without dose-dependence and slightly increased net inhibition when added to the (-) isomer (10 mg/kg). The induction of faecal pellet production by 5-HTP was significantly and dose-dependently inhibited by (-)-tianeptine. The (+) isomer neither altered this effect of 5-HTP nor its inhibition by (-)-tianeptine. Results show that inhibition of 5-HTP-induced WDS and faecal pellet formation by tianeptine was almost completely dependent on the (-) isomer.

Tianeptine treatment induces regionally specific changes in monoamines

Tianeptine is an atypical tricyclic antidepressant that facilitates serotonin (5-HT) reuptake. Tianeptine (10 mg/kg) or saline was administered intraperitoneally to male rats daily for 4 days. Monoamine levels were measured in micropunches of discrete brain nuclei that are implicated in mood and cognition. In addition, the rates of 5-HT and norepinephrine (NE) accumulation were determined by the pargyline method. Few changes were noted in the 5-HT system. 5-HT levels were increased by short-term tianeptine in the CA3 region of hippocampus, and 5-hydroxyindoleacetic acid (5-HIAA) was increased in the ventromedial nucleus of hypothalamus, while 5-HT turnover was decreased in preoptic area (POA). In addition, short-term tianeptine treatment increased NE levels in POA, parietal sensory cortex (SCTX) and dorsal raphe (DR), and decreased NE in dentate gyrus. NE turnover was also decreased in DR, SCTX and parietal motor cortex. These data suggest that the short-term neural and behavioral actions of tianeptine may be attributable, in part, to alterations of the norepinephrine system.

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)

Effects of the antidepressant drug tianeptine on plasma and platelet serotonin of depressive patients and healthy controls

We have examined the effects of a single 12.5 mg dose and of 12 weeks treatment up to 37.5 mg daily with tianeptine, a new antidepressant drug that potentiates in vivo the uptake of serotonin (5-HT). On day 0, tianeptine reduced plasma 5-HT concentration. This acute effect occurred also on subsequent examination days. However, long-term treatment tended (P < 0.06) to increase basal plasma 5-HT concentrations, in covariation with decreases of MADRS (Montgomery-Asberg Depression Rating Scale) and HARS (Hamilton Anxiety Rating Scale). Platelet 5-HT increased only in elderly patients, probably due to the higher plasma concentration of the drug in this group than in younger patients. These results show that the acute effects of therapeutic doses of tianeptine are consistent with an enhancement of the 5-HT uptake. However, long-term treatment does not result in a decreased plasma 5-HT, as might be expected from the acute effects of the drug.

Behavioural and neurochemical evidence for the decrease of brain extracellular 5-HT by the antidepressant drug tianeptine

The effects of the novel antidepressant tianeptine on behaviours induced by the serotonin (5-HT) precursor 5-hydroxytryptophan (5-HTP) and the 5-HT1A agonist 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) were investigated. Tianeptine (10 mg/kg, i.p.) significantly attenuated wet dog shakes (WDS) induced by 5-HTP (75 mg/kg, i.p.; 30 min after carbidopa 25 mg/kg, i.p.). The effect was most marked when 5-HTP and tianeptine were given together. The main metabolite of tianeptine also attenuated WDS. Components of the 5-HT syndrome (i.e. reciprocal forepaw treading, hind limb abduction, flat body posture) induced by 8-OH-DPAT (0.5 mg/kg, s.c.) were unaffected by tianeptine and 5-HTP given both singly or together. However, tianeptine significantly reduced faecal pellet formation but not cage crossings resulting from 8-OH-DPAT administration. These cage crossings but not the associated faecal pellet formation were reduced by 5-HTP. This reduction was prevented by tianeptine. The increase of extracellular 5-HT in the frontal cortex following administration of 5-HTP was opposed and the concurrent increase of extracellular 5-hydroxyindoleacetic acid (5-HIAA) was enhanced by tianeptine. The above behavioural and neurochemical findings indicate that tianeptine opposes the increase of 5-HT at receptor sites due to 5-HTP administration.

Effects of tianeptine on 5-HTP- and dextrofenfluramine-induced hypophagia in the rat

The aim of this work was to analyze whether tianeptine, a 5-hydroxytryptamine (5-HT) reuptake enhancer, opposes the loss in food intake elicited by 5-HT release. Rats were food deprived for 20 h, pretreated either with saline or 7-[3-chloro-6-methyl-5, 5-dioxo-6,11-dihydro- (c,f)-dibenzo-(1,2-thiazepine)-11-yl-amino]-heptanoic acid (tianeptine, 10 mg/kg, IP), and injected 1 h afterwards either with saline, with the 5-HT precursor L-5-hydroxytryptophan (5-HTP, 20 or 40 mg/kg, IP), or with the 5-HT reuptake inhibitor/5-HT releaser dextrofenfluramine (d-FEN, 1.5 or 3 mg/kg, IP). Diets were then presented 30 min later, and individual food intakes were measured 1, 2, 3, and 4 h after food presentation. Saline- and tianeptine-pretreated saline-injected rats ate the most, and to a similar extent, during the first hour of food presentation; however, in these animals tianeptine pretreatment tended to diminish rates of eating throughout the last 3 h of analysis. Administration of 5-HTP or d-FEN triggered immediate dose-dependent decreases in food intake that were not affected by tianeptine pretreatment. In addition, tianeptine pretreatment did not alter either brain d-FEN or d-norfenfluramine levels, thereby suggesting that the lack of effect of tianeptine against d-FEN-elicited hypophagia could not be accounted for by changes in d-FEN metabolism. This study opens the possibility that tianeptine counteracts the effects of 5-HT release in some paradigms but not in others.

Differential effects of the novel antidepressant tianeptine on L-5-hydroxytryptophan (5-HTP)-elicited corticosterone release and body weight loss

Biochemical and behavioural experiments have indicated that the novel antidepressant tianeptine stimulates 5-hydroxytryptamine (5-HT) reuptake. The present study has explored the influence of acute tianeptine pretreatment upon corticosterone release and body weight loss following L-5-hydroxytryptophan (5-HTP) administration in conscious rats. Administration of 5-HTP (20 mg/kg i.v.) increased plasma corticosterone levels to a similar extent in rats pretreated either with saline or tianeptine (10 mg/kg i.p., 60 min beforehand). Besides, prior administration of benserazide (50 mg/kg i.p., 30 min beforehand), an inhibitor of peripheral aromatic L-amino acid decarboxylase, prevented 5-HTP-induced corticosterone release in both saline- and tianeptine-pretreated rats. However, combined administration of benserazide and 5-HTP decreased overnight body weight in saline-, but not in tianeptine-pretreated rats. These results suggest that tianeptine preferentially activates 5-HT reuptake in central serotonergic neurones.

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.