Antidepressant-like behavioral effects in 5-hydroxytryptamine(1A) and 5-hydroxytryptamine(1B) receptor mutant mice

The development of serotonin receptor knockout mice has provided an opportunity to study antidepressant drug effects in animals with targeted genetic deletion of receptors involved in antidepressant responses. In the current study, the effects of two types of antidepressant drugs, the selective serotonin reuptake inhibitors fluoxetine and paroxetine and the selective norepinephrine reuptake inhibitor desipramine, were examined in 5-hydroxytryptamine (5-HT)(1A) and 5-HT(1B) receptor mutant mice using the tail suspension test (TST). Under baseline conditions, the immobility of 5-HT(1A) receptor mutant mice, but not 5-HT(1B) receptor mutant mice, was significantly lower than that of wild-type mice. The decreased baseline immobility in 5-HT(1A) receptor mutant mice was reversed by pretreatment with alpha-methyl-para-tyrosine, but not by para-chlorophenylalanine, suggesting mediation by enhanced catecholamine function. In wild-type mice, fluoxetine (10.0--20.0 mg/kg i.p.) and desipramine (5.0--20.0 mg/kg i.p.) both significantly decreased immobility in the TST. In 5-HT(1A) receptor mutant mice, desipramine (20.0 mg/kg i.p.) significantly decreased immobility, whereas fluoxetine (20.0 mg/kg i.p.) and paroxetine (20.0 mg/kg i.p.) had no effect. The immobility of 5-HT(1B) receptor mutant mice was decreased similarly by desipramine (5.0--20.0 mg/kg i.p.). However, the effect of low doses of fluoxetine were significantly augmented in the 5-HT(1B) receptor mutant mice (2.5--20.0 mg/kg i.p.) compared with wild-type mice. Administration of selective 5-HT receptor antagonists in wild-type mice partially reproduced the phenotypes of the mutant mice. These results suggest that 5-HT(1A) and 5-HT(1B) receptors have different roles in the modulation of the response to antidepressant drugs in the TST.     

Antidepressant‐like effect of riparin II from Aniba riparia in mice: evidence for the involvement of the monoaminergic system

In a previous study conducted by our group, riparin II (ripII) isolated from the green fruit of Aniba riparia presented antianxiety effects in mice. This study investigates a possible antidepressant activity of rip II using two predictive tests for antidepressant activity in rodents: the forced swimming test (FST) and tail suspension test (TST). Additionally, the mechanisms involved in the antidepressant‐like effect in mice were also assessed. Rip II was acute administered by intraperitoneal (i.p.) and oral (p.o) routes to male mice at doses of 25 and 50 mg/kg. Results showed that ripII at both tested doses and administration routes produced a significant decrease of immobility time in FST and TST. The pretreatment of mice with prazosin (1 mg/kg, i.p., an α1‐adrenoceptor antagonist), SCH23390 (15 μg/kg, i.p., a dopamine D1 receptor antagonist), sulpiride (50 mg/kg, i.p., a dopamine D2 receptor antagonist), p‐chlorophenylalanine (100 mg/kg, an inhibitor of serotonin synthesis), or NAN‐190 (0.5 mg/kg, a serotonin 5‐HT1A receptor antagonist) completely blocked the anti‐immobility effects elicited by riparin II (50 mg/kg, p.o.) in the FST. This study indicates that riparin II produces significant antidepressant‐like activity in the forced swimming and TSTs, and this effect seems to be dependent on its interaction with noradrenergic, dopaminergic, and serotonergic systems.     

应用高通量筛选体系寻找抗抑郁新药的实验研究

背景目前抑郁症发病率日益趋高,运用新技术新方法开发新型高效低毒抗抑郁药具有重要意义.目的通过高通量筛选与体内试验相结合,建立寻找抗抑郁新药先导化合物的研究体系.设计随机对照实验.地点、材料和干预本研究地点为中国医学科学院药物研究所.实验选用昆明种雄性小鼠70只,体质量(20±2)g.雄性Wistar大鼠10只,体质量(200±20)g.取雄性Wistar大鼠,断头处死,快速取脑用于5羟色胺重摄取实验.将小鼠随机分为对照组、氟西汀组(2.6 mg/kg)、J01113组(30 mg/kg),J01114组(30 mg/kg),J10745组(30 g/kg).连续灌胃给药5 d,每天给药1次,从给药第2天开始隔日进行小鼠悬尾试验.比较给药组及对照组小鼠自挂上后6 min内的不动时间.分组给药同小鼠悬尾实验,隔日进行小鼠强迫游泳实验.比较给药组及对照组小鼠在后4 min内的不动时间.主要观察指标突触体5-羟色胺重摄取抑制活性,抑郁模型小鼠静止时间.结果体外试验表明5 000多种化合物经高通量筛选后,J01113,J01114和J10745均显示较强的5羟色胺重摄取抑制活性.J01113,J01114和J10745的半数有效剂量(IC50)分别为(1.304×10-10),(9.036×10-10),(1.447×10-7)mol/L.小鼠悬尾试验结果显示J01113连续给药3 d或5d悬尾小鼠的静止时间[(67.2 ±47.33),(95.2±47.5)s]明显少于对照组[(117.8±33.2),(170.2±40.47)s](t=2.77,P＜0.05;t=3.8,P＜0.01).小鼠游泳试验结果表明,J01113组小鼠连续给药3天或5天静止时间[(9.8±16.59),(19.4±24.64)s]也显著低于对照组[(63.7±35.4),(48.7 ±33.9)s](t=4.36,P＜0.01;t=2.21,P＜0.05).在这两种模型中J01114,J10745与对照组比静止时间虽有减少趋势,但均差异无显著性意义(P＞0.05).结论应用高通量筛选体系,可实现大规模高效率抗抑郁药先导化合物的发现,活性化合物J01113可能是潜在的一种新型抗抑郁药.     

The effect of lithium administration in animal models of depression: a short review

The aim of this short review was to collate the data involving the effects of lithium alone, or in combination, with antidepressant drugs in several animal models of depression. It has been shown that lithium administration reduced immobility in the mouse forced swimming test when given 30 min, but not 45 min, before testing. Further studies indicated that this activity was probably a result of an activity on serotonin (5-HT) 1A and 1B receptor subtypes. Lithium treatment has been shown to reverse helpless behaviour in the learned helplessness model of depression after chronic treatment (30 days), where lithium was administered in the drinking water. Further studies showed that acute (5 days) administration of lithium failed to reverse behavioural deficits. In the olfactory bulbectomised rat model of depression, several immunological and enzymatic functions have been shown to be altered and these changes are regularised by antidepressant treatment as well as lithium administration for 15 days. Hypokinesia (reduced locomotor activity) is a phenomenon observed following immobilisation stress in rats. This behavioural deficit was attenuated by lithium together with a wide range of antidepressant drugs used in the treatment of unipolar depression at non-stimulant doses. In addition, a single administration of lithium slightly inhibited midbrain raphe lesion-induced muricidal behaviour (25%); however, repeated treatment (5 days) significantly attenuated this behavioural deficit. Lithium treatment has also been shown to reverse behavioural and biochemical deficits induced by reserpine together with those induced by acute administration of single intracerebroventricular (i.c.v.) dose of the Na, K-ATPase-inhibiting compound, ouabain. Long-term studies of lithium augmentation have not been performed, so that no clear recommendations for the duration of this therapy can be made. The points raised in this short review endorse the commencement of such studies.     

Rapid down regulation of beta adrenergic receptors by combining antidepressant drugs with forced swim: a model of antidepressant-induced neural adaptation

The hypothesis that behavioral responses to antidepressant drugs in the forced swim test are related to a rapid neural adaptation produced by the combination of drug treatment and swim stress was explored. As a measure of adaptation, brain beta adrenergic receptors were assayed using [3H]dihydroalprenolol [( 3H]DHA) binding to brain membranes from rats that were processed in the forced swim test. The combination of swim stress and imipramine treatment antagonized immobility induced by forced swimming and resulted in a reduction in [3H] DHA binding to membranes from forebrain preparations which did not include the corpus striatum. Administration of antidepressant drugs from other chemical classes, including pargyline, iprindole and nomifensine, also reduced immobility induced by the forced swim and produced a reduction in [3H]DHA binding to forebrain membranes. In homogenates of the corpus striatum, [3H]DHA binding was not altered by swim stress combined with antidepressant drug treatment. Chlordiazepoxide was without an effect on immobility or beta receptor binding when combined with forced swim. Even though atropine and amphetamine exhibited a positive activity in the forced swim test, they did not reduce [3H]DHA binding. Therefore, by combining behavioral and neurochemical analysis of animals processed in the forced swim test, it may be possible to differentiate, with greater confidence, potential antidepressant drugs from "false positives." The present studies support the hypothesis that antidepressant drug action in the forced swim test involves a rapid neural adaptation as reflected by the down regulation of beta adrenergic receptors. Thus, this behavioral paradigm may serve as a model of adaptive mechanisms induced by antidepressant drugs.     

Involvement of monoaminergic system in the antidepressant‐like effect of riparin I from Aniba riparia (Nees) Mez (Lauraceae) in mice

In past studies conducted by our group, riparin I (rip I) isolated from the green fruit of Aniba riparia presented antianxiety effects in mice, while its analogs rip II and III showed anxiolytic and antidepressant‐like actions. This time around, we investigated a possible antidepressant activity of rip I using the forced swimming test (FST) and tail suspension test (TST) as predictive tests for antidepressant activity in rodents. In addition, the involvement of the monoaminergic system in this effect was also assessed. rip I was acutely administered by intraperitoneal (i.p.) and oral (p.o) routes to male mice at doses of 25 and 50 mg/kg. Results showed that rip I at both tested doses and administration routes produced a significant decrease in immobility time in FST and TST. The pretreatment of mice with prazosin (1 mg/kg, i.p., an α₁‐adrenoceptor antagonist), yohimbine (1 mg/kg, i.p., an α₂‐adrenoceptor antagonist), SCH23390 (15 μg/kg, i.p., a dopamine D1 receptor antagonist), sulpiride (50 mg/kg, i.p., a dopamine D2 receptor antagonist), p‐chlorophenylalanine (100 mg/kg, an inhibitor of serotonin synthesis) or ritanserin (4 mg/kg, a serotonin 5‐HT2_a/2_c receptor antagonist) blocked the anti‐immobility effects elicited by rip I (50 mg/kg, p.o.) in the FST. Taken together, results indicate that rip I produces significant antidepressant‐like activity in the FST and TST, and this effect seems to be dependent on its interaction with noradrenergic, dopaminergic and serotonergic systems.     

Antidepressant‐like effect of bis‐eugenol in the mice forced swimming test: evidence for the involvement of the monoaminergic system

Dehydrodieugenol, known as bis‐eugenol, is a eugenol ortho dimer, and both compounds were able to exhibit anti‐inflammatory and antioxidant activities in previous studies. Furthermore, eugenol showed antidepressant‐like effect; however, the biological actions of bis‐eugenol on experimental models for screening antidepressant activity are still unknown. The present study investigated a possible antidepressant‐like activity of bis‐eugenol in the forced swimming test (FST) and tail suspension test (TST) in mice and the involvement in the monoaminergic system in this effect. In addition, a neurochemical analysis on brain monoamines of mice acutely treated with bis‐eugenol was also conducted. Bis‐eugenol decreased the immobility time in the FST and TST without accompanying changes in ambulation in the open field test at 10 mg/kg, i.p.. Nevertheless, it induced ambulation at 25 and 50 mg/kg doses. The anti‐immobility effect of bis‐eugenol (10 and 50 mg/kg, i.p.) was prevented by pretreatment of mice with p‐chlorophenylalanine (PCPA, 100 mg/kg, i.p., an inhibitor of serotonin synthesis, for four consecutive days), yohimbine (1 mg/kg, i.p., an α2‐adrenoceptor antagonist), SCH23390 (15 μg/kg, s.c., a dopamine D1 receptor antagonist) and sulpiride (50 mg/kg, i.p., a dopamine D2 receptor antagonist). Monoamines analysis using high‐performance liquid chromatograph revealed significant increase in the 5‐HT, NE and DA levels in brain striatum. The present study indicates that bis‐eugenol possesses antidepressant‐like activity in FST and TST by altering dopaminergic, serotonergic and noradrenergic systems function.     

ECT in the treatment of recurrent psychotic depression.

Two cases of recurrent psychotic depression are reported in which ECT (electroconvulsive therapy) was administered with good results for previous episodes of depression, but treatment of the current episode with combined drug therapy (antidepressant and antipsychotic drugs) in one case and antidepressant chemotherapy in the other resulted in failure to improve. The patients were transferred to another facility, and improved when ECT was administered. Pertinent literature on ECT and drug treatment of depression is reviewed, and the conditions for which ECT is probably the treatment of choice are enumerated.     

ECT in an Adolescent with Down Syndrome and Treatment-Refractory Major Depressive Disorder

The efficacy of electroconvulsive therapy (ECT) as a treatment for patients with major depressive disorder who are intolerant of or refractory to antidepressant medications is well known. This treatment may be overlooked in children and adolescents, and in those with developmental disabilities. The case report of a 15-year-old male with Down syndrome and treatment-refractory major depressive disorder who received ECT is presented. Four bilateral ECT treatments resulted in a substantial improvement of the patient's depressive symptoms. In this case, ECT was a safe and effective treatment for an adolescent with Down syndrome. Although no generalization can be based on a single case report, when appropriate, ECT should be considered as a treatment for this patient population.     

重复经颅磁刺激治疗重型抑郁症的对照研究

背景:高频(15～25Hz)重复经颅磁刺激(repetitive transcranial magnetic stimulation,rTMS)技术能更多地兴奋大脑皮层水平走向连接神经元,导致皮层局部代谢浓度增高,与电休克疗法(electro convulsive therapy,ECT)相比较,其安全性高,副作用少。 目的:评价rTMS对重型抑郁症患者的治疗作用,探讨其治疗机制。 设计:以诊断为依据的病例对照研究。 地点和对象:36例来自于川北医学院附属医院的重型耐药性抑郁症患者,采用随机数字法将其分为rTMS治疗组和ECT组,每组18例患者。 方法:两组患者分别于治疗前及2周后采用汉密尔顿抑郁量表(Hamilton depression,HAMD)进行评定,同时测定rTMS治疗前后血浆5-羟色胺和去甲肾上腺素(norepinephrine,NE)含量变化。 主要观察指标:两组治疗前后HAMD评分;rTMS组治疗前后血浆5-羟色胺及NE含量;两组患者治疗后产生的副作用。 结果:rTMS治疗组和ECT组有效率分别为89％(16/18)、83％(15/18),差异无显著性意义(χ~2=0.812,P>0.05);两组患者治疗后HAMD评分分别为11.6±3.0、12.1±2.9,均较治疗前评分(27.8±3.2、26.7±2.8)明显下降,差异有显著性意义(t=2.891～3.279,P<0.05～0.005)。rTMS治疗组治疗后血浆5-羟色胺含量[(8.42±1.65)ng/L]较治疗前[(2.45±0.86)ng/L]显著增加(t=2.295     

Antidepressant‐like effect of carvacrol (5‐Isopropyl‐2‐methylphenol) in mice: involvement of dopaminergic system

Carvacrol (5‐isopropyl‐2‐methylphenol) is a monoterpenic phenol present in the essential oil of many plants. It is the major component of the essential oil fraction of oregano and thyme. In this study, the effect of carvacrol was investigated in two behavioral models, the forced swimming and tail suspension tests in mice, to investigate the possible antidepressant effect of this substance. Additionally, the mechanisms involved in the antidepressant‐like effect of carvacrol in mice were also assessed. Carvacrol (cvc) was administered orally at single doses of 12.5, 25 and 50 mg/kg. The acute treatment of cvc decreased the immobility time in the forced swimming and tail suspension tests without accompanying changes in ambulation in the open‐field test. The anti‐immobility effect of carvacrol (25 mg/kg) was not prevented by pretreatment of mice with p‐chlorophenylalanine, prazosin and yohimbine. On the other hand, the pretreatment of mice with SCH23390 or sulpiride completely blocked the antidepressant‐like effect of carvacrol (25 mg/kg) in the forced swimming test. These results show that carvacrol presents antidepressant effects in the forced swimming and tail suspension tests; this effect seems to be dependent on its interaction with the dopaminergic system, but not with the serotonergic and noradrenergic systems. Keywords: Carvacrol; Antidepressant; Forced swimming; Tail suspension; Dopaminergic system.     

ELEctroconvulsive therapy (ECT) vs. Ketamine in patients with Treatment-resistant Depression: The ELEKT-D study protocol

Major depressive disorder (MDD) is the most common mental illness and the leading cause of disability worldwide. Electroconvulsive therapy (ECT) is the most effective treatment for MDD and the gold-standard therapy for treatment-resistant depression (TRD), yet it remains underutilized due to factors such as limited availability, stigma, and concerns about cognitive side effects. Ketamine has emerged as the first rapid-acting antidepressant and shows robust short-term efficacy in clinical trials, but there are concerns about its long-term safety and efficacy. While response rates are similar between ECT and ketamine in clinical trials, these treatments have never been compared head-to-head in a sufficiently large, well-powered randomized study. Here we describe the study protocol for ELEctroconvulsive therapy (ECT) vs. Ketamine in patients with Treatment-resistant Depression (ELEKT-D), a non-inferiority, comparative effectiveness trial. Patients with TRD seeking clinical treatment are randomized (1:1) to receive ECT (thrice weekly) or intravenous ketamine (twice weekly) for 3–5 weeks. The primary outcome is the proportion of responders in each group at the end of study visit, as measured by a patient-reported outcome measure (Quick Inventory of Depressive Symptomatology-Self Report). The study is powered such that the non-inferiority margin allows for ketamine to retain 90% of the ECT treatment effect, with a projected sample size of 400 patients (200 per group). Secondary outcomes include remission rates, depression severity, cognitive functioning, quality of life, adverse events, and tolerability. The results of the ELEKT-D study will have important implications for patient choice, clinical practice, and health insurance policies.     

Cyclosporine induces progressive attenuation of baroreceptor heart rate response and cumulative pressor response in conscious unrestrained rats

Cyclosporine A (CsA) use is associated with hypertension and reduced baroreceptor sensitivity (BRS), but the underlying mechanisms remain unresolved. In this study, we investigated whether CsA attenuation of BRS is 1) dependent on treatment regimen, and 2) causative of the pressor response. Furthermore, we investigated whether a reduction in plasma testosterone contributes to BRS attenuation caused by short-term CsA administration. The effects of the clinically used CsA formulation (15 mg/kg/day i.v. for 5 days) on mean arterial pressure (MAP), heart rate, BRS, and body weight were investigated in conscious rats. CsA caused reproducible pressor responses (15.1 +/- 3.0 mm Hg) starting after the first dose and continuing through the 5 days of the study. BRS and baseline MAP were inversely related in the CsA group because of a progressive reduction in BRS, which started on day 2 and reached approximately 50% of baseline on day 5 and a cumulative elevation in MAP. The inverse BRS and MAP responses required daily administration of CsA because neither response was evident throughout the 5-day observation period after a single dose of CsA. Plasma testosterone levels were similar in all groups, whereas the body weight decreased approximately 10% in the CsA group on day 5. These findings suggest 1) CsA attenuation of BRS is relatively rapid and cumulative; 2) the attenuation of BRS may contribute to the delayed, but not to the acute, pressor elicited by CsA; and 3) the cumulative reduction in BRS caused by short-term (5-day) CsA treatment is not testosterone-related.     

临床护理路径在选择性吻合器痔切闭术(TST)围术期的应用

目的 探讨临床护理路径(CNP)在选择性吻合器痔切闭术(TST)围术期护理的应用效果。方法 将60例混合痔行TST手术的患者随机分为对照组和实验组各30例。以整体护理为基础,对照组给予传统常规护理,实验组应用CNP方法进行护理。比较两组患者的住院天数、医疗费用、并发症的发生率、疾病相关知识掌握情况及患者满意度。结果 实验组患者的住院天数明显缩短,医疗费用下降,并发症的发生率降低,疾病相关知识掌握情况及患者满意度均明显提高(P<0.01)。结论 在混合痔行TST围术期中应用CNP护理方法优于传统护理,患者效果满意,适合临床路径的管理模式。     

Calcitonin-induced impairment in conditioning is antagonized by chronic antidepressant drug treatment

The purpose of this study was to test the effect of calcitonin, when injected into the lateral ventricle, on conditioning behaviour and to see whether antidepressant drug treatment can antagonize calcitonin-induced impairment of this behaviour. Conditioned response by conditional stimulus (CS) was compared in control rat (CO) and in rats that received intraventricular perfusion of calcitonin (CA), acute antidepressant drug treatment (ADa), acute antidepressant drug treatment + calcitonin (ADa + CA), chronic antidepressant drug treatment (21 days) + calcitonin the day after (ADc + CA). Control rats acquired easily the conditioned response, the CA group and ADa + CA had problems in making the correlation between CS and unconditional stimulus (US), and consequently did not acquire a conditioned response, but in the ADc + CA group, rats exhibited more conditioned responses. The results indicate that calcitonin disrupts conditioning processes and chronic but not acute antidepressant drug treatment can reverse the effects of calcitonin.     

Antidepressant‐like activity of gallic acid in mice subjected to unpredictable chronic mild stress

This study was designed to evaluate antidepressant‐like activity of gallic acid in Swiss young male albino mice subjected to unpredictable chronic mild stress and to explore the possible underlying mechanisms for this activity. Gallic acid (5, 10, 20 mg/kg, i.p.) and fluoxetine (10 mg/kg, i.p.) per se were administered daily to unstressed mice and other groups of mice subjected to unpredictable mild stress, 30 min after the injection for 21 successive days. The antidepressant‐like activity was evaluated using forced swim test (FST) and sucrose preference test. Stress significantly increased immobility period of mice in FST. Gallic acid (10 and 20 mg/kg, i.p.) and fluoxetine significantly decreased immobility period of unstressed and stressed mice in FST and prevented the stress‐induced decrease in sucrose preference, indicating significant antidepressant‐like activity. There was no significant effect on locomotor activity of the mice by the drugs. Gallic acid (10 and 20 mg/kg, i.p.) significantly decreased Monoamine oxidase‐A (MAO‐A) activity, malondialdehyde levels, and catalase activity in unstressed mice; and significantly prevented the stress‐induced decrease in reduced glutathione and catalase activity; and also significantly prevented stress‐induced increase in MAO‐A activity, malondialdehyde levels, plasma nitrite, and corticosterone levels. Thus, gallic acid showed antidepressant‐like activity in unstressed and stressed mice probably due to its antioxidant activity and through inhibition of MAO‐A activity and decrease in plasma nitrite levels. In addition, gallic acid also showed antidepressant‐like activity in stressed mice probably through decrease in plasma corticosterone levels.     

Headache and Electroconvulsive Therapy

SYNOPSIS
While headache is a documented side effect of electroconvulsive therapy (ECT), there is little information on this phenomenon. Studies of the mechanisms of ECT as a treatment for depression indicate that alterations in serotonergic neurotransmission appear to be related to its efficacy. While ECT and many of the antidepressant drugs have similar effects on serotonergic transmission, they are notably different in the changes they induce in type 2 receptors for 5-hydroxytryptamine (5-HT). ECT upregulates 5-HT₂, and antidepressants down regulate the receptor's expression. 5-HT₂ receptor sensitization has been associated previously with headache genesis, which may explain why ECT induces headache, and amitriptyline relieves headache.
In our study we surveyed 98 patients retrospectively about their experiences with headache prior to and following ECT. Of the 54 patients who submitted properly completed questionnaires, five reported new onset of headaches following ECT, four reported exacerbation of a previous headache problem, and two reported their headaches improved. The patients experienced changes in the character or location of pain, with a tendency to progress from tension-type to migrainous headache. In all but two cases these developments persisted at least eight months after ECT. We discuss the possible reasons and significance of our findings.     

MMH、PPH、TST在混合痔手术中的应用

目的:探讨外剥内扎切除术(MMH)、痔上黏膜环切术(PPH)、选择性痔上黏膜环切除术(TST)治疗混合痔的临床疗效、安全性、效费比。方法:将195例混合痔患者随机分为MMH组、PPH组、TST组,每组65例。分别观察三组术后的疼痛评分、手术时间、住院时间、术后并发症、诊疗费用等指标。结果:MMH组、TST组、PPH组在治愈率方面无明显差异,TST组在疼痛评分、住院时间、术后出血方面均优于其他两组,TST组、PPH组在创面愈合、残留赘皮及复发方面优于MMH组,MMH组在住院费用方面明显低于TST组、PPH组。结论:MMH、PPH、TST治疗混合痔疗效确切,PPH及TST,特别是TST术后疼痛较小,恢复迅速,但治疗费用较高;针对不同的患者,采取不同的手术方式,采用个体化的治疗,更能取得更好的疗效及满意度。     

Evidence for the involvement of the serotonergic, noradrenergic, and dopaminergic systems in the antidepressant-like action of riparin III obtained from Aniba riparia (Nees) Mez (Lauraceae) in mice

Previous work has shown that intraperitoneal administration of riparin III (ripIII) reduces immobility time in the forced swimming test (FST), which suggests potential antidepressant activity. As the mechanism of action is not completely understood, this study is aimed at investigating the antidepressant‐like action of ripIII. Following intraperitoneal administration of ripIII at doses of 25 and 50 mg/kg, there were decreases in the immobility time in the FST and tail suspension test without accompanying changes in ambulation (data not shown). The pretreatment of mice with sulpiride (50 mg/kg, i.p.), prazosin (1 mg/kg, i.p.), yohimbine (1 mg/kg, i.p.), and p‐chlorophenylalanine (PCPA, 100 mg/kg, i.p. for, four consecutive days) significantly prevented the anti‐immobility effect of ripIII in the FST. On the other hand, the anti‐immobility effect of ripIII (50 mg/kg, v.o.) was not altered by pretreatment of mice with SCH23390 (15 μg/kg, i.p.) Furthermore, ripIII potentiated the sleeping latency and sleeping time of the pentobarbital‐induced sleeping time test and also potentiated apomorphine (16 mg/kg, i.p.)‐induced hypothermia in mice. In conclusion, the present study provides evidence that the antidepressant‐like effect of ripIII is dependent on its interaction with the serotonergic, noradrenergic (α₁‐ and α₂‐ receptors), and dopaminergic (dopamine D₂ receptors) systems.     

Tianeptine and its main metabolite. Disposition in chronic renal failure and haemodialysis

The disposition of the antidepressant tianeptine and its MC5 metabolite (pentanoic acid analogue of tianeptine) was studied following a single 12.5 mg oral dose of tianeptine sodium salt in 20 patients with chronic renal failure. In 12 patients (group I) having a creatinine clearance of less than 19 ml.min-1 the pharmacokinetics parameters for tianeptine and MC5 metabolite were determined and compared with those obtained in a matched control group (group II). The other 8 patients (group III) were functionally anephric and were studied during 1 dialysis to assess the haemodialysis clearances of tianeptine and MC5 metabolite. The comparison between groups I and II showed that renal failure did not appear to affect the disposition of parent tianeptine. However, the MC5 metabolite terminal half-life was found to be increased in renal patients compared to controls (14.2 +/- 9.3 h vs 4.9 +/- 1.7 h). Due to a large interindividual variability the difference did not reach a significant level (P = 0.054). According to the antidepressant activity of the MC5 metabolite in pharmacological tests, the sustained rise in its plasma level suggests that a reduced daily dose should be administered and 12.5 mg of tianeptine should be given twice daily to patients with chronic renal failure. In patients from group III elimination of the compounds by haemodialysis was found to be low. The dialysis clearances were 3.9 +/- 9.9 ml.min-1 and 19.2 +/- 8.6 ml.min-1 for tianeptine and its MC5 metabolite respectively. This low dialysability has 2 clinical implications. Firstly, patients currently undergoing haemodialysis and treated by tianeptine could be given the drug without taking dialysis into account. Secondly, haemodialysis does not appear to be an effective method for tianeptine elimination in cases of overdosage.