1例永久性三叉动脉显微解剖与文献复习

目的：报道1例偶然发现的右侧永久性三叉动脉形态、特点，并进行文献复习。方法：利用显微解剖对此例永久性三叉动脉的起源、走行、分支、分布、与后循环连接关系、以及相关动脉解剖特点等进行了研究。结果：此例永久性三叉动脉与脑膜垂体干共干起源于颈内动脉海绵窦段，于展神经外侧进入后颅窝，分支与基底动脉和小脑上动脉吻合，其终末支之一延续为同侧的小脑下后动脉，此动脉与三叉神经关系密切，分支分布于脑干和小脑。结论：永久性三叉动脉与后循环关系复杂，广泛参与正常脑组织供血。     

针刺过程中有衣小泡的形成、形态特征及其数量变化的研究

针刺大鼠“人中”、“四白”穴使之产生明显镇痛效果后,再将针刺时间分别延长至1、2、4、6、8、10、12h,到预定时间立即将动物灌流杀死取材,采用定量电镜方法观察计数了三叉神经尾侧脊束核胶状质亚核内各种有衣小泡的数量、形态以及在不同针刺时间内数量的变化。结果发现:大单壁有衣小泡的形成与针刺时间无明显正比例关系;而双壁有衣小泡则显然与之不同,它不仅形态多样,数目也随针刺时间而改变。本文将观察到的双壁有衣小泡归纳为以下五种类型:1、尚未与相邻两终末质膜脱离的孤立存在者。2、游离于终末内孤立存在者。3、与终末质膜相连且融合而成簇存在者;4、游离于终末内融合成簇者;5、树突棘凸入另一轴突或树突内并与之共同形成的不典型的双壁有衣小泡簇。本研究还发现,在针刺过程中双壁有衣小泡在1～8h内的形成与时间成正比,即1h时开始增多,4h显著增多,8h达高峰;以后开始下降,10h已恢复到4h的水平,到12h恢复到针刺前的状态。对照组仅见少数孤立的双壁有衣小泡,其形成基本上不随时间而变化。本文认为双壁有衣小泡的形成,是较大单壁有衣小泡的形成更为有效地继大致密核心小泡非突触部位胞吐之后膜再循环的一条新途径。     

大鼠三叉神经本体觉中枢通路二级神经元中继咬肌本体觉传入的微超结构证据

将Ricin注入大鼠咬肌神经,存活2周左右,再将HRP分别定位电泳于作为三叉神经本体觉中枢通路三级传入神经元所在地的三叉神经感觉主核背内侧部(Vpdm)和三叉神经运动核腹侧区(AVM)。电镜观察结果表明,在三叉神经本体觉中枢通路二级传入神经元所在地的三叉神经脊束核吻侧亚核背内侧部(Vodm),初级传入的溃变终末与HRP逆标的树突间形成非对称型突触,确证了Vodm是三叉神经本体觉中枢通路的中继核团。突触后树突多为中间树突和近侧树突。此外,在Vodm区还发现来自Vpdm的顺行标记终末与非标记的树突形成突触。本研究证明Vodm区超微结构有以下几个特征:(1)轴-体突触极少见;(2)轴-棘突触少见;(3)突触小球结构少见;(4)大扇贝形终末较少见;(5)这一区域也有小颗粒泡和大颗粒泡终末。这些超微结构特征,可能是Vodm与三叉神经感觉核簇其它部位区别之点,也可能是本体感觉中继核团特有的结构特征。     

延髓感觉核向丘脑和下丘的投射——荧光素双标记法

本文应用荧光素双标记法研究了后索核、孤束核、三叉神经脊束核向下丘和丘脑投射神经元的分布及其分支投射。作者将Propidium Iodide注入大白鼠右侧丘脑,Bisbenzimide注入右侧下丘,结果如下:楔束核内被标记的神经元中有88.2％向丘脑投射,它们位于核的主部;11.2％向下丘投射,它们在尾侧主要位于核的边缘部,向吻侧(至闩平面)主要位于核的背外侧端。薄束核内被标记的神经元中向下丘投射者(10.9％)与向丘脑投射者(86.7％)混杂在一起。在此两核内仅有极少量分支投射的双标神经元。孤束核和三叉神经脊束核内被标记的神经元中约有2/3投向丘脑,1/3投向下丘,未见分支投射的双标神经元。     

细胞外信号调节激酶在三叉神经痛动物模型中的表达

为了研究细胞外信号调节激酶(ERK)信号转导通路在三叉神经痛动物模型中的表达,将24只雄性SD大鼠分为三叉神经痛模型组和对照组两组,模型组大鼠以铬制羊肠线疏松结扎大鼠一侧眶下神经,对照组大鼠眶下神经不结扎。应用免疫组化和免疫荧光染色方法,分别检测大鼠三叉神经节(TG)和三叉神经脊束核尾侧亚核(Vc)中磷酸化ERK(p-ERK)的表达。本研究发现p-ERK在模型组和对照组大鼠的TG和Vc中均有不同程度的表达,但模型组大鼠中p-ERK表达明显高于对照组(P<0.05)。提示ERK可能参与了三叉神经痛(TGN)痛觉信号的传导,在三叉神经痛的发病机制中发挥重要的作用。     

Depletion of calcitonin gene-related peptide from the caudal trigeminal nucleus of the rat after electrical stimulation of the Gasserian ganglion

Electrical stimulation of the Gasserian ganglion resulted in partial depletion of calcitonin gene-related peptide (CGRP) from ipsilateral central terminals of pseudounipolar primary sensory ganglion cells. Affected terminals exhibit decreased CGRP immunoreactivity as shown by cytophotometric densitomery of the caudal trigeminal nucleus. The decrease in CGRP immunoreactivity is statistically significant only in the medial one-third of the caudal trigeminal nucleus. Since earlier studies have shown that electrical stimulation of the Gasserian ganglion induces first accumulation then depletion of CGRP from perivascular sensory terminals in the dura mater, the present experiments suggest that CGRP is depleted also from central terminals of primary sensory trigeminal neurons, which might be of importance in the pathogenesis of migraine headache. Received: 18 December 1996 / Accepted: 26 June 1997     

The medullary projection from the mesencephalic trigeminal nucleus. An experimental study with comments on the intrinsic trigeminal connections

Summary The medullary projection from the mesencephalic trigeminal nucleus has been studied in cats where the wheat germ agglutinin-horseradish peroxidase complex has been used as a retrograde and anterograde tracer. All injections were made at the level of the caudal pole of the inferior olive and show that it is especially the lateral part of nucleus parvicellularis of the reticular formation which is the main area for termination of the fibres. In addition, it can not be excluded that the descending fibres also reach the medialmost part of the spinal trigeminal sensory nucleus (pars magnocellularis and the adjoining pars gelatinosa). All three cell types of the mesencephalic trigeminal nucleus are labelled, the large globular, the small globular and the polygonal cells. Some of these cells are only faintly labelled. The observations confirm previous studies of the intrinsic trigeminal connections, but show that when the wheat germ agglutinin-horseradish peroxidase complex is used as a tracer, the origin as well as the termination for the intrinsic fibres (also the commissural) can be studied in the same section. The use of this sensitive tracer also shows new details within the intrinsic connections. The findings are discussed with special reference to the recent observations by Ruggiero et al. (1982). These authors found that in rabbit and rat there is a more restricted termination for the descending mesencephalic trigeminal fibres. The discrepancies between the observations seem to indicate that there are species differences as regards the connections between the mesencephalic trigeminal nucleus and the nuclei in the lower part of the brain stem.     

面口部炎性刺激条件下PPTA mRNA在大鼠三叉神经脊束核尾侧亚核神经元中的表达变化及与FOS的共存

将鹿角菜胶注射到大鼠口周皮下作成炎性刺激模型，用原位杂交法结合免疫组化法观察了三叉神经尾侧亚核中PPTAmRNA的表达变化及其与FOS蛋白表达的关系。结果发现：鹿角菜胶注射后，注射侧三叉神经尾侧亚核浅层内PPTAmRNA阳性神经元的数量与对照例相比明显增多。鹿角菜胶产生的炎性刺激也诱导了FOS蛋白在三叉神经尾侧亚核中的表达，FOS蛋白阳性神经元主要位于刺激侧三叉神经尾侧亚核浅层，而对照侧仅有少量分布。在三叉神经尾侧亚核浅层约60％的PPTAmRNA阳性神经元同时表达了FOS蛋白，而双重反应阳性的神经元仅占FOS阳性神经元的30％。上述结果提示：在面口部伤害性刺激诱导的三叉神经尾侧亚核内PPTAmRNA增强表达的过程中，FOS蛋白可能起着重要的调节作用。     

A microiontophoretic study of the action of kainic acid and putative neurotransmitters in the rat mesencephalic trigeminal nucleus

The ‘excitotoxic’ hypothesis proposes that neurotoxic amino acids exert their effect through neuronal excitation (Olney, Ho &;Rhee, 1971).Colonnier, Steriade &;Landry (1979) have found that trigeminal mesencephalic neurons in the cat are resistant to the neurotoxic effect of kainic acid. In the present study it was found that the same neurons in the rat also resist the cytotoxic action of this amino acid. In addition, kainic acid, applied iontophoretically onto these neurons failed to alter their firing frequency. The resistance of these neurons to both neurotoxic and excitatory actions of kainic acid is consistent with the ‘excitotoxic’ hypothesis.Other putative neurotransmitters were applied by microiontophoresis on these neurons and none were found to alter their rate of discharge. Procaine however applied with relatively low ejecting currents consistently reduced their firing rates. The failure of the putative neurotransmitters tested to influence the rate of discharge of the trigeminal mesencephalic neurons suggests that the chemical synapses present on these neurons in the rat (Hinrichsen &;Larramendi, 1970) utilize another neurotransmitter from those tested. Alternatively the synapses might have a role other than the direct regulation of the firing frequency of these primary afferent neurons.