IPSI- and contralateral changes in acetylcholinesterase and choline acetyltransferase activities in the hippocampus following unilateral septal lesions in the rat

Unilateral, left electrocoagulative septal lesions of the rat brain were performed. Acetylcholinesterase and choline acetyltransferase activities in the left and right hippocampi were measured 6–8 and 14–17 days postoperatively.Small lesions, damaging mainly the nucleus lateralis evoked a small (10–20%) decrease in the activity of both enzymes on the ipsilateral and side a tendency to an increase in the enzymatic activity on the contralateral side. No differences were observed between values obtained on the sixth-eighth and the fourteenth-seventeenth days after the operation. Larger lesions, including the nucleus fimbriatus and the nucleus of the diagonal band evoked on the sixth-eighth day a decrease (40–50%) in the activity of both enzymes on the ipsilateral side, but on the fourteenth-seventeenth day a significant recovery in the enzymatic activity was noted. Contralaterally, following larger lesions, an initial decrease on the sixth-eighth day in choline acetyltransferase activity was followed by an overshoot in comparison to controls on the fourteenth-seventeenth day; acetylcholinesterase activity remained unchanged on the sixth-eighth day, but also surpassed the control value on the fourteenth-seventeenth day.It is suggested that the post-lesion changes in enzyme activity in the ipsilateral hippocampus occur mainly within the cholinergic system, while in the contralateral hippocampus they may be the result of damage to non-cholinergic fibres followed by sprouting of cholinergic axons.     

The nucleus basalis magnocellularis: The origin of a cholinergic projection to the neocortex of the rat

The cells of origin of a neocortical cholinergic afferent projection have been identified by anterograde and retrograde methods in the rat. Horseradish peroxidase injected into neocortex labelled large, acetylcholinesterase-rich neurons in the ventromedial extremity of the globus pallidus. This same group of neurons underwent retrograde degeneration following cortical ablations. The region in which cell depletion occurred also showed significant decreases in the activities of choline acetyltransferase and acetylcholinesterase. Discrete electrolytic and kainic acid lesions restricted to the medial part of the globus pallidus each resulted in significant depletions of neocortical choline acetyltransferase and acetylcholinesterase. Hemitransections caudal to this cell group did not result in such depletions. Taken together these observations suggest that the acetylcholinesterase-rich neurons lying in the ventromedial extremity of the globus pallidus, as mapped in this study, constitute the origin of a major subcortical cholinergic projection to the neocortex. The utility of acetylcholinesterase histochemistry in animals pretreated with di-isopropylphosphorofluoridate in identifying cholinergic neurons is discussed in the light of this example; specifically, it is proposed that high acetylcholinesterase activity 4–8 h after this pretreatment is a necessary, but not sufficient, criterion for the identification of cholinergic perikarya.The neurons in question appear to be homologous to the nucleus basalis of the substantia innominata of primates, and are thus termed ‘nucleus basalis magnocellularis’ in the rat. No evidence was obtained to support the hypothesis that nucleus of the diagonal band projects to neocortex. However, striking similarities in size and acetylcholinesterase activity were observed among the putative cholinergic perikarya of the nucleus basalis magnocellularis, the nucleus of the diagonal band, and the medial septal nucleus.Kainic acid lesions of the neocortex produced uniform and complete destruction of neuronal perikarya. These lesions decreased neocortical glutamic acid decar?ylase activity, suggesting that there are GABAergic perikarya in the neocortex. However, the same lesions did not affect neocortical choline acetyltransferase. This observation suggests that there are no cholinergic perikarya in the neocortex, a conclusion that is consistent with the absence of intensely acetylcholinesterase-reactive neurons in the neocortex.     

Cortical projections arising from the basal forebrain: a study of cholinergic and noncholinergic components employing combined retrograde tracing and immunohistochemical localization of choline acetyltransferase

The neurochemical identity of ascending putative cholinergic pathways from the rat basal forebrain was investigated employing a method for simultaneously visualizing choline acetyltransferase immunoreactivity and retrogradely transported horseradish peroxidase-conjugated wheatgerm agglutinin. This histochemical procedure revealed three distinct populations of neurons: (1) cells which stained only for choline acetyltransferase immunoreactivity; (2) cells which stained only for retrograde tracer and (3) cells which stained simultaneously for choline acetyltransferase immunoreactivity and retrograde tracer. The results demonstrated that this projection is topographically organized and consists of both cholinergic and noncholinergic components. The relative contribution of each component varied with the telencephalic target area as follows: the olfactory bulb receives a projection from cells of the horizontal limb nucleus, 10-20% of which are cholinergic (Ch3); the hippocampal formation receives afferents from cells of the medial septal and vertical limb nuclei, 35-45% of which are cholinergic (Ch1 and Ch2); and the cortical mantle receives afferents primarily from cells within the substantia innominata-nucleus basalis complex, 80-90% of which are cholinergic (Ch4). The topographical organization of Ch4 projections is not as completely differentiated as we have previously observed in the primate.     

A lectin horseradish peroxidase study of the origin of ascending fibers in the medial forebrain bundle of the rat. The lower brainstem

The origins of projections within the medial forebrain bundle from the lower brainstem were examined with the horseradish peroxidase technique. Labeled cells were found in at least 15 lower brainstem nuclei following injections of a conjugate or horseradish peroxidase and wheat germ agglutinin at various levels of the medial forebrain bundle. Dense labeling was observed in the following cell groups (from caudal to rostral): A1 (above the lateral reticular nucleus); A2 (mainly within the nucleus of the solitary tract); a distinct group of cell trailing ventrolaterally from the medial longitudinal fasciculus at the level of the rostral pole of the inferior olive; raphe magnus; nucleus incertus; dorsolateral tegmental nucleus (of Castaldi); locus coeruleus; nucleus subcoeruleus; caudal part of the dorsal (lateral) parabrachial nucleus; and raphe pontis. Distinct but light labeling was seen in raphe pallidus and obscurus, nucleus prepositus hypoglossi, nucleus gigantocellularis pars ventralis, and the ventral (medial) parabrachial nucleus. Sparse labeling was observed throughout the medullary and caudal pontine reticular formation. Several lower brainstem nuclei were found to send strong projections along the medial forebrain bundle to very anterior levels of the forebrain. They were: A1, A2, raphe magnus (rostral part), nucleus incertus, dorsolateral tegmental nucleus, raphe pontis and locus coeruleus. With the exception of the locus coeruleus, attention has only recently been directed to the ascending projections of most of the nuclei mentioned above. Evidence was reviewed indicating that fibers from lower brainstem nuclei with ascending medial forebrain bundle projections distribute to widespread regions of the forebrain.It is concluded from the present findings that several medullary cell groups are capable of exerting a direct effect on the forebrain and that the medial forebrain bundle is the major ascending link between the lower brainstem and the forebrain.     

胞二磷胆碱治疗轻度脑梗塞急性期52例的疗效分析

目的　探讨在轻、中度脑梗塞急性期使用胞二磷胆碱的临床疗效。方法　本文选择轻度脑梗塞急性期5 2例 ,在使用抗凝、溶栓治疗的基础上加用胞二磷胆碱作治疗组 ,另选择 31例不加用胞二磷胆碱作对照组进行临床疗效观察。治疗组使用胞二磷胆碱 0 .5加入 10 %葡萄糖注射液 2 5 0ml,一日一次 ,静滴 ,十天为一疗程 ,连用 1-3个疗程。结果　治疗组有效率为 92 .31% ,其中显效率 36 .5 4% ;对照组 5 4.84% ,显效率 16 .13% ,显著低于治疗组 (P <0 .0 1)。疗程观察以第三个疗程为宜 ,其有效率占治疗组有效率的 5 8.33%。结论　胞二磷胆碱在脑梗塞急性期使用 ,主要是促进脑梗塞可逆性组织损伤的恢复 ,防止脑缺血后改变的加重 ,使脑细胞活化 ,促进脑细胞机能的修复 ,是一种既安全可靠 ,又经济实用的脑细胞活化剂。     

Embryonic development of four different subsets of cholinergic neurons in rat cervical spinal cord

The developmental stage at which a neuron becomes committed to a neurotransmitter phenotype is an important time in its ontogenetic history. The present study examines when choline acetyltransferase (ChAT) is first detected within each of four different subsets of cholinergic neurons previously identified in the cervical enlargement of the spinal cord: namely, motor neurons, partition cells, central canal cluster cells, and dorsal horn neurons. By examining the temporal sequence of embryonic development of these cholinergic neurons, we can infer the relationships between ChAT expression and other important developmental events. ChAT was first detected reliably on embryonic day 13 (E13) by both biochemical and immunocytochemical methods, and it was localized predominantly within motor neurons. A second group of primitive-appearing ChAT-positive cells was detected adjacent to the ventricular zone on E14. These neurons seemed to disperse laterally into the intermediate zone by E15, and, on the basis of their location, were tentatively identified as partition cells. A third group of primitive ChAT-immunoreactive cells was detected on E16, both within and around the ventral half of the ventricular zone. By E17, some members of this "U"-shaped group appeared to have dispersed dorsally and laterally, probably giving rise to dorsal horn neurons as well as dorsal central canal cluster cells. Other members of this group remained near the ventral ventricular zone, most likely differentiating into ventral central canal cluster cells. Combined findings from the present study and a previous investigation of neurogenesis (Phelps et al.: J. Comp. Neurol. 273:459-472, '88), suggest that premitotic precursor cells have not yet acquired the cholinergic phenotype because ChAT is not detectable until after the onset of neuronal generation for each of the respective subsets of cholinergic neurons. However, ChAT is expressed in primitive bipolar neurons located within or adjacent to the germinal epithelium. Transitional stages of embryonic development suggest that these primitive ChAT-positive cells migrate to different locations within the intermediate zone to differentiate into the various subsets of mature cholinergic neurons. Therefore, it seems likely that spinal cholinergic neurons are committed to the cholinergic phenotype at pre- or early migratory stages of their development. Our results also hint that the subsets of cholinergic cells may follow different migration routes. For example, presumptive partition cells may use radial glial processes for guidance, whereas dorsal horn neurons may migrate along nerve fibers of the commissural pathway. Cell-cell interactions along such diverse migratory pathways could play a role in determining the different morphological, and presumably functional, phenotypes expressed by spinal cholinergic neurons.     

中药复方962对老龄大鼠皮质胆碱乙酰转移酶和乙酰胆碱酯酶活性的影响

为研究中药复方 962胶囊对老龄大鼠皮质胆碱乙酰转移酶 (ChAT)和乙酰胆碱酯酶 (AchE)活性的影响 ,将2 2月龄和 2 4月龄Wistar大鼠分为青年对照组、老年模型组、阳性对照脑复康组 ( 0 .56g/kg)、962中剂量组 ( 0 .9g/kg)和 962大剂量组 ( 1 .8g/kg) 5组 ,分别灌胃给药 1～ 2个月后处死大鼠。用Fonnun法和羟胺比色法分别测定 5组大鼠皮质的ChAT和AchE的活性。结果 :中药复方 962大剂量 ( 1 .8g/kg)对老龄大鼠皮质ChAT活性有提高作用 (P <0 .0 5) ,但对AchE无显著影响。提示 :中药复方 962可能通过影响老龄大鼠中枢胆碱能神经系统而改善其衰老的变化     

Activation of the reticulothalamic cholinergic pathway by the major metabolites of aniracetam

The aim of the study was to further investigate the effects of aniracetam, a cognition enhancer, and its metabolites on the brain cholinergic system. We measured choline acetyltransferase activity and acetylcholine release using in vivo brain microdialysis in stroke-prone spontaneously hypertensive rats (SHRSP). The enzyme activity in the pons–midbrain and hippocampus, and basal acetylcholine release in the nucleus reticularis thalami were lower in SHRSP than in age-matched Wistar Kyoto rats, indicating central cholinergic deficits in SHRSP. Repeated treatment of aniracetam (50 mg/kg p.o.×11 for 6 days) preferentially increased the enzyme activity in the thalamus, whereas decreased it in the striatum. Among the metabolites of aniracetam, local perfusion of N-anisoyl-γ-aminobutyric acid (GABA, 0.1 and/or 1 μM) and p-anisic acid (1 μM) into the nucleus reticularis thalami, dorsal hippocampus and prefrontal cortex of SHRSP produced a significant but delayed increase of acetylcholine release. We failed, however, to find any effect of aniracetam itself. A direct injection of N-anisoyl-GABA (1 nmol) into the pedunculopontine tegmental nucleus of SHRSP enhanced the release in the nucleus reticularis thalami. Thus, these data prove that aniracetam can facilitate central cholinergic neurotransmission via both metabolites. Based on its pharmacokinetic profile, N-anisoyl-GABA may contribute to the clinical effects of aniracetam, mainly by acting on the reticulothalamic cholinergic pathway.     

Autoradiography of 14C-choline uptake in endplates and skeletal muscle of mice

Summary The uptake of ¹⁴C-choline into the axonal part of the motor endplate and muscle of mouse diaphragms was investigated by autoradiography. With i. v. doses of 0.1 g/g choline chloride, the uptake into the nerve endings is fast (<2 min) and into muscle slower (>2 min). With higher doses (1.0 g/g) the uptake into muscle tissue is accelerated.The radioactivity in the endplates decreases with a halflife time of 20 min and remains constant in the muscle fibres over 60 min. Denervation by cutting the phrenic nerve reduces the uptake into endplates by 40% within 14 h, but probably induces uptake into regenerating Schwann cells during 30 days. Some compounds with choline-like structure (hemicholinium-3, decamethylen-dicholine, triethyl-choline) reduce the high-affinity uptake of choline into the nerve endings with sublethal doses, whereas tetraethylammonium and N-hydroxyethyl-4-(1-naphthylvinyl)-pyridinium, an inhibitor of cholinacetyltransferase, are less active. Half lethal doses of cocaine, imipramine and reserpine have no significant action on uptake of choline into the endplates. Chlorpromazine slightly diminishes the uptake into endplates. Chlorpromazine and imipramine reduce uptake into the muscle fibres.     

高效液相色谱法固相酶检测系统测试生物样本中胆碱与乙酰胆碱的研究

以大孔径玻璃微粒为载体,将生物酶化学键合于玻璃体,制备成Φ5×50mm短柱串联于色谱分离柱后,配合电化学检测器,构建了高效液相色谱固相酶检测平台。采用了AtlantisC18反相色谱柱(一种适用于强极性化合物分析的反相色谱柱)成功分离了胆碱与乙酰胆碱,并特异、灵敏地获取检测信号。研究目标组份在AtlantisC18柱的保留特性,比较了流动相不同组成对酶促反应的影响,优化了色谱条件。色谱条件:AtlantisC18柱,电化检测,流动相:Na2HPO450mmol/L,检测限(S/N=2)在1.1￣3.4pmol以下,绝对回收率均>95.50%,样品日内相对标准差<1.49%。方法精密、准确。