Analgesic effect of tianeptine in mice

WOS: 000079240800008PubMed ID: 10227587The effects of tianeptine, a novel and unusual tricyclic antidepressant drug, on tail-flick and hot-plate tests, which are two thermal analgesia evaluating methods, have been investigated in mice. Tianeptine (5 and 10 mg/kg), para-chlorophenylalanine (pCPA) (100 mg/kg) and a combination of pCPA and tianeptine (10 mg/kg) or saline were injected to mice intraperitoneally. pCPA (100 mg/kg) was injected 24 h before tianeptine or saline treatment when it was combined with tinaeptine (10 mg/kg) or tested alone. The tail-flick latencies and hat-plate reaction times of the mice were measured between 15(th) and 180(th) minutes following injections. Tianeptine (10 mg/kg) exhibited a significant antinociceptive activity that could be measured by both tests as compared to groups which were treated with saline or pCPA alone between 15(th) and 180(th) min of the observation period. The lower dose of tianeptine (5 mg/kg) or pCPA (100 mg/kg) did not produce any significant changes on tail-flick latency or hot-plate reaction time of the mice. However, pretreatment with pCPA completely blocked the antinociceptive effect induced by tianeptine (10 mg/kg) in both tests used in the present study. Furthermore, tianeptine (10 mg/kg) did not cause any significant impairment effects on rotarod performance of the mice. Our results suggested that tianeptine has a prominent thermal antinociceptive activity in mice and that increased serotonergic activity may be responsible for the analgesic effect of tianeptine

Gamma-vinyl-GABA potentiates the severity of naloxone-precipitated abstinence signs in morphine-dependent rats

Effects of gamma-vinyl-GABA (GVG), an antiepileptic drug that inhibits GABA transaminase and increases extracellular GABA concentrations in the brain, were investigated on the morphine abstinence syndrome (AS) in male Wistar rats. Two morphine pellets (75 mg morphine base in each) were implanted subcutaneously on the back of the rats. Seventy-two hours after the morphine implantation, naloxone (NL, 2 mg kg(-1)) was injected intraperitoneally (i.p.) to induce precipitated morphine AS. GVG was administered at the doses of 250 mg kg(-1) (n = 11) and 500 mg kg(-1) (n = 11) i.p. 24 h prior to AS and at the dose of 500 mg kg(-1) (n = 13) i.p. 6 h prior to AS. Immediately after NL injections, rats were observed for 5 min and AS signs (jumping, teeth chattering, wet dog shake, diarrhoea, ptosis and defecation) were assessed. The behavioural signs of GVG-treated rats were compared with the control groups (n = 10) during the AS. Jumping, wet dog shake, teeth chattering were found to be significantly increased in all of the GVG-treated groups. Ptosis was found to have increased in only 500 mg kg(-1) GVG groups. GVG potentiated the severity of morphine AS signs. GVG does not seem to have any therapeutic potential for treatment of morphine abstinence unlike some other drugs that enhance GABAergic transmission. (C) 1998 The Italian Pharmacological Society

Effects of fluoxetine on ethanol withdrawal syndrome in rats

The present study was designed to investigate the effects of fluoxetine, a selective serotonin reuptake inhibitor, on ethanol withdrawal syndrome in rats. Adult male Wistar rats (218-255 g) were subjects. Ethanol (7.2%, v/v) was given to rats by a liquid diet for 21 days. Control rats were pair fed an isocaloric liquid diet containing sucrose as a caloric substitute to ethanol. Fluoxetine (2.5, 5 and 10 mg/kg) and saline were injected to rats intraperitoneally just before ethanol withdrawal. After 2nd, 4th and 6th hour of ethanol withdrawal, rats were observed for 5 min, and withdrawal signs that included locomotor hyperactivity, agitation, stereotyped behavior, wet dog shakes and tremor were recorded or rated. A second series of injections was given at 6 h after the first one, and subjects were then tested for audiogenic, seizures. Fluoxetine produced some dose-dependent and significant inhibitory effects on all the signs of ethanol withdrawal during ethanol withdrawal period. Our results suggest that acute fluoxetine treatment has some beneficial effects on ethanol withdrawal in rats. Thus, this drug may be useful for treatment of ethanol withdrawal syndrome. (C) 2003 Elsevier Ltd. All rights reserved

Effects of venlafaxine on ethanol withdrawal syndrome in rats

The present study was designed to investigate the effects of venlafaxine, a serotonin and noradrenaline reuptake inhibitor (SNRI), on ethanol withdrawal syndrome in rats. Adult male Wistar rats (187-319 g) were used for the study. Ethanol (7.2%, v/v) was given to rats by a liquid diet for 21 days. Control rats were pair-fed an isocaloric liquid diet containing sucrose as a caloric substitute to ethanol. Venlafaxine (5, 10, 20 and 40 mg/kg) and saline were injected to rats intraperitoneally just before ethanol withdrawal. After the 2nd, 4th and 6th hour of ethanol withdrawal, rats were observed for 5 min, and withdrawal signs that included locomotor hyperactivity, agitation, stereotyped behaviour and wet dog shakes were recorded or rated. A second series of injections was given at the 6th hour after the first one, and rats were then tested for audiogenic seizures. Venlafaxine produced some inhibitory effects on locomotor hyperactivity, stereotypic behaviours and wet dog shakes. However, a two-way ANOVA of the data did not indicate any significant effect. It reduced the incidence of the audiogenic seizures at the 6th hour of ethanol withdrawal. Venlafaxine (20 mg/kg) also prolonged the latency of the seizures significantly. Our results suggest that acute venlafaxine treatment has limited beneficial effects on ethanol withdrawal syndrome in rats