摘要:

AbstractMale rats aged 30 to 35 days were provided with 1.75% sodium chloride solution as drinking fluid for two weeks, to create a chronic increase in plasma osmolality. During this time, the animals and a control group of water‐drinking rats received two injections per day of 1 μCi of3H‐thymidine per gram body weight to label dividing cells and their progeny. At the end of this period, the animals were sacrificed by aldehyde perfusion. Sections 1 μm‐thick were saved at intervals from a series cut throughout the length of the supraoptic nucleus; these sections and others taken from the caudate nucleus and the neural lobe of the hypophysis were processed for radioautography.Neuronal nuclei and nucleoli were enlarged in the supraoptic nucleus of salttreated rats, in accord with previous work indicative of neuronal enlargement associated with increased protein synthesis and probably enhanced vasopressin production. Furthermore, most axon terminals in the neural lobe were depleted of neurosecretory granules in the salt‐treated group, a fact suggesting increased release of vasopressin.Cell counts in radioautographs of the supraoptic nucleus revealed that 20.6% of the astrocytes were labeled in salt‐treated rats, but only 5.9% in controls, indicating a marked increase in the production of new astrocytes in the treated animals. Also, endothelial cells were more frequently labeled in salt‐treated rats (52.9%) than in controls (17.4%). In the caudate nucleus, by contrast, the labeling percentages of astrocytes or of endothelial cells did not differ between control and treated rats. In the neural lobe, the labelling percentage of pituicytes was 45.8% in treated, but only 3.1% in control animals. The endothelial cell labeling was also greater in treated (46.5%) than controls (23.9%). Thus, in young rats, a period of salt ingestion elicited both an enlargement of supraoptic neurons and an increase in the production of the astrocytes, pituicytes, and endothelial cells associated with these neurons and th

ISSN:0092-7317    

DOI:10.1002/cne.901750402

出版商:The Wistar Institute of Anatomy and Biology    

年代:1977

数据来源: WILEY

摘要:

AbstractThe cells of origin of cortico‐cortical and subcortical projections from the subfields of the somatic sensory area and from the motor cortex have been identified in cynomolgus and squirrel monkeys by the retrograde axonal transport method.The somata of the cells of origin of a particular fiber system have a specific laminar or sublaminar distribution. The somata of the majority of cortico‐cortical cells lie in the supragranular layers. Those projecting to the opposite cortex are confined to the deeper half of layer III (layer IIIB). Ipsilateral cortico‐cortical neurons lie mainly superficial to them in layers IIIA and II, but in the second somatic sensory area (SII) and in area 2 of the first (SI), small numbers are also found in layer V. Corticospinal cells lie in the deeper part of layer V and corticostriatal cells in the superficial part. Corticopontine, corticobulbar and corticorubral cells lie in between. The majority of corticothalamic cells lies in layer VI but a second, smaller population is found in the deep part of layer V.The cells giving rise to a particular set of efferent connections can be distinguished in terms of size and, with the exception of the corticospinal cells, their size does not vary greatly from area to area. In many cases, the size and laminar specificity indicates that cells sending axons to one site cannot have collateral branches projecting to another.In most of the fiber systems studied, labeled cells form single or multiple strips, 0.5–1 mm wide and oriented mediolaterally across the cortex. The strips appear in all of the subfields of the somatic sensory and motor areas and may form the basis of the clustering of like groups of efferent neurons demonstrable in physiological

ISSN:0092-7317    

DOI:10.1002/cne.901750403

出版商:The Wistar Institute of Anatomy and Biology    

年代:1977

数据来源: WILEY

摘要:

AbstractStimulation of the dorsomedial or ventrolateral perforant pathways resulted in quantitatively different extracellularly recorded EPSPs in the fascia dentata of the rat. The two potential differed in latency to peak and in width at half amplitude in a manner consistent with the different locus of termination of the two pathways on the granule cell dendrites. Both potentials were able to follow brief stimulus trains of 100 Hz, which suggests that they are monosynaptic. Medially elicited responses had their peak negativity approximately 100 to 180 μm deeper in the molecular layer than laterally elicited responses. Stimulation at short intervals along a dorsomedial to ventrolateral track in the angular bundle yielded a step function rather than a continuum of EPSP peak latency and half‐width, in agreement with Hjorth‐Simonsen's ('72) evidence for the separateness of the two pathways. Both pathways were able to induce granule cell discharge. Laterally elicited spikes, however, were delayed. Stimulation at intermediate locations frequently elicited double spikes from granule cell population. Population spikes elicited by either pathway were inhibited for as long as 100 msec after a single discharge. Both pathways showed facilitation with double stimuli at short intervals, and both showed post‐tetanic potentiation lasting at least 30 minutes. Under conditins where it could be shown that the two pathways at least partially converged onto the same granule cells, the response of one pathway did not increase when long lasting potentiation was induced on the

ISSN:0092-7317    

DOI:10.1002/cne.901750404

出版商:The Wistar Institute of Anatomy and Biology    

年代:1977

数据来源: WILEY

摘要:

AbstractExperiments using anterograde and retrograde tracing techniques have been used to identify projections to and from the region of mouse SmI cortex which contains the posteromedial barrel subfield (PMBSF, Woolsey and Van der Loos, '70). Microinjections containing horseradish peroxidase (HRP) and tritiated amino acids were placed unilaterally into the topographic center of the PMBSF. Brains were perfuse‐fixed and frozen sectioned. All sections were reacted for HRP and alternate sections were autoradiographed. Examination of sections cut tangential to the pial surface in the region of the injection site showed that diffusion of the injection was limited to cortex above and below the PMBSF in layer IV (i.e., PMBSF cortex). A “column” of HRP reaction product and developed silver grains was present in ipsilateral cortical area 40, in the face area of SmII. HRP positive cell bodies were mainly in layer III and VI of this “column.” A similar “column” was present in ipsilateral cortical area 6, in a region which in the rat corresponds to the vibrissal area of MsI (Hall and Lindholm, '74), but here HRF positive cells bodies were situated mainly in layer V. HRP labeled cells bodies were also present in layer V of ipsilateral cortical area 29c. The ipsilateral nucleus ventralis thalami pars lateralis and the nucleus posterior thalami contained many HRP positive cell bodies and were associated with dense aggregations of developed silver grains. Numerous silver grains were also present over portions of the ipsilateral caudate, reticular nucleus of the thalamus and ventral pontine nuclei, but no HRP positive cell bodies occurred in these regions.HRP‐filled axons left the injection site and traveled via the corpus callosum to contralateral PMBSF cortex where HRF labeled cell bodies were present mainly in layers III and V. Usually only one or two labeled somata were located superficial or deep to a contralateral PMBSF barrel. A few HRF positive cell bodies were also present in layers II and III of contralateral pyriform cortex.These results indicate that PMBSF cortex is reciprocally connected with ipsilateral cortical areas 6 and 40 and with the ipsilateral ventral and posterior nuclei of the thalamus. A small, homotopic callosal connection with contralateral PMBSF cortex has been demonstrated, and it is presumed that this projection is also reciprocal. PMBSF cortex projects to, but receives no projections from the ipsilateral caudate, reticular nucleus of the thalamus and the ventral pontine nuclei. Thus, many of the same projections of primary somatosensory cortex in higher animals, such as the monkey have been shown to occ

ISSN:0092-7317    

DOI:10.1002/cne.901750405

出版商:The Wistar Institute of Anatomy and Biology    

年代:1977

数据来源: WILEY

ISSN:0092-7317    

DOI:10.1002/cne.901750401

出版商:The Wistar Institute of Anatomy and Biology    

年代:1977

数据来源: WILEY