Distinctive stress effects on learning during puberty

Puberty is a time of significant change in preparation for adulthood. Here, we examined how stressful experience affects cognitive and related hormonal responses in male and female rats prior to, during and after puberty. Groups were exposed to an acute stressor of brief periodic tailshocks and tested 24 h later in an associative memory task of trace eyeblink conditioning. Exposure to the stressor did not alter conditioning in males or females prior to puberty but enhanced conditioning in both males and females during puberty. The enhancement occurred in pubescent females irrespective of the estrous cycle. In adulthood, sex differences in trace conditioning and the response to stress emerged: females outperformed males under unstressed conditions, but after stressor exposure, trace conditioning in females was impaired whereas that in males was enhanced. These differences were not related to changes in gross motor activity or other nonspecific measures of performance. The effects of acute stress on corticosterone, estradiol, progesterone, and testosterone were also measured. Stressor exposure increased the concentration of corticosterone in all age groups, although sex differences were only evident in adults. All reproductive hormones except estradiol increased with age in a predictable and sex dependent fashion and none were affected by stressor exposure. Estradiol decreased in male rats across age, and remained stable for female rats. Together, these data indicate that males and female respond similarly to learning opportunities and stressful experience before and during puberty; it is in adulthood that sex differences and the opposite responses to stress arise.     

Illuminating the impact of habitual behaviors in depression

Researchers have hypothesized that habitual behaviors are zeitgebers for the circadian clock. However, few studies have examined the relationship between habitual behaviors and light, the strongest zeitgeber. Depression is an ideal model in which to explore this relationship because depression is a disorder associated with disruptions in circadian biological activity, sleep, and social rhythms (or patterns of habitual behaviors). We hypothesized that individuals with fewer habitual behaviors have less average exposure to light from morning rise time to evening bedtime and that a reduction in light exposure increases the likelihood of depression. Thirty-nine depressed and 39 never-depressed participants wore an ambulatory light monitor and completed the Social Rhythm Metric over the course of 2 weeks. Linear and logistic regression techniques were used to calculate regression coefficients, and confidence limits based on the distribution of the product of two normal random variables were computed to test the significance of the mediation effect. Infrequent habitual behaviors were associated with a decrease in average levels of light exposure, and low levels of light increased the likelihood of depression. This mediation effect was partial; the overall number of habitual behaviors had a direct relationship with depression above and beyond the association with light exposure. Longitudinal studies are needed to empirically demonstrate the direction of relationships between each of the variables tested.     

Modulation of glutamate receptors: strategies for the development of novel antidepressants

Summary.  On a biochemical level, conventional antidepressants have been shown to modulate synaptic levels of biogenic amines (i.e., serotonin, norepinephrine, and dopamine), most often by interfering with reuptake processes or inhibiting metabolism. Strategies directed at modulating glutamatergic transmission may overcome the principal limitations (i.e., delayed onset and low efficacy) that appear to be inherent to these conventional agents. In this brief overview, I summarize two glutamate-based approaches to develop novel antidepressants. These distinct and (on a cellular level) seemingly diametric strategies may converge on intracellular pathways that are also impacted upon by chronic treatment with biogenic amine based agents. Received July 6, 2001 Accepted August 6, 2001 Published online June 17, 2002     

内蒙古二连盆地白音查干凹陷早白垩世介形类及其古生态

本文报道了近年来采自二连盆地白音查干凹陷下白垩统钻井剖面中的介形类属种,其中新种７个,未定种４个。并进行了描述。同时对介形类动物群的地质年代和古生态特征作了简要探讨。     

Serotonin transporter affinity of (−)-loliolide,a monoterpene lactone from Mondia whitei

Mondia whitei (Apocynaceae) is used in traditional medicine to treat nervous disorders. Previous studies have shown in vivo antidepressant-like activity in the forced swimming test and affinity to the serotonin transporter of an ethanolic leaf extract of M. whitei. The aim of this study was to isolate the compound(s) responsible for in-vitro serotonin transporter affinity in M.whitei. Bioassay guided isolation lead to the identification of the monoterpene lactone (−)-loliolide. An ethanol extract was prepared from dry leaves. The residue was dissolved in ethyl acetate, extracted with water by liquid–liquid partitioning. This was followed by VLC fractionation. Through HPLC-UV separation the active compound was isolated and characterized by GC-MS, LC-MS and ¹H-NMR. The activity of (−)-loliolide was tested in a serotonin transporter binding assay using [³H]-citalopram as ligand, giving an IC₅₀-value of 997 µM, corresponding to a K_i-value of 409 µM. Loliolide is a non-nitrogenous compound and might bind to the transporter in a different way to nitrogen-containing inhibitors. The results provide a rationale for the use of M.whitei in the treatment of depression and other central nervous system diseases in traditional medicine.     

N-acetylcysteine for therapy-resistant tobacco use disorder: a pilot study

Abstract

Introduction

N-Acetylcysteine (NAC) may have efficacy in treating tobacco use disorder (TUD) by reducing craving and smoking reward. This study examines whether treatment with NAC may have a clinical efficacy in the treatment of TUD.

Methods

A 12-week double blind randomized controlled trial was conducted to compare the clinical efficacy of NAC 3 g/day versus placebo. We recruited 34 outpatients with therapy resistant TUD concurrently treated with smoking-focused group behavioral therapy. Participants had assessments of daily cigarette use (primary outcome), exhaled carbon monoxide (CO_EXH) (secondary outcome), and quit rates as defined by CO_EXH<6 ppm. Depression was measured with the Hamilton Depression Rating Scale (HDRS). Data were analyzed using conventional and modified intention-to-treat endpoint analyses.

Results

NAC treatment significantly reduced the daily number of cigarettes used (Δ mean±SD = ?10.9 ± 7.9 in the NAC-treated versus ?3.2 ± 6.1 in the placebo group) and CO_EXH (Δ mean± SD = ?10.4 ± 8.6 ppm in the NAC-treated versus ?1.5 ± 4.5 ppm in the placebo group); 47.1% of those treated with NAC versus 21.4% of placebo-treated patients were able to quit smoking as defined by CO_EXH<6 ppm. NAC treatment significantly reduced the HDRS score in patients with tobacco use disorder.

Conclusions

These data show that treatment with NAC may have a clinical efficacy in TUD. NAC combined with appropriate psychotherapy appears to be an efficient treatment option for TUD.     

肠道菌群紊乱所致炎症反应与抑郁症

抑郁症是一种与炎症反应、神经免疫关系密切的神经精神疾病。微生物,尤其是肠道菌群,则与人类免疫调节机制形成、感染和炎症反应息息相关。研究已证实,肠道菌群在炎症性肠病、哮喘等自身免疫性疾病的发生发展过程中起了相当大的作用。这些探讨非感染性疾病与微生物的关系的研究和理论形成了卫生学假说,亦即"老朋友"假说。目前,很多研究正在运用卫生学假说的观念,探索肠道菌群与抑郁症发生、发展、预防和治疗之间的联系,并取得了一些进展。本文重点就肠道菌群失调是否能够促进抑郁症发生及其可能机制做一综述。     

多巴胺能药物对早期帕金森病患者睡眠障碍发生的影响

目的:探讨多巴胺能药物及其它因素与早期帕金森病患者睡眠障碍之间的关系。方法:选择84名早期帕金森病患者作为病例组,87名健康人作为对照组。采用帕金森病睡眠量表(PDSS)评价患者的睡眠状况。采用非条件Logistic回归分析早期帕金森病患者睡眠障碍的影响因素。结果:早期帕金森病组PDSS总评分显著低于对照组(P=0.000);HAMD评分则显著高于对照组(P=0.000)。早期帕金森病患者睡眠障碍的主要类型为失眠。使用多巴胺能药物(OR=5.50,95%CI:1.96-15.81)是早期帕金森病患者发生睡眠障碍的危险因素;而较低的HAMD评分(OR=0.35,95%CI:0.13-0.93)则显著降低其睡眠障碍风险。结论:早期帕金森病患者存在睡眠障碍,多巴胺能药物和抑郁可能促进和加重其睡眠障碍。     

青年卒中后抑郁/焦虑危险因素logistic回归分析

目的:探讨青年卒中患者抑郁/焦虑发生的危险因素,为制定科学的管理策略提供依据。方法:选择2012年7月至2013年7月我院收治的69例青年卒中患者,采用《Hamilton抑郁量表(HAMD)》和《Hamilton焦虑量表(HAMA)》筛选出抑郁/焦虑病例作为病例组,其他病例作为对照组,通过多因素非条件Logistic回归模型分析青年卒中后抑郁/焦虑产生的危险因素。结果:69例青年卒中病人中,抑郁、焦虑的发生率分别约26.0%和36.2%。多因素Logistic回归分析显示NIHSS评分(OR值5.002,95%CI为4.015~6.023)、幕下病变(OR值0.466,95%CI为0.145~1.505)、伴随基础疾病(OR值0.093,95%CI为0.008~1.129)是青年卒中后抑郁/焦虑出现的危险因素。结论:对青年卒中患者要积极控制基础疾病,重视幕下病变和严重残疾,有助于预防及早期识别卒中后抑郁/焦虑的产生。