四氢吖啶类化合物的合成与脑神经保护作用

早老性痴呆（ＡＤ）为一种慢性进行性神经功能衰退性疾病。以他克林为先导物,设计合成了２０个未见文献报道的新化合物,其中目的物１４个。初步药理试验结果表明,所合成狐对谷氨酸诱导的神经细胞损伤有一定的保护作用,其中３ｃ和３ｋ活性较好,抑制率分别为６１．１％和６４．８％。     

手掌部浅血管神经层与屈肌支持带关系的观测

目的：为腕管松解术及掌中间隙引流术提供解剖学基础。方法：１８例（男１２、女６）３６侧成人固定上肢标本上对手掌部屈肌支持带、正中神经、尺神经在胱掌部分支点和掌浅弓最高点与屈肌支撑带下缘的距离以及足动脉终末支与正中神经间距观察。结果：正中神经掌部分支点距屈肌支持下缘９±３ｍｍ。尺神经掌部分支点距屈肌支持带下缘５±２ｍｍ。正中神经于与尺动脉终末间距为１０±２ｍｍ。结论：在手掌部裳托肌腱与第三指蹼尺侧缘     

Action of ryanodine on neurogenic responses in rat isolated mesenteric small arteries

1. Rat mesenteric arteries (∼250 μm) were set up in a single-channel isometric myograph designed to allow fluorescence measurements concurrent with field stimulation of intramural nerves. Vessels were loaded with 6 μM fura-2AM for 2 h and simultaneous recordings of neurogenic contraction (force) and intracellular calcium [Ca²⁺]_i were obtained. In other experiments, arteries were loaded with 1 μCi ml⁻¹ [³H]-noradrenaline (NA) for 30 min in order to measure release of [³H]-NA in response to field stimulation to examine whether ryanodine directly inhibited neuronal release of NA.
2. Arteries were activated by single intermittent field stimulation or continuously to excite intrinsic sympathetic nerves, or by cumulative addition of noradrenaline (1 nM–10 μM) to the bathing solution.
3. Pre-incubation with ryanodine markedly inhibited the contraction and [Ca²⁺]_i release in response to single-pulse nerve stimulation. Ryanodine also inhibited an early phasic component of the response to continuous field stimulation and reduced the rate of rise in force in response to continuous field stimulation. However, stable maximal contraction and [Ca²⁺]_i in response to continuous field stimulation as well as maximal responses to exogenous NA were unaffected. Release of [³H]-NA in response to single intermittent field stimulation was not affected by ryanodine when compared to vehicle.
4. Our results suggest that brief intermittent activation of intramural sympathetic nerves increases [Ca²⁺]_i and contracts small arteries primarily by releasing Ca²⁺ from a ryanodine-sensitive intracellular store. In contrast, the stable rise in tone and [Ca²⁺]_i resulting from continuous nerve stimulation may largely depend on sources of Ca²⁺ other than the ryanodine-sensitive intracellular store.

     

The relevance of pulse repetition rate and radiant exposure to the neurophysiological effects of low-intensity laser (820 nm/pulsed wave) irradiation upon skin temperature and antidromic conduction latencies in the human median nerve

The effects of low-intensity near-infra-red laser irradiation (820 nm; 1.5 and 9.0 J cm^–2; pulsed at 12 Hz, 73 Hz and 5 kHz) upon peripheral neurophysiology and skin temperature were investigated using antidromic conduction studies in the human median nerve in vivo. Healthy human volunteers (n = 90) were recruited and allocated randomly to either a control group (n=10) or one of eight experimental groups (two radiant exposures, 1.5 J cm^–2 and 9.0 J cm^–2 at one of three pulse repetition rates, 12 Hz, 73 Hz or 5 kHz, in addition to a placebo group for each radiant exposure;n = 10 all groups). Analysis of variance (ANOVA) demonstrated a significant (p0.05) decrease in skin temperature following irradiation at the lowest radiant exposure (1.5 J cm^–2) combined with pulse repetition rates of 73 Hz and 5 kHz, with the greatest effect at 73 Hz. These changes in skin temperature were coupled with increases in negative peak latency (NPL); ie changes in NPL were inversely related to changes in skin temperature. However, in contrast to the authors' previous findings using continuous wave (CW) laser irradiation, differences in NPL were not found to be significant. These findings, therefore, provide little evidence of the neuro-physiological effects of low-intensity infra-red irradiation at the dosage levels and pulse repetition rates used here.     

Tonic inhibition of neuronal calcium channels by G proteins removed during whole-cell patch-clamp experiments

The barium current through voltage-dependent calcium channels was recorded from cultured rat cortical neurons with the whole-cell configuration of the patch-clamp technique. The maximal current evoked by depolarising pulses from –80 mV to 0 mV was divided into inactivating and non-inactivating fractions. During the first minutes of whole-cell recording, the amplitude of the inactivating fraction increased from less than 0.1 nA to an average value of 1 nA, whereas the amplitude of the non-inactivating component remained essentially the same. This increase in amplitude was prevented when the perforated-patch technique was used, suggesting that some intracellular factor that inhibited the barium current was lost or destroyed during conventional whole-cell experiments. When GTP[-S] or GTP was added to the pipette solution, no increase or only a weak rise of the inactivating current was seen, whereas GDP[-S] accelerated its increase. The results suggest that some of the calcium channels expressed in cultured cortical neurons are inhibited by a G protein even in the absence of added neurotransmitter. The current increase observed during whole-cell recordings may be due to a loss of intracellular GTP and the subsequent inactivation of an inhibitory G protein.     

基于神经营养因子探讨经颅直流电刺激对缺血性脑卒中患者的影响

目的 探讨经颅直流电刺激（tDCS）对缺血性脑卒中患者的影响,以及与外周血神经营养因子的相关性。 方法 将40例缺血性脑卒中患者按随机数字表法分为对照组与治疗组,每组20例。2组患者均给予常规药物治疗及康复训练,治疗组在此基础上增加tDCS,强度2.0 mA,每次20 min,每日1次,共14次,对照组给予伪刺激。治疗前及治疗2周后（治疗后）,采用改良Barthel指数（MBI）、简易精神状态量表(MMSE) 、汉密尔顿抑郁量表（HAMD）、抑郁自评量表(SDS)对2组患者进行评估,用ELISA法测定外周血脑源性神经营养因子(BDNF）、神经生长因子(NGF）水平。 结果 治疗前,2组患者MBI、MMSE、HAMD、SDS评分及外周血BDNF、NGF水平比较,差异均无统计学意义（P>0.05）。与组内治疗前比较,2组患者治疗后上述指标均改善（P<0.05）。与对照组比较,治疗组治疗后MBI评分［（68.00±14.81）分］、MMSE评分［（24.85±3.12）分］较高（P<0.05）,HAMD评分［（19.70±2.11）分］较低（P<0.05）,外周血BDNF水平［（108.20±36.96）pg/ml］、NGF水平［（2.90±1.03）pg/ml］较高（P<0.05）。 结论 tDCS可以有效改善缺血性脑卒中患者的认知功能,减轻抑郁症状,提高生活自理能力,其作用机制可能与神经营养因子水平升高有关。     

基于TNFR/RIPK1通路探索紫草素对大鼠脊髓损伤的作用及机制

目的:初步探讨紫草素对大鼠急性脊髓损伤(spinal cord injury,SCI)后神经功能恢复的影响及作用机制。方法:将96只Sprague-Dawley(SD)雄性大鼠分为4组:假手术组,即A组;假手术+紫草素组,即B组;脊髓损伤+二甲基亚砜(dimethyl sulfoxide,DMSO)组,即C组;脊髓损伤+紫草素组,即D组;每组24只。C、D组采用钳夹法制作大鼠急性SCI 模型。所有大鼠硬膜下置管,A 组不给药,B组和D组造模后30 min 经导管注射紫草素100 mg·kg^-1,C组注射等量 DMSO,每日1次,至取材时间点。各组分别于造模后6、12 h和3 d 每组取8只大鼠,行 Basso-Beattie-Bresnahan(BBB)评分及造模后1、3、7、14、21 d行斜板实验,再处死动物取脊髓组织。造模后1 h 每组大鼠腹腔注射碘化丙啶(propidine iodide,PI)1 mg·kg^-1,术后24 h取材检测脊髓组织 PI 红染细胞数;24 h 时取材采用苏木素-伊红(haematoxylin eosin,HE)染色观察脊髓损伤情况,尼氏(Nissl)染色观察神经元存活数量,使用Western-blot技术检测 B细胞淋巴瘤-2(B cell lymphoma-2,Bcl-2)蛋白及凋亡相关蛋白受体相互作用蛋白激酶1(receptor-interacting protein kinase 1,RIPK1)的表达水平。结果:造模后A组和B组各时间点的 BBB 评分均正常,C、D组各时间点均低于A、B组,D组造模后12 h和3 d的 BBB 评分高于同时间点C组(P<0.05)。造模后12 h,D组PI 红染细胞较C 组明显减少,神经元崩解减轻(P<0.05)。造模后24 h,A 组和 B 组脊髓组织 HE 和 Nissl 染色正常,D 组脊髓组织损伤程度和存活神经元数量均优于 C 组(P<0.05)。Bcl-2、RIPK1蛋白在A 组、B 组表达很低; RIPK1 在C组表达明显增高,在D组表达明显下降,差异有统计学意义(P<0.05);Bcl-2蛋白在D 组表达高于C 组(P<0.05)。结论:紫草素可减轻大鼠急性SCI后的病理变化,改善行为学评分,促进脊髓神经功能恢复。其具体机制可能与抑制TNFR/RIPK1信号通路介导的坏死性凋亡有关。     

Apoptotic cascade of neurons in the subcortical sensory relay nuclei following the neonatal infraorbital nerve transection

A terminal transferase-mediated dUTP nick end labeling (TUNEL) method was utilized for detection of neuronal death in the subcortical relay nuclei of the trigeminosensory system following the infraorbital nerve transection in newborn rats. At 18-24 h after injury, numerous TUNEL-positive profiles were found within the ventroposteromedial thalamic nucleus (VPM) contralateral to the injury, whereas the VPM on the ipsilateral side and of the age-matched normal control contained only a few profiles per section. Electron microscopy revealed that the TUNEL-positive profiles were apoptotic neurons. The ventral part of the ipsilateral brainstem sensory trigeminal nuclear complex (the nucleus principalis, and the subnuclei oralis and interpolaris) exhibited statistically significant 65-70% increase in number of apoptotic neurons compared to the contralateral side. Taken together with our previous study [T. Sugimoto, C. Xiao, H. Ichikawa, Neonatal primary neuronal death induced by capsaicin and axotomy involves an apoptotic mechanism, Brain Res. 807 (1998) 147-154], the present results demonstrated a cascade of apoptosis in the primary, secondary and tertiary order sensory neurons along the neuroaxis.     

Myelinated afferent fiber types that become spontaneously active and mechanosensitive following nerve transection in the rat

It is difficult to know which afferent types preferentially develop ectopic firing characteristics following nerve injury because axotomy disconnects the sensory receptor ending from the remainder of the afferent neuron. We compared the prevalence of ectopic firing originating in nerve-end neuromas of nerves serving muscle and skin in the rat. Spontaneous firing was much more prevalent in the injured medial gastrocnemius nerve, a hindlimb muscle nerve, than in the saphenous and sural nerves which primarily innervate hindlimb skin. Ectopic mechanosensitivity, on the other hand, was more prominent in neuromas of the cutaneous nerves. In neuromas of the facial nerve, a cranial nerve which serves striated muscles of the face, there was no spontaneous discharge and very little ectopic mechanosensitivity. We conclude that the development of spontaneous ectopic discharge and ectopic mechanosensitivity depends on the type of myelinated afferent fiber involved.     

Sprouting of bladder nerves into cystoplastic cecal segment in the rat

Incorporation of bowel into the bladder (enterocystoplasty) has been widely used to increase bladder capacity. It has been reported by others that the response of smooth muscle from the cystoplastic segment of the intestine shifts from that of the intestine (relaxation to α-agonists and ATP) to that of the bladder (contraction to α-agonists and ATP). This suggests a functional integration of the intestinal muscle into the bladder; the mechanisms are unknown. The aims of the present study were (1) to elucidate if there are signs of bladder nerves sprouting across the anastomosis into the intestinal segment, and (2) to study what happens with the intrinsic innervation of the intestinal segment. As a model, we used cecocystoplasty in rats. The bladder was opened and a patch of cecum with intact vascular supply was anastomosed to the bladder. After two to 11 months the rats were sacrificed and the bladders mounted as wholemounts and stained for acetylcholinesterase-containing nerves, or embedded in paraffin for histology. A pronounced degeneration of the myenteric plexus was found in the cecal segments. In some areas, this had proceeded to the extent that the ganglia were isolated ovoid lumps of cells with no apparent connection to other ganglia. Areas lacking ganglia and nerve trunks but still with muscle could be found in all specimens. Abundant axon bundles were demonstrated sprouting from the cut bladder nerves close to the anastomosis. The bundles spread out in a fan-like pattern or were organized as fewer thicker nerves. There were many nerve bundles entering the cecal segment where they branched and the diameter decreased till they no longer became visible. Some nerves reached surviving lumps of myenteric ganglion cells. The results show that the bladder nerves sprout into the anastomosed cecal segment. It is reasonable to assume that these nerves are responsible for the changes in receptor pharmacological properties of the cecal smooth muscle towards that of bladder muscle. Received: 30 October 1998 / Accepted: 18 May 1999