慢性炎症性脱髓鞘性多神经病的轴索损害

目的探讨慢性炎症性脱髓鞘性多神经病（CIDP）的轴索病理改变。方法对18例CIDP患者进行电生理和腓肠神经的病理检查，分析不同患者的腓肠神经病理改变特点，并对病理改变不同的两组进行临床、电生理及病理比较。结果5例以脱髓鞘改变为主者，主要出现薄髓鞘神经纤维和有髓神经纤维的洋葱球样结构，其中3例出现轴索损害。8例以轴索损害为主者，主要出现有髓神经纤维的Wallerian变性和再生簇结构。3例出现有髓神经纤维的髓鞘和轴索混合性损害。2例轻微病理改变。脱髓鞘损害为主者和轴索损害为主者的单核细胞浸润程度无明显差异，且两者可同时存在脱髓鞘和轴索损害的电生理改变特点。结论轴索损害是CIDP比较常见的病理改变，不应当作为该病的绝对排除标准。单核细胞的浸润是一种普遍改变。     

遗传性感觉交感神经病Ⅰ型一家系的临床、电生理和病理改变

目的报道一个遗传性感觉交感神经病Ⅰ型（HSANⅠ）家系的临床、病理和电生理改变特点。方法先证者为28岁男性，出现双下肢痛觉缺失1年余，伴随双脚多发溃疡，先证者之母在30岁出现双足麻木和溃疡。对先证者的周围神经和自主神经进行电生理检查，对腓肠神经进行病理检查。结果先证者手部皮肤交感反应延长，在足部没有引出；感觉神经传导速度在上肢出现减慢，（右尺神经33m／s，左正中神经45m／s），在下肢无反应；运动神经传导速度在上肢正常或减慢，在下肢减慢或无反应。腓肠神经的有髓神经纤维完全脱失，无髓神经纤维出现严重脱失。结论我国存在HSANⅠ型家系，病理检查显示有髓神经纤维和无髓神经纤维均被严重累及。皮肤交感反应检查交感神经损害的程度有助于该病的诊断。     

急性感觉性神经元神经病两例的临床病理观察

目的明确感觉性神经元神经病（SND）的临床表现、神经电生理、颈椎核磁共振的影像学特点以及皮肤神经活检、腓肠神经活检和脊髓后索病变的病理学特征。方法分析2例胃肠道感染后死于SND的患者的临床与辅助检查资料，后者包括神经电生理检查、周围神经和脊髓的尸检病理，结合相关文献进行复习。结果患者独特的临床表现为早期出现共济失调，广泛分布的感觉减退和腱反射减低。电生理检查见感觉神经动作电位广泛异常，与神经纤维长度无关。SND患者脊髓后索髓鞘脱失，腓肠神经活检可见以大有髓纤维为主的神经纤维丢失，无再生神经丛。本组2例患者颈椎磁共振检查结果正常。结论SND独特的临床表现与神经电生理检查特点提示周围感觉神经纤维广泛受累。脊髓后索尸检病理证实感觉神经中枢传导纤维变性脱失，支持病变位于脊髓后根神经节。SND早期颈椎磁共振可能正常。     

有机磷中毒后迟发性周围神经病的临床和神经病理四例

目的探讨有机磷中毒后迟发性周围神经病(OPIDP)的临床及神经病理改变特点。方法对4例口服有机磷后出现周围神经损害症状的患者进行电生理和腓肠神经活检检查。结果 4例患者于急性中毒后平均20.5(10～24)天出现以下肢受累为主的逆行性运动感觉周围神经病,其中2例患者存在锥体束征。电生理检查提示以运动神经受累为主的轴索性周围神经损害。腓肠神经活检主要表现为与病程相关的轴索损害及再生现象,可见急性期的炎性反应、小纤维损害和继发的髓鞘改变。结论有机磷中毒后迟发性周围神经病表现为以运动障碍为主的逆行性神经病,中枢神经系统亦可能受累及;周围神经病理表现为轴索损害为主,同时存在小纤维损害及继发的髓鞘改变。     

GM1-IgM抗体阳性慢性炎性脱髓鞘性多神经病临床、电生理与病理特点

目的探讨GM1-IgM抗体阳性的慢性炎性脱髓鞘性多神经病(chronic inflammatory demyelinating polyneuropathy,CIDP)的临床、电生理和病理改变特点。方法纳入研究的4例患者,分别为2例男性和2例女性,发病年龄在12~64岁之间,发病到就诊时间在6 m~2 y之间,3例出现非对称性下肢无力,1例表现为单侧上肢和对侧下肢无力。对4例患者进行血和脑脊液的GM1-IgM和IgG抗体检查,进行神经电生理检查和腓肠神经活检。结果 4例均出现血清GM1-IgM抗体阳性,电生理检查提示多个感觉神经和运动神经传导速度减慢和诱发电位波幅降低,1例出现神经传导阻滞现象。病理检查发现腓肠神经的轻度有髓神经纤维轴索变性和髓鞘脱失。结论GM1-IgM抗体阳性CIDP多表现为以下肢无力为主的非对称性神经病。     

腊肠体样周围神经病的临床、电生理和病理特点

目的总结腊肠体样周围神经病的临床、电生理和病理特点。方法收集3例患者病史、体格检查以及电生理检查及病理检查资料。结果3例患者中男2例、女1例,13～28岁发病,阳性家族史2例;机械性压迫或牵拉后导致双侧腓总神经麻痹1例,隐袭和慢性起病各1例。电生理检查可见广泛的周围神经损伤,正中神经运动传导远端潜伏期（DML）均延长。腓肠神经活检均可见少数明显增粗的有髓神经纤维,电镜下可见髓鞘板层数增多。1例患者肌肉活检示轻微病理改变。结论腊肠体样周围神经病为周围神经髓鞘发育障碍所致,神经电生理和神经病理对诊断有特异性。     

儿童慢性炎症性脱鞘性多神经病的临床和病理改变特点

目的探讨儿童慢性炎症性脱鞘性多神经病(chronic inflammatory demyelinating polyneuropathy,CI-DP)的临床及病理改变特点。方法根据欧洲神经肌肉病中心修订的儿童CIDP诊断标准诊断的10例17岁以下患者,收集其临床资料,进行周围神经电生理以及腓肠神经的病理检查。结果所有患者主要表现为肢体无力,分别有4例和3例出现四肢感觉减退和颅神经损害。9例有脑脊液蛋白细胞分离现象。10例均出现运动或感觉神经传导速度减慢及远端潜伏期延长,9例患者的动作电位波幅降低。所有患者的有髓神经纤维出现轻-重度减少,其中3例患者的纤维脱失程度在不同束间存在差异,6例患者以脱髓鞘为主;3例以轴索损害为主。1例患者仅出现轻微改变。9例患者存在炎细胞浸润。结论儿童CIDP以肢体无力为主。部分患者以轴索损害为主,神经纤维脱失程度可以存在束间差异。     

神经活检在周围神经疾病诊断中的意义及与电生理检查相关性分析

目的探讨神经活检在周围神经疾病诊断中的意义,以及神经活检与电生理检查的相关性。方法 12例周围神经病患者均予腓肠神经活检、神经电生理检查,比较二者对轴索、髓鞘损害的诊断情况,统计电生理检查与神经活检诊断的符合率。结果 (1)电生理检查结果检出轴索损害/髓鞘损害9例,神经活检结果发现11例患者伴有髓鞘或轴索损害。(2)神经活检对于周围神经疾病诊断有决定性意义有3例,其余9例也均起到了证实临床诊断的作用。(3)光镜诊断、电镜诊断与电生理检查结果比较无明显差异(P>0.05)。结论神经活检技术对于发现间质改变及亚临床、亚电生理神经损害有明显优势,对于判断周围神经疾病患者的损害类型仍需联合电生理检查进行综合诊断。     

高同型半胱氨酸血症对大鼠周围神经结构和功能的影响

目的 观察高同型半胱氨酸血症(hyperhomocysteinemia,Hhcy)对大鼠周围神经组织结构和传导功能的影响.方法 通过高蛋氨酸饮食建立Hhcy大鼠模型.应用电生理技术检测大鼠尾神经传导功能;光镜下计数大鼠腓肠神经单位面积有髓神经纤维密度(fiber density,FD)、平均髓鞘面积(mean myelin area,MMA);免疫组化方法分析腓肠神经髓鞘碱性蛋白(myelin basic protein,MBP)、神经丝蛋白(neurofilament protein,NF)表达;电镜观察腓肠神经超微结构.结果 Hhcy组大鼠尾神经运动神经传导速度(motor nerve conduction velocity,MCV)、感觉神经传导速度(sensory nerve conduction velocity,SCV)与复合肌肉动作电位(compound muscle action potential,CMAP)、感觉神经动作电位(sensory nerve action potential,SNAP)波幅均较对照组减慢和下降(均P＜0.05);Hhcy组大鼠腓肠神经FD、MMA与MBP、NF积分光密度均较对照组减小(均P＜0.05);Hhcy组大鼠有髓神经纤维出现了髓鞘脱失、轴突肿胀、间质水肿等超微结构改变.结论 Hhcy可造成大鼠周围神经组织结构与传导功能的损害.     

无脑白质影像学改变的晚发婴儿型异染性脑白质营养不良

目的 分析3例脑白质影像学无改变的晚发婴儿型异染性脑白质营养不良患儿的临床、电生理、影像学和病理学改变特点，总结其特征表现和诊断规律。方法 3例均为男性婴儿，月龄分别为20个月、27个月和28个月。均于出生后15～21个月出现运动发育停滞和倒退，以下肢运动障碍为主，表现有锥体束征。收入院后予以体格检查、电生理检查、头部MRI检查及腓肠神经活检。结果 （1）体格检查：例1双下肢肌力4级，肌张力降低；双膝腱反射亢进，双侧Babinski征阳性。例2四肢肌力5级，肌张力明显增高；腱反射亢进，双侧Babinski征阳性。例3眼球向左、右注视时可发现细小水平眼震，四肢肌力4级，肌张力低；四肢腱反射对称引出，双下肢病理征阴性。（2）辅助检查：3例患儿电生理检查均提示为周围神经病变，MRI检查无异常发现。（3）实验室检查：仅例1行外周血白细胞芳基硫酯酶A检查，显示活性显著下降。（4）腓肠神经活检：3例患儿均显示髓神经纤维显著减少，残存的有髓神经纤维的髓鞘变薄，甲苯胺蓝染色见部分雪旺细胞及吞噬细胞内出现紫红色异染颗粒，超微结构呈指纹样、髓样和平行排列的棒状结构。结论 病理检查证实细胞内沉积物具有异染性，而周围神经病变具有髓鞘发育不良特点。由于脑白质MRI无改变，这组以周围神经损害为主的息儿可能是异染性脑白质营养不良的一种特殊类型，诊断为伴有中枢神经系统损害的异染性周围神经病更符合临床表现规律。     

Tau-induced neurodegeneration: mechanisms and targets

The accumulation of hyperphosphorylated tau is a common feature of several dementias. Tau is one of the brain microtubule-associated proteins. Here we discuss tau’s functions in microtubule assembly and stabilization and with regard to its interactions with other proteins. We describe and analyze important post-translational modifications: hyperphosphorylation, ubiquitination, glycation, glycosylation, nitration, polyamination, proteolysis, acetylation, and methylation. We discuss how these post-translational modifications can alter tau’s biological function. We analyze the role of mitochondrial health in neurodegeneration. We propose that microtubules could be a therapeutic target and review different approaches. Finally, we consider whether tau accumulation or its conformational change is related to tau-induced neurodegeneration, and propose a mechanism of neurodegeneration.     

The effect of risperidone on reward‐related brain activity is robust to drug‐induced vascular changes

Dopamine (DA) mediated brain activity is intimately linked to reward‐driven cerebral responses, while aberrant reward processing has been implicated in several psychiatric disorders. fMRI has been a valuable tool in understanding the mechanism by which DA modulators alter reward‐driven responses and how they may exert their therapeutic effect. However, the potential effects of a pharmacological compound on aspects of neurovascular coupling may cloud the interpretability of the BOLD contrast. Here, we assess the effects of risperidone on reward driven BOLD signals produced by reward anticipation and outcome, while attempting to control for potential drug effects on regional cerebral blood flow (CBF) and cerebrovascular reactivity (CVR). Healthy male volunteers (n = 21) each received a single oral dose of either 0.5 mg, 2 mg of risperidone or placebo in a double‐blind, placebo‐controlled, randomised, three‐period cross‐over study design. Participants underwent fMRI scanning while performing the widely used Monetary Incentive Delay (MID) task to assess drug impact on reward function. Measures of CBF (Arterial Spin Labelling) and breath‐hold challenge induced BOLD signal changes (as a proxy for CVR) were also acquired and included as covariates. Risperidone produced divergent, dose‐dependent effects on separate phases of reward processing, even after controlling for potential nonneuronal influences on the BOLD signal. These data suggest the D2 antagonist risperidone has a wide‐ranging influence on DA‐mediated reward function independent of nonneuronal factors. We also illustrate that assessment of potential vascular confounds on the BOLD signal may be advantageous when investigating CNS drug action and advocate for the inclusion of these additional measures into future study designs.     

星形胶质细胞对天冬氨酸特异性半胱氨酸蛋白酶介导β淀粉样蛋白早期突触毒性作用的影响

目的探讨星形胶质细胞(astrocyte,AS)对天冬氨酸特异性半胱氨酸蛋白酶(cysteinyl aspartate specific proteinase,caspase)介导β淀粉样蛋白(β-amyloid,Aβ)早期突触毒性作用的影响,以期为进一步研究与血管性痴呆(vascular dementia,Va D)的发病机制奠定基础。方法以原代培养大鼠海马纯神经元体系(NE-S)及混合培养体系(MIX-S,主要包含神经元及AS)为研究对象,各体系分为6组:对照组、caspase-8抑制剂组、caspase-9抑制剂组、Aβ处理组、caspase-8抑制剂预处理加Aβ组和caspase-9抑制剂预处理加Aβ组。免疫荧光检测各组近胞体10μm段树突中突触后密度蛋白(postsynaptic density-95,PSD95)表达量的变化。结果 1在NE-S与MIX-S中,与对照组相比,caspase-8抑制剂组、caspase-9抑制剂组PSD95的表达量均无明显差异,Aβ处理组PSD95的表达量均显著降低(P均0.001)。2在NE-S中,与Aβ处理组相比,caspase-9抑制剂预处理加Aβ组PSD95的表达量显著回升至对照组水平,caspase-8抑制剂预处理加Aβ组则无显著改变;在MIX-S中的结果则相反,即caspase-8抑制剂预处理加Aβ组PSD95的表达量显著回升至对照组水平,而caspase-9抑制剂预处理加Aβ组则无显著改变。3MIX-S与NE-S两种培养系统间相比较,对照组间及Aβ处理组间PSD95的表达量均无显著差异,而caspase-8抑制剂预处理加Aβ组间及caspase-9抑制剂预处理加Aβ组间PSD95的表达量差异有显著性。结论在Aβ早期突触毒性作用中,AS参与caspase-8介导的死亡受体通路激活过程,且参与抑制神经元的线粒体通路。     

Ultrastructure of non-myelinated neurons during energy deprivation

Summary This paper examines the neuropathology of oxygen-glucose deprivation uncomplicated by stagnant conditions. Rabbit vagus nerves were pulled into asmulti-compartment perfusion chamber, stimulated five times per second and deprived of energy by substituting nitrogen and deoxyglucose for oxygen and glucose in the Locke's perfusate. After incubation the compartments were perfused with gluteraldehyde solution, and the nerves were prepared for electron microscopy. Fixation in the compartments ensured precise cross and longitudinal sections which permitted quantitative comparisons. Although the action potentials ceased in 45 min, 1 h of energy deprivation did not significantly affect the ultrastructure. After 2 h of deprivation the axons were smaller and flattened and microtubules appeared packed together. In the smallest axons the microtubules were gone, the neurofilaments were compacted and the few mitochondria had a dense, homogenous appearance. By 4 h the shrinking was extreme, yet 8% were swollen much larger than any of the controls. Longitudinal views showed these balloned areas were greatly expanded regions of the smallest axons. Both tiny and huge regions were devoid of microtubules and the swollen axons contained expanded mitochondria.Calcium is indirectly implicated in the pathogenesis by the concurrence of mitochondrial alteration as the microtubules disappear coupled with the known role of mitochondria in calcium regulation and the reported effect of high calcium on microtubual dissociation. In is suggested that axons first shrink as osmotially active molecules are used or washed out. After a time without energy the mitochondria can no longer regulate the intracellular calcium, microtubules dissociate, and calcium-activated phospholipases create osmotically active molecules. Finally, high-amplitude, disruptive swelling occurs.Supported, in part, by a Grant-in-aid from the American Heart Association with funds contributed by the American Heart Association, Kansas Affiliate and by the University of Kansas Biomedical Sciences Support Grant RR0737     

Development of 18F-labeled radiotracers for neuroreceptor imaging with positron emission tomography

Positron emission tomography (PET) is an in vivo molecular imaging tool which is widely used in nuclear medicine for early diagnosis and treatment follow-up of many brain diseases. PET uses biomolecules as probes which are labeled with radionuclides of short half-lives, synthesized prior to the imaging studies. These probes are called radiotracers. Fluorine-18 is a radionuclide routinely used in the radiolabeling of neuroreceptor ligands for PET because of its favorable half-life of 109.8 min. The delivery of such radiotracers into the brain provides images of transport, metabolic, and neurotransmission processes on the molecular level. After a short introduction into the principles of PET, this review mainly focuses on the strategy of radiotracer development bridging from basic science to biomedical application. Successful radiotracer design as described here provides molecular probes which not only are useful for imaging of human brain diseases, but also allow molecular neuroreceptor imaging studies in various small-animal models of disease, including genetically-engineered animals. Furthermore, they provide a powerful tool for in vivo pharmacology during the process of pre-clinical drug development to identify new drug targets, to investigate pathophysiology, to discover potential drug candidates, and to evaluate the pharmacokinetics and pharmacodynamics of drugs in vivo.     

Norharman-induced motoric impairment in mice: neurodegeneration and glial activation in substantia nigra

Summary. The β-carboline norharman is present in cooked food and tobacco smoke and show structural resemblance to the neurotoxicant 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. C57BL/6 mice were injected subcutaneously with norharman (3 and 10 mg/kg) twice per day for five consecutive days. Eighteen hours after the last dose an increased expression of glial fibrillary acidic protein and fluoro-jade staining were demonstrated whereas the number of tyrosine hydroxylase positive cells were unchanged in the substantia nigra. Two weeks after the last treatment a decreased motor activity was observed whereas cognitive functions remained intact. In cultured PC12 cells norharman treatment induced mitochondrial dysfunction and increased the number of caspase-3 and TUNEL-positive cells. The results demonstrate that norharman induced apoptosis in cultured cells as well as early neurodegeneration, glial activation and sustained motor deficits in mice and suggest that exposure to norharman may contribute to idiopathic Parkinson’s disease.     

The ENIGMA‐Epilepsy working group: Mapping disease from large data sets

Epilepsy is a common and serious neurological disorder, with many different constituent conditions characterized by their electro clinical, imaging, and genetic features. MRI has been fundamental in advancing our understanding of brain processes in the epilepsies. Smaller‐scale studies have identified many interesting imaging phenomena, with implications both for understanding pathophysiology and improving clinical care. Through the infrastructure and concepts now well‐established by the ENIGMA Consortium, ENIGMA‐Epilepsy was established to strengthen epilepsy neuroscience by greatly increasing sample sizes, leveraging ideas and methods established in other ENIGMA projects, and generating a body of collaborating scientists and clinicians to drive forward robust research. Here we review published, current, and future projects, that include structural MRI, diffusion tensor imaging (DTI), and resting state functional MRI (rsfMRI), and that employ advanced methods including structural covariance, and event‐based modeling analysis. We explore age of onset‐ and duration‐related features, as well as phenomena‐specific work focusing on particular epilepsy syndromes or phenotypes, multimodal analyses focused on understanding the biology of disease progression, and deep learning approaches. We encourage groups who may be interested in participating to make contact to further grow and develop ENIGMA‐Epilepsy.     

缺血性卒中并发2型糖尿病患者颈动脉斑块内新生血管分布特点的超声造影研究

目的 应用超声造影观察缺血性卒中并发2型糖尿病患者颈动脉斑块内新生血管分布情况,明确其 斑块内新生血管分布特征。 方法 病例组选取因急性缺血性卒中住院的糖尿病患者40例（入组前未服用降糖药）,卒中同侧颈 动脉斑块形成;对照组为同期门诊就诊的颈动脉斑块形成患者,无卒中病史,性别及年龄匹配的非 糖尿病患者32例。两组患者行弓上计算机断层扫描血管造影（computed tomography angiography,CTA） 检查排除主动脉弓斑块及颅内动脉病变,排除卵圆孔未闭及心房颤动等。对所有患者均行常规超声 及超声造影检查。常规超声观察斑块厚度及内部回声,超声造影观察斑块增强情况,横切面多角度 观察,将超声造影结果分为近内膜处有增强（代表新生血管）及近内膜处无增强两种。 结果 两组患者颈动脉斑块厚度及回声情况差异无统计学意义。超声造影结果显示病例组颈动脉 斑块近内膜处增强者34例（85%）,对照组近内膜处增强12例（37.5%）,差异有统计学意义（χ 2=17.38, P＜0.01）。 结论 未服用降糖药的2型糖尿病并发急性缺血性卒中的患者颈动脉粥样硬化斑块内近内膜处新生 血管增生多于无糖尿病患者,提示血糖升高与颈动脉斑块内血管新生有关。     

轻型缺血性卒中静脉溶栓后双重抗血小板疗效观察

目的 观察rt-PA静脉溶栓联合双重抗血小板治疗轻型缺血性卒中的有效性及安全性。 方法 以2013年12月-2016年12月在石家庄市第一医院连续住院治疗的轻型缺血性卒中患者为研究 对象,将其随机分为对照组、溶栓+单抗组和溶栓+双抗组。对照组不进行静脉溶栓,长期口服阿 司匹林（100 mg/d）抗血小板治疗;溶栓+单抗组在rt-PA静脉溶栓（0.9 mg/kg,最大剂量90 mg）基 础上长期单用阿司匹林（100 mg/d）抗血小板治疗;溶栓+双抗组在溶栓后单抗基础上加用氯吡格雷 （75 mg/d）双重抗血小板治疗,双抗治疗21 d后改为阿司匹林长期单抗治疗。随访3个月,有效性指标 为3个月时NIHSS 0～1分、Barthel指数（Barthel index,BI）95～100分和mRS 0～1分的比例,3个月时缺 血性卒中的复发率;安全性指标为治疗24 h出血转化和症状性出血转化的发生率。另外比较三组间 基线和3个月时血清hs-CRP和IL-6的水平差异。 结果 研究共纳入85例患者,对照组28例,溶栓+单抗组28例,溶栓+双抗组29例,全部患者均完 成3个月随访,无死亡患者。对照组、溶栓+单抗组和溶栓+双抗组3个月随访时NIHSS 0～1分比例分 别为46.43%、78.57%和93.10%,BI 95～100分比例分别为53.57%、82.14%和89.66%,mRS 0～1分 的比例分别为50.00%、82.14%和93.10%,三组上述有效性指标差异均有统计学意义,两两比较显 示,溶栓+双抗组高于溶栓+单抗组和对照组,溶栓+单抗组高于对照组,差异均有统计学意义;对 照组、溶栓+单抗组和溶栓+双抗组3个月时缺血性卒中复发率分别为32.14%、7.14%和3.45%,差异 有统计学意义。安全性指标方面,三组均无出血转化事件。对照组、溶栓+单抗组和溶栓+双抗组3 个月时的hs-CRP水平分别为11.92±3.58 mg/L、9.04±2.85 mg/L和6.04±2.65 mg/L,IL-6水平分别为 26.18±4.65 ng/L、16.11±6.93 ng/L和12.84±2.57 ng/L,三组上述炎症因子水平差异均有统计学意 义,其中溶栓+双抗组低于溶栓+单抗组和对照组,溶栓+单抗组低于对照组。 结论 对于急性轻型缺血性卒中患者,rt-PA静脉溶栓治疗后短期双重抗血小板治疗可显著改善患 者神经功能,降低炎症因子水平,降低复发率,且不增加出血风险。     

Yohimbine increases the binding potential for [11C]flumazenil in the monkey brain

Summary. We evaluated the impact of yohimbine administration on benzodiazepine (BDZ) receptor binding in the central nervous system of non-human primates (rhesus monkeys). Estimates of the binding potential (B_max/K_d) of BDZ receptors were made following intravenous administration of yohimbine, an α₂-adrenoceptor antagonist. Positron emission tomography was used in conjunction with [¹¹C]flumazenil (Ro 15-1788), a tracer for central BDZ receptor binding activity. The effects of yohimbine were compared with a control condition in which saline was administered. Yohimbine significantly increased the binding potential in the hippocampus, as assessed using a Student's t-test with Bonferroni correction. The result that the administration of yohimbine readily induces an increase in the binding potential for BDZ receptors in the primate brain suggests that the presence of an anxiety state potentiates the effect of anxiolytics. Accepted August 10, 2001