Acetylcholinesterase and synapses in the nervous system of Phocanema decipiens (Nematoda): a histochemical and ultrastructural study

1976 ◽  
Vol 54 (5) ◽  
pp. 752-771 ◽  
Author(s):  
S. L. Goh ◽  
K. G. Davey
Keyword(s):  
Nervous System ◽  
Electron Microscope ◽  
Enzymatic Activity ◽  
Ultrastructural Study ◽  
Neuromuscular Junctions ◽  
Nerve Ring ◽  
Synaptic Contacts ◽  
Longitudinal Nerve ◽  
Specific Inhibitors ◽  
Nerve Cords

The nervous system of Phocanema decipiens was examined histochemically for acetylcholinesterases (EC 3.1.1.7) using the acetylthiocholine method with specific inhibitors (eserine and diisopropylfluorophosphate) and different substrates (butyrylthiocholine and acetylthiocholine). The enzymes, which are localized mainly as small discrete granules, are found in the nerve ring, the six longitudinal nerve cords, and the three pharyngeal nerves. With the electron microscope, these neurons are found to contain presumptive cholinergic synaptic contacts with aggregations of small lucent vesicles in the presynaptic axons. In the nerve ring, such synapses are observed in axoaxonal, neuromuscular and axoglial cell contacts. The longitudinal nerve cords have neuromuscular junctions similar to those observed in other nematodes. In the four sublateral nerve cords, the alternating regions with and without synaptic contacts correspond to the discontinuous histochemical pattern of enzymatic activity. The pharyngeal nerves have axoaxonal and axooesophageal musculature synapses. In most of the synapses, some large dense or dense-core vesicles are found intermingled with the small lucent vesicles. This coexistence of different vesicles is discussed in the light of the cholinergic link hypothesis, whereby acetylcholine is initially released to facilitate the release of other neurotransmitters.

Echinoderm Nervous System

2018 ◽  
Author(s):  
Carlos A. Díaz-Balzac ◽  
José E. García-Arrarás
Keyword(s):  
Nervous System ◽  
Radial Nerve ◽  
Regulatory Networks ◽  
Nerve Ring ◽  
Neural Net ◽  
System P ◽  
Embryonic Nervous System ◽  
Body Wall Muscles ◽  
Areas Of Interest ◽  
Nerve Cords

The nervous system of echinoderms has been studied for well over a century. Nonetheless, the information available is disparate, with in-depth descriptions for the nervous component of some groups or of particular organs while scant data is available for others. The best studied representatives to date are the nervous system of echinoid embryos and larva, and the adult holothurian nervous system. Although described sometimes inaccurately as a neural net, the echinoderm nervous system consists of well-defined neural structures. This is observed since early embryogenesis when activation of the anterior neuroectoderm gene regulatory networks initiate the formation of the embryonic nervous system. This system then undergoes expansion and differentiation to form the larval nervous system, which is centered on the ciliary bands. This “simpler” nervous system is then metamorphosed into the adult echinoderm nervous system. The adult echinoderm nervous system is composed of a central nervous system made up of a nerve ring connected to a series of radial nerve cords. Peripheral nerves extending from the radial nerve cords or nerve ring connect with the peripheral nervous system, located in other organs or effectors including the viscera, podia, body wall muscles, and connective tissue. Both the central and peripheral nervous systems are composed of complex and diverse subdivisions. These are mainly characterized by the expression of neurotransmitters, namely acetylcholine, catecholamines, histamine, amino acids, GABA, and neuropeptides. Other areas of interest include the amazing regenerative capabilities of echinoderms that have been shown to be able to regenerate their nervous system components; and the analysis of the echinoderm genome that has provided essential insights into the molecular basis of how echinoderms develop an adult pentaradial symmetry from bilaterally symmetric larvae and the role of the nervous system in this process.

Immunocytochemical demonstration of a neuropeptide in Ascaris suum (Nematoda) using an antiserum to FMR Famide

Parasitology ◽  
1988 ◽  
Vol 97 (1) ◽  
pp. 81-88 ◽  
Author(s):  
T. R. B. Davenport ◽  
D. L. Lee ◽  
R. E. Isaac
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Peripheral Nervous System ◽  
Ascaris Suum ◽  
Nerve Ring ◽  
Immunocytochemical Technique ◽  
The Central Nervous System ◽  
Nerve Cords

SUMMARYA FMRFamide-like peptide has been detected in the nematode Ascaris suum, using the peroxidase-anti-peroxidase (PAP) immunocytochemical technique. Positive reactions were obtained in both the central nervous system and the peripheral nervous system of the worm, the strongest reactions being in the anterior nerve ring, the cephalic papillary ganglia, the lateral ganglia and the dorso-rectal ganglion. Immunoreactivity was observed along the length of the main nerve cords of the worm and, to a lesser extent, in the pharyngeal nerve cords. The possible role of this neuropeptide in the physiology of the nematode is discussed.

Glutamate-like immunoreactivity in the cestode Hymenolepis diminuta

1990 ◽  
Vol 68 (11) ◽  
pp. 2417-2423 ◽  
Author(s):  
Harley Eklove ◽  
Rodney A. Webb
Keyword(s):  
Nervous System ◽  
Hymenolepis Diminuta ◽  
Basal Region ◽  
Light Microscopic Level ◽  
Cerebral Ganglia ◽  
Large Groups ◽  
Longitudinal Muscles ◽  
Longitudinal Nerve ◽  
Nerve Cords

Glutamate-like immunoreactivity in the cestode Hymenolepis diminuta was investigated at the light-microscopic level by immunohistochemistry with an antiglutamate antibody. Immunoreactivity was seen in the basal region of the suckers, in the rostellum, subtegumental regions, central nervous system, and longitudinal nerve cords, and in eggs. In the scolex the cerebral ganglia were diffusely immunoreactive, and immunoreactive tracts, passing from the cerebral ganglia to the suckers, were observed. The longitudinal nerve cords contained large groups of intensely stained cell bodies and processes throughout the length of the strobila. Immunoreactive tracts from the longitudinal nerve cords formed junctions with the deep longitudinal muscles only in the lateral regions of the proglottids. However, neuron-like varicose swellings were seen in the subtegumental area of the mature region. The localization of glutamate-like immunoreactivity in various parts of the nervous system and tissues of Hymenolepis diminuta provides further support for the role of glutamate as an excitatory neuromuscular transmitter in the platyhelminths.

Immunocytochemical demonstration of neuropeptides in the central nervous system of the roundworm, Ascaris suum (Nematoda: Ascaroidea)

Parasitology ◽  
1993 ◽  
Vol 106 (3) ◽  
pp. 305-316 ◽  
Author(s):  
D. J. A. Brownlee ◽  
I. Fairweather ◽  
C. F. Johnston ◽  
D. Smart ◽  
C. Shaw ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Peptide Yy ◽  
Ascaris Suum ◽  
Nerve Ring ◽  
Gonadotropin Releasing Hormone ◽  
Releasing Hormone ◽  
Indirect Immunofluorescence Technique ◽  
The Central Nervous System ◽  
Nerve Cords

SUMMARYThe localization and distribution of neuropeptides in the central nervous system of the pig roundworm, Ascaris suum, have been determined by an indirect immunofluorescence technique in conjunction with confocal microscopy. Antisera to 25 vertebrate peptides and two invertebrate peptides were used to screen the worm for immunoreactivity (IR). Immuno-staining was obtained with antisera to pancreatic polypeptide (PP), peptide YY (PYY), neuropeptide Y (NPY), gastrin, cholecystokinin (CCK), substance P (SP), atrial natriuretic peptide (ANP), salmon gonadotropin-releasing hormone (SGnRH), mammalian gonadotropin-releasing hormone (MGnRH), chromogranin A (CGA) and FMRFamide. The most extensive patterns of IR occurred with antisera to PYY, FMRFamide and gastrin. IR was evident in nerve cells and fibres in the ganglia associated with the anterior nerve ring and in the main nerve cords and their commissures; IR to FMRFamide also occurred in the posterior nerve ring. Immunostaining for the other peptides was confined to the nerve cords, with the number of immunoreactive nerve fibres varying from peptide to peptide.

The distribution of neuroactive substances within the cercaria of Sanguinicola inermis

1996 ◽  
Vol 70 (4) ◽  
pp. 309-317 ◽  
Author(s):  
D.F. McMichael-Phillips ◽  
J.W. Lewis ◽  
M.C. Thorndyke
Keyword(s):  
Nervous System ◽  
Nerve Cord ◽  
The Body ◽  
Double Labelling ◽  
Cerebral Ganglia ◽  
Whole Mount ◽  
Antibodies To Serotonin ◽  
Longitudinal Nerve ◽  
Longitudinal Nerve Cord ◽  
Nerve Cords

AbstractThe serotoninergic and peptidergic components of the nervous system of the cercaria of Sanguinicola inermis (Digenea: Sanguinicolidae) were examined using whole-mount immunocytochemistry and a plan of the nervous system has been described. Antibodies to serotonin (5-hydroxytryptamine, 5-HT) and the neuropeptides, FMRFamide, GFNSALMFamide (S1) and SGPYSFNSGLTFamide (S2) were used in the study. Immunoreactivity (IR) was demonstrated to all but the S2 antisera and showed a similar fundamental distribution. IR was found in paired cerebral ganglia located anteriorly within the body and connected by a cerebral commissure. From the ganglia paired ventral and dorsal longitudinal nerve cords extend anteriorly into the cephalic organ and into the body. There is no apparent connection with the tail. Several transverse commissures connect the longitudinal nerve cords throughout the body and several associated cell bodies have been located. A double-stranded dorsal and ventral longitudinal nerve cord extends the length of the tail and six cell bodies are associated with these cords, uniquely demonstrating either FMRFamide and S1, or 5-HT-like IR. Only 5-HT-like IR was found to extend into the posterior tail furcae and there appears to be a lack of any peripheral tegumental innervation. Double-labelling experiments suggest that the serotoninergic and peptidergic components of the cercarial nervous system are distinct.

Nerve cells inAcanthobothrium coronatum(Rud.) (Cestoda: Tetraphyllidea)

Parasitology ◽  
1966 ◽  
Vol 56 (1) ◽  
pp. 45-54 ◽  
Author(s):  
Gwendolen Rees
Keyword(s):  
Nervous System ◽  
Close Association ◽  
Nerve Cells ◽  
Lateral Nerve ◽  
Cerebral Ganglia ◽  
Anterior Half ◽  
Stretch Receptors ◽  
Longitudinal Nerve ◽  
Nerve Cords

The nervous system ofAcanthobothrium coronatumconsists of paired bilobed cerebral ganglia in the scolex joined by a transverse and a dorsal and ventral commissure, and a number of longitudinal nerve cords joined by ring commissures from which arise delicate nerves supplying various organs.Bipolar neurons are present in the transverse commissure and scattered throughout the longitudinal nerves in the strobila.Multipolar neurons occur outside and in close association with the nerve cords.A band of ganglionic cells lies on the inner side of the lateral nerve cords in the scolex.Binding cells are present around the longitudinal nerve cords and ring commissures in the strobila.Stretch receptors are present in the anterior half of the scolex in association with the powerful muscles moving the bothridia and hooks.

The anatomy of Cysticercus taeniae-taeniaeformis (Batsch 1786) (Cysticercus fasciolaris Rud. 1808), from the liver of Rattus norvegicus (Erx.), including an account of spiral torsion in the species and some minor abnormalities in structure

Parasitology ◽  
1951 ◽  
Vol 41 (1-2) ◽  
pp. 46-59 ◽  
Author(s):  
Gwendolen Rees
Keyword(s):  
Nervous System ◽  
Rattus Norvegicus ◽  
Neck Region ◽  
Internal Organs ◽  
Nervous Systems ◽  
Complicated System ◽  
Cysticercus Fasciolaris ◽  
Lateral Margins ◽  
Longitudinal Nerve ◽  
Nerve Cords

1. The musculature and excretory and nervous systems of Cysticercus taeniae-taeniaeformis are described.2. The nervous system consists often longitudinal nerve cords in the strobila and of a brain and complicated system of nerves in the scolex. The nervous system of the scolex shows several variations on the earlier description by Bartels (1902).3. Minor abnormalities have been found in the form of multiplication of the lateral margins and duplication of the ventral excretory vessels.4. Three specimens showed spiral torsion of the internal organs involving the musculature and excretory and nervous systems of the strobila. The number of turns of the spiral and the positions of the chiasmata are variable. It is suggested that the spiral twisting occurs before growth and strobilation in the neck region has begun, the chiasmata being carried back as new segments are formed.

Further Observations on the Virus of Epizootic Diarrhea of Infant Mice. An Electron Microscopic Study

1967 ◽  
Vol 25 ◽  
pp. 110-111
Author(s):  
W. G. Banfield ◽  
G. Kasnic ◽  
J. H. Blackwell
Keyword(s):  
Electron Microscope ◽  
Infected Cell ◽  
Microscopic Study ◽  
Intestinal Epithelium ◽  
Ultrastructural Study ◽  
Osmium Tetroxide ◽  
Lead Citrate ◽  
Electron Microscopic ◽  
Virus Particles ◽  
Infected Cells

An ultrastructural study of the intestinal epithelium of mice infected with the agent of epizootic diarrhea of infant mice (EDIM virus) was first performed by Adams and Kraft. We have extended their observations and have found developmental forms of the virus and associated structures not reported by them.Three-day-old NLM strain mice were infected with EDIM virus and killed 48 to 168 hours later. Specimens of bowel were fixed in glutaraldehyde, post fixed in osmium tetroxide and embedded in epon. Sections were stained with uranyl magnesium acetate followed by lead citrate and examined in an updated RCA EMU-3F electron microscope.The cells containing virus particles (infected) are at the tips of the villi and occur throughout the intestine from duodenum through colon. All developmental forms of the virus are present from 48 to 168 hours after infection. Figure 1 is of cells without virus particles and figure 2 is of an infected cell. The nucleus and cytoplasm of the infected cells appear clearer than the cells without virus particles.

The innervation of toad lymph hearts: An ultrastructural study

1992 ◽  
Vol 50 (1) ◽  
pp. 898-899
Author(s):  
A.M. Pucci ◽  
C. Fruschelli ◽  
A. Rebuffat ◽  
M. Guarna ◽  
C. Alessandrini ◽  
...  
Keyword(s):  
Ultrastructural Study ◽  
Neuromuscular Junctions ◽  
Nerve Fibers ◽  
Lack Of Information ◽  
Lymph Heart ◽  
Muscular Pump ◽  
Structure And Ultrastructure ◽  
Heart Wall

Amphibians have paired muscular pump organs, called “lymph heart”, which rhythmically pump back the lymph from the large subcutaneous lymph sacs into the veins. The structure and ultrastructure of these organs is well known but to date there is a lack of information about the innervation of lymph hearts. Therefore has been carried out an ultrastructural study in order to study the distribution of the nerve fibers, and the morphology of the neuromuscular junctions in the lymph heart wall.

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