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At least 775 records · Page 43Linked to original sources
PubMed1978

The neuronal connections of the frontal ganglion of the cockroach Periplaneta americana. A histological and iontophoretical study.

The frontal ganglion of the cockroach Periplaneta americana was studied histologically and its neuronal pathways were mapped by use of axonal cobalt iontophoresis. Neurons and fiber tracts of the frontal ganglion are directly linked with different regions of the central nervous system (tritocerebrum, protocerebrum, subesophageal ganglion) and with the more caudal parts of the stomatogastric nervous system (hypocerebral ganglion, nervus oesophagei).

Animals↗
PubMed1981

The mechanosensory apparatus of the femoral tactile spine of the cockroach, Periplaneta americana.

Tactile spines are large cuticular sense organs that appear to provide insects with a sense of touch which is spatially coarse but of great sensitivity. Cockroach legs have a number of these spines on each leg and a particularly prominent spine on the end of each femur, the femoral tactile spine. The ease of recording afferent activity from this spine during mechanical stimulation has made it one of the most thoroughly studied insect mechanoreceptors and yet it has never been examined by electron microscopy. We report here the results of an examination of the femoral tactile spine by both scanning and transmission electron microscopy, as well as by light microscopy. The spine is shown to be innervated by a single sensory bipolar neuron with its soma located in the base of the spine. A canal through the wall of the spine leads to the outside and emerges just above the junction between the base of the spine and its articulating socket membrane. The sensory dendrite of the neuron passes from the soma through this canal and forms a modified ciliary sensory ending with the typical dendritic sheath and dense tubular body that is characteristic of insect mechanosensory cuticular sensilla. The tubular body is embedded in a cuticular terminal plug which closes the exterior end of the canal but appears to be fastened to the spine by a very flexible ring of cuticle. This plug is connected to the socket membrane by a specialized socket attachment which presumably serves to move the plug relative to the wall of the spine during movement of the spine within the socket. The morphology of this sensillum is discussed in terms of the possible ways in which it is stimulated by movements of the spine and also in light of the dynamic behaviour of the receptor which is now very well described.

Animals↗
PubMed1983

Monoamine-containing neurons and their projections in the brain (supraoesophageal ganglion) of cockroaches. AN aldehyde fluorescence study.

Fluorogenic monoamines were studied in the brain of three cockroach species by use of aldehyde-fluorescence techniques. All three optic ganglia contain fluorogenic monoamines. The lamina contains fibres with an indolylalkylamine-fluorophore. The medulla is innervated by local CA neurons which contribute to four fluorescent strata. The lobula receives both CA- and 5-HT-fibres, predominantly of central origin. CA occur in almost all areas of the brain. The areas are interconnected by a CA-fibre system. All parts of the mushroom body are innervated by CA-fibres from the surrounding neuropil. The CA innervation in the mushroom body divides it into a fronto-ventral part (alpha-lobe, beta-lobe, anterio-ventral peduncle) and a dorso-caudal part (caudo-dorsal peduncle, calices) leaving a fluorescence-free central part of the peduncle in between. CA-fibres run between the mushroom bodies of both hemispheres and also between the mushroom body and the lobula. The central body complex contains CA. The pons aggregates indolylalkylamine-containing fibres. The olfactory glomeruli are surrounded by CA-fibres originating from deutocerebral cell bodies. CA-fibres are further linked to the protocerebral neuropil. CA-fibre tracts pass from the brain to the suboesophageal ganglion and the stomatogastric nervous system. The cell bodies of the frontal ganglion are of indolylalkylamine type. Non-fluorescent neuropils (n. ocellaris, tractus olfactorio-globularis, lobus glomerulatus) are innervated by the CA-fibre system.

Aldehydes↗
PubMed1976

The ocellus of the cockroach, Periplaneta americana (Blattariae): receptory area.

The ocelli of Periplaneta americana were studied by light and electron microscopy. The view that the ocellus of the cockroach represents a degenerated structure can no longer be supported. All organelles necessary for function are present. The club-shaped retinular cells lie homogeneously distributed in the cupule of the ocellus. Rhabdoms are seen as sickle-, y-, x- or star-shaped structures with up to six cells in formation. Cells were found which had formed two rhabdomeres. The mass of cell organelles lies in the cytoplasm between the cell nucleus and the rhabdom. Smooth endoplasmic reticulum is wound into a spindle formation of considerable size at the origin of the axon in some cells. A cylindrical body in which 10-40 microtubules are packed, as yet unknown in insect retinular cells, is described. The receptory area of the ocellus terminates in a tapetum which contains granules, soluble in alcohol. The axon bundles of the retinular cells run through the tapetum and immediately thereafter make synaptic contact with dendrites of the ocellar nerve cells, while still within the ocellus.

Animals↗
PubMed1987

Gastrin/CCK-like immunoreactivity in the corpus cardiacum-corpus allatum complex of the cockroach Leucophaea maderae.

By use of immunocytochemistry, a gastrin/CCK-like material has been demonstrated in the corpus cardiacum-corpus allatum complex of the cockroach Leucophaea maderae. Reactivity toward gastrin and CCK with region-specific antisera suggests that the gastrin/CCK-like peptide of this insect contains the COOH-terminal tetrapeptide sequence which is common to gastrin and CCK, and that the material is more gastrin-like than CCK-like. The results indicate that, like other neuropeptides, the gastrin/CCK peptide family appeared early in evolution within neuronal elements, and that the COOH-terminal region of gastrin has been conserved during phylogeny.

Animals↗
PubMed1984

Duplication of a peripheral sensory neuron in the cockroach Periplaneta americana.

We have recently examined the electrophysiology and ultrastructure of approximately 100 tactile spines from the metathoracic legs of adult cockroaches. In only one animal the single sensory neuron that innervates the spine was replaced with a pair of apparently identical neurons which we believe were both functional. As far as we are aware this is the first reported study of unprovoked duplication in a peripherally-located insect sensory neuron.

Animals↗
PubMed1988

Embryogenesis of the connective chordotonal organ in the pedicel of the American cockroach: cell lineage and morphological differentiation.

The ontogenesis of single scolopidia of the chordotonal organ of the American cockroach, Periplaneta americana, takes about 4 days. At 23% embryogenesis (100%=30 d) the first anlagen of scolopidia were identified within the eipithelium by staining with anti-horseradish peroxidase. Reconstruction of the cell lineage of the scolopidial cells was facilitated by two facts: (i) the arrangement of the cells throughout ontogenesis follows a strict pattern, and (ii) daughter cells are recognizable for several hours after mitosis by the cytoplasmic bridge and midbody joining them. When they separate, the midbody undergoes lysosomal degeneration in one of these cells. The earliest recognizable stage is a pair of cells, one of which (cell 1) encloses the other (cell 2) apically. The enclosing cell becomes the accessory cell. Cell 2 divides, yielding the mother cell (cell 3) of two sensory cells which degenerate later, and cell 2'. Cell 2' gives rise to the attachment cell and to cell 2'', which in turn produces the scolopale cell and the mother cell (cell 2'' 2''') of a second pair of sensory cells; the latter are the definitive sensory cells. The end result is the total of 5 cells characteristic of the adult scolopidium. Secretion of the scolopale and cap together with the migration of the sensory cell perikarya into the antennal lumen complete development.

Animals↗
PubMed1985

Ultrastructure of corpora allata of known activity during the vitellogenic cycle in the cockroach Diploptera punctata.

Ultrastructure was correlated with rates of juvenile hormone synthesis in corpora allata from females of the viviparous cockroach Diploptera punctata at seven daily intervals during the first vitellogenic cycle. Synthetic activity of the glands was determined by in vitro radiochemical assay before the glands were fixed for electron microscopic analysis. The cycle in rates of juvenile hormone synthesis progressed from about 20 pmol h-1 per gland pair (oocytes 0.60 mm long) to a maximum mean rate of 140 pmol h-1 per pair (oocytes 1.40-1.47 mm long) and declined to about 20 pmol h-1 per pair at ovulation (oocytes about 1.65 mm long). Conspicuous ultrastructural changes occurred with changing synthetic rates. In glands with increasing rates of synthesis, mitochondria showed less electron-dense matrix, greater diameter and more irregular shape. Smooth endoplasmic reticulum changed from easily seen to obscure tubules, networks, and vesicles. Rough endoplasmic reticulum appeared in longer, more curved segments. Newly formed autophagic vacuoles appeared in all glands of highest activity rates. In glands with decreasing rates of synthesis, the mitochondrial matrix became denser, width smaller, and shapes less irregular. Smooth endoplasmic reticulum again appeared tubular and distinct. Golgi complexes were more conspicuous. Rough endoplasmic reticulum in whorls and large numbers of autophagic vacuoles continued to be present.

Animals↗
PubMed1982

External structure of the sensillum capitulum, a hygro- and thermoreceptive sensillum of the cockroach, Periplaneta americana.

The antennal hygro- and thermoreceptive sensillum (sensillum capitulum) of the cockroach, Periplaneta americana, has been identified electrophysiologically and examined by scanning electron microscopy. It appears basiconic and has a characteristic cuticular apparatus; a mushroom-shaped inner stem and a non-perforated outer wall. The head of the inner stem, which is a cap of about 0.5 micrometer diameter, protrudes from the distal margin of the outer wall. The inner stem is not perforated, though in some cases a tiny hollow is observed in the apex of the cap. This kind of cuticular apparatus is not found in other sensilla and may be modality-specific to hygro- and/or thermoreception. The sensillum capitulum occurs singly on the distal part of each alternating segment of the flagellum and on each segment of some distal meristal segments.

Animals↗
PubMed1981

Immunocytochemical identification of proctolinlike immunoreactivity in the terminal ganglion and hindgut of the cockroach Periplaneta americana (L.).

In the American cockroach, the distribution and connections of neuronal elements of the terminal ganglion-proctodeal nerve-hindgut system were investigated by means of immunohistochemical methods and axonal CoCl2 iontophoresis. Proctolinlike immunoreactivity was localized within neurons of the terminal ganglion projecting into the proctodeal nerve on the one hand, and in nerve cells without a direct connection to this system on the other. Immunohistochemically, in whole mount preparations fibres of the proctodeal nerve and terminal structures in the hindgut musculature exhibit strong proctolinlike immunoreactivity. At the light- and electron-microscopic levels the pathways of about 30 somata of the proctodeal neural system were characterized by cobalt chloride iontophoresis. The relationships of cobalt filled and immunoreactive neuronal structures are discussed.

Animals↗
PubMed1978

Histological and cytological studies on the fat body of the cockroach Nauphoeta cinerea during the first reproductive cycle.

The central fat body of the ovoviviparous cockroach Nauphoeta cinerea was studied during the first reproductive cycle of the female by means of light microscopy, autoradiography and electron microscopy. Comparative studies in larval stages were also undertaken. The fat body of Nauphoeta contains a large amount of lipid droplets and the remaining cytoplasm is very scarce. The cytological cyclicity of the fat body is consistent with the known biochemical rhythms of vitellogenin production. The proteosynthetic apparatus appears about 3 days after imaginal ecdysis, along with vitellogenin. The ribosomal endoplasmic reticulum (RER) shows a tremendous increase by the 7th day of the first cycle. The most active period of vitellogenin production lasts from day 7 to 12. The proteosynthetic apparatus then returns to an inactive stage and disappears. This inactive condition lasts to the end of the gestation period. The autoradiographic results are consistent with the cytological features.

Adipose Tissue↗
PubMed1975

Ultrastructural study of the neural fat-body system in the cockroach Periplaneta americana.

The neural fat-body system of the ventral nerve cord in the cockroach Periplaneta americana was studied with the light and electron microscopes. This adipose tissue surrounds the connectives and extends over the ganglia. The adipose cells typically contain numerous extremely large lipid inclusions, pleomorphic lysosomes, and tightly packed glycogen granules. The neural lamella consists of a thick inner layer rich in collagen fibers and a thin outer layer of granular material. At points where the fat body is attenuated, this granular layer is split and the outer lamina is reflected superficially to ensheath and apparently to anchor the fat body.

Adipose Tissue↗
PubMed1988

Distribution of glutamate decarboxylase-like immunoreactivity in the sixth abdominal ganglion of the cockroach Periplaneta americana.

An antiserum against glutamate decarboxylase (GAD) of the rat brain was used to locate GAD activity in sections of the nervous system of the cockroach, Periplaneta americana. The sixth abdominal ganglion was chosen because electrophysiological evidence suggests the presence of GABAergic inhibitory synapses in the cercal-giant interneuron system. Groups of somata and numerous fibres and tracts were positively labelled by the GAD antiserum. A posterior group of labelled somata could be identified close to the entry of the cercal nerves. A line of somata clusters lay along a ventro-lateral furrow. Another discrete row of GAD-like cells was located dorso-laterally. Some small cells among the dorsal unpaired neurons were labelled. A small central group appeared under these cells. An abundance of GAD-like processes and transversal tracts were found within the neuropile. The different systems of GABAergic inhibitors in the ganglion are discussed; in particular we show that the fibres of cercal nerve X are not labelled. This demonstrates that the latter act on the giant fibres via interneurons. We suggest that the group that sends axons into the overlapping region between the cercal nerve and the giant fibre could be the inhibitory interneurons involved in this system.

Abdomen↗
PubMed1978

The ultrastructure and histochemistry of the mesenteric connective tissue of the cockroach Periplaneta americana L. (Insecta, Dictyoptera).

The thick layer of collagenous connective tissue around the mesenteron of the cockroach Periplaneta americana has been examined by light microscopy, electron microscopy and histochemical techniques. This sheath, connected to the mesenteric epithelium by a basal lamina and traversed by longitudinal and circular musculature, tracheae and nerves, contains numerous collagen fibrils, elastic fibers, fibroblasts and rare hemocytes. Development starts during the first instars with the production of connective tissue material by fibroblasts. Glycosaminoglycans have been observed with the use of various histochemical reactions, in particular alcian blue staining, metachromasia and enzymatic digestion. The reactions indicate the presence of hyaluronic acid in the various instars, the appearance and increase of sulphated components during development, and the presence of neutral glycoproteins.

Animals↗
PubMed1978

The salivary glands of the cockroach Nauphoeta cinerea (Olivier). A study of its innervation by light and scanning electron microscopy.

The innervation of the salivary gland of the cockroach Nauphoeta cinerea (Olivier) has been investigated with the use of light and scanning electron microscopy. Light microscopy of methylene blue stained glands reveals the presence of a dual innervation arising from the ventral nerve cord and the stomodeal nervous system; the principal innervation is that from the ventral nerve cord which passes to the gland via the reservoir ducts. Branches of these nerves form a plexus on the acinar surface, the axons of which exhibit swelling at irregular intervals. The presence of this surface plexus and the axonal swellings was confirmed by scanning electron microscopy both in normal glands and in those in which the basal lamina had been removed by means of an HCl-collagenase digestion method. No acinar plexus was seen to be formed by branches of the stomatogastric nerve that were associated with the gland. However, other branches of this nerve were clearly connected with a complex network of multipolar neurones on the surfaces of the anterior regions of both salivary reservoirs.

Animals↗
PubMed1979

The mechanism of sensory transduction in the sensilla of the trochanteral hair plate of the cockroach, Periplaneta americana.

The trochanteral hair plate of the cockroach leg contains approximately 60 hair sensilla that are deflected by a joint membrane during flexion of the leg. Previous work has shown that the organ is a mechanoreceptor which limits leg flexion during walking by reflex connections to flexor and extensor motoneurons. Functional analysis of the largest sensilla has shown that their behaviour may be well approximated by a velocity detector followed by a unidirectional rectifier. We report here the results of an examination of the largest sensilla by scanning and transmission electron microscopy in an attempt to correlate the structure with the known functional elements. Each hair is innervated by a single sensory dendrite which is surrounded by an electron dense dendritic sheath. The dendrite terminates below the hair shaft in a tubular body containing a parallel array of microtubules embedded in an electron dense matrix, while the dendritic sheath extends beyond the tubular body to form the walls of the ecdysial canal. At the proximal end of the tubular body the dendritic sheath and sensory dendrite are anchored to the cuticular socket by a fibrous dome which seems to form a flucrum around which the tubular body can be deflected by movements of the hair. We suggest that the basis for the detection of velocity shealth and the tubular body. The structure is also discussed with relation to the mechanism of sensory transduction and the possible causes of the unidirectional sensitivity.

Animals↗
PubMed1980

Identification of neuronal pathways between the stomatogastric nervous system and the retrocerebral complex of the cockroach Periplaneta americana (L.).

The neuronal pathways connecting the stomatogastric nervous system with the retrocerebral complex of the cockroach, Periplaneta americana, were investigated by means of axonal cobalt chloride iontophoresis. Somata in the hypocerebral ganglion and in the nervus recurrens sending their axons to different parts of the stomatogastric nervous system were traced. Some axons in the oesophageal nerve arise from large perikarya in the anterior part of the pars intercerebralis and pass via the NCCI to the corpora cardiaca and the oesophageal nerve. The form a profuse dendritic tree in the protocerebrum. Fibers of the NCC I and NCC II as well as the NCA I and NCA II enter the stomatogastric nervous system via the hypocerebral ganglion.

Animals↗
PubMed1981

The sensillum capitulum, an antennal hygro- and thermoreceptive sensillum of the cockroach, Periplaneta americana L.

The sensillum capitulum, a hygro- and thermoreceptive sensillum of the cockroach Periplaneta americana L. is comprised of four receptor cells, one glial cell, two gland cells and four enveloping cells. Each receptor cell sends a single axon to the CNS, and has a single dendrite which extends distally. The perikarya of three receptor cells are enclosed by one of the enveloping cells (number one) and the fourth by a gland cell. The dendrites of all four receptor cells are enclosed by the same enveloping cell. The dendrites contain rootlets and many microtubules. The sensory cilia arise at the end of the dendrites at the level of the inner cavity, expand from the connecting cilium in a manner similar to those of the amphinematic scolopidia, and have numerous microtubules. The 1st enveloping cell contains scolopale rod-like structures. The sensory cilia are surrounded distally by a cuticular sheath formed within the 1st enveloping cell. One of the sensory cilia disappears distally, and the remaining ones enter the sensillum cone. Of these, one branches and the other two do not. The distal ends of the unbranched cilia are differentiated into tubular structures. The sensillum cone is comprised of an inner stem and a guard wall, neither of which is perforated. The outer cavity is enclosed by the 2nd, 3rd, and 4th enveloping cells, and distally in the antenna is closely apposed to the cuticular wall. This cavity contains lipid deposits. These structural features are discussed with regard to the mechanism of hygroreception in P. americana.

Animals↗