Location of motoneurones projecting to the cat distal forelimb. II. Median and ulnar motornuclei

The position of the motornuclei projecting through the median (Mn) and ulnar (Ul) nerves to the cat distal forelimb has been investigated. Horseradish peroxidase (HRP) and fluorescent (Fl) compounds have been used as retrograde tracers. They were either injected into forelimb muscles or applied to the proximal end of transected forelimb nerves. Limb muscles that were not investigated were carefully denervated. The position and the architecture of the individual motornuclei were traced with HRP. The topographical relations between the nuclei were established with application of up to three different Fl compounds in the same animal. The Mn motoneurones had a bimodal distribution in the brachial spinal cord. The motoneurones to the pronator teres and flexor carpi radialis muscles were located in C7 and the other Mn motoneurones were located in C8 and Th1. In C7 the Mn motoneurones occupied a single representation area, which is located some distance medially of the lateral funiculus. In C8 and Th1 two Mn representation areas were found: A dorsal one that contacts the lateral funiculus and is located at the level of the central canal; a ventral one that is located ventrally in the ventral horn. The dorsal area is occupied by the motornuclei projecting to the intrinsic hand muscles and the ventral one by the nuclei projecting to the limb. The Ul motoneurones extend with an unimodal distribution from the caudal C7 to the caudal Th1 segments. They occupy a single, broad representation area. The dorsal part, which contacts the lateral funiculus, is located at the level of the central canal and harbours the nuclei to the intrinsic hand muscles. The other Ul nuclei are located ventromedially deep in the ventral horn. These results, together with those from the companion paper on the location of the deep radial motornuclei, provide important anatomical information for the investigation of the cat brachial enlargement.     

Peripheral innervation patterns of vestibular nerve afferents in the bullfrog utriculus

Vestibular nerve afferents innervating the bullfrog utriculus differ in their response dynamics and sensitivity to natural stimulation. They also supply hair cells that differ markedly in hair bundle morphology. To examine the peripheral innervation patterns of individual utricular afferents more closely, afferent fibers were labeled by the extracellular injection of horseradish peroxidase (HRP) into the vestibular nerve after sectioning the vestibular nerve medial to Scarpa's ganglion to allow the degeneration of sympathetic and efferent fibers. The peripheral arborizations of individual afferents were then correlated with the diameters of their parent axons, the regions of the macula they innervate, and the number and type of hair cells they supply. The utriculus is divided by the striola, a narrow zone of distinctive morphology, into medial and lateral parts. Utricular afferents were classified as striolar or extrastriolar according to the epithelial entrance of their parent axons and the location of their terminal fields. In general, striolar afferents had thicker parent axons, fewer subepithelial bifurcations, larger terminal fields, and more synaptic endings than afferents in extrastriolar regions. Afferents in a juxtastriolar zone, immediately adjacent to the medial striola, had innervation patterns transitional between those in the striola and more peripheral parts of the medial extrastriola. Most afferents innervated only a single macular zone. The terminal fields of striolar afferents, with the notable exception of a few afferents with thin parent axons, were generally confined to one side of the striola. Hair cells in the bullfrog utriculus have previously been classified into four types based on hair bundle morphology (Lewis and Li: Brain Res. 83:35–50, 1975). Afferents in the extrastriolar and juxtastriolar zones largely or exclusively innervated Type B hair cells, the predominant hair cell type in the utricular macula. Striolar afferents supplied a mixture of four hair cell types, but largely contacted Type B and Type C hair cells, particularly on the outer rows of the medial striola. Afferents supplying more central striolar regions innervated fewer Type B and larger numbers of Type E and Type F hair cells. Striolar afferents with thin parent axons largely supplied Type E hair cells with bulbed kinocilia in the innermost striolar rows. © 1994 Wiley-Liss, Inc.     

A projection from the entorhinal cortex to the nucleus accumbens in the rat

A study was performed in which both anterograde ([³H]leucine radioautography) and retrograde (horseradish peroxidase (HRP) histochemistry) tracing methods were employed to identify the origin of the fimbrial projection to the nucleus accumbens in the rat. The data reveal that this pathway arises predominantly from layers II–III of the anterior two-thirds of entorhinal cortex rather than from any part of hippocampal formation.     

Sources of subcortical projections to the superior colliculus in the ferret

We have identified brainstem and other subcortical afferents to the superior colliculus (SC) in the ferret, by examining the pattern of retrograde labelling that resulted from unilateral injections of red and green fluorescent latex microspheres or of wheat germ agglutinin conjugated to horseradish peroxidase into different regions of this midbrain nucleus. Labelled neurons were found in many structures, including somatosensory, visual and auditory nuclei. These subcortical inputs are almost all bilateral, although most are primarily ipsilateral. Despite some differences in organization, the subcortical projections to the ferret SC broadly resemble those described in other species. Following injections of red and green microspheres in either the rostral and caudal or the medial and lateral regions of the SC, double-labelled cells usually accounted for less than 10% of the total number of retrogradely labelled cells, indicating that most of the subcortical neurons project to discrete regions of the SC. Many of these afferents show some topographic organization, which is much more evident along the rostrocaudal axis of the SC than in the medial-lateral dimension. The intercollicular projection is restricted mainly to the rostral SC and demonstrates a point-to-point organization. Most of the subcortical structures caudal to the central region of the SC were labelled mainly by the tracers injected in caudal SC, while those rostral to this region, including the zona incerta and the pretectal nuclei, were labelled largely by injections in rostral SC. These findings suggest that projections originating from nuclei posterior to the central region of the SC terminate principally in caudal SC whereas afferents from structures anterior to the central region project largely to rostral SC.     

Organization of the cerebellum in the pigeon (Columba livia): II. Projections of the cerebellar nuclei.

The projections of the deep cerebellar nuclei in the pigeon have been delineated using autoradiographic and histochemical (WGA-HRP) tracing techniques. A medial (CbM) and lateral (CbL) cerebellar nucleus are recognized and CbM may be further partitioned into internal, intermediate, and intercalate divisions. As in mammals, most extracerebellar projections of CbM travel in the fasciculus uncinatus (FU); the rest travel with those of CbL in the brachium conjunctivum (BC). In the pigeon, both of these pathways are bilaterally but primarily contralaterally projecting systems. FU is a predominantly descending tract, with terminations within (1) the vestibular complex, (2) a column of contiguous medial reticular nuclei from pontine to caudal medullary levels; (3) the plexus of Horsley portion of the parvicellular reticular formation, continuing through the nucleus centralis medullae oblongatae, pars dorsalis, into intermediate layer VII of the cervical spinal cord, down to cervical segment 8-9; (4) the lateral reticular nucleus and the paragigantocellular reticular nucleus; (5) the dorsal lamella of the inferior olive. Rostrally FU terminals are found in the locus ceruleus and dorsal subcerulean nucleus. Minimal FU projections are also seen to the motor trigeminal nucleus and the subnucleus oralis of the descending trigeminal system. A small projection from the intercalate division of CbM travels in BC and projects upon the midbrain central grey, the intercollicular nucleus, the lateral tectal periventricular grey, the stratum cellulare externum and, sparsely, upon the dorsolateral thalamus. The bulk of BC originates from the lateral cerebellar nucleus and consists of a massive ascending and a small descending branch. The ascending system projects upon the red nucleus and the dorsally adjacent interstitial nucleus of Cajal and midbrain central grey, the prerubral fields continuing into the stratum cellulare externum, the nucleus intercalatus thalami, the ventrolateral thalamic nucleus, the medial spiriform nucleus, the nucleus principalis precommissuralis, the nucleus of the basal optic root, the nucleus geniculatus lateralis pars ventralis, the dorsolateral thalamus, including the dorsal intermediate posterior, and the dorsolateral intermediate and anterior nuclei. BC also contains axons from the infracerebellar nucleus, which projects upon the trochlear and the oculomotor nuclei. The descending branch of BC distributes to the papilioform nucleus, the medial pontine nucleus, the gigantocellular and paramedian reticular nuclei, and, minimally, the rostral portions of the medial column and ventral lamella of the inferior olive. Taken in conjunction with data on amphibia and reptiles the present findings suggest that the fundamental ground plan of vertebrate cerebellar organization involves a medial and lateral cerebellar nucleus.(ABSTRACT TRUNCATED AT 400 WORDS)     

The pelvic innervation in the rat: different spinal origin and projections in Sprague-Dawley and Wistar rats

WGA-HRP was applied to the pelvic and pudendal nerves of Sprague-Dawley and Wistar rats to compare the segmental levels of the resulting labeling. L₆ and S₁ were the segme its at which the sacral parasympathetic nucleus and the denser primary afferents occurred in Sprague-Dawley rats. The levels found in Wistar rats were S₁ and S₂, Thus indicating a disparity between both strains of rats in the spinal level of the sacral parasympathetic nucleus and the primary afferents.     

次声作用对大鼠大脑皮层脂质过氧化的影响

目的：观察8Hz,130dB次声作用于大鼠不同时间后，大脑皮层脂质过氧化相关指标的变化，以探讨次声引起脑损伤的机理。方法：将35只Ⅱ级、雄性、SD大鼠随机分为对照组和次声作用7d,14d,21d,28d组五组，用8Hz,130dB次声作用，每天1次，每次2h，各组于最后一次作用结束后0．5－1h内取大脑皮层，制成10％的组织匀浆测定GSH－Px活性，MDA含量和SOD活性的变化。结果：与对照组相比，大鼠大脑皮层GSH－Px活性在7d组无显著性变化（P＞0．05），在14d组、21d组、28d组和显著性升高（P＜0．05）；MDA含量在7d组、14d组有显著怀升高（P＜0．05),21d组、28d组恢复至对照组水平（P＞0．05）；SOD活性有下降的趋势，但无显著性意义（P＞0．05）。结论：次声作用后，引发大鼠大脑皮层组织的脂质过氧化－抗氧化反应，造成脑组织的损伤。     

Thyroid peroxidase identified in human granulosa cells: another piece to the thyroid-ovary puzzle?

Thyroid hormones seemingly influence the maturation of the human oocyte. Thyroid hormone receptors have been isolated in granulosa mural and cumulus cells and the mature oocyte of the human ovarian follicle. Thyroid hormones are present in follicular fluid in concentrations similar to those in serum. Most importantly, enzymes involved in the chain that regulate the generation of thyroid hormones have been found in granulosa cells. For the first time, we have isolated thyroid peroxidase by immunocytochemistry in the granulosa cumulus cells of the human ovarian follicle, thereby supporting the hypothesis that the human ovarian follicle may be an independent thyroid-hormone producing unit.     

支气管哮喘患儿红细胞免疫功能与脂质过氧化关系的探讨

目的 :探讨了支气管哮喘患儿红细胞免疫功能的变化及其与脂质过氧化的关系。方法 :应用红细胞酵母花环法测定了 32例支气管哮喘患儿红细胞免疫功能和化学比色法测定血浆丙二醛 (MDA) ,超氧化物歧化酶 (SOD) ,谷胱甘肽过氧化物酶 (GSH -PX)含量 ,并与 35名正常健康儿童作对照。结果 :支气管哮喘患儿RBC-IC花环率和MDA水平明显地升高 (P <0 .0 1 ) ,而RBC -C3bR、SOD、GSH -PX、SOD/MDA低于正常 (P <0 .0 1 ) ,相关分析显示 :RBC -C3b花环与MDA呈显著的负相关 (r=- 0 .4 30 7,P <0 .0 5 ) ,RBC -ICR与MDA呈正相关 (r=0 .6 384 ,P <0 .0 1 )。结论 :支气管哮喘患儿红细胞免疫粘附功能降低 ,与活性氧代谢紊乱密切相关