Histochemical demonstration of monoamine oxidase in the hypothalamo-hypophysial system of the tree sparrow and the rat

Summary Localization of monoamine oxidase (MAO) was investigated essentially according to the method of Glenner et al. (1957) in the hypothalamo-hypophysial system of the tree sparrow and the rat. The hypothalamic neurosecretory cells of both species showed relatively weak MAO activity. A similar localization of MAO activity was observed in the median eminence of both species: (1) slight or no MAO activity was observed in the ependymal layer, (2) relatively strong activity was revealed in the tissue just beneath the ependymal layer, (3) strong activity was revealed in the outer layer, particularly in the tissues surrounding capillary loops of the primary plexus. It is suggested that an adrenergic mechanism functions in the median eminence. In the pars nervosa, strong reaction was observed in the rat, while a weak reaction occurred in the tree sparrow. However, the color and the size of formazan crystals deposited in the rat pars nervosa differed from those in the hypothalamus. As a whole, the distribution of the neurosecretory material differed from the localization of MAO activity in the hypothalamo-hypophysial system. It is discussed that the neurosecretory neuron is not adrenergic but cholinergic.Aided by Grant A-3678 from the United States Public Health Service. The authors are indebted to Dr. S. Kambara, Zoological Institute, and Dr. H. Hirano, Department of Anatomy, University of Tokyo, for their valuable advice, and also to Assoc. Prof. S. Yamamoto, Department of Hygiene, University of Tokyo, for making available some facilities. They also wish to thank Dr. L. M. Barbato, University of Illinois, and Mr. K. Asami, National Institute of Radiological Sciences, Chiba, and Mr. Suzuki, Research Laboratory, Chugai Pharmaceutical Company Ltd., Tokyo, for the kind supply of MAO inhibitors.     

The ultrastructural localization of a cholinesterase in the body muscle of plaice (Pleuronectes platessa)

Summary By means of a histochemical method adapted for electron microscopy a cholinesterase in body muscle cells of plaice (Pleuronectes platessa) has been localized to the sarcolemma. The cholinesterase activity disappeared from the sarcolemma after the muscle tissue had been incubated with a bacterial enzyme, which had earlier been shown, by biochemical methods, to be able to liberate this cholinesterase activity from plaice muscle.The provision of live plaices from Kristineberg Zoological Station, Fiskebäckskil, Sweden, is gratefully acknowledged. We are greatly indebted to Dr. Åke Bovallius, FOA, who provided the starting material for the bacterial enzyme. We would like to express our sincere thanks to Prof. Lennart Nicander for valuable discussions and for placing the resources of the Department of Anatomy and Histology, Royal Veterinary College, to our disposal.     

Über die segmentale Ausbildung der Neurophysis spinalis caudalis bei einigen Fischarten

Zusammenfassung Das Kaudalrückenmark von Thunfischen (Thunnus, Neothunnus, Parathunnus), Igelfisch (Canthigaster rivulatus) und Zenopsis nebulosa wurde makroskopisch und histologisch im Hinblick auf die Ausbildung einer Neurophysis spinalis caudalis untersucht. Bei allen untersuchten Spezies wurden außer der Neurophysis spinalis caudalis im Bereich des letzten Wirbels noch neurophysäre Anschwellungen im kaudalen Rückenmarksanteil beobachtet. Die Neurophysen vom Thunfisch treten in einigen kaudalen Rückenmarkssegmenten regelmäßig auf. Die Neurophyse der Teleostier ist nicht immer ein einziges Organ. Bei einigen Fischarten ist sie multipel ausgebildet.Herrn Prof. Dr. T. Ogawa zum 60. Geburtstag gewidmet.     

An ultrastructural and physiological investigation of the retractor muscles of Gené's organ in the cattle ticksBoophilus microplus andAmblyomma variegatum

The ultrastructures of the retractor muscles of Gené's organs in the cattle ticksBoophilus microplus andAmblyomma variegatum are described. The innervation, neuromuscular junctions, and insertions of the muscles are also described. The retractor muscles are important in controlling the actions of Gené's organ, the egg waxing organ in ticks, during oviposition in the female. The ultrastructural features of the muscles are typical of arthropod muscles, and the nerve terminals at the neuromuscular junctions contain small electron lucent synaptic vesicles with a diameter of 50 nm, and also larger dense core vesicles with a diameter of 100 nm. Evidence is presented implicatingl-glutamate andl-aspartate as putative excitatory transmitters at the tick neuromuscular junction. The excitatory post-synaptic potentials recorded in the muscles were abolished in the presence of low concentrations ofl-glutamic acid andl-aspartic acid, but were unaffected by acetyl-choline, 4-aminobutyric acid and octopamine, suggesting that glutamic acid and aspartic acid interact with receptors on the muscle membrane.     

Micropinocytotic invaginations in the axolemma of peripheral nerves

Summary Coated invaginations of the axolemma in myelinated axons of the sciatic nerve of young mice are described. Such invaginations occur preferentially in the area of the inner Schwann cell lip. It is suggested that they may be involved in the transport of metabolites between Schwann cell and axon.Supported by Grants NB-07512-01, NB-02665 (NIH), and GY-108, GB-3128 (NSF). The author wishes to thank Prof. J. D. Robertson for his support of early parts of this work, which was carried out in part at the Dept. of Anatomy, University College London.     

On the glycocalyx,the external coat of the plasma membrane,of some secretory cells

Summary The free surface of epithelial cells of secretory organs (human placenta, lactating mammary gland of the rat, choroid plexus of man and rat) and of the accessory organs of the genital tract of the male rat is characterized by a plasmalemmal differentiation named glycocalyx or surface mucous coat. This structure is built up by filamentous or globular substructures.Two main ultrastructural types of the glyeocalyx were observed: 1) The filamentous type such as in the rat epididymis, which resembles the cat intestinal glyeocalyx (Ito, 1965) and that one of human transitional epithelium (Monis and Zambrano, 1968), and 2) The globular type, as observed in the lumen of the lactating mammary gland of the rat.Sialic acid was demonstrated histochemically in the luminal glyeocalyx of all organs studied. In addition, the glyeocalyx of acinar cells of the lactating mammary gland contains sulfate and phosphate groups which were identified by histochemical technics, using enzymatic digestion procedures, suggesting the chemical heterogeneity of this glyeocalyx.Present investigations follow the working hypothesis that the complex carbohydrates of glycocalyces become part of the product of activity of secreting cells.We thank Mr. Luis Iwakawa, Miss Silvia Falcón, Miss Elsa M. Orgnero for technical help, Miss Graciela Aliaga for secretarial assistance. Photography by Mr. H. Magnani. Dr. Hugo F. Carrer cooperated in the initial stages of this investigation.The authors acknowledge the use of the electron microscope of the Department of Pathology, Córdoba University Medical School, for which they thank Prof. E. Mosquera and Dr. E. Hliba. Dr. Hliba photographed picture number 4.     

DEVELOPMENT OF THE NEUROMUSCULAR JUNCTION : II. Cytological and Cytochemical Studies on the Neuromuscular Junction of Dedifferentiating Muscle in the Regenerating Limb of the Newt Triturus

Following amputation of the limb of the newt, Triturus viridescens, muscle fibers dedifferentiate giving rise to mesenchymal cells. The earliest changes detected in neuromuscular junctions of dedifferentiating muscle fibers are the appearance of a few vacuoles and decrease in density of the terminal axoplasm. Later, synaptic vesicles become tightly clustered in the axon termination, and their content appears denser than normal. Then, vesicles diminish in number until few are seen in the ending. While these changes are occurring, the area of contact of nerve with muscle becomes smaller. Junctional folds persist only where the nerve maintains contact with muscle, but these are shorter than normal and appear as slight ridges on the muscle surface. Subsequently, the nerve withdraws from the muscle cell and is completely invested by Schwann cell cytoplasm, and all traces of junctional folds are lost at the former region of contact. Cholinesterase activity was localized with the thiolacetic acid-lead nitrate method. Even before marked morphological changes occur in the junction, DFP- and physostigmine-sensitive activity in the cleft between nerve and muscle is decreased in intensity. Activity continues to decrease as the area of nerve-muscle contact diminishes and junctional folds disappear. When the nerve has withdrawn from the muscle surface, only a few small deposits of lead are left in the intervening region. These results show that as muscle becomes less specialized during dedifferentiation, the neuromuscular junction also loses the cytological and cytochemical specializations associated with synaptic function.     

Die Inhaltsstoffe einigerPertusaria-Arten mit C+ rot reagierendem Thallus (Lichenes,Pertusariaceae)

Zusammenfassung 67 Proben von 5Pertusaria-Arten, deren Thallus C+ rot Reaktion zeigt, wurden dünnschicht- und papierchromatographisch geprüft.P. hemisphaerica undP. velata (beide mit Lecanorsäure) sowieP. bryontha undP. subviridis (beide mit Gyrophorsäure) wurden erstmals chemisch untersucht. InP. lactea wurde das Vorkommen von Lecanorsäure und Variolarsäure bestätigt. 2 Proben, die nur alsP. lactea bestimmt werden können, jedoch dem Typ nicht entsprechen, enthielten zusätzlich Spuren Psoromsäure. Weiterhin wurden 5 Proben vonP. rupestris (C-)geprüft (mit Stictinsäure und dem Xanthon Coronaton).Beide Autoren: 1 Berlin 41, Grunewaldstr. 35.Für die Entleihung von Herbarmaterial danken wir den Herren Prof. Dr. G.Follmann (B), Prof. Dr. H.Merxmüllee (M), Prof. Dr. J.Poelt (Berlin) und Dipl.-Ing. H.Ullrich (Goslar), für die Überprüfung einiger Proben Herrn Dr. O.Almborn (Lund). Für die Überlassung von Testsubstanzen sind wir den Herren Prof. Dr. G.Follmann (B), Dr. habil. S.Huneck (Freital) und Frau Dr. C. F.Culberson (Durham, N. C.) zu Dank verpflichtet. — Herrn Prof. Dr. J.Poelt danken wir sehr für die Anregung der Arbeit und die ständige Beratung bei der Durchführung.     

Study of mast cell and histamine contents of the pineal body

Summary The number and distribution of mast cells were studied in pineal bodies of 16 mammalian species. In cattle, goat, monkey and guinea-pig the cells occurred in large numbers; in man, sheep, marmoset and mouse there was a moderate amount, and they were almost absent in pineal bodies of horse, rat, pig, dog, hamster, fox, cat and rabbit.In 17 human pineal bodies, 11 of which were obtained from normal individuals, the mast cell population was 3 ± 0.5 mast cells per microscopical field (0.32 mm in diameter).The histamine content in pineal bodies of several mammals was also determined. The substance occurred in high amount in the pineal body of cattle, in moderate amount in that of goat, man and sheep, and could not be detected in horse, pig, rabbit and rat.In human and cattle pineal bodies the histamine content could be correlated to the mast cell population; in other species the same correlation was only suggested.In in vitro experiments octylamine released histamine from the pineal body of cattle, while compound 48/80 was ineffective.It is suggested that the hypotensive action of pineal extract reported by several authors might be due to the histamine content of this gland.This work was supported in part by funds received from the Conselho Nacional de Pesquisas of Brazil and The Rockefeller Foundation (Grant 61119). — Acknowledgement. For encouragement and criticism the authors wish to express their gratitude to Prof. Dr. W. T. Beraldo (Department of Physiology) and Prof. Dr. L. J. A. Di Dio (Department of Anatomy).Fellow of the Conselho Nacional de Pesquisas of Brazil.     

Über den Feinbau der Duftdrüsen von Heteropteren

The scent-production and the scent-delivery in the posterior larval gland of the cotton bug Dysdercus intermedius Dist. was explored by means of light microscopy and electron microscopy.

---

---

Mit dankenswerter Unterstützung durch die Deutsche Forschungsgemeinschaft.

---

Herrn Prof. Dr. R. Danneel danke ich für beratende Hilfe. Für die Anfertigung der elektronenmikroskopischen Aufnahmen stellte mir freundlicherweise Herr Prof. Dr. E. Scholtyseck das Mikroskop Zeiss EM 9A zur Verfügung. Fräulein Karin Wenzelmann und Fräulein Barbara Vogt danke ich für technische Assistenz.

---

Herrn Prof. Dr. Dr. R. Lermensick zum 70. Geburtstag gewidmet.     

Histochemical detection of l-gulonolactone: phenazine methosulfate oxidoreductase activity in several mammals with special reference to synthesis of vitamin C in primates

Summary An improved detection of activity of l-gulonolactone oxidase, which is responsible for the final oxidative step in the synthetic process of l-ascorbate from glucose in animals, was achieved using phenazine methosulfate and cyanide. Cold acetone fixation eliminated non-specific deposition of formazan on lipid droplets. The specificity of the method was tested and proven by a biological control, histochemical controls, inhibitors and activators. By application of the method, strong reactivity was found in the cytoplasm of centrilobular parenchymal cells of livers of the opossum, rat, ground squirrel and flying squirrel. Staining of dog liver was moderate and centrilobular. Prosimians were strongly positive: The centrilobular localization was found in the tree shrew and galago; slow lorises and some pottos showed strong reactivity in centrilobular cells and some peripheral cells as well. These prosimians seem to be able to synthesize l-ascorbate as many lower mammals are. On the contrary, true simians (i.e. the squirrel monkey, spider monkey, rhesus monkey and chimpanzee) were negative as guinea pigs were, suggesting their probable inability for l-ascorbate synthesis.Visiting scientist from the Department of Anatomy, Tokyo Medical and Dental University, Tokyo, Japan. T. R. Shanthaveerappa in previous publications, also fellow, Department of Anesthesiology, Emory University.     

Development of the myoneural junction in the rat

Summary The structure of the myoneural junction in the striated muscle of rat embryos and postnatal rats was studied by electron microscopy in order to assess at ultrastructural level the roles of neuronal and muscular elements and the sequence of events resulting in the formation of a functionally mature synaptic organization.From the observations it is concluded that the axon terminals enveloped by Schwann cells contain vesicles prior to apposition of the prospective synaptic membranes. Subsequently, subsarcolemmal thickening of the postsynaptic membrane takes place after the synaptic gap has been formed by disappearance of the teloglial cell from between the synaptic membranes but before the primary synaptic cleft in the strict sense is formed. Secondary synaptic clefts are formed later, when the primary synaptic cleft is regular in width, by local finger-like invaginations of the postsynaptic membrane, which thereafter expand basally, in a plane transverse to the axis of the axon terminal, to resemble flattened flasks. The junction is formed between multinucleated muscle cells and multiple axons, which at first lie side by side and later, when formation of adult-type secondary synaptic clefts is in progress, become separated by folds of the sarcoplasm and the teloglia. In extraocular muscles of adult rats the sarcoplasmic reticulum is closely associated with the postjunctional sarcoplasm.In the light of earlier observations on the development of contractibility after nerve stimulation, cholinesterase histochemistry and muscle fibre physiology, these observations are interpreted to indicate that functional differentiation of the myoneural synapse results from induction by the motor axon and that the association of the sarcoplasmic reticulum with the postjunctional sarcoplasm in adult extraocular muscles is related to modified fibre physiology.The author wishes to thank Prof. Antti Telkkä, M.D., Head of the Electron Microscope Laboratory, University of Helsinki, for placing the electron microscopic facilities at his disposal.     

Supramolecular organization of the subsarcolemmal cytoskeleton of adult skeletal muscle fibers. A review

This review is focused on the composition and organization of the junctional subsarcolemmal cytoskeleton of adult muscle fibers. The cytoskeleton of muscle fibers is organized in functionally distinct compartments and the subsarcolemmal cytoskeleton itself can be broadly divided into junctional (myotendinous junction, neuromuscular junction and costameres) and non-junctional domains. In junctional zones three different multimolecular cytoskeletal complexes coexist: the focal adhesion-type, the spectrin-based and the dystrophin vs utrophin-based membrane skeleton systems. These complexes extend over several levels, from intracytoplasmic to subsarcolemmal and transmembranous; their common feature is the anchorage of actin filaments emanating from the intracytoplasmic level. The different cytoskeletal proteins, their putative roles and their interactions with various signaling pathways are presented here in detail. The subsarcolemmal cytoskeleton complexes are thought to play distinct physiological roles (membrane stabilization, force transmission to extracellular matrix, ionic channel anchorage, etc) but their colocalization on the three sarcolemmal junctional domains strongly suggests interrelated or common functions.     

Electron microscopic observations of lung alveolar epithelial cells of normal young mice,with special reference to formation and secretion of osmiophilic lamellar bodies

Summary Using the electron microscopy and electron microscopic histochemistry the authors studied the lung alveolar epithelial cell of normal young mice.Type II cell of the alveolar epithelium has characteristically numerous osmiophilic lamellar bodies. The lamellar boies are formed in the cytoplasmic vesicle, and never originate from the mitochondrion. These bodies have abundant acid phosphatase activity in their limiting membrane therefore it is considered to be lysosomal origin, but the mitochondria have no such enzyme activity.The body which is newly formed in the cytoplasmic vesicle grows up to the large lamellar body as a result of an accumulation of the fibrous dense substance, migrates to the free margin of the type II cell of alveolar epithelium, and then is discharged into the alveolar lumen as a merocrine type secretion.Acknowledgement is given to Professor Dr. Y. Sano and Professor Dr. H. Fujita, Department of Anatomy, and Assistant Professor Dr. S. Fujita, Department of Pathology, for their kind advice and criticism.     

Unusual neuromuscular junctions in the heart of the crayfish (Procambarus clarkii)

Summary The neuromuscular junctions in the crayfish heart were studied with the electron microscope and were classified into two types based on the characteristics of the post-synaptic side. Type I junction was characterized by a mazy post-synaptic apparatus which has been referred to in this work as the junctional envelope, consisting of the cytoplasmic processes and/or lamellae of the muscle cell. Type II junction on the other hand, lacked the junctional envelope. The nerve terminals in both Type I and Type II junctions contained two types of synaptic vesicles: large granular and small agranular vesicles, which were about 1000 Å and 450 Å in diameter respectively. The physiological significance of these neuromuscular junctions and the nature of their synaptic vesicles are discussed.Acknowledgement. The author wishes to express sincere gratitude to Prof. T.Yamamoto for the kind encouragement and guidance during the course of this study.The presence of this unusual neuromuscular junction, coupled with the histological characteristics of heart muscles themselves (Komuro, 1968), may be involved in the different physiological properties of the crustacean heart. This subject will be discussed in a later publication by the author.     

Formation of the neuromuscular junction: molecules and mechanisms

The vertebrate skeletal neuromuscular junction is the site at which motor neurons communicate with their target muscle fibers. At this synapse, as at synapses throughout the nervous system, efficient and appropriate communication requires the formation and precise alignment of specializations for transmitter release in the axon terminal with those for transmitter detection in the postsynaptic cell. Classical developmental studies demonstrate that synapse formation at the neuromuscular junction is a mutually inductive event; neurons induce postsynaptic differentiation in muscle cells and myofibers induce presynaptic differentiation in motor axon terminals. More recent experiments indicate that Schwann cells, which cap axon terminals, also play an active role in the formation and maintenance of the neuromuscular junction. Here, we review recent advances in the identification of molecules mediating such inductive interactions and the mechanisms by which they produce their effects. Although our discussion concerns events at developing neuromuscular junctions, it seems likely that similar molecules and mechanisms may act at neuron–neuron synapses in the peripheral as well as the central nervous system. BioEssays 20 :819–829, 1998. © 1998 John Wiley & Sons, Inc.     

Vascularization of the hypophysial region of the normal and adenohypophysectomized toad

Summary The study of standarized sections of the hypophysial regions, and in vivo observations showed the presence of communicating vessels between the capillary network of the median eminence and the large capillaries of the neurointermediate junction. Moreover, direct branches from the hypophysial artery are described which give off branches, at the level of the neural stalk, to the median eminence and to the large capillaries of the neurointermediate junction.A second portal system similar to the one described by Cruz has been observed. Its primary plexus originates in several encephalic regions, and its secondary plexus is distributed through the neural lobe and thence to the pars intermedia. The course of flow in this system is a descending one. The arterial contribution to this system appears to arise from branches from the basilar and retroinfundibular arteries. — There are small venous-type vessels between the large capillaries of the neurointermediate junction and the posterodorsal region of the pars distalis. — After adenohypophysectomy, the blood which normally goes towards the pars distalis, flows towards the pars intermedia, following the path of the communicating vessels between the median eminence and the pars intermedia.This paper was presented at the VII Reunion de la Asociación Latinoamericana de Ciencias Fisiológicas (A.L.A.C.F.), Mar del Plata, Argentina, 1966. It was carried out under the auspices of the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the Rockefeller Foundation (School grant RF-58028).Fellows of the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina. — The authors wish to thank Prof. B. A. Houssay and Drs. J. H. Tramezzani and J. la Pointe for their criticism, to Prof. M. H. Burgos and Dr. F. Sacerdote for their help.     

Ein Beitrag zur Kenntnis vonApatococcus lobatus (Chlorophyta,Chaetophorales, Leptosiroideae)

Comparative investigations on the morphology, life-history, and reproduction of 3 cultivated strains of the atmophytic green algaApatococcus lobatus are presented. Some ultrastructural features are added to the results of earlier investigations, and comments on the systematics and ecology are given. Morphology and cytology of each strain is variable and shows considerable overlapping. The results support the view thatApatococcus consists of a single variable species (A. lobatus) only. For the epiphytic algal associationPleurococcetum vulgaris the more significant termApatococcetum lobati is proposed.

Herrn Prof. Dr.Lothar Geitler zu seinem 90. Geburtstag gewidmet.     

Enzyme-histochemical studies on the muscle spindle

Summary Detailed studies have been made on the distribution of several enzymes in the muscle spindles of the hand and foot interosseous muscles and M. longissimus dorsi of the rhesus monkey as well as in those of the hand interosseous muscles of the squirrel monkey. The intrafusal muscle fibers (IMF) of the rhesus monkey can be classified into two types by the reaction intensity at the polar regions for adenosine triphosphatases and by the enzymes concerning the carbohydrate metabolism except glucose-6-phosphate dehydrogenase, while the extrafusal muscle fibers (EMF) show three types of reactions for the enzymes of the Embden-Meyerhof pathway and the tricarboxylic acid (TCA) cycle. The IMF and EMF of the squirrel monkey are more variable than those of the rhesus monkey for the glycogen breakdown enzyme. It is possible that the small IMF are more capable of energy production through the TCA cycle than the large IMF and the EMF in both species. The positive cholinesterases reactions are found around the polar regions of the IMF, while only the rim of the equator of the IMF shows monoamine oxidase activity. The pericapsular epithelial cells of the muscle spindle seem to be metabolically similar to the perineural epithelial cells.Visiting scientist from the Department of Anatomy, Tokyo Medical and Dental University, Tokyo, Japan. T. R. Shanthaveerappa in previous publications.