摘要:

AbstractThe cellular localization of 5‐hydroxytryptamine (5‐HT) was investigated in the pennatulid anthozoanRenilla koellikeriby means of peroxidase‐antiperoxidase‐immunohistochemistry with an antiserum against 5‐HT‐formaldehyde‐protein conjugate. In many colonies, strong 5‐HT‐immunoreactivity was displayed by the cell bodies and beaded processes of relatively small neuronlike elements predominating in the outer ectoderm or scattered in the underlying mesoglea. The immunostained neurons of the mesoglea were generally bipolar and their relatively short processes extended toward myoepithelial cells. In the ectoderm, most immunostained neurons appeared pseudounipolar. These cell bodies were endowed with a small, superficially directed, conical appendage reaching the outer surface of the epithelium. Their neurites emerged from the inner pole of the perikarya and branched toward other immunopositive ectodermal and mesogleal nerve cells, or nematocytes in the tentacles. The networklike distribution of the presumed 5‐HT ectodermal neurons varied between the different regions of colonies and along the autozooid column. In the context of earlier observations in cnidarians, these cytological features suggest a sensory as well as a modulatory function for 5‐HT

ISSN:0092-7317    

DOI:10.1002/cne.902910202

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

年代:1990

数据来源: WILEY

摘要:

AbstractAngiotensin converting enzyme converts angiotensin I to angiotensin II, a peptide that plays an important role in the central regulation of blood pressure and fluid and electrolyte homeostasis. However, the distribution of this enzyme in the human brain has not been well described. In this study, angiotensin converting enzyme was mapped in the human basal forebrain and midbrain by using quantitative in vitro autoradiography employing a derivative of a potent converting enzyme inhibitor,125I‐351A, as radioligand. This radioligand binds specifically and with high affinty to angiotensin converting enzyme and also exhibited these properties in binding to slide‐mounted sections of human basal ganglia.In the basal ganglia, high levels of binding of125I‐351A are found in the caudate nucleus, putamen, nucleus accumbens, both divisions of the globus pallidus, and substantia nigra pars reticulata. High densities of labelling also occur in the ventral pallidum. In the hypothalamus, a moderate level occurs in the paraventricular and supraoptic nuclei, and a diffuse, low level of binding is found throughout the periventricular region.The organum vasculosum of the lamina terminalis, one of the circumventricular organs, displays the highest concentration of binding. The choroid plexus contains only moderate density of labelling in contrast to other mammalian species previously studied. Major fibre tracts are devoid of activity except for the posterior limb of the internal capsule, which contains fascicles of intense activity.In the midbrain, a moderate density of binding is detected in the periaqueductal gray. The dorsal, central linear, and, more caudally, the centralis superior medialis raphe nuclei also contain moderate densities of labelling.Angiotensin converting enzyme is heterogeneously distributed in the caudate nucleus and putamen, with distinct patches of high concentrations surrounded by a matrix of diffuse, lower levels. In the caudate nucleus, these patches of high binding corresponded to striosomes since they register with acetylcholinesterase‐poor zones.The high concentration of angiotensin converting enzyme found in the basal ganglia suggests that the enzyme may be involved in processing neuropeptides that occur in high concentrations in these structures. Possible substance P and enkephalins, which are also concentrated in str

ISSN:0092-7317    

DOI:10.1002/cne.902910203

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe dorsolateral pontine tegmentum of the cat is known to contain enkephalinergic neurons, with most of the enkephalin co‐contained in the catecholaminergic neurons; however, enkephalinergic cells projecting to the spinal cord have not been identified. This study employs retrograde transport of horseradish peroxidase in combination with methionine‐enkephalin or tyrosine hydroxylase immunocytochemistry to 1 determine the locations of pontospinal enkephalinergic neurons and 2 compare these with the locations of pontospinal catecholaminergic neurons.Pontospinal enkephalinergic neurons were observed in the nuclei locus coeruleus and subcoeruleus and the Kölliker‐Fuse nucleus. A high concentration of these neurons was evident in the Kölliker‐Fuse nucleus when compared to the nuclei locus coeruleus and subcoeruleus (P.05). Quantitative data concerning the pontospinal enkephalinergic neurons correlated well with previous data an pontospinal catecholaminergic neurons (Reddy et al., Brain Res. 491:144–149, '89). A majority of the descending neurons from the dorsolateral pontine tegmentum contain enkephalin (72–80%) and catecholamine (80–87%). The observations suggest that enkephalin is contained in many of the pontospinal catecholam

ISSN:0092-7317    

DOI:10.1002/cne.902910204

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

年代:1990

数据来源: WILEY

摘要:

AbstractWe examined the differntiation and maturation of neurons and glia of the inner nuclear layer (INL) and ganglion cell layer (GCL) in the retina of a human fetus of 15 weeks gestation. Serial, ultrathin sections were cut from a resinembedded specimen from the posterior pole of the retina. The region of the putative fovea was defined by the absence of rod photoreceptors from the outer nuclear layer; only sections through the putative fovea were studied. Cell somata were classified on the basis of morphological criteria and, through the analysis of serial sections, morphological characteristics of the cell processes were established. In the inner plexiform layer (IPL), the types of synapses were analysed. The majority of cells in the INL and GCL were differentiated and could be identified. Ganglion cell somata were observed in the GCL and INL. Of 186 somata analysed in the INL, 66 were Muller cells, 21 amacrine cells, and 2 ganglion cells; a further 7 cells were classified as either amacrine or ganglion. Bipolar cells were thought to comprise the majority of the remaining 90 somata, but these could not be positively identified, as it was not possible to trace bipolar cell axons to their cell bodies deep in the INL. A detailed description of the morphological characteristics of the identified cells and their processes, and of the axonal processes of bipolar cells, is provided. Puncta adherentia and other simple intercellular junctions were commonly seen in the IPL and involved all cell types. Amacrine cell synapses and immature, monad bipolar cell synapses were common within the IPL. Dyad bipolar synapses were uncommon at this stage of development. A possible sequence of synaptogenesis in the IPL is discussed.

ISSN:0092-7317    

DOI:10.1002/cne.902910205

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe superior colliculus of mammals is generally divided into seven layers on the basis of the distribution of myelinated fibers, which are densely packed in layers III, V, and VII but sparse in the other layers. The laminar distribution of afferents and efferents allows, in addition, for the distinction of a superficial visual zone (layers I‐III) and a deeper multimodal and premotor zone (layers IV‐VII). Collicular neurons, however, do not show a lamination pattern, but are rather homogeneously distributed with only gradual transitions (Albers et al.:J. Comp. Neurol. 274:357‐370, '88).The present study analyses whether the distribution of collicular synapses is correlated with the laminar organization of collicular axons or rather with the more homogeneous distribution of collicular neurons. For this purpose, the size and density of synaptic terminals and contacts as well as synapse‐to‐neuror ratios were determined in all collicular layers of albino rats by means of quantitative analysis of electron microscopic pictures.The size of presynaptic terminals and contacts does not differ significantly between individual collicular layers. On average, presynaptic terminal diameter is 1,079 nm, and synaptic contact size 338 nm, while 23% of all contacts are of the symmetrical type with pleiomorphic vesicles. The average numerical synaptic density is 422 million per mm3. This value is significantly higher in layers I and II (on average 670 million per mm3) than in layers III–VII (on average 370 million per mm3). The synapse‐to‐neuron (S/N) ratios calculated show that collicular neurons have on average 6,120 synaptic contacts on their receptive surface. The S/N ratio is lowest in layer III (4,330), while this ratio is highest in layers I and VII (i.e., 8,970 and 8,560 respectively). Layer II has a significantly higher S/N ratio than layer III (i.e., 8,060 and 4,330, respectively).Our results show that the size of synaptic terminals and contacts is not correlated with the different connectivity patterns of the distinct collicular layers. However, the density of synapses as well as the synapse‐to‐neuron ratios show a certain degree of laminar differentiation. In particular the superficial visual zone appears to be inhomogeneous in this respect, since layers I and II have a significantly higher density of synapses and higher S/N ratios than layer III. The deeper collicular zone is more homogeneously organized with synaptic densities similar to that of layer III and gradually increasing synapse‐to‐neuron ratios fro

ISSN:0092-7317    

DOI:10.1002/cne.902910206

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

年代:1990

数据来源: WILEY

摘要:

AbstractFocal injections of horseradish peroxidase (HRP) in dimethylsulfoxide (DMSO) were targeted into mouse somatosensory cortex, in vitro, with a template. Injections were made at different depths and in different locations in the whisker‐barrel‐defined somatosensory map in order to determine quantitative connectivity patterns within and between barrel‐defined cortical columns. Cortices were sectioned in a plane parallel to the pia at 75 βm. Data were collected directly from microscope slides by computer.Data are presented as: (1) Plots of computer‐mapped HRP reaction product density in neurons and cell locations for each section in relation to barrel boundaries; (2) histograms of label in cortical layers related to individual barrel‐defined columns; (3) polar plots of relative amounts of label within individual barrel columns in sections through each barrel column; (4) vectors which represent HRP reaction product density as a function of direction and distance from the injection site; (5) statistical analysis of the shape of the label distribution pattern in the plane of the cortex as a function of injection site depth; and (6) probability of labeling of any other barrel column given a labeled barrel column.The principal findings are: (1) The pattern of label distribution, after an injection directly above or directly below an individual barrel, is hour‐glass shaped with the waist of the hour‐glass in layer IV. (2) Connections within barrel cortex are asymmetrical. Barrel‐related columns within a row are more strongly interconnected than those in different rows. (3) Connections of the small barrels associated with whiskers on the upper lip are strongest with other small barrels, but strong connections also exist between these small barrels and the larger barrels. (4) The pattern of intracortical connections in SII is not asymmetrical; interlaminar connections in SII are fundamentally different from those in barrel cortex. (5) Quantitative intracortical projection patterns are highly consistent with functional data on intracortical processing of whisker information. As such, the quantitative data clearly indicate the spatial extent and relative magnitude of populations of neurons involved in intracortical processing of sensory information.The spatial arrangements of these intracortical connections, in conjunction with known developmental events, make it highly likely that the distribution of intracortical axons in mouse barrel cortex is sculpted in pa

ISSN:0092-7317    

DOI:10.1002/cne.902910207

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

年代:1990

数据来源: WILEY

摘要:

AbstractThe morphology of the antennal muscles of two cricket species,Gryllus campestrisandG. bimaculatus, and their innervation are described. The motoneurons innervating the five tentorio‐scapal muscles M4 and M5 and the two scapo‐pedicellar muscles M6 and M7 were stained with cobalt chloride introduced via the cut axonal endings in the muscle. The seven antennal muscles are innervated by a total of 17 excitatory motoneurons and one common inhibitory neuron. These neurons branch in the dorsal neuropil of the deuto‐and tritocerebrum. No difference in the morphology of the motoneurons between the two species was evident. Two dorsal‐unpaired‐medial (DUM) neurons located in the suboesophageal ganglion also innervate the antennal muscles. Intracellular recordings of some motoneurons combined with Lucifer Yellow injections corroborated the motoneuron morphology obtained by cobalt backfilling from the muscles. The recordings showed that the motoneurons are either of the fast or the

ISSN:0092-7317    

DOI:10.1002/cne.902910208

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

年代:1990

数据来源: WILEY

摘要:

AbstractConcurrent and sequential dual immunohistochemical labeling methods were used in combination, along with retrograde tracing techniques, to determine the extent to which inhibin<(Iβ), somatostatin‐28 (SS‐28), and enkephalin (ENK) immunoreactivity (IR) might be jointly expressed in neurons centered in the caudal part of the nucleus of the solitary tract )NTS( that project to the paraventricular nucleus of the hypothalamus (PVH). The results indicate that at least 65% of Iβ‐stained neurons in the NTS also express SS‐28 IR, and at least 33% are ENK‐positive. At least 25% of the Iβ IR population stains positively for all three peptides. A substantial number of cells stained with markers for two, or all three, peptide families, could be retrogradely labeled following tracer deposits centered in the PVH. Prominent Iβ and SS‐28 IR projections from the caudal medulla to the hypothalamus have been described and include a preferential input to oxytocinergic (OT) compartments of the magnocellular neurosecretory system. The present results suggest that these arise in large measure from a common pool of neurons, a subset of which also shows ENK IR. Implications for the control of OT secretion, and for the processing of sensory information through the NTS

ISSN:0092-7317    

DOI:10.1002/cne.902910209

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

年代:1990

数据来源: WILEY

摘要:

AbstractGABA‐ergic and glycinergic circuitry in the inner plexiform layer of the goldfish retina was evaluated by electron microscopic autoradiography of3H‐GABA and3H‐glycine uptake, combined with retrograde horseradish peroxidase (HRP) labeling of ganglion cells. GABA‐ergic and glycinergic synapses were found on labeled ganglion cells throughout the inner plexiform layer. This reinforces the idea that physiological evidence of GABA‐ergic and glycinergic influence on a variety of ganglion cells in goldfish and carp often reflects direct inputs. Double‐labeled synapses are presented as evidence of direct type Ab amacrine cell input to on‐center ganglion cells. At least one population of type Aa sustained‐off GABA‐ergic amacrine cell is proposed, on the basis of profuse GABA‐ergic inputs onto bipolar cells in sublamina a. Similar GABA‐labeled profiles are shown to synapse onto HRP‐labeled probable offcenter ganglion cells. Thus GABA‐ergic amacrine cells not only provide the predominant feedback to depolarizing (on‐center) and hyperpolarizing (offcenter) bipolar cells but also provide feed‐forward inputs to on‐ and off‐center ganglion cells. Large‐caliber GABA‐ergic dendrites present in both sublaminae a and b resemble those expected of a previously described bistratified, transient amacrine cell. These processes synapse onto HRP‐labeled ganglion cell profiles in both sublaminae. Two morphologies of glycinergic amacrine cell are proposed on the basis of light microscopic autoradiography, (1) the previously described small pyriform cell and (2) a multipolar cell. The differential connectivity of the glycinergic neurons described, however, remains indistinguishable. Whereas abundant glycinergic inputs to ganglion cells occur throughout the inner plexiform layer, contacts between glycinergic profiles and bipolar cells are extremely rare. Therefore, interpreting the meaning of glycinergic input to ganglion cells will require f

ISSN:0092-7317    

DOI:10.1002/cne.902910210

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

年代:1990

数据来源: WILEY

摘要:

AbstractPhe‐Met‐Arg‐Phe (FMRF‐NH2) and structurally related peptides enhance neuromuscular transmission and contraction of the M. extensor tibiae preparations of the locustsLocusta migratoriaandSchistocerca gregaria(Walther et al.:Neurosci. Lett. 45:99‐104, '84). Similar effects could also be obtained with extracts of locust ganglia (Walther and Schiebe:Neurosci. Lett. 77:209‐214, '87). By using two HPLC systems, we have partially purified extracts of the unpaired median nerves (including their neurohaemal organs) of different locust ganglia. The biological activity of the extracts served as an estimate for the degree of purification. Six different bioactive fractions were identified migrating at and close to retention times of known ‐RFamide peptides with similar bioactivity. No fraction coeluted with authentic FMRF‐NH2 or FLRF‐NH2. We demonstrate that extensor tibiae muscle contractions were potentiated by HPLC fractions from raw material with ‐RF‐NH2 immunoreactivity, but also by HPLC fractions from raw material without

ISSN:0092-7317    

DOI:10.1002/cne.902910211

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

年代:1990

数据来源: WILEY