摘要:

AbstractWith autoradiographic procedures, cells which bind3H‐estradiol were found in preoptic, hypothalamic and limbic structures in the brains of ovariectomized, adult female rhesus monkeys. Estrogen‐binding cells were seen in the medial preoptic area, medial anterior hypothalamus, ventromedial nucleus, and especially heavy labelling was seen throughout the extent of the arcuate (infundibular) nucleus of the hypothalamus. In limbic structures, cells in the bed nucleus of the stria terminalis and in the medial nucleus of the amygdala were well labelled. Systematic charting also revealed smaller numbers of estrogen‐concentrating cells in other specific hypothalamic and limbic locations. In the anterior pituitary, significant numbers of basophils and acidophils were found to bind estrogen. Pars intermedia and the posterior lobe were virtually unlabelled. In the uterus, heavily labelled cells were seen in the endometrial stroma and in the myometrium. These autoradiographic findings agree with results of parallel biochemical experiments.In monkeys injected with3H‐corticosterone, the most extensive high‐intensity binding found with autoradiography was in the hippocampus. Both pyramidal neurons and dentate gyrus granule cells were labelled. Biochemical experiments, also, showed highest cell nuclear accumulation of corticosterone in the hippocampus.Findings with estradiol in the rhesus monkey extend to primates conclusions based on autoradiographic experiments with steroid sex hormones in a wide variety of vertebrates, including fish, amphibians, birds, and various mammalian species (Morrell et al., '75a). All of these vertebrate forms have sex hormone‐concentrating neurons, which are found in specific preoptic, hypothalamic and limbic structures. In the species studied, such hormone‐concentrating neurons appear to be involved in the hormonal control of behavioral and pitui

ISSN:0092-7317    

DOI:10.1002/cne.901700302

出版商:The Wistar Institute of Anatomy and Biology    

年代:1976

数据来源: WILEY

摘要:

AbstractThe accessory optic system of the ferret has been studied both by silver degeneration staining and by autoradiography after intraocular3H leucine injections. There is no anterior accessory optic tract but a posterior tract containing only crossed fibres leaves the brachium of the superior colliculus and ends in the two nuclei, the medial and lateral terminal nuclei, lying either side of the cerebral peduncle. Both suprachiasmatic nuclei receive retinal fibres visible only on autoradiographs; most fibres end in the contralateral nucleus. No other area in the hypothalamus appears to receive retinal fibres demonstrated by these methods.

ISSN:0092-7317    

DOI:10.1002/cne.901700303

出版商:The Wistar Institute of Anatomy and Biology    

年代:1976

数据来源: WILEY

摘要:

AbstractMotor hyperplasia following the enlargement of the periphery by implantation of a supernumerary leg is not due to “remote control” of proliferation, as shown by motor neuron counts in 6‐day chick embryos. We have tested the alternative hypothesis that we are dealing with reduction of the naturally occurring cell death. In normal development, the lumbar lateral motor column (l.m.c.) undergoes motor neuron degeneration resulting in a cell loss of at least 40%, which occurs between six and one‐half and nine and one‐half days. Following transplantation of supernumerary legs, cases selected for vigorous motility showed a numerical difference between experimental and contralateral (control) sides amounting to +11.0% to +27.5%. The transplants were innervated by varying combinations of thoracic and rostral lumbar nerves. We interpret our data in terms of survival of motor neurons which normally would have failed in a competition at the periphery but which were sustained by the enlarged peripheral fields. Our data do not permit a decision between the two alternatives: competition for synaptic sites or for a trophic agent. The surviving motor neurons are not limited to the rostral segments of the motor column but in most instances distributed along its entire rostro‐caudal extent, implying a redistribution of all l.m.c. axons. The term “hyperplasia” is no longer appropriate for the phenomenon under consideration and should be replaced by the term

ISSN:0092-7317    

DOI:10.1002/cne.901700304

出版商:The Wistar Institute of Anatomy and Biology    

年代:1976

数据来源: WILEY

摘要:

AbstractThe axoplasmic retrograde transport of horseradish peroxidase (HRP) from axon terminals to their parent cell bodies and histochemical fluorescence microscopy have been used to study the ipsilateral centrifugal fibers to the olfactory bulbs and anterior olfactory nucleus in the rabbit. Focal injections of peroxidase were placed unilaterally into the main or accessory olfactory bulb or into the anterior olfactory nucleus. In animals with injected HRP confined within the main bulb, perikarya retrogradely labeled with the protein in the ipsilateral forebrain were observed in the anterior prepyriform cortex, horizontal limb of the nucleus of the diagonal band, and far lateral preoptic and rostral lateral hypothalamic areas. Brain stem cell groups that contained HRP‐positive somata include the locus coeruleus and midbrain dorsal raphe nucleus. Except for the prepyriform cortex, the basal forebrain structures with labeled perikarya correlate well with locations of cell bodies containing acetylcholinesterase and choline acetyltransferase. These somata may represent a cholinergic afferent system to the main olfactory bulb. Peroxidase‐labeled cell bodies in the locus coeruleus and midbrain raphe are indicative of noradrenergic and serotonergic innervations respectively of the olfactory bulb. In rabbits in which peroxidase was injected or diffused into the accessory olfactory bulb and anterior olfactory nucleus, HRP‐positive somata were identified in the prepyriform cortex bilaterally, the horizontal limb of the diagonal band nucleus, lateral hypothalamic region, nucleus of the lateral olfactory tract, corticomedial complex of the amygdala, mitral and tufted cell layers of the ipsilateral main olfactory bulb, locus coeruleus, and the midbrain raphe. Evidence for centrifugal fibers to the accessory olfactory bulb from the corticomedial complex of the amygdala, locus coeruleus, and possibly the nucleus of the lateral olfactory tract and midbrain raphe is discussed. A similar distribution of labeled perikarya in the forebrain and brain stem was seen in rats in which peroxidase injected into the main olfactory bulb had spread into the accessory bulb and anterior olfactory nucleus.Histochemical fluorescence microscopy of the main and accessory olfactory bulbs in the rabbit and rat revealed fine caliber, green fluorescent fibers and varicosities predominantly in the granule cell layer and less so among cells in the glomerular layer. In sections through the root of the main olfactory bulb, a similar fluorescence was seen in the deep half of the plexiform layer of the pars externa of the anterior olfactory nucleus. These fluorescent fibers likely represent the noradrenergic innervation of the olfactory bulbar and retrobulbar formations. A fluorescent yellow hue was observed in the glomerular layer of the main bulb and may signify a serotonergic innervation of this lamina.The results of this study provide continued support for the existence of main and accessory olfactory systems and offer greater insight into the organization of the olfactory brain and the interrelationship of the hypothalamus and olfa

ISSN:0092-7317    

DOI:10.1002/cne.901700305

出版商:The Wistar Institute of Anatomy and Biology    

年代:1976

数据来源: WILEY

摘要:

AbstractPhotoreceptor synaptogenesis in the embryonic and hatchling chick retina was studied with conventional EM techniques and ethanolic phosphotungstic acid (E‐PTA). The photoreceptors line up between 11 and 13 embryonic days with their undifferentiated synaptic bases facing the outer plexiform layer (OPL). E‐PTA staining at 11 embryonic days does not reveal any paramembranous specializations of the receptors but numerous stainedpunctae adhaerentesare observed in the OPL. At 13 embryonic days neurites of presumed bipolar and horizontal neurons are aligned parallel to the bases of the receptors and cytoplasmic protrusions of the receptors project between some of these neurites to form dyad appositions. An osmiophilic undercoating, which is not E‐PTA positive at this time, is present on the cytoplasmic face of the receptor membrane in these apposition regions. Between 13 and 15 embryonic days the filopodial protrusions of the receptors continue to elongate further and become aligned with neurites in dyad and triad appositions. The osmiophilic undercoating now extends along the entire inner surface of the receptor pedicle protrusions and becomes E‐PTA positive. Between 15 and 17 embryonic days focal aggregations of osmiophilic and E‐PTA stained material appear along the membranes of the protrusions and there is some E‐PTA staining of the postsynaptic densities and intervening cleft material. Between 17 and 21 embryonic days mature ribbon synapses are observed on the surfaces of the conical‐shaped, receptor pedicles where the ribbons and their synaptic vesicles are associated with the dense aggregations (arciform densities), seen earlier as isolated focal aggregations, and the receptor undercoating is restricted to non‐synaptic regions. E‐PTA staining shows that ribbons are positively stained around their borders only and that they are contiguous with the intensely stained arciform densities. The cleft material and postsynaptic densities of some synapses first stain as V‐shaped junctions and later as Y‐shaped junctions. These observations suggest that ribbon synaptic junction formation begins with an alignment of pre‐ and postsynaptic membranes and the presence of the receptor presynaptic membrane undercoating, followed by the appearance of the presynaptic arciform densities and some staining of the cleft material and postsynaptic densities. These events are followed by the appearance of synaptic ribbons which are associated with the presynaptic arciform densities and by a further differentiation of the cleft material and

ISSN:0092-7317    

DOI:10.1002/cne.901700306

出版商:The Wistar Institute of Anatomy and Biology    

年代:1976

数据来源: WILEY

摘要:

AbstractMossy fiber endings and their synapses have an increasing morphological complexity along the phylogenetic scale which is specially evident when the evolution from reptiles to birds is considered. Among birds and mammals, only scanty and merely qualitative differences have been noticed in the mossy fiber organization. In the present study, the mossy fiber endings organization within the neuropil of four pigeons, four rats and six men was studied at optic and ultrastructural levels using morphometric methods. No significant differences were found in the fraction of volume of the neuropil and in the number of granule cells per unit volume of granular layer in all the three species. In man, a significant decrease in the volume of mossy fiber endings per unit volume of neuropil, and significant increases in their surface‐to‐volume ratio, in the fraction of their neurolemma occupied by synaptic contacts and in the average length of their synaptic contact zones, were found. The total synaptic area of mossy fiber endings per unit volume of neuropil was larger in man than in other animals in spite of their more reduced volume.These results show that significant differences in mossy fiber organization can be demonstrated when man is compared with a small mammal (the rat) and a bird (the pigeon). It is suggested that differences in the stereological organization of man's terminals might be related to his capacity for making finely graded movements. Moreover, it is suggested that the phylogenetic evolution of the mossy fiber organization has progressed among the higher vertebrates as it did in the rest of the animal sc

ISSN:0092-7317    

DOI:10.1002/cne.901700307

出版商:The Wistar Institute of Anatomy and Biology    

年代:1976

数据来源: WILEY

摘要:

AbstractThe central nervous system ofHirudo medicinalisis contained within a blood vessel, the ventral longitudinal sinus, but the nervous system is separated from the blood by the visceral endothelium. The visceral endothelium possesses many pinocytotic vesicles and basal infoldings and thus appears active whereas the parietal endothelium appears inactive. The junction between the visceral and parietal endothelia is abrupt. Peripheral nerves in this animal, as in vertebrates, are covered by endoneurium, perineurium, and epineurium. The endoneurium is continuous with the fibrous tissue of the segmental ganglia. The perineurium, consisting of a single layer of flattened cells that surrounds the peripheral nerve like a sleeve, is not continuous with the endothelium of the ventral sinus, but is separated from it by 5–10 microns. Therefore, at the point where the peripheral nerve joins the segmental ganglion, the extracellular spaces of the central nervous system, the peripheral nervous system, and the body wall are all confluent. Thus, there are only two compartments of the extracellular space in the leech: the blood, which is enclosed by the endothelia of the coelomic sinuses, and the extracellular fluid of the body, which includes the extracellular fluid of the nervous system. There seems to be no equivalent of cerebrospinal fluid in the gnathobdellid leec

ISSN:0092-7317    

DOI:10.1002/cne.901700308

出版商:The Wistar Institute of Anatomy and Biology    

年代:1976

数据来源: WILEY

摘要:

AbstractAutoradiographic and anterograde degeneration tracing methods were used to study and compare the organization of retinofugal pathways in two marsupial opossums,Didelphis virginianaandMarmosa mitis. Seven identical retinal targets were demonstrated for each opossum. These include: (1) the suprachiasmatic nucleus of the hypothalamus, (2) the dorsal and (3) ventral lateral geniculate nuclei, (4) the lateral posterior nucleus, (5) the pretectal complex, (6) the superior colliculus and (7) the accessory optic nuclei.While the pattern of retinal input to six of the seven targets was quite similar in the two species, the organization of the retinogeniculate pathways exhibited striking differences. In particular, our autoradiographs reveal no separation of ocular inputs within the lateral geniculate nucleus ofDidelphis, i.e. the ipsilateral input is overlapped completely by the more extensive contralateral projection.In contrast, there is considerable separation, as well as overlap, of the ocular inputs within the lateral geniculate nucleus ofMarmosa. Our autoradiographs reveal several distinct bands of label within each geniculate nucleus, and upon superimposing the nuclei, ipsilateral and contralateral to the placement it is apparent that two of the bands overlap, while five do not (three ipsi, two contra).

ISSN:0092-7317    

DOI:10.1002/cne.901700309

出版商:The Wistar Institute of Anatomy and Biology    

年代:1976

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.901700301

出版商:The Wistar Institute of Anatomy and Biology    

年代:1976

数据来源: WILEY