Anti-aggressive effects of GHB in OF.1 strain mice: involvement of dopamine D2 receptors.

Numerous studies indicate that gamma-hydroxybutyric acid (GHB) influences the endogenous dopamine system. Both GHB and most dopaminergic D(2) receptor antagonists are effective anti-aggressive agents in animal models. The present study aimed to investigate the effects of GHB on agonistic behaviour and to implicate D(2) dopamine receptor on these behaviours. For this purpose, the effects of GHB (80, 120 and 160 mg/kg, IP) and tiapride (60 mg/kg) administered alone or in combination were examined on agonistic behaviour elicited by 'isolation' in male mice. Individually housed mice were exposed to anosmic "standard opponents" 30 min after drug administration, and the encounters were videotaped and evaluated using an ethologically based analysis. The administration of 80 and 120 mg/kg of GHB reduced threat without impairing motor activity, but the administration of 160 mg/kg of GHB or the co-administration of GHB+tiapride (a selective D(2) receptor antagonist) significantly reduced threat and attack but concomitantly increased immobility. The co-administration of GHB+tiapride had different effects to those observed by the administration of these drugs separately. It is concluded that the anti-aggressive effect of GHB appears to be mediated, at least in part, by D(2) dopamine receptors. This anti-dopaminergic activity is an indirect effect, probably induced by the activation of GHB receptors of low affinity, and in this way, this compound would reduce levels of dopamine without blockading of D(2) postsynaptic dopamine receptors.

Actions of sulpiride and tiapride in a simple model of anxiety in mice.

A two-compartment activity box is described in which the actions of anxiolytic compounds may be readily detected. The box is designed with a partition which divides a dimly-lit black area and a brightly-illuminated white area. Free access to each section is enabled by means of a small opening in the partition. Measures of locomotion and rearing are recorded as well as transitions from black to white and vice versa. Time spent in each section is also measured. In this situation mice demonstrated a clear preference for the dim black section, a finding not inconsistent with the nocturnal nature of this species. By contrast, treatment with diazepam (0.125-5 mg/kg) or triazolam (0.01-0.1 mg/kg) produced a significant increase in activity in the white section. Locomotion and rearing in the black section showed a corresponding decrease. Sulpiride (0.5-20 mg/kg) and tiapride (0.5-40 mg/kg) had similar effects. These actions would appear to be independent of their effects on general activity, as amphetamine (1.25-2.5 mg/kg) increased and haloperidol (0.05-0.2 mg/kg) decreased overall exploratory behaviour in a non-selective manner. These data suggest the "two-compartment activity box" to be a model sensitive to the actions of clinically-active anxiolytics.

Tiapride. A review of its pharmacology and therapeutic potential in the management of alcohol dependence syndrome.

Tiapride, an atypical neuroleptic agent, is a selective dopamine D2-receptor antagonist with little propensity for causing catalepsy and sedation. It shows preferential activity at receptors previously sensitised to dopamine and those located extrastriatally. Tiapride demonstrates antidyskinetic activity reflecting antidopaminergic actions, and also anxiolytic activity mediated by mechanisms that are poorly understood. Unlike the benzodiazepines, tiapride does not affect vigilance and has a low potential for interaction with alcohol (ethanol), and possibly for abuse. Tiapride facilitates management of alcohol withdrawal, but its use in patients at risk of severe reactions in acute withdrawal should be accompanied by adjunct therapy for hallucinosis and seizures. Since it may prove difficult to identify such patients and there is also a small risk of neuroleptic malignant syndrome (particularly with parenteral administration), the usefulness of tiapride in this setting is likely to be limited. Nevertheless, relative freedom from the complications associated with benzodiazepine therapy suggest a possible role for the drug in the treatment of individuals suitable for alcohol detoxification as outpatients. Preliminary clinical studies in alcoholic patients following detoxification have shown that tiapride ameliorates psychological distress, improves abstinence, and reduces drinking behaviour, and in the short term facilitates reintegration within society. These benefits were associated with reduced consumption of health care resources. However, the potential risk of tardive dyskinesia at the dosage employed (300 mg/day) requires evaluation and necessitates medical supervision. Thus, with its lack of adverse effects on vigilance and low propensity for interaction with alcohol and possibly for abuse, tiapride will probably find particular use in the management of alcoholic patients suitable for detoxification in an outpatient setting; and, if initial findings are confirmed in large well-designed trials, in the short term (< or = 6 months) therapy of reformed alcoholic patients under medical supervision.

Effects of tiapride on homovanillic acid levels in human cerebrospinal fluid drawn at pneumoencephalography.

The effect of tiapride on HVA and 5-HIAA levels in the CSF drawn at pneumoencephalography (PEG) was studied. Five consecutive 5 ml fractions of CSF were drawn from control and tiapride-treated subjects. In both groups, a linear increase in HVA concentrations was found between the first and subsequent fractions. On the contrary, no significant difference in 5-HIAA concentrations was found in sequential CSF samples. Tiapride increased the mean HVA concentrations and caused a steeper caudocranial gradient of this metabolite but failed to modify 5-HIAA concentrations. The results suggest that tiapride blocks dopamine (DA) receptors and increases DA synthesis.

Preferential involvement of D3 versus D2 dopamine receptors in the effects of dopamine receptor ligands on oral ethanol self-administration in rats.

There is evidence that dopamine transmission is involved in reinforcement processes and the present study investigated the relative involvement of D3 versus D2 dopamine receptors in the effects of dopamine ligands on the reinforcing action of ethanol. Rats were trained to self-administer ethanol (10% v/v) orally in a free-choice two-lever operant task using a saccharin-fading procedure. When preference in responding for ethanol over water had developed the rats were tested with several dopamine agonists and antagonists. Pretreatment with the non-selective dopamine agonist, apomorphine (0.01-0.1 mg/kg), the preferential D2 agonist, bromocriptine (1-10 mg/kg) and the selective D3 agonists, 7-OH-DPAT (0.003-0.1 mg/kg), PD 128907 (0.1-3 mg/kg), (+)3PPP (0.3-3 mg/kg), quinelorane (0.0001-0.003 mg/kg) and quinpirole (0.003-0.03 mg/kg), resulted in dose-dependent decreases in responding for ethanol. The relative potencies of the dopamine agonists to decrease ethanol self-administration were highly correlated with their published potencies to produce in vitro functional D3 but not D2 responses. Active doses could be considered as those selectively stimulating receptors involved in the control of dopamine release, suggesting that reduction of dopamine transmission was associated with a decrease in ethanol-reinforced responding. This conclusion was further supported by the finding that pretreatment with the D2/D3 dopamine antagonists, haloperidol (0.1-0.4 mg/kg) and tiapride (10-60 mg/kg), decreased responding for ethanol at doses which have been shown previously to block dopamine transmission.

The effects of substituted benzamides on frog rectus abdominis.

The substituted benzamides metoclopramide, bromopride, tiapride and sulpiride (10(-5) and 10(-4) M) significantly increased the sensitivity of frog rectus abdominis muscle to exogenous acetylcholine but not to carbachol. This supersensitivity could be correlated with the anticholinesterase activity of these drugs measured in homogenates from frog skeletal muscle. Sultopride, like procainamide, has only inhibitory effects on the responses of the rectus abdominis to acetylcholine and has no anticholinesterase activity in this preparation.

Influence of tiapride on platelet counts in healthy volunteers and patients with movement disorders.

BACKGROUND: The selective D2 antagonist tiapride is administered in various movement disorders. Furthermore, there are indications that tiapride increases platelet counts. AIM: To characterize tiapride's potential to increase platelet counts in healthy subjects and patients with movement disorders. METHODS: In Part A, 10 healthy volunteers received tiapride (300 mg/day) for 21 days in a longitudinal, prospective, open trial. One hundred healthy subjects served as controls. Part B was a retrospective analysis of 15 patients with movement disorders on tiapride [Huntington's disease (n=6), Morbus Little (n=3), hyperkinetic syndromes of undetermined etiology (n=3), blepharospasm (n=1), cervical dystonia (n=1), perioral dyskinesia (n=1)] and 15 age- and sex-matched controls. RESULTS: Part A: Although serum prolactin levels increased by 526+/-14%, confirming good drug compliance, tiapride elicited only minor changes in platelet counts. Part B: Platelet counts correlated positively with the dose of tiapride (100-800 mg/day; r=.67; P=.007). Platelet counts were significantly higher in patients on tiapride compared to healthy age-matched controls (P<.001). Four patients responded to an increase in the tiapride dosage with an increase in platelet count by 97-173 cells/nl. CONCLUSION: Three weeks of treatment with tiapride (300 mg/day) is insufficient to elevate platelet counts to a clinically relevant extent in young healthy volunteers. However, in elderly patients with movement disorders tiapride treatment is associated with markedly increased platelet counts.

Effects of a series of substituted benzamides on rat prolactin secretion and 3H-spiperone binding to bovine anterior pituitary membranes.

The potency of seven substituted benzamide drugs (AHR-5531B, AHR-5645B, AHR-6092, AHR-8764, bromopride, sultopride and tiapride) to stimulate rat prolactin (PRL) secretion in vivo was found to be three orders of magnitude greater than that of non-benzamide neuroleptic drugs relative to their respective abilities to inhibit 3H-spiperone binding to bovine anterior pituitary membranes. Nevertheless, the IC50 values for the inhibition of 3H-spiperone binding by the seven substituted benzamide drugs was significantly correlated with their high potency to stimulate rat PRL secretion in vivo. Further, the slope of the regression line for these substituted benzamides paralleled that of a series of butyrophenone, phenothiazine, morphanthridine and dibenzodiazepine neuroleptic drugs. Two benzamide (sulpiride and metoclopramide) and three non-benzamide neuroleptic drugs gave intermediate results. This data suggests that blockade of different subgroups of dopamine receptors in the anterior pituitary gland labeled by 3H-spiperone may be responsible for the in vivo stimulation of PRL secretion by the benzamide and non-benzamide neuroleptic drugs.

Tiapride. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in geriatric agitation.

Tiapride is a substituted benzamide derivative with selective dopamine D2-receptor antagonist properties which appears to have preferential affinity for extrastriatal dopamine receptors. Animal and clinical studies show that tiapride has anxiolytic properties but the mechanism of action is uncertain. Results from limited studies indicate that the clinical efficacy of tiapride in the treatment of agitation, aggressiveness, anxiety and sleep disorders in the elderly appears superior to that of placebo, chlorpromazine, lorazepam and meprobamate. Tiapride also exerts a beneficial effect on vigilance and alertness in elderly patients and causes less sedation than chlorpromazine. Tiapride is well tolerated at the dosages recommended for elderly patients. Further well designed comparative studies with newer drugs are needed to determine the relative place of tiapride in the treatment of geriatric agitation, and such studies should also address the quality-of-life benefits for the patient. Additional clinical experience to determine the efficacy of tiapride in elderly patients with more than one disease condition, receiving concomitant medications, and/or with renal impairment is also required. However, despite these current limitations, tiapride may have potentially important applications in this difficult area of clinical medicine.

Effects of tiapride on electroencephalograms and cognitive functions in the elderly.

Tiapride is a substituted benzamide with selective dopamine D2 and D3-antagonist properties which appears to have preferential affinity for extra-striatal dopamine receptors. Tiapride is used in the treatment of agitation, aggressiveness and anxiety in the elderly. To define the effects of a single dose of tiapride 100 mg on psychomotor performance and cognitive functions and electroencephalogram (EEG), a randomized, double-blind, three-way crossover, placebo-controlled study using lorazepam 1 mg as a positive control was carried out in 12 elderly individuals (six women and six men, mean age +/- SD: 69 +/- 3 years). A 1-week wash-out interval was allowed between each administration. Psychomotor and cognitive functions were assessed using both objective [EEG, critical flicker fusion, simple reaction time, tapping, body sway, continuous performance task (CPT), digit symbol substitution test, Sternberg memory scanning and a learning memory test using word lists] and subjective (visual analogue scales) measures before and up to 6 h after dosing. Tiapride was devoid of any detrimental or sedative effects on EEG and all of the performance tasks used and did not impair memory compared with-placebo. In contrast, a single dose of lorazepam produced significant deleterious effects on psychomotor performance (decrease in tapping and in sustained attention (CPT) and an increase in reaction time and body sway), and sedative effects on EEG (significant increase in delta and decrease in alpha waves) as well as significant impairment in working memory (Sternberg) and anterograde amnesia (decrease in immediate and delayed free recall) up to 6 h after dosing compared with placebo and tiapride. In conclusion, the present study showed that in contrast to lorazepam 1 mg there is no evidence to suggest that a single dose of tiapride 100 mg has any sedative and amnestic effects in the elderly which may interfere with everyday life activities.

Withdrawal syndrome following subchronic treatment with anxiolytic agents.

The acute administration of diazepam (0.1-2.5 mg/kg IP), sulpiride (0.5-20 mg/kg IP) and tiapride (0.5-40 mg/kg IP) to the mouse enhanced exploratory activity (rearings/line crossings) in the brightly illuminated white area of a two compartment white/black anxiety test box, with a corresponding decrease in the black, indicating an anxiolytic action. This profile of change was maintained during a twice daily administration for 7 days with diazepam (2.5 and 10 mg/kg), sulpiride (5 and 20 mg/kg) and tiapride (10 and 40 mg/kg). However, 8 and 48 hr following withdrawal of diazepam, the profile of exploratory behaviour was reversed to a preference for the black area: by 96 hr values for behaviour had returned to control levels. In contrast, an anxiolytic profile of action was maintained 8 and 48 hr following the withdrawal of sulpiride and tiapride, the values returning to control levels after 96 hr. It is concluded that a sub-chronic treatment with diazepam, sulpiride and tiapride induces an anxiolytic profile of action in the mouse model, that an anxiogenic profile follows the abrupt withdrawal of diazepam but that this is not recorded following the abrupt withdrawal of sulpiride and tiapride.

Acute and subchronic effects of tiapride on isolation-induced aggression in male mice.

Although the antiaggressive properties of several atypical neuroleptics are known, the actions of tiapride (a selective dopaminergic D2-receptor antagonist) on agonistic behavior have not been explored and there are no studies comparing acute and subchronic effects of this compound on aggression in rodents. In this work, the effects of tiapride (20-100 mg/kg, IP), administered acutely or subchronically for 10 days, on agonistic behaviour elicited by isolation in male mice were examined. Individually housed mice were exposed to anosmic "standard opponents" 30 min after drug administration, and the encounters were videotaped and evaluated using an ethologically based analysis. Tiapride decreased time spent in offenssive behaviors significantly, without an impairment of motor activity (60 and 80 mg/kg). Moreover, no tolerance to tiapride antiaggressive activity was observed after repeated administration of the drug. On the contrary, the action on immobility showed a clear tolerance development with repeated injections (100 mg/kg). The divergence found in the temporal course of tolerance to tiapride in its antiaggressive and motor effects is discussed.

The anxiolytic and anxiogenic actions of ethanol in a mouse model.

The administration to mice of ethanol in the drinking water for 7 days modified exploratory activity (rearings/line crossings) in an anxiety testing box separated into white and black sections with an interconnecting door. During ethanol intake mice exhibited reduced anxiety responding, shown as increased rearings and line crossings in the white section, to which the mice are normally averse, with corresponding decreased behaviour in the black section. When naive mice were presented with a choice between normal drinking water and drinking water containing ethanol, they consumed sufficient of the latter to secure a full anxiolytic response, making up the total volume of fluid required by also drinking the former. A 48 h withdrawal from a 14 day treatment with ethanol caused a reversed profile of exploratory behaviour, directed preferentially at the black section of the test box, and indicative of an anxiogenic response. Diazepam, tiapride or clonidine given twice daily during withdrawal from ethanol could each secure a reduction in the withdrawal anxiogenesis. It is concluded that the simple model of anxiety described in the mouse may be useful for eludicating the mechanisms involved in the anxiolytic and anxiogenic potential of ethanol and may aid the search for novel agents having potential to suppress withdrawal anxiogenesis.

The preclinical pharmacologic profile of tiapride.

Tiapride is a benzamide derivative that has been used successfully in the clinic for a number of years for the treatment of agitation and aggressiveness in elderly patients. Like many substituted benzamides, tiapride specifically blocks dopamine receptors in the brain. It has affinity for dopamine D(2) (IC(50) = 110-320 nM) and D(3) (IC(50) = 180 nM) receptors in vitro but lacks affinity for dopamine D(1) and D(4) receptors and for non-dopaminergic receptors including H(1), alpha(1), alpha(2)-adrenergic and serotonergic receptors. Tiapride also shows dose-related inhibition of [3H]-raclopride binding in limbic areas and in the striatum of the rat in vivo (ED(50) approximately 20 mg/kg, ip). In microdialysis experiments, tiapride (over the range 10-30 mg/kg, ip) increased extracellular levels of dopamine in the nucleus accumbens and striatum, a reflection of its blockade of postsynaptic dopamine receptors in these brain areas. In behavioral experiments in rats, lower doses of tiapride (ED(50) = 10 mg/kg, ip) antagonised dopamine agonist-induced hyperactivity while higher doses (ED(50) = 60 mg/kg, ip) were required to block stereotyped movements. In addition, doses of tiapride up to 200 mg/kg, ip failed to induce catalepsy, an effect observed with many other drugs which block dopamine receptors. In tests of conditioned behavior in rats, tiapride was found to give rise to an interoceptive stimulus associated with dopamine receptor blockade at doses (ED(50) = 2.2 mg/kg, ip) much lower than those producing motor disturbances or sedation (ED(50) = 40 mg/kg, ip), in striking contrast to a range of conventional or atypical neuroleptics that produced interoceptive stimulus and sedation at similar doses. Furthermore, the acquisition by rats of a place-learning task in a water maze was not affected by tiapride (over the range 3-30 mg/kg, ip), whereas haloperidol (MED = 0.25 mg/kg, ip) and risperidone (MED = 0.03 mg/kg, ip) impaired performance. The preclinical pharmacologic and behavioral profile of tiapride suggests that its clinical activity may be due to a selective blockade of dopamine D(2) and D(3) receptors in limbic brain regions. The results are also consistent with a lack of motor or cognitive side effects.

Effect of some benzamide derivatives on stress-induced behavior and striatum dopamine receptors.

The effects of a new benzamide derivative LIS-630 and the well-known neuroleptic, tiapride, were studied on stress-induced hyper- and hypoactive emotional behavioral reaction of animals depending on the individual ability for perceptive-cognitive activity in stress situations, and their affinity to striatal DA receptors. A modified variant of forced swimming method was used. The affinity of the substances to striatal DA receptors was studied by the radioligand binding method using 3H-spiroperidol. The results show that the psychopharmacological profile of LIS-630 differs significantly from the neuroleptic, tiapride. LIS-630 restored escape behavior from stress situation after preliminary exposure of rats to forced swimming and did not disturb escape behavior in animals more resistant to emotional hypoactivity. LIS-630 reduced immobility time at forced swimming. However, it is not effective in preventing hyperemotional reactions induced by L-dopa and stress. The radioligand binding study shows that LIS-630 did not displace 3H-spiroperidol from the binding sites of striatum membranes. The parameters of displacement with tiapride were satisfactory.

[Analgesic effect of tiapride in healthy volunteers]. / Les effets antalgiques du tiapride chez le volontaire sain.

Twenty male volunteers, average age 23, were studied in the fasting state at a week interval in the morning between nine and ten a.m. A brachial blood pressure cuff was inflated to a pressure of 250 mmHg and the subject squeezed a hand dynamometer to half of maximum strength for two ten seconds periods. The subject then started to report his sensory experience every ten seconds for 15 minutes by pointing at a scale consisting of six categories from "nothing" to "extremely painful". The first trial was performed on all unmedicated subjects, the non dominating arm was used. The second trial was performed on the opposite arm, 45 minutes after oral double-blind randomized administration of a capsule containing either 1 g aspirin or 300 mg tiapride. The answers of the subjects were statistically analysed using paired comparisons tests. Results indicate that tiapride exerts a significant antalgic effect from the 6th minute to the end of the experiment when compared to the control (p less than 0.05 to p less than 0.01). Aspirin produces a similar antalgic effect which occurs earlier, after 4 minutes. The mechanism of the antalgic effect of tiapride has been attributed to the release of beta-endorphine produced by benzamide which is associated with a decrease in plasma dopamine and a parallel increase in prolactine.

[Clinical and instrumental evaluation of the effect of tiapride in senile involutional syndrome]. / Valutazione clinica e strumentale dell'effetto della tiapride sulla sindrome involutiva senile.

Twenty elderly patients with pathological cerebral involution were treated with tiapride (200 mg/die) and investigated with psycho-clinical tests. After three months, the group of patients demonstrated a significant improvement compared to a control group treated with placebo.

[Anxiolytics and mnemonic ability of the aged subject. Apropos of a double-blind study between tiapride and lorazepam]. / Anxiolytiques et capacités mnésiques du sujet âgé. A propos d'une étude en double aveugle entre tiapride et lorazépam.

Starting from a study of memory performances while prescription in double blind of lorazepam (2 mg/day) versus tiapride (100 mg/day), during ten days, to patients over sixty years of age, the authors try to analyse the links between anxiety, anxiolysis and attention and memory capacities. Results seem to indicate that beyond anxiolysis, these products could have an independent action over memory performances. Statistical trial of results show significantly that performances decrease under lorazepam and increase under tiapride.