电针足三里穴和侧脑室注射微量吗啡对大鼠丘脑后核中内脏痛神经元电活动的影响

在大鼠的丘脑后核(PO)中观察了电针足三里穴和侧脑室注射微量吗啡对内脏痛兴奋神经元电活动的影响。结果提示,电针可抑制大多数的内脏痛兴奋神经元的电活动,使这些神经元自发放电减少或消失,内脏痛和躯体痛反应减弱或完全消失。侧脑室注射微量吗啡也能抑制内脏痛兴奋神经元的电活动,其抑制作用与电针相似。     

5'-FITC标记的PCNA反义寡核苷酸在人膀胱癌细胞BIU-87中的分布及稳定性分析

目的观察硫代修饰型及天然型PCNA反义寡核苷酸在脂质体介导下或直接转染人膀胱癌细胞BIU-87后在细胞内的分布及其稳定性。方法将异疏氰酸荧光素（5＇－FITC）标记的18mer硫代磷酸化修饰型及未修饰型PCNA反义寡核苷酸在脂质体介导下或直接转染人膀胱癌细胞BIU－87，应用荧光显微镜观察转染细胞从细胞内的时相分布。结果修饰型反义核酸直接转染细胞后30分钟，少数细胞胞浆荧光呈离散型、点状分布，4小时后有少数细胞胞核有强荧光聚积。在脂质体介导下，荧光细胞数目明显增加，4小时后绝大多数细胞迅速积聚于细胞核，4～8小时后，细胞核内荧光强度进一步增强，12小时后细胞荧光减弱甚至消失。而非修饰型反义核酸在直接转染或脂质体介导下均发现荧光在3小时后消失。结论脂质体增加PCNA修饰型反义寡核苷酸与膀胱癌细胞BIU－87结合的数量，同时使其在细胞核内分布聚积明显；PCNA反义寡核苷酸硫代修饰具有更好的稳定性。     

Brainstem terminations of extraocular muscle primary afferent neurons in the monkey

The central terminations of afferent nerve fibers from the extraocular muscles of the monkey were investigated by means of transganglionic transport of wheat germ agglutinin-conjugated horseradish peroxidase (WGA/HRP). Following injections of selected extraocular muscles with WGA/HRP, terminal labeling was apparent in the ipsilateral trigeminal sensory and cuneate nuclei. The density of trigeminal projections varied markedly from one rostrocaudal level to the next, being heaviest within the ventrolateral portion of pars interpolaris of the spinal trigeminal nucleus. A second extraocular muscle afferent representation was noted in ventrolateral portions of the cuneate nucleus. This projection was restricted to rostral portions of pars triangularis of the cuneate nucleus, partially overlapping the afferent termination from dorsal neck muscles. It is likely that some of the problems encountered in formulating conclusions regarding the functional role of extraocular muscle proprioception are due to a lack of detailed information of the central termination pattern of muscle afferents. Taken together, the present findings should provide a basis for further anatomical and physiological studies designed to elucidate the role played by extraocular muscle proprioceptors in vision and oculomotor control.     

Identification of glycinergic synapses in the cochlear nucleus through immunocytochemical localization of the postsynaptic receptor

The distribution and morphology of glycinergic synapses in the cochlear nucleus were investigated using monoclonal antibodies against the glycine receptor. Glycine receptor immunoreactivity was seen on somas and proximal processes of most cells in all divisions of the cochlear nucleus; distribution of label in neuropil was denser in the dorsal cochlear nucleus and granule cell cap than in the ventral cochlear nucleus. At the ultrastructural level, glycine receptor immunoreactivity was specifically distributed postsynaptically to terminals that contained flattened vesicles in the guinea pig anteroventral cochlear nucleus. These studies show that the immunocytochemical localization of the glycine receptor can provide a means of identifying and characterizing glycinergic synapses throughout the central nervous system.     

Biogenic Amine and Corticotrophin-Releasing Factor Concentrations in Hypothalamic Paraventricular Nucleus and Biogenic Amine Levels in the Median Eminence of Normal Dogs, Chronic Dexamethasone-Treated Dogs, and Dogs with Naturally-Occurring Pituitary-Dependent Hyperadrenocorticism (Canine Cushing's Disease)

We measured dopamine, norepinephrine, serotonin and epinephrine concentrations in the paraventricular nucleus and median eminence, and corticotrophin-releasing factor levels in the paraventricular nucleus. Tissue was isolated by micropunch technique from hypothalami of normal dogs, dogs treated for one week with dexamethasone (1 mg/kg/day) and dogs with spontaneous pituitary-dependent hyperadrenocorticism. Concentrations of corticotrophin-releasing factor and most of the neurotransmitters were found to be similar between our three groups of dogs. However, we found the mean dopamine concentration in the median eminence tissue to be significantly decreased in dogs with Cushing's disease and in steroid-treated dogs. Epinephrine levels were elevated in the hypothalamic paraventricular nucleus of steroid-treated dogs.     

Expression of “retinal” contrast gain control by neurons of the cat's lateral geniculate nucleus

Summary This paper describes the temporal tuning of cells in the lateral geniculate nucleus of the cat (27 X cells, 51 Y cells) and how this changes with stimulus contrast. Drifting sinusoidal gratings of optimal spatial frequency were presented at 7 temporal frequencies (0.5, 1, 2, 4, 8,16 and 32 Hz) and 4 contrasts (10, 20, 40, 80%). For some cells response growth at all temporal frequencies was proportional to changes in contrast. Thus, their temporal tuning functions, on log-log axes, were displaced vertically with increasing contrast. This shift also largely characterizes the response to low temporal frequencies of the other neurons studied. For these other cells, however, responses to high temporal frequencies grew disproportionately large with increasing contrast generally causing their tuning functions to change shape. Typically the peaks of these functions shifted to higher frequencies at higher contrasts. Most of the X cells studied displayed behavior of the first type, while Y cells usually followed the second pattern. This qualitative impression was confirmed quantitatively. Cubic spline functions were fit to the temporal tuning functions obtained at different contrast levels and the peaks of the curves were extracted. X and Y cells preferred similar temporal frequencies at low contrast levels (X mean=8.1 Hz; Y mean=8.4 Hz) but Y cell values were significantly higher at higher contrasts (80%) (X mean= 12.0 Hz; Y mean=16.8 Hz). These contrast-dependent changes in the temporal characteristics of geniculate cells resemble those described for retinal ganglion cells by Shapley and Victor (1978 and subsequent). Thus, the gain control behavior of geniculate cells probably reflects the temporal properties of their retinal inputs with relatively little modification.     

大鼠尾壳核微量注射锂盐对痛反应的影响

本工作利用慢性埋置导管的方法将氯化锂直接注射于大鼠尾壳核头前区及头中心区,在核团水平分析锂盐影响动物痛阈的机制.结果表明:(1)尾壳核头前区注射锂盐可产生明显的镇痛作用,并可分别被纳洛酮、阿托品、酚妥拉明、心得安、荷包牡丹碱和二乙基麦角酰胺所对抗,但不能被氟哌啶醇所阻断.(2)尾壳核头中心区微量注射锂盐不能产生镇痛作用     

下丘脑背内侧核注射纳洛酮对束旁核痛兴奋单位放电的影响

用玻璃微电极记录大鼠丘脑束旁核痛兴奋单位(PfPE)放电。观察到下丘脑背内侧核(DMH)微量注射纳洛酮(Nx)后:(1)PfPE的自发和痛诱发放电频率增加,时程延长;(2)部份PfPE的自发放电类型由散在单脉冲变成散在间簇状或完全的簇状发放,而窟诱发放电类型由持续性发放转变为间断性暴发式放电。本实验提示:DMH局部的内源性阿片肽对PfPE放电活动有抑制性调控作用。     

The subcortical generated somatosensory evoked potentials in non-cephalic,cephalic, and anterior neck referenced recordings in a patient with a cervico-medullary lesion: a clue to the identification of the P14/N14 and N13 generators

Summary Median nerve somatosensory evoked potentials (SEPs) were studied in a patient before and after the development of a cervico-medullary lesion. The first examination demonstrated normal subcortical generated potentials N13 and N14. The second examination, following a subarachnoid haemorrhage at the cervico-medullary junction, displayed a delayed and reduced amplitude P14/N14 peak on both sides. P14/N14 showed the same latency in all montages, using noncephalic, cephalic and anterior neck references. The N13 component was not significantly changed in latency compared with the first examination. The latencies of the N13 peak were variable in the different montages. They increased from the lower (C7) to the upper (C2) neck, whereas the latency of the N13 onset was identical in all montages. This alteration might be caused by a delayed near-field activity at C2 overlapping the N13 component. These results fit the hypothesis of two major generators responsible for subcortical SEPs; a near-field N13 component at the level of the lower neck and a far-field P14 component arising from the level of the cervico-medullary junction. An additional minor near-field activity generated by the cuneate nucleus is suspected.