猫颈部食管的交感神经支配—HRP法

用5只猫于左侧颈部食管壁内注入 HRP 溶液,通过 HRP 逆行追踪法研究颈部食管的交感神经支配,结果表明:1.长轴突型交感节前神经元直接分布到食管壁内,其标记细胞位于双侧脊髓的胸1～3节段,以胸2节段最多(占标记细胞总数的66.45％),注射侧占优势。标记细胞主要位于中间带外侧核(约占95.02%),其次为侧索、中介核、前角腹后外侧核。其细胞形态不一,以中小型细胞为主(占标记细胞总数的90.4％)。2.支配颈部食管的交感节后神经元主要位于星状神经节(约占61.99％),余者位于双侧颈前、中和2～5胸交感节内、以小细胞最多。     

Morphology of corticotectal cells in the primary visual cortex of hooded rats

In primary visual cortex of hooded rats, pyramidal cells in layer V may be classified as long, medium, or short, on the basis of the layer in which the apical dendrite terminates. The present study determines which of these types of pyramidal cells project to the superior colliculus. Two different strategies were used to label corticotectal cells with horseradish peroxidase (HRP). In the first set of experiments, a large number of corticotectal cells were labeled by retrograde transport following injection of HRP into the superior colliculus. In the second set of experiments, single unit recording was used to identify corticotectal cells physiologically by antidromic activation from the superior colliculus. These cells were then impaled and labeled by intracellular iontophoresis of HRP. The results from both techniques suggest that only long pyramidal cells send an axon to the superior colliculus. These cells are distinguished by an apical dendrite that extends into layer I. We conclude that in hooded rats corticotectal cells in primary visual cortex are the long pyramids in layer V.     

Morphological assessment in pinealectomy and foetal pineal gland transplantation in rats: Part I

Summary The effects of pineal gland, an endocrine organ known to affect the physiology of various organs and systems including the hypothalamo-hypophyseal axis, on the morphological characteristics of target organs were investigated in rats after pinealectomy and foetal pineal gland transplantation to a subpial cortical area close to the pinealectomized region.It was demonstrated that weight gain was significantly slower in pinealectomized male rats (p<0.01); pituitary gland weight was lower in the pinealectomized group (p<0.01) and transplantation had no effect on the weight of this organ; weight of adrenal gland and testis were lower after pinealectomy (p<0.01) but restored back to control levels after transplantation; the mitotic activity in seminiferous tubules increased with pinealectomy and returned back to control indexes after transplantation.Research on hypothalamic catecholaminergic content revealed a diminished histofluorescence in pinealectomized rats which showed a potentiated restoration after transplantation.The innervation of the pineal gland was studied by anterograde and retrograde injections of Wheat Germ Agglutinin Horse Radish Peroxidase from superior cervical ganglion and pineal gland, respectively. It was demonstrated that cell bodies were traced both at the transplanted tissue and hypothalamus.In view of these data, the multifunctional and a probable high level homeostatic harmony regulator essence of pineal gland is discussed.The paper has been awarded the 1993 Upjohn prize for Neurosurgical Research of the European Association of Neurosurgical Societies.     

Difference in projections to the lateral and medial facial nucleus: anatomically separate pathways for rhythmical vibrissa movement in rats

Summary The present paper demonstrates that the lateral and medial subdivisions of the rat facial motor nucleus (NVII) receive differing mesencephalic and metencephalic projections. In order to study brain projections to facial nucleus, horseradish peroxidase (HRP) was injected iontophoretically into the entire facial nucleus or the following subdivisions: lateral, dorsolateral, medial, intermediate, and ventral. In the mesencephalic region, the retrorubral nucleus was found to project to the contralateral medial subdivision of NVII, while the red nucleus was found to project to the contralateral lateral subdivision of NVII. Other mesencephalic projections to the facial nucleus arose from the deep mesencephalic nucleus, oculomotor nucleus, central gray including inter stitial nucleus of Cajal and nucleus Darkschewitsch, superior colliculus and substantia nigra (reticular). In the metencephalic region, the Kölliker-Fuse nucleus, parabrachial nucleus, and the ventral nucleus of the lateral lemniscus projected mainly to the ipsilateral lateral subdivision of NVII. In addition, the trapezoid, pontine reticular, vestibular, and motor trigeminal nuclei were observed to have predominantly ipsilateral connections to the facial nucleus. In contrast, projections from the myelencephalic region were to both the lateral and medial subdivision of NVII. The medullary reticular nucleus, ambiguus nucleus, spinal trigeminal nucleus and parvocellular reticular nucleus projected to both lateral and medial subdivisions of NVII with an ipsilateral predominance. The gigantocellular and paragigantocellular reticular nuclei, raphe magnus, external cuneate nucleus and the nucleus of the solitary tract also projected to the facial motor nucleus. Surprisingly, no direct projections to the NVII were observed from diencephalic and telencephalic regions. Our findings that the lateral subdivision of NVII which innervates vibrissa-pad-muscles (Dom et al. 1973; Martin and Lodge 1977; Watson et al. 1982) receives different metencephalic and mesencephalic projections than medial subdivision which controls pinna movement (Henkel and Edwards 1978), suggest that the functional difference between these subdivisions is mediated by the anatomically separate pathways. We confirmed our anatomical findings by eliciting exclusively vibrissa responses by electrical stimulation of the nuclei which project to the lateral subdivision of NVII.     

大鼠孤束核含酪氨酸羟化酶、神经降压素和胆囊收缩素样神经元向伏核的投射—HRP和免疫细胞化学双重标记法的研究

本文应用HRP顺、逆行追踪法结合免疫细胞化学双重标记法,对大鼠孤束核向伏核的投射进行了研究。主要结果如下:1.WGA-HRP注入孤束核尾侧段,在伏核后部的腹、内侧区,出现较密集的标记纤维、终末和标记细胞;将HRP注入伏核后部的腹、内侧区,在孤束核尾侧段(主要在连合核和内侧亚核)出现大量的顺、逆行标记,以同侧为主。2.HRP注射到伏核并结合免疫细胞化学反应,在孤束核尾侧段发现HRP-TH,HRP-NT、HRP-CCK双重标记细胞。HRP-TH的数目最多,其次是HRP-NT双标细胞,HRP-CCK双标细胞最少。     

雄性大白鼠球海绵体肌和坐骨海绵体肌的运动神经元—HRP法研究

本实验用HRP注射于大白鼠的一侧球海绵体肌和坐骨海绵体肌后,在脊髓腰骶段的不同平面可观察到支配该两肌的运动神经元胞体出现标记并具有一定的局部定位关系。支配球海绵体肌的运动神经元主要位于L_5～S_1的背内侧群,而支配坐骨海绵体肌的运动神经元主要位于背外侧群和腹侧群。本文认为大白鼠腰骶段前角背内侧群和背外侧群同腹外侧群细胞一样,同属于Onuf's核的同源神经细胞。本文还观察了大白鼠腰骶段脊髓前柱细胞的配布。     

Neuronal migration and dendritic maturation of the medial cerebellar nucleus in rat embryos: an HRP in vitro study using cerebellar slabs

The morphological maturation of medial nuclear neurons of fetal rat cerebella was studied using an in vitro assay. Neurons of this nucleus were identified in isolated preparations of rhombencephalon between embryonic days 16 and 20 (E16-E20) by the intracerebellar decussation of their outgrowing axons within the uncinate fascicle. A small crystal of horseradish peroxidase (HRP) applied either in the region containing the inferior cerebellar peduncle or, preferably, in the lateral cerebellum retrogradely labeled contralateral medial nuclear neurons. In the youngest embryos (E16-E17), HRP-marked neurons were situated rostrally at the dorsal surface of the cerebellum. By E18, the cell mass containing labeled neurons had shifted in a rostrocaudal and dorsoventral direction and finally reached the adult position in E19-E20 embryos. Dendritic differentiation of these neurons followed a similar positional gradient, closely corresponding to the pattern of temporal development. From the most immature monopolar forms located dorsally to the virtually adult stellate neurons in a ventral position, it was possible to trace a continuum of intermediary forms grouped into six well-defined stages. Immature monopolar cells first became transversely bipolar. Then, they changed orientation, assuming a longitudinal radial direction. During this stage, neurons sank into the cerebellar parenchyma. As they reached their final destination, these neurons gradually developed dendrites which radiated from the cell body in an adult-like pattern. It is concluded that the medial nuclear neurons occupy a superficial dorsal position in early phases of cerebellar ontogeny, thereafter undergoing a second, inward migration. The main stages of neuronal dendritic differentiation occur between E16 and E20, indicating that the ingrowth of afferent in puts to the medial nucleus most probably occurs rather early and is concomitant with dendritic development.     

Functional organization of mustached bat inferior colliculus: II. Connections of the FM2 region

Echolocating bats estimate target distance by analyzing the time delay between frequency-modulated portions of their emitted ultrasonic vocalizations and the resultant echoes. In the companion paper we investigated, in the central nucleus of the inferior colliculus, the representation of the predominant second-harmonic frequency-modulated component (FM2) of the mustached bat biosonar signal (O'Neill et al.: J. Comp. Neurol. 283:000-000,'89). In the present paper we report the connections of this part of the colliculus, as determined by focal, iontophoretic injections of HRP following single-unit mapping of the FM2 representation. It was found that the major inputs to the FM2 region of the inferior colliculus come from the contralateral cochlear nucleus; ipsilaterally from the medial superior olive, periolivary nuclei, and ventral and intermediate nuclei of the lateral lemniscus; and bilaterally from the lateral superior olive and dorsal nucleus of the lateral lemniscus. This study identifies for the first time those specific regions of brainstem nuclei providing input to the central nucleus of the inferior colliculus that process FM2 information in the mustached bat. The primary outputs of the FM2 region project to the medial and dorsal divisions of the medial geniculate body. In sharp contrast to other mammals, we found little evidence of connections to the ventral division of the medial geniculate. Other regions receiving significant inputs from the FM2 area include the deep superior colliculus ipsilaterally and the ipsilateral lateral pontine nuclei. Some fibers also terminated near the midline in the dorsal midbrain periaqueductal gray. Sparse intrinsic connections were also seen to the ipsilateral dorsoposterior division of the central nucleus and to the contralateral inferior colliculus at a location homologous to the injection site in the anterolateral division. The finding that FM2 projections to the medial geniculate heavily favor the medial and dorsal divisions is consistent with the location of "FM-FM" delay-dependent facilitation neurons found by Olsen (Processing of Biosonar Information by the Medical Geniculate Body of the Mustached Bat, Pteronotus parnellii. Dissertation, Washington Univ., St. Louis, '86) in these divisions, and with thalamocortical projection patterns in this species. These findings demonstrate that for the FM portions of the biosonar signal, a transformation from a tonotopic form of processing to a more specialized, convergent pattern of organization occurs at the level of the inferior colliculus outputs.     

Morphology of retinal ganglion cells in lungless salamanders (fam. Plethodontidae): an HRP and Golgi study

The family Plethodontidae consists of nearly two-thirds of all living urodeles; most of them possess highly developed visual abilities. We investigated the morphology of retinal ganglion cells (RGCs) in four representative species by means of the horseradish peroxidase method in flatmounts and in transverse sections and with the Golgi method in transverse sections. In flatmount preparations, four classes of RGCs were found, differing in dendritic arborization, dendritic field size, and stratification pattern of dendrites in the inner plexiform layer (IPL). Class-1 cells had small dendritic fields (29-44 microns 2) and arborized throughout the entire depth of the IPL. Class-2 cells had medium to large dendritic fields (75-206 microns 2) and mostly arborized in two or three laminae or in a diffuse fashion in the IPL. Class-3 cells had medium to large dendritic fields (72-200 microns 2) but sparse dendritic arborization. They only arborized in the proximal lamina of the IPL. Class-4 cells had large dendritic fields (273-626 microns 2) and branched in the most sclerad stratum of the IPL. No large differences in intraspecific soma size of the different RGC classes were detected (although interspecific soma size varied to a considerable degree) and no "giant" cells typically found in other vertebrate retinas were present. The results suggest that, with respect to the pattern of arborization and stratification of dendrites, lungless salamanders possess morphological classes of RGC similar to those found in frogs, but the morphology of RGCs in lungless salamanders seems to be simplified in comparison to frog RGCs. This simplification might be a consequence of paedomorphosis.