摘要:

AbstractThe dopaminergic neurons in the midbrain of the rat are located in three cell groups: nucleus A8 cells in the retrourbal field, nucleus A9 cells in the substantia nigra, and nucleus A10 cells in the ventral tegmental area and related nuclei. The purpose of the present study was to map and quantify the midbrain dopaminergic neurons in two and three dimensions in the rat brain, using immunohistochemical staining and computer imaging techniques. The cells were identified with an antibody against tyrosine hydroxylase, and counted in six midbrain nuclei: the retrorubral field, substantia nigra pars compacta, substantia nigra pars reticulata, central linear nucleus, ventral tegmental area, and interfascicular nucleus. Outlines were traced around the perimeters of the coronal tissue sections, and the locations of all immunoreactive ventral midbrain cells were mapped. On one side of the brain there are approximately 1,300 nucleus A8 cells, 10,500 nucleus A9 cells, and 10,200 nucleus A10 cells. The 2‐ and 3‐dimensional reconstructions illustrate the region‐specific density of dopaminergic neurons throughout the midbrain cell complex, and provide a visual appreciation of the location and distribution of the three dopaminergic cell groups in relation to their position in the midbrain. Information about the number and location of midbrain dopaminergic neurons will be useful in conjunction with future studies that characterize these cells more specifically, for example, in terms of their co‐transmitters, and afferent and efferent projections. © 1993 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903310302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThe distribution of cholecystokinin‐like, enkephalin‐like, and substance P‐like immunoreactivities is described in the dentate area, hippocampus, and subiculum of the domestic pig (Sus scrofa domesticus) as a baseline for future experimental studies. The distributions in the pig are compared with previous observations in other species.Cholecystokinin‐like immunoreactive nerve cell bodies were intensely stained and present in large numbers in all subfields studied. Cholecystokinin‐like immunoreactive terminals appeared as stained puncta, whereas fibers were only rarely encounterd. The puncta were mainly seen in the dentate molecular layer and dentate granule cell layer, the pyramidal cell layer of the hippocampal regio inferior, stratum moleculare of the hippocampal regio superior, and in the subiculum.Enkephalin‐like immunoreactive nerve cell bodies were faintly stained and generally present in very small numbers, except for some pyramidal cells in the subicular cell layer. Enkephalin‐like immunoreactive fibers were few in number, whereas stained puncta appeared with variable densities. Puncta of particularly high densities were found in the dentate molecular layer, whereas they appeared of moderate density in the dentate hilus, stratum moleculare of the hippocampal regio superior, and in the subiculum.Substance P‐like immunoreactive nerve cell bodies were few and very faintly stined. They primarily occurred in the dentate hilus, stratum oriens of the hippocampus, and in the subicular cell layer. Stained fibers were few in number, whereas stained puncta were present in abundant numbers corresponding to the mossy fiber projection in the dentate hilus and the layer of mossy fibers of the hippocampal regio inferior, and in moderate numbers in stratum moleculare of the hippocampal regio superior and in the subiculum.For all three neuropeptides there were consistent and very characteristic variations in the distribution of immunoreactivity along the septotemporal axis of the hippocampus.When viewed in a comparative perspective the distribution of enkephalin‐like and substance P‐like terminals in the domestic pig displayed striking differences from the basic pattern observed in other species. This contrasted with the distribution of cholecystokinin‐like neurons and terminals, which resembled more closely these species.

ISSN:0092-7317    

DOI:10.1002/cne.903310303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThere is increasing evidence that the archicortex in mammals and reptiles is not a homogeneous structure. However, little is known about the regional specialization of this cortical area in reptiles. Therefore, the efferent connections of the medial cortex of the lizardGekko geckowere studied with the anterograde tracerPhaseolus vulgaris‐leucoagglutinin. The small‐celled part of the medial cortex (Cxms) projects to various parts of the septum in a topological way: the rostral part projects to the anterior septal nucleus, whereas the caudal part projects to the lateral septal nucleus and the nucleus septi impar. In addition, Cxms projects to the large‐celled part of the medial cortex (Cxml). Axons that originate from the dorsal part of Cxms terminate at the proximal parts of the apical and basal dendrites of the neurons of Cxml caudal to the injection site. In contrast, fibers originating from the ventral part terminate on more distal parts of the dendrites of neurons of Cxml rostral to the injection site. Other projections from Cxms to the dorsal cortex (Cxd) and the external amygdaloid nucleus were found.The Cxml projects bilaterally to Cxms. These projections terminate in the superficial and deep plexiform layers. In addition, projections to the cell plate of Unger, Cxd, and to the lateral septal nucleus were found.It appears, on the basis of the efferent connections, that Cxms can be divided into a rostral and caudal part, while hodological differences also exist between the dorsal and ventral parts of Cxms. The results of the present study do not suggest a subdivision of Cxml. The regional variations of the medial cortex in the lizardGekko geckodiffer from the regional variations described in other reptilian species. © 1993 Wiley‐L

ISSN:0092-7317    

DOI:10.1002/cne.903310304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractNonradioactive in situ hybridization methods with digoxigenin‐labeled cRNA probes were used to localize two glutamic acid decarboxylase (GAD) mRNAs in rat brain. These mRNAs encode two forms of GAD that both synthesize GABA but differ in a number of characteristics including their molecular size (65 and 67 kDa). For each GAD mRNA, discrete neuronal labeling with high cellular resolution and low background staining was obtained in most populations of known GABA neurons. In addition, the current method revealed differences in the intensity of labeling among neurons for each GAD mRNA, suggesting that the relative concentrations of each GAD mRNA may be higher in some groups of GABA neurons than in others.Most major classes of GABA neurons were labeled for each GAD mRNA. In some groups of GABA neurons, the labeling for the two mRNAs was virtually identical, as in the reticular nucleus of the thalamus. In other groups of neurons, although there was substantial labeling for each GAD mRNA, labeling for one of the mRNAs was noticeably stronger than for the other. In most brain regions, such as the cerebellar cortex, labeling for GAD67 mRNA was stronger than for GAD65 mRNA, but there were a few brain regions in which labeling for GAD65 mRNA was more pronounced, and these included some regions of the hypothalamus. Finally, some groups of GABA neurons were predominantly labeled for one of the GAD mRNAs and showed little or no detectable labeling for the other GAD mRNA, as, for example, in neurons of the tuberomammillary nucleus of the hypothalamus where labeling for GAD67 mRNA was very strong but no labeling for GAD65 mRNA was evident. The findings suggest that most classes of GABA neurons in the central nervous system (CNS) contain mRNAs for at least two forms of GAD, and thus, have dual enzyme systems for the synthesis of GABA. Higher levels of one or the other GAD mRNA in certain groups of GABA neurons may be related to differences in the functional properties of these neurons and their means of regulating GABA synthesis. © 1993 Wiley‐Liss,

ISSN:0092-7317    

DOI:10.1002/cne.903310305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractTo obtain insight into the noradrenergic system of amphibians, the distribution of noradrenaline was studied immunohistochemically with antibodies against noradrenaline (NA) and dopamine‐β‐hydroxylase (DBH) in the brain of the South African clawed frogXenopus laevis. Noradrenaline‐containing cell bodies are found in the hypothalamic periventricular organ, the isthmic region, and in an area ventral and medial to the solitary tract. Noradrenaline‐immunoreactive (NAi) fibers are widely, but not uniformly, distributed throughout the brain and spinal cord. In the telencephalon, dense plexuses of NAi fibers are present dorsomedial to the nucleus accumbens, in the nucleus of the diagonal band, the dorsolateral part of the striatum, the medial amygdala, and in an area that encompasses the lateral forebrain bundle. In the diencephalon, dense plexuses are found ventrolateral to the periventricular organ, in the posterior tubercle, and in the intermediate lobe of the hypophysis. Compared to the forebrain, the brainstem and spinal cord are less densely innervated by NAi fibers.The distribution of DBHi cell bodies and fibers resembles the pattern revealed with the NA antibodies. An exception is formed by the liquor contacting cells of the hypothalamic periventricular organ, which are immunonegative for the DBH antiserum. It is suggested that these cells accumulate rather than metabolize catecholamines. The present study, combined with the results of a previous report inXenopuson the distribution of dopamine (González, Tuinhof, Smeets, '93, Anat. Embryol.187:193–201) offers the opportunity to differentiate between the two catecholamines. For example, it is now shown that both dopaminergic and noradrenergic fibers innervate the intermediate lobe of the hypophysis and that, therefore, both catecholamines are likely involved in background adaptation. © 1993 Wil

ISSN:0092-7317    

DOI:10.1002/cne.903310306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractOriginally characterized as the calcium‐ and phospholipid‐dependent protein kinases, the protein kinases C include at least eight separate isoforms, some of which are calciumindependent and all of which are highly enriched in brain. Of the calcium‐independent isoforms, the delta subspecies of protein kinase C has the most restricted complement of lipid activators and substrate specificity, suggesting that it may have a unique role in cell signalling pathways. Using immunocytochemistry, we report that the distribution of protein kinase C‐δ immunoreactivity in rat brain is also restricted, being present in all sensory systems. Moreover, it is found in alternating hierarchies of sensory pathways: in all sensory systems except auditory, it is found in first‐ and third‐order neurons, while in the auditory system, it is found in second‐ and fourth‐order neurons. Thalamocortical systems are intensely immunoreactive, including barrel fields of the rat parietal cortex. Outside of sensory systems, protein kinase C‐δ is present in cerebellum within longitudinal stripes in Purkinje neurons, and in the caudateputamen, it appears to be associated with the striosome (patch) compartment. In contrast to all other protein kinase C isoforms, protein kinase C‐δ is absent from hippocampus. These findings suggest that protein kinase C‐δ may have a unique role in signal transduction in the central nervous system (CNS), especially in sensory system

ISSN:0092-7317    

DOI:10.1002/cne.903310307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThe distribution of somatostatin receptors (SRIF‐R) was analyzed in the limbic system of the adult rat by in vitro autoradiography with [125I‐Tyr0, DTrp8]S14 as a radioligand. Precise quantification of the density of binding sites, at 0.2 mm intervals throughout the different areas revealed a marked heterogeneity of labeling in most structures. In particular, SRIF‐R were concentrated in the basal (104.4 ± 3.3 fmol/mg proteins) and basolateral amygdaloid nuclei (94.8 ± 4.3 fmol/mg proteins), and in the nucleus of the lateral olfactory tract (121.6 ± 2.4 fmol/mg proteins), whereas moderate densities were detected in the amygdalo‐hippocampal nucleus (76.4 ± 2.8 fmol/mg proteins). The medial (41.3 ± 1.9 fmol/mg proteins) and the central (24.0 ± 1.4 fmol/mg proteins) amygdaloid nuclei contained lower SRIF‐R concentrations. It appears from these observations, in the light of the anatomical pathways of the amygdala, that intra‐amygdalian SRIF‐containing neurons project to the amygdalo‐hippocampal nucleus, and that SRIF‐R in the basolateral complex are the target of afferents from limbic cortical areas. SRIF‐R were detected at different levels of the hippocampal formation but their distribution was more restricted than that of SRIF‐containing fibers. The maximal density of sites was detected in the ventral and dorsal parts of the subiculum (115.0 ± 3.4 and 87.0 ± 2.8 fmol/mg proteins, respectively) and in the parasubiculum (100.1 ± 5.4 fmol/mg proteins). In Ammon's horn, the stratum oriens and stratum radiatum of the CA1 field were the only sites enriched in SRIF‐R (74.1 ± 2.0 and 74.6 ± 1.9 fmol/mg proteins, respectively). The apparent lack of receptors in the pyramidal cell laver indicated that, in Ammon's horn, SRIF is involved in intra‐hippocampal communication. Low levels of receptors were found in the hippocampal CA2 and CA3 fields. SRIF‐R in the dentate gyrus were mainly concentrated in the molecular layer (57.3 ± 1.2 fmol/mg proteins). A very high density of sites was also observed in the entorhinal cortex (up to 123.1 ± 1.5 fmol/mg proteins). A clear mismatch between SRIF and SRIF‐R was detected in the septum and the habenula. In the profound layers of the cingulum and retrosplenial cortex, a heterogeneous distribution of SRIF‐R was observed. High concentrations of sites were detected in the rostral zone of the cingulate cortex (93.4 ± 2.0 fmol/mg proteins) while the posterior cingulate only exhibited moderate concentrations of sites (66.5 ± 0.7 fmol/mg proteins). The density of SRIF‐R increased toward the caudal part of the retrosplenial cortex (94.7 ± 1.4 fmol/mg proteins). The results suggest that SRIF is likely to exert specific activity depending on field specialization in the deep layers of these cortical areas.The present findings show that in the rat the distribution of the receptor sites is more restricted than that of SRIF‐immunoreactive fibers in discrete areas of most subdivisions of the limbic system. Thus these data, together with the known localization of somatostatinergic perikarya and fibers, provide detailed information concerning the sites of action of SRIF in the various r

ISSN:0092-7317    

DOI:10.1002/cne.903310308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractGolgi‐stained material of cerebellar cortices from 17 species was examined by measuring the fractal dimensions of the borders of Purkinje cells, which is a quantitative, objective measure of morphological complexity. Nine species (from birds to man) were chosen for a comparison with ANOVA and no statistically significant differences were found in their fractal dimensions. In contrast, a wide range of differences was found in the membrane areas across species lines. The Sholl coefficient, a measure of branch formation and temination and termination away from the soma, showed no consistent pattern for each cell. We interpret our results as indicating a constancy in morphological cellular complexity of Purkinje cells during late evolutionary time. © 1993 Wiley‐Liss,

ISSN:0092-7317    

DOI:10.1002/cne.903310309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThe pattern of innervation of the skin of the rocklingCiliata mustelawas investigated to sort out spinal from facial nerve innervation of cutaneous chemosensory and mechanosensory systems. This fish has a variety of appendages with different functional sensory specializations, i.e., the chin barbel, pelvic fin, anterior dorsal fin, and dorsal trunk skin. The carbocyanine dye, diI, was applied to nerve stumps in dissected aldehyde‐fixed tissue. In the case of the chin barbel, the dye was applied to both the trigeminal and facial nerve components. In the other cases, the dye was applied either selectively to the spinal nerves, to the facial nerves, or to both components. In the chin barbel, diI labeled nerve fibers associated with taste buds (TBs) and solitary chemosensory cells (SCCs) as well as relatively blunt free nerve endings, which closely approach the epidermal surface. In the pelvic fin, anterior dorsal fin, and dorsal trunk skin, taste buds, solitary chemosensory cells, and their innervation were labeled only after diI was applied to the facial nerve stumps. Application of diI to spinal nerves labeled delicate, free nerve endings and nerve fibers associated with small cells deep in the epidermis with features characteristic of Merkel cells. Transmission electron microscopy supports these results; after denervation of the facial component of the anterior dorsal fin, synaptic contacts with Merkel cells remained intact, whereas the synapses with the SCCs vanished. © 1993 Wiley‐Liss,

ISSN:0092-7317    

DOI:10.1002/cne.903310310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractBehavioral tests of absolute sensitivity and sound localization in African naked mole rats show that, despite their communal social structure and large vocal repertoire, their hearing has degenerated much like that of other subterranean species. First, their ability to detect sound is limited, with their maximum sensitivity being only 35 dB (occurring at 4 kHz). Second, their high‐frequency hearing is severely limited, with their hearing range (at 60 dB sound pressure level [SPL]) extending from 65 Hz to only 12.8 kHz. Third, determination of the effect of duration on noise thresholds indicates that, compared with other animals, mole rats require a sound to be present for a much longer duration before reaching asymptotic threshold. Finally, they are unable consistently to localize sounds shorter than 400 ms and cannot accurately localize sounds of longer duration, raising the possibility that they are unable to use binaural locus cues. Thus, it seems that the essentially one‐dimensional burrow system of a subterranean habitat produces severe changes in hearing comparable to the changes in vision that result from the absence of light. To explore the relation between vision and sound‐localization acuity, retinal ganglion cell densities were determined. The results indicate that naked mole rats have a broad area of best (albeit poor) vision, with maximum acuity estimated at 44 cycles/degree. That mammals with wide fields of best vision have poorer sound‐localization acuity than those with narrower fields is consistent with the thesis that a major function of sound localization is to direct the gaze to the source of a sound. However, the fact that subterranean mammals have little use for vision in a lightless environment suggests that they represent an extreme case in this relationship and may explain the fact that, unlike surface‐dwelling mammals, they have virtually lost the ability to localize brief sounds. Finally, despite their very limited auditory abilities, the major brainstem auditory nuclei, although relatively small, appear to be present. © 1993 Wiley

ISSN:0092-7317    

DOI:10.1002/cne.903310311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY