Monoamine innervation of the oculomotor nucleus in the rat. A radioautographic study

The serotonin and noradrenaline innervations of the rat oculomotor nucleus were examined by high resolution radioautography after in vivo labeling with tritiated 5-hydroxytryptamine and dopamine, respectively. Noradrenaline as well as serotonin endings (axonal varicosities) pervaded the entire nucleus, but the latter were at least six times more numerous (1.3 X 10(6) per mm3 of tissue) and were often found in the immediate vicinity of neuronal somata and proximal dendrites. The axon terminals of both types were of similar size and exhibited some large dense-cored vesicles in association with aggregated small and clear vesicles. The dense-cored vesicles were, however, more frequent and the content in clear vesicles more pleomorphic in serotonin than noradrenaline endings. In single thin sections, the proportion of noradrenaline and serotonin profiles exhibiting a synaptic junction was relatively small (15%). These were either symmetrical or asymmetrical when made on dendritic branches but invariably symmetrical on spines. In addition, a significant number of serotonin terminals were seen in close apposition or synaptic contact with neuronal perikarya and large dendrites, allowing for a direct, "proximal" action of serotonin. Moreover, many such terminals appeared to be coupled with unlabeled endings of another category, characterized by dispersed, uniformly round and clear synaptic vesicles, providing an alternate route for a proximal effect of serotonin in the oculomotor nucleus. In line with previous investigations on other motor nuclei, these data support the likelihood of a close involvement of both noradrenaline and serotonin in the control of motoneuronal activity.     

Serotonergic terminals in the neural sheath of the blowfly nervous system: electron microscopical immunocytochemistry and 5,7-dihydroxytryptamine labelling

With serotonin immunocytochemistry we have demonstrated an extensive plexus of immunoreactive varicose fibres in the neural sheath of the nervous system of the blowfly, Calliphora. These fibres are located in the neural sheath of the following regions: the maxillary-labial and labrofrontal nerves of the cerebral ganglia, the cervical connective, the dorsal surface of the thoracicoabdominal ganglia, two pairs of prothoracic nerves and the median abdominal nerve. We identified the serotonin-immunoreactive neural processes in the electron microscope by means of the peroxidase-antiperoxidase method. Immunoreactivity was seen in large granular vesicles (ca 100 nm), on membranes of smaller (ca 60 nm) and larger (ca 100 nm) agranular vesicles, along the inner surface of the axolemma, along neurotubules and outer membranes of mitochondria. By conventional electron microscopy we found numerous varicose neural processes in the neural sheath of some of the above regions. These varicosities are of at least two types. One type corresponds to the serotonin-immunoreactive profiles. A second type contains large granular vesicles (ca 200 nm) of variable electron density. 5,7-Dihydroxytryptamine injected into the head capsule labelled varicosities in the neural sheath, corresponding to the ones identified with serotonin immunocytochemistry. The electron-dense labelling was seen in flattened vesicles within these varicosities. We propose that the serotonin-immunoreactive fibers in the neural sheath constitute neurohemal regions for the release of serotonin into the circulation. The finding of another morphological type of varicose fibers in the neural sheath suggests the presence of further putative neurohormones in these regions.     

A study of excitatory neuromuscular transmission in the bovine trachea

1. The excitatory innervation of bovine tracheal smooth muscle has been studied with the sucrose-gap apparatus.2. Single 2 ms electrical stimuli applied to the whole tissue excited intrinsic nerves, and produced a small transient depolarization of the smooth muscle, the excitatory junction potential (e.j.p.). The e.j.p. caused a twitch-type contraction; twitches and e.j.p.s summated during repetitive stimulation but facilitation was not observed, and action potentials were never elicited.3. The effects of electrical stimulation could be abolished by atropine (5 x 10(-7) mol/l) and augmented by neostigmine (4 x 10(-6) mol/l), and were mimicked by exogenous acetylcholine (1.0 mug/ml).4. With the electron microscope, the density of innervation was found to be low (one axon per ninety smooth muscle cells). Axons were found in small groups in the clefts between bundles of cells, but no axons penetrated within the muscle bundles. Naked axon varicosities containing agranular vesicles were seen, but no axon approached within 200 nm of a smooth muscle cell.5. It is difficult to reconcile the sparsity of innervation with the dependence of the tissue on nerve excitation to initiate activity.     

Development of neuromuscular junctions on small mesenteric arteries of the rat

This ultrastructural study has investigated the development of the innervation of second order mesenteric arteries from the ileum region of the rat intestine, particularly, the time course of the formation of the plexus of varicose axons around the arteries, and the formation of autonomic neuromuscular junctions. The time points studied were postnatal days-2, -4, -8 and -13. This study has revealed that the formation of neuromuscular junctions with mature structural characteristics occurred at ~2 weeks postnatal. The plexus of varicose axons developed predominantly between day-4 and day-13, which agrees with previous light microscopy studies of catecholamne containing nerves around similar vessels. At day-2 and day-4, the axons lacked varicosities and were mainly contained in large bundles located in the outer region of the adventitia. The medio-adventitial border consisted of a dense layer of extracellular matrix and fibroblasts. By day-8, there were more axons and most were distributed in smaller bundles. Some had grown through the adventitia to lie at the medio-adventitial border and axon varicosities were also observed. Some varicosities had formed rudimentary neuromuscular contacts. By day-13, there were significantly more contacting varicosities compared to day-8. They were structurally more mature, being twice the size with three times the number of synaptic vesicles and consistently contained a mitochondrion. Conversely, the neuromuscular contact areas were similar at both time points. Some organisation of the synaptic vesicles associated with the prejunctional membrane, was evident in varicosities at day-8 but there were no presynaptic membrane specialisations similar to the putative neurotransmitter release sites found at mature skeletal neuromuscular junctions. The aggregation of small vesicles at the prejunctional membrane was more pronounced in neuromuscular junctions at day-13 with some having presynaptic membrane specialisations. Comparison of the structure of developing autonomic neuromuscular junctions with that of skeletal neuromuscular junctions has revealed a number of similarities.     

Regional and laminar density of the dopamine innervation in adult rat cerebral cortex

The topographic distribution and density of the dopamine innervation in adult rat cerebral cortex were investigated by means of a recently improved radioautographic procedure for the light microscopic visualization and counting of monoamine axonal varicosities. Dopamine terminals were specifically labeled by high-affinity uptake in whole cerebral hemisphere slices incubated for 15 min at 35 degrees C with 10(-6) M tritiated dopamine in the presence of 10(-4) M pargyline and 5 X 10(-6) M desipramine. The slices were subsequently fixed, embedded in Epon and processed for light microscope radioautography as large 4-micron-thick (whole hemisphere) or smaller, semi-thin sections (selected areas). In radioautographs of serial semi-thin sections exposed for various periods of time, the number of labeled axonal varicosities reached a plateau after 12-14 days of exposure. Counts on such sections of increasing thickness allowed to calculate a correcting factor to transform numbers obtained from 4-micron-thick sections into their equivalent for a tissue thickness of 0.5 micron from which all varicosities were detected. The number of labeled varicosities could then be expressed per mm3 of tissue after measuring their mean caliper diameter in electron microscope radioautographs. As visualized at 3 transverse levels representing most of the major cytoarchitectonic divisions of cerebral cortex, two novel aspects were recognized in the topographic distribution of dopamine terminal: (1) the presence of a dopamine innervation in layer VIb of the frontal, parietal, temporal and occipital neocortex, and (2) a significant contingent of dopamine varicosities within the deep and not only upper layers of supragenual cingulate cortex. A fair number of dopamine varicosities were also detected in the upper layers of the dorsomedial frontal area, in the retrosplenial and adjacent occipital cortex as well as in the ventral subiculum and field CAl of the hippocampus. As measured in 10 sectors representing different cortical regions, the highest density of dopamine innervation was found in the supragenual cingulate cortex (1.7 X 10(6] and particularly in its layers II and III (3.1 X 10(6)). A slightly lower density was measured in the anteromedian "prefrontal" cortex (1.0 X 10(6)). The rostrorhinal and the perirhinal cortex showed moderate dopamine innervation (3.0 and 5.5 X 10(5)) with varicosities in every layer. The piriform and the posterior entorhinal cortex were also moderately and ubiquitously innervated (2.5 and 3.0 X 10(5)).(ABSTRACT TRUNCATED AT 400 WORDS)     

Localization of tritiated norepinephrine in the renal arteriolar nerves

The innervation of the glomerular arterioles was investigated by light and electron microscopy autoradiography for localization of exogenous tritiated norepinephrine. By light microscopy accumulations of grains were seen associated with afferent arterioles and in lesser numbers with efferent arterioles and neighboring tubules. Accumulations of grains were noted to be in contact with juxtaglomerular granular cells. Electron microscopy autoradiography revealed that nearly two-thirds of the silver grains were on axons. Most of the label was on varicosities packed with small, clear and dense-cored, vesicles. Most varicosities, including those in contact with smooth muscle, juxtaglomerular granular or tubular cells, were labeled. Some varicosities which appeared unlabeled in a given section were labeled in subsequent sections. These findings are consistent with the notion that the glomerular arterioles are innervated mainly by adrenergic nerves. This view is supported by the previously reported observations of the concomitant virtual disappearance of fluorescent and acetylcholinesterase-positive nerves from the region of the glomerular arterioles after two injections of six-hydroxydopamine (a drug which selectively destroys adrenergic nerves) and the presence of small dense-cored vesicles in all axons of the juxtaglomerular region when examined by serial section electron microscopy.     

Sensory components in the terminal innervation of the ovine cardiac conduction system

Neuromuscular relationships in the cardiac conduction system of the ovine heart were studied by means of light and electron microscopy. Fluorescence microscopy was used to demonstrate the distribution of adrenergic nerves. Histochemical methods demonstrated sites of acetylcholinesterase and nonspecific cholinesterase activity at both light and electron microscopic levels. Surgical denervation was used in an attempt to support the identification of different types of nerve endings. A dense plexus of nerves strongly positive for acetylcholinesterase was present in all parts of the conduction system. Nonspecific cholinesterase was found to be limited to large nerve bundles which were presumed to be preganglionic. A dense plexus of adrenergic nerve fibers was identified in both the SA and AV nodes, but such fibers were very sparsely distributed along the AV bundle and its branches. On the basis of morphology as demonstrated by electron microscopy, three types of nerve endings or varicosities associated with the specialized cells of the conduction system were identified. Cholinergic endings, presumably post-ganglionic parasympathetic, contained many nongranulated synaptic vesicles. Adrenergic or post-ganglionic sympathetic endings or varicosities contained granulated synaptic vesicles. Axonal enlargements containing numerous mitochondria and varying numbers of pleomorphic dense bodies were identified as sensory endings on the basis of their morphologic similarity to such endings found elsewhere in the animal body. These were found in 22% of the blocks examined by electron microscopy, were present in all parts of the conduction tissue, and were acetylcholinesterase positive. They did not show obvious signs of degeneration following vagotomies or thoracic sympathectomy, suggesting the possibility that they were endings of neurons intrinsic to the heart. No signs of degeneration were noted in the endomysial plexus following vagotomy either proximal or distal to the distal (nodose) ganglion. Degeneration of small fibers of the plexus was noted following thoracic sympathectomy. This study provides evidence suggesting a significant sensory innervation to the cardiac conduction system, with the cell bodies of the sensory neurons located in or near the heart.     

Development and ageing of intestinal musculature and nerves: the guinea-pig taenia coli

The fine structure of taenia coli was studied by electron microscopy in guinea-pigs from birth to old age (over 2 years old). Smooth muscle cells are approximately 1,000 microm(3) in volume at birth, 2,200 microm(3) in young adults and 4,500 microm(3) in old age. Muscle growth and muscle cell enlargement continue throughout life, an increase in muscle volume of about 240 times. Differentiated muscle cells divide during development and in adults. Because mitoses are found in any part of the muscle, the tissue grows from within, rather than by addition at the ends or borders. There is progressive increase in nucleus volume, and decrease in surface-to-volume ratio and in nucleus-cell volume ratio in muscle cells. At all ages the taenia consists of a uniform population of muscle cells (apart from dividing cells); there are no undifferentiated cells, no precursor cells or myoblasts, and no degenerating cells. Interstitial cells and fibroblasts are observed at all ages with only small variations in relative number. The amount of intramuscular collagen increases in old age. There is roughly one capillary for every 170 muscle cell profiles at birth, and one for every 200 in adults and in old age. The innervation is dense and reaches all parts of the muscle. In adults there are approximately 1,300 axons per 10,000 microm(2) of sectional area, or between 8,000 and 38,000 axons in a full cross section of taenia; this amounts to approximately 2% of the muscle volume. An answer to the question of why there are so many nerves in the taenia was not found. Expanded axon profiles are part of typical varicose fibres. Varicosities are packed with small clear vesicles and lie at the surface of nerve bundles. Absence of strong, constant patterns indicating specialized contacts of the nerve terminals is a feature of these nerves at all ages. Some varicosities are closest to interstitial cells; more commonly they are close to muscle cells at sites that strongly suggest a neuro-muscular junction. The additional possibility that some varicosities are part of afferent fibres is discussed. The innervation is well developed at birth and the highest density of innervation is found around day 4 when 4% of the taenia consists of nervous tissue. The innervation of immature taenia is characterized by close juxtaposition of axons and muscle cells. Axon profiles packed with vesicles, varicosities and presumptive neuro-muscular junctions are present at birth. The extent of Schwann cells in intramuscular nerves is markedly less than in adults, and virtually all the axons have maximal membrane-to-membrane contact with other axons. In taenia of aged guinea-pigs, the density of innervation is reduced. There is no actual loss of nerve tissue; the total amount of nerve tissue is greater than in young adults, and the apparent reduction reflects a more intense growth of muscle cells. The Schwann cell component becomes more conspicuous than in young adults and there is a greater number of axons fully wrapped by a Schwann cell. Presumptive neuro-muscular junctions are common and probably commoner than in young adults. Growth of muscle cells, changes in their cytological features and in the stroma occur throughout life, including old age. Nerves too continue to grow and undergo structural changes in pattern of distribution, relation with Schwann cells and effector cells.     

Suggestive evidence for a direct innervation of mucosal mast cells

Mast cells are often observed near nerves and functional evidence suggests an innervation of these cells. In the present ultrastructural study, nerve terminals containing many small clear vesicles and a few large vesicles with dense matrix were observed in direct contact with the plasma membrane of mucosal mast cells in the rat ileum, strongly suggestive of a direct innervation.     

Quantification of the dopamine innervation in adult rat neostriatum

Conditions leading to specific and integral visualization of dopamine axon terminals (varicosities) were tested in adult rat cerebral hemisphere slices incubated with [3H]dopamine and processed for high resolution radioautography. Specific visualization of the dopamine endings was achieved after incubation with 10(-6) M [3H]dopamine in the presence of a monoamine oxidase inhibitor (pargyline 10(-4) M), and of desipramine (5 X 10(-6) M), an inhibitor of catecholamine uptake by noradrenaline and serotonin neurons. [3H]Dopamine varicosity labeling was eliminated by the addition of 5 X 10(-5) M benztropine (an inhibitor of catecholamine uptake by catecholamine neurons), and was almost absent when dopamine nerve cell bodies of the midbrain had been previously destroyed with 6-hydroxydopamine. In dopamine-denervated neostriatum incubated without desipramine, a second set of labeled terminals was also visible. These were identified as serotoninergic, since their labeling was suppressed by citalopram, an inhibitor of monoamine uptake highly specific for serotonin neurons. There was no desipramine-sensitive but citalopram-resistant varicosity labeling suggestive of neostriatal noradrenaline innervation. In normal striatum, incubation at 35 degrees C always resulted in a labeling of dopamine varicosities restricted to a narrow band which followed the contours and cut surface of this anatomical region. This unusual distribution was the result of an uptake barrier generated by the tightly packed dopamine varicosities. Indeed, the striatal dopamine varicosity labeling was more widespread after partial 6-hydroxydopamine denervation or in normal tissue incubated either with a higher [3H]dopamine concentration (5 X 10(-6) M), in the presence of relatively low benztropine concentrations (10(-5) M), or at lower temperature (15 degrees C). Material incubated at 15 degrees C for 90 min was suitable for purposes of quantification: labeled varicosities were then visualized throughout the striatum and across the full thickness of the slices; moreover, the number of labeled varicosities plotted against radioautographic exposure time increased in parallel and reached a plateau at the same time in neostriatal sectors with widely different innervation densities. At a rostral transverse level across neostriatum, the dorsolateral quadrant showed hyperdense "patches" of labeled terminals distinguishable from an already dense surrounding "matrix", whereas, ventromedially, the dopamine innervation appeared more uniform and somewhat less dense.(ABSTRACT TRUNCATED AT 400 WORDS)     

Ultrastructural immunocytochemical study of the dopaminergic innervation of the rat lateral septum with anti-dopamine antibodies

The dopaminergic innervation of the rat lateral septum has been investigated at ultrastructural level by immunocytochemistry using the unlabelled peroxidase-anti-peroxidase method with anti-dopamine antibodies. The specificity of the reaction has been carefully checked by immunological and histochemical controls. A strong immunoreaction was observed in fibres of the lateral septum as well as in their cells of origin in the ventral tegmental area. In the lateral septum, dopamine-immunoreactive fibres were localized in two distinct areas. A first area, located ventrally in the anterior part of the septum was characterized by a high density of immunoreactive varicosities with barely visible intervaricose segments. A more dorsal area, extending throughout the anteroposterior region of the septum, was characterized by immunoreactive fibres in pericellular arrangements. Electron microscopic observations revealed no difference in the ultrastructure of dopamine-immunoreactive profiles in the different areas. Reaction product was found in vesicles, linked to microtubules and in the cytoplasm. Three types of vesicles were seen: (i) small vesicles (30-50 nm) with varying intensity of immunoreaction, filling up the varicosities; (ii) rare large clear vesicles (50-80 nm) with no internal immunoreaction; (iii) very rare large dense vesicles (50-100 nm) with a strong dopamine immunoreactivity. Labelled profiles were observed in clearly defined asymmetrical synaptic contacts with somata and dendrites. Due to the lack of previous work dealing with the use of anti-dopamine antibodies for electron microscope immunocytochemistry, our observations are compared to previous data obtained by more indirect labelling techniques.     

Innervation of human nasal glands

Summary The innervation of human nasal glands was investigated with the electron microscope in 14 males and 11 females using osmium and permangante fixed material. Acetylcholinesterase activity was localized electron microscopically in formalin fixed tissues.It was found that the tubuloalveolar glands possessed myoepithelial cells which extended over the basal surfaces of the secretory cells and were attached to them by desmosomes. The glands were supplied by fenestrated capillaries. Periacinar and intraepithelial nerves of the glands exhibited high positive acetylcholinesterase and negative butyrocholinesterase activity. The reaction product was localized in the interval between the axolemma and the cell membranes of the secretory, myoepithelial or Schwann cells, respectively. The axon varicosities of the periacinar nerves and the intraepithelial endings contained accumulations of agranular vesicles in preparations fixed with osmic acid, formalin or permanganate solutions, signifying cholinergic nerves. The blood vessels of the nasal glands were supplied by cholinergic and adrenergic nerves.     

Scanning electron microscopic studies of bullfrog sympathetic neurons exposed by enzymatic removal of connective tissue elements and satellite cells

Summary The ninth and tenth abdominal sympathetic ganglia of bullfrogs were studied by light microscopy and transmission and scanning electron microscopy after the removal of the connective tissue elements overlying the neurons. Digestion of tissues with trypsin and subsequent acid hydrolysis exposed the unipolar neurons, which remained covered by their satellite cells. The preganglionic innervation was visible on the proximal segment and axon hillock region of the postganglionic neurite. Clusters of small cells seen at the periphery of ganglia probably corresponded to groups of cells with abundant catecholamine-containing granules (SIF cells). Digestion with collagenase and protease removed some or all of the satellite cells in addition to the connective tissue. The true neuronal surfaces had short finger-like processes, whereas the external surfaces of satellite cells were smooth. Preganglionic nerve varicosities were clearly visible on the proximal segment of the postganglionic neurite, on the axon hillock and on the cell body of neurons. A few axonal varicosities were fractured to reveal the synaptic vesicles within. The possible effects of the distribution and glial ensheathment of nerve varicosities on their function are discussed.     

Origin,distribution, and morphology of serotonergic afferents to the cat superior colliculus: a light and electron microscope immunocytochemistry study

Summary We have studied the serotonergic (5-HT) projection to the cat superior colliculus (SC) using serotonin antibody immunocytochemistry and retrograde transport of peroxidase-conjugated wheatgerm agglutinin (WGA-HRP). In 3 experiments, the two labels were combined in order to double label cells with both anti-5-HT and WGA-HRP. In the remaining experiments, the two labels were examined separately. Serotonin-like immunoreactive fibers were found throughout all layers of SC, but were most densely distributed within the zonal and upper superficial gray layers. Most 5-HT fibers were thin and had characteristic varicosities and terminal swellings. At the EM level, immunoreactive terminals and varicosities were found to contain small agranular vesicles and occasionally large granular vesicles (LGVs). Conventional synaptic densities were only rarely observed. Injections of WGA-HRP into SC resulted in labeling of neurons throughout the dorsal raphe nucleus and surrounding ventrolateral periaqueductal gray. Only a few cells were found in the raphe medianus and raphe pontis and none within the raphe magnus or other medullary raphe nuclei. Cells in the dorsal raphe giving rise to the SC projection varied in shape, size, and morphology and must represent more than one cell type. The morphology of these cells was indistinguishable from that of cells in the dorsal raphe which were double labeled by anti-5-HT and WGA-HRP. We conclude that the 5-HT innervation of the superior colliculus varies in density in different laminae, arises from several different cell types, and originates primarily from the dorsal raphe nucleus with minor projections from raphe medianus and raphe pontis.     

Ultrastructural basis of monoamine and acetylcholine function in CNS

Recent immunoelectron microscopic studies of the acetylcholine innervation in adult rat cerebral cortex, neostriatum and hippocampus reveal a frequency of synaptic relationships as low for these axon terminals (varicosities) as previously demonstrated for the noradrenaline innervation in cerebral cortex or hippocampus, and the serotonin innervation in neostriatum. The dopamine system is more synaptic, but shows regional variability in this regard (50–100% synaptic in cerebral cortex and 30–40% in neostriatum). The microenvironment of non-synaptic varicosities consistently lacks the enrichment in dendritic spines commonly observed around control populations of unlabeled terminals randomly selected from the same electron micrographs. It is hypothesized that in brain regions densely innervated by varicosities that are mostly non-junctional (e.g. acetylcholine and dopamine in neostriatum), a basal level of transmitter is permanently maintained around all cellular elements, contributing to the modulatory properties of the corresponding systems.     

Innervation of human adrenal gland and adrenal cortical lesions

The innervation of the human adrenal gland and of cortical lesions was studied in sections of cortical tissue (n=10), hyperplastic cortical tissue (n=3), and tissue from cortical adenomas (n=5) and carcinomas (n=6). The presence and distribution of nerve structures containing neuronal markers indicating sympathetic and parasympathetic innervation were studied by immunohistochemistry and the co-existence and co-localization patterns of the different markers by immunofluorescence. The cortex and hyperplastic cortical tissue had a moderate to rich supply of nerve structures containing the typical neuronal markers: protein gene product 9.5 (PGP 9.5), neuron-specific enolase (NSE), small vesicle synaptic protein type 2 (SV2), and nerves showing immunoreactivity to the adrenergic marker tyrosine hydroxylase (TH). All these immunoreactive nerves were located predominantly adjacent to blood vessels, but also among parenchymal cells. The cortex showed numerous nerve structures containing the neuropeptide substance P (SP), neuropeptide Y (NPY) and vasoactive intestinal protein (VIP), but few nerves containing these peptides were seen in hyperplastic cortical tissue. Typical markers were occasionally observed in cortical adenomas but were not found in carcinomas, except in a few cases where PGP 9.5 and NSE were present, but only adjacent to necrotic areas. Nerves containing NPY and VIP occurred in varying numbers in both adenomas and carcinomas. NPY- and VIP-immunoreactive nerve structures were seen mostly alongside blood vessels. There were several types of co-existence. For instance, NSE/VIP-, TH/VIP- and TH/NPY-immunoreactive nerve structures were often seen in the same trunk, but were only partly co-localized. Received: 19 January 1999 / Accepted: 18 May 1999     

神经生长因子诱导后的交感神经元样PC12细胞与新生大鼠心肌细胞共培养的实验研究

探讨神经生长因子(NGF)诱导的交感神经元样PC12细胞作为体外再造心肌神经支配研究模型的可行性。用含0.04?TA的0.25%胰酶分离新生大鼠原代心肌细胞,然后与NGF诱导的交感神经元样PC12细胞共培养,通过光学显微镜观察、常规H.E.染色、激光共聚焦显微镜和扫描电镜观察等对其进行评价。结果表明:在二维共培养模型中,NGF诱导的交感神经元样PC12细胞长出神经突起,突起及其上的膨体能够到达跳动的心肌细胞表面,神经突起随心肌细胞一起跳动。采用神经元样PC12细胞作为体外再造心肌神经支配研究模型是可行的,神经细胞与心肌细胞可能存在支配关系。     

Ciliated Cells in the Human Gastric Mucosa Evidence of Metaplastic Change

In the gastric mucosa of Japanese patients, ciliated cells were found in association with intestinal metaplasia. The cells occurred frequently in the pyloric mucosa of nearly half of the cases examined but rarely in the cardiac mucosa of total 12 cases, but never adjacent to the chief cells of gastric glands. The ciliated cells were always found in the basal part of cardiac and pyloric glands, but never in the surface or in the foveolar epithelium. Furthermore, ciliated cells containing a few small mucus granules and simultaneously possessing numerous cilia and basal bodies were noted. Ciliated cells in the gastric mucosa have been found mainly in elderly Japanese patients, but were also observed exceptionally in one Chinese, two Swedes and one American. These ciliated cells are not present in the normal human gastric and intestinal mucosa, and therefore a new term, "ciliated metaplasia", is proposed for their occurrence. Acta Pathol Jpn 40: 98–106, 1990.     

Ultrastructural demonstration of adenylate cyclase activity in the rat neostriatum.

The ultrastructural histochemical localization of adenylate cyclase activity in the rat neostriatum was studied using cobalt as a precipitating agent. Basal adenylate cyclase activity was found intracellularly in some dendrites, whereas the neuronal cell bodies and glial cells were negative. In vitro stimulation of the tissue slices with dopamine before the histochemical procedure increased the adenylate cyclase activity which was also found associated with the postsynaptic membranes of axodendritic and axo-spinous synapses mainly containing small empty vesicles. Activity was also seen intracellularly in some nerve terminals containing synaptic vesicles.The significance of the cytochemical localization of dopamine-stimulated adenylate cyclase and the possible morphology of the dopaminergic synapses, including their possible interconnections, are discussed.