Joachim Ude

A comparative study of the immunohistochemical localization of a presumptive proctolin-like peptide, thyrotropin-releasing hormone and 5-hydroxytryptamine in the rat central nervous system.

A proctolin (PROC)-like peptide was studied immunohistochemically in the hypothalamus, lower brainstem and spinal cord of the rat using an antiserum against PROC conjugated to thyroglobulin. Neuronal cell bodies containing PROC-like immunoreactivity (PROC-LI) were observed in the dorsomedial, paraventricular and supraoptic nuclei of the hypothalamus and in the nucleus raphe magnus, nucleus raphe pallidus, nucleus raphe obscurus and nucleus interfascicularis nervi hypoglossi in the medulla oblongata. Fibers containing PROC-LI were seen in the median eminence and in other hypothalamic nuclei, and in the lower brainstem in cranial motor nuclei including the dorsal motor nucleus of the vagus nerve, the motor trigeminal nucleus, the facial nucleus and nucleus ambiguous, and in lower numbers in the nucleus of the solitary tract and locus coeruleus. Fibers containing PROC-LI were also located in the spinal cord, in the intermediolateral cell column at thoracic levels and in the ventral horns at all levels of the spinal cord. After transection of the spinal cord, all PROC-immunoreactive fibers below the lesion disappeared. Following injection of Fast blue into the thoracic spinal cord, retrogradely labeled cells in the nuclei raphe pallidus, obscurus and magnus and nucleus interfasciculari nervi hypoglossi were seen to contain PROC-LI. PROC-LI had a similar distribution as thyrotropin-releasing hormone (TRH)-LI in the above-mentioned areas and coexistence of TRH-LI and PROC-LI was shown in cell bodies in the hypothalamus and medulla oblongata. PROC-LI could also be shown to coexist with 5-hydroxytryptamine (5-HT)-LI in neuronal cell bodies in the lower brainstem. The results demonstrate the occurrence of a PROC-like peptide in the mammalian nervous system, and these neurons seem to be at least largely identical to previously described TRH systems. A possible involvement of the PROC-like peptide in spinal motor control is discussed in relation to the well-established role of PROC in control of motor behavior in insects and invertebrates.

The distribution of a proctolin-like immunoreactive material in the terminal ganglion of the cockroach, Periplaneta americana L.

SummaryNeurons with proctolin-like immunoreactivity were mapped in the terminal ganglion of Periplaneta americana. The effect of different fixation methods on the variability of immunostaining is described and discussed. The appearance of immunoreactive presynaptic terminals, described here for the first time in insects, points to a function of proctolin as neurotransmitter or neuromodulator in the central nervous system of P. americana besides its known role in the periphery. Proctolin-like immunoreactivity was shown in pre- and postsynaptic profiles. Synaptic contacts are described in detail.

Ultrastructure of the prothoracic gland cells of the last instar of Galleria mellonella in relation to the state of development

SummaryThe prothoracic glands of the last instar of Galleria mellonella undergo characteristic alterations of their cellular fine structure closely related to cellular activity. During progressive secretory activity of the gland cells there are extensive plasmalemmal infoldings and formation of a pronounced lacunar system. Mitochondria of the active cell phase are characterized by a specific increase in size and paler colour of the matrix. In contrast to the alterations, nuclei, ER and Golgi cisterns do not undergo any submicroscopic changes during the different phases of cellular activity. The relationships between the substructural phenomena and the specific phases of cellular activity are discussed.

FMRFamide-like and allatostatin-like immunoreativity in the lateral heart nerve of Periplaneta americana: Colocalization at the electron-microscopic level

Both allatostatin immunoreactivity (AS-IR) and FMRFamide immunoreactivity (FMRFa-IR) have been demonstrated light-microscopically in the lateral heart nerve of Periplaneta americana. The identifical labeling of some fibers suggests the coexistence of the two antigens. Electron-microscopically, six granule types in the peripheral part of the lateral heart nerve can be distinguished according to their size and density (types 1–6). These granule types can be subdivided immunocytochemically by means of a new mirror-section technique. Granules of types 4 and 5 always exclusively show FMRFa-IR. In the populations of fibers containing granules of types 1 and 6, axon profiles can be found that contain granules colocalizing FMRFa-IR and AS-IR. Other axon profiles of these populations only contain immunonegative granules of the same ultrastructure. Granules of type 2 can be differentiated immunocytochemically in three forms in the same section: In some fibers, they are nonreactive; in other fibers of the same section, they show FMRFa-IR, whereas in a third fiber type, granules show AS-IR. Finally, granules of type 3 can be observed with FMRFA-IR. In other fibers, they occur with the same ultrastructure but exhibit no immunoreactivity. Two soma types occur in the lateral heart nerve. Soma type I is characterized by the production of electron-dense granules that show FMRFa-IR. Type II is in close contact with various fibers, forming different types of axosomatic synapses, hitherto unknown in Insecta.

Elektronenmikroskopische Untersuchungen zur Dynamik neurosekretorischer Zellen von Enchytraeus (Oligochaeta)

Von lichtmikroskopischen Befunden der Neurosekretion bei dem Oligochaeten Enchytraeus ausgehend, haben wir an zwei elektronenmikroskopisch genau bezeichneten und festgelegten Zellen bzw. Zelltypen, die bereits lichtmikroskopisch charakterisiert worden waren, Untersuchungen uber die submikroskopisch fasbare Zelldynamik durchgefuhrt. Die beiden Arten neurosekretorischer Zellen (Q-Zelle und P-Zellen) sind elektronen-mikroskopisch schon durch ihre Lage zu erfassen. Sie konnen nicht nur durch die Zellgrose, sondern auch durch ihre Elementargranula, den Aufbau des endoplasmatischen Retikulums und den Golgi-Apparat eindeutig unterschieden werden. Wie schon in den lichtmikroskopischen Untersuchungen wurde die Sekretionsaktivitat mit der Amputation ausgelost. Sowohl in der Q -als auch in der P-Zelle bewirkt die Amputation eine unmittelbare Sekretentleerung. Die darauf einsetzende Phase der Sekretproduktion ist submikroskopisch durch eine erhohte Zahl von Golgistrukturen in diesen Zellen, durch das deutlich in Erscheinung tretende granulare endoplasmatische Retikulum und durch eine fortschreitende Vergroserung und Verdichtung von Lysosomen in beiden Zelltypen gekennzeichnet. Fur die Q-Zelle sind weiterhin die Verstarkung des diesen Zelltyp besonders noch charakterisierenden Bereiches von Membranzisternen und die dortige Ribosomenbildung typisch. Auf Grund der Feststellungen wird die Frage der Beziehung einzelner Strukturen in diesen beiden Zelltypen zur Produktion des Neuro-sekrets diskutiert. Die elektronenmikroskopische Untersuchung fuhrte zur Entdeckung eines weiteren Zelltyps, der im Lichtmikroskop bisher nicht erkannt worden war und der sich durch besonderen Reichtum an Mitochondrien und grosen Lipoid (?)-Komplexen auszeichnet (M-Zelle). Uber seine Bedeutung ist jedoch noch keine Aussage moglich.SummaryThe cytophysiology of two types of neurosecretory cells (Q and P cell) in the brain of the oligochete Enchytraeus was studied at the ultrastructural level. These cell types can be identified by their location, and particularly by the size difference of their elementary granules. Amputation of the last ten segments caused a release of secretory product followed by a phase of renewed production. This was characterized by changes in the endoplasmic reticulum, the Golgi apparatus, and the lysosomes. The role of these structures in the production of neurosecretory material was discussed. Furthermore, a cell type with extraordinarily numerous mitochondria, hitherto unknown in Enchytraeus, was described. Its function has not yet been determined.ZusammenfassungVon lichtmikroskopischen Befunden der Neurosekretion bei dem Oligochaeten Enchytraeus ausgehend, haben wir an zwei elektronenmikroskopisch genau bezeichneten und festgelegten Zellen bzw. Zelltypen, die bereits lichtmikroskopisch charakterisiert worden waren, Untersuchungen über die submikroskopisch faßbare Zelldynamik durchgeführt. Die beiden Arten neurosekretorischer Zellen (Q-Zelle und P-Zellen) sind elektronen-mikroskopisch schon durch ihre Lage zu erfassen. Sie können nicht nur durch die Zellgröße, sondern auch durch ihre Elementargranula, den Aufbau des endoplasmatischen Retikulums und den Golgi-Apparat eindeutig unterschieden werden. Wie schon in den lichtmikroskopischen Untersuchungen wurde die Sekretionsaktivität mit der Amputation ausgelöst. Sowohl in der Q -als auch in der P-Zelle bewirkt die Amputation eine unmittelbare Sekretentleerung. Die darauf einsetzende Phase der Sekretproduktion ist submikroskopisch durch eine erhöhte Zahl von Golgistrukturen in diesen Zellen, durch das deutlich in Erscheinung tretende granuläre endoplasmatische Retikulum und durch eine fortschreitende Vergrößerung und Verdichtung von Lysosomen in beiden Zelltypen gekennzeichnet. Für die Q-Zelle sind weiterhin die Verstärkung des diesen Zelltyp besonders noch charakterisierenden Bereiches von Membranzisternen und die dortige Ribosomenbildung typisch. Auf Grund der Feststellungen wird die Frage der Beziehung einzelner Strukturen in diesen beiden Zelltypen zur Produktion des Neuro-sekrets diskutiert. Die elektronenmikroskopische Untersuchung führte zur Entdeckung eines weiteren Zelltyps, der im Lichtmikroskop bisher nicht erkannt worden war und der sich durch besonderen Reichtum an Mitochondrien und großen Lipoid (?)-Komplexen auszeichnet (M-Zelle). Über seine Bedeutung ist jedoch noch keine Aussage möglich.

Submicroscopic characterization of proctolin-like immunoreactivity in the nervous system of the cockroach Periplaneta americana L.

SummaryProctolin-like immunoreactivity (PLI) was found in different parts of the arthropod central nervous system and in nerve fibers of muscles. In order to examine whether this PLI is related to a uniform type of secretory vesicle, hindgut musculature and frontal and hypocerebral ganglia were examined with the immunogold technique. PLI occurs exclusively within membran-bounded secretory granules. Neither granular ER nor Golgi stacks show PLI. In some cases close relationships between PLI-bearing granules and lysosomes were observed. In presynaptic areas, PLI-reactive granules are associated with numerous clear synaptic vesicles and restricted to an area distinctly separate from the presynaptic membrane. Three types of granules were found, differing in diameter and electron density: (1) dense, 80 nm; (2) dense, 150 nm; (3) low density, 150 nm. The results demonstrate that: (1) the PLI of the produced peptide occurs shortly after its separation from the Golgi stack; (2) the occurrence of PLI in three different granule types could be the morphological expression of the common occurrence of proctolin with other neuroactive substances. However, a possible cross-reactivity with other, hitherto unknown substances must be considered as well.

The frontal ganglion of Periplaneta americana L. (insecta)

SummaryThe frontal ganglion, part of the stomatogastric nervous system, contains about 60 to 80 neurons, 25 to 30 μm in diameter. A well developed Golgi system, producing dense-core vesicles, lysosomes, multivesicular bodies and dense bodies are abundant. Glia elements are sparsely distributed. Many nerve fibres contain granules of different size and electron density. Five groups of fibres can be distinguished: Fibres with granules of about 200 nm (type A), fibres with granules of about 160 to 170 nm (type B), fibres with granules of about 80 to 100 nm (type C) and those with synaptic vesicles of 50 nm (type D) respectively. A fifth very small type contains neither vesicles nor granules. Special attention was paid to synaptic contacts. The divergent dyad seems to be the main type in the frontal ganglion. Frequently, neurosecretory endings are observed in presynaptic position. Immunocytochemical “staining” of neurosecretory material closely corresponds to the distribution of type A fibres, as observed electron microscopically. Immunoelectrophoresis of extracts from frontal ganglia with polyspecific anti-neurosecretion-serum reveals a single precipitation line, indicating that the immunocytochemical localization of neurosecretory material is due to reaction with a specific as well as a crossreagent antibody.

The submicroscopic morphology of the heart ganglion of the spider Tegenaria atrica (C. L. Koch) and its neuroendocrine relations to the myocard

Abstract 1. 1. The main part of the cardiac ganglion consists of three types of axons. 2. 2. Two of these types can be distinguished by electron-dense granules ranging between 700–1000 and 1000–2300 A respectively. 3. 3. Besides a few Gray Type I synapses there also occur multiple contacts (dyads) of different types forming convergent and divergent connections. 4. 4. Terminals of cardiac ganglion cells contain synaptic vesicles and electrondense granules of different diameters and form specialized contacts on the heart muscle cells.

Nicht-nervse Sekretzellen im Ventralnervenstrang von Pachydrilus lineatus (Oligochaeta)

Es wurden die im Bauchmark des Oligochaeten Pachydrilus lineatus vorkommenden Sekretionszellen mit ihren zur Epidermis ziehenden Fortsatzen untersucht. Fluoreszenzmikroskopisch sind diese Zellen elektiv mit Pseudoisozyanin darstellbar. Elektronenmikroskopisch erkennt man 2 Typen von Sekretzellen auser neurosekretorischen Zellen, normalen Neuronen und Gliazellen. Die beiden Typen von Sekretzellen unterscheiden sich durch ihre Sekrete, das verschiedenartig ausgebildete endoplasmatische Retikulum, die unterschiedliche Haufigkeit von Mitochondrien und Lysosomen sowie durch die Ausbildung ihrer Fortsatze. Letztere weisen in beiden Fallen Mikrotubuli auf. Auf Grund dieser Befunde werden grundsatzliche Aspekte hinsichtlich der Beziehung Epidermis-Zentralnervensystem einerseits und hinsichtlich der Frage der Ableitung neurosekretorischer Zellen andererseits diskutiert.SummaryThe secretory cells in the ventral nerve cord of the oligochete Pachydrilus lineatus and their processes, extending to the epidermis were studied. These cells are selective stainable with the fluorescence dye pseudoisocyanine. At the ultrastructural level two types of secretory cells are recognizable. They are well distinguishable from neurosecretory cells, ordinary neurons and glia cells. Both types of secretory cells differ in their secretory products, the size of endoplasmatic reticulum and the different accumulation of mitochondria and lysosomes. In the processes of these secretory cells microtubules are present.The fundamental aspects of the relation between central nervous system and epidermis and the origin of neurosecretory cells are discussed.ZnsammenfassungEs wurden die im Bauchmark des Oligochaeten Pachydrilus lineatus vorkommenden Sekretionszellen mit ihren zur Epidermis ziehenden Fortsätzen untersucht. Fluoreszenzmikroskopisch sind diese Zellen elektiv mit Pseudoisozyanin darstellbar. Elektronenmikroskopisch erkennt man 2 Typen von Sekretzellen außer neurosekretorischen Zellen, normalen Neuronen und Gliazellen. Die beiden Typen von Sekretzellen unterscheiden sich durch ihre Sekrete, das verschiedenartig ausgebildete endoplasmatische Retikulum, die unterschiedliche Häufigkeit von Mitochondrien und Lysosomen sowie durch die Ausbildung ihrer Fortsätze. Letztere weisen in beiden Fällen Mikrotubuli auf. Auf Grund dieser Befunde werden grundsätzliche Aspekte hinsichtlich der Beziehung Epidermis-Zentralnervensystem einerseits und hinsichtlich der Frage der Ableitung neurosekretorischer Zellen andererseits diskutiert.

Synaptic connections of the Nervus connectivus in the frontal ganglion of Periplaneta americana L. (Insecta)

SummaryThe course of the Nervus connectivus (N.c.), its branches, and synaptic connections within the frontal ganglion (FG) were investigated electron microscopically after cobalt iontophoresis of the N.c. The subsequent treatment of ultrathin sections with Timms method was found to be very suitable for identifying the smallest branches. In the neuropil, fibers of the N.c. form Gray-I-type synapses, but also dyads are abundant, whereby the N.c. fibers occur exclusively in postsynaptic position with neurosecretory fibers. The possible role of these relationships is discussed.