Régulations aminergique et cholinergique du système caudal neurosécréteur de l'omble de fontaine, Salvelinus fontinalis, en relation avec l'osmo-iono-regulation

1983 ◽  
Vol 61 (12) ◽  
pp. 2856-2867 ◽  
Author(s):  
Laurent Gauthier ◽  
Céline Audet ◽  
Gaston Chevalier
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Light And Electron Microscopy ◽  
Neurosecretory Cells ◽  
Regulatory Function ◽  
Synthetic Activity ◽  
Neurosecretory System ◽  
Neurosecretory Material ◽  
Electron Microscopic ◽  
Caudal Neurosecretory System

The innervation of the caudal neurosecretory system of the brook trout, Salvelinus fontinalis, was studied under light and electron microscopy in order to characterize its nature, distribution, and regulatory function over the activity of the caudal neurosecretory cells. A dual innervation of the cell bodies and axons of neurosecretory cells was disclosed. One type of axosomatic connection exhibited small lucent vesicles and large dense-cored granules. These boutons were identified as monoaminergic since they appeared depleted after reserpine treatment and they were selectively labeled with 5-OH-dopamine. In fish exposed to demineralized water, reserpine induced a condition that stimulated the synthetic activity of caudal neurosecretory cells, a clear reduction of this activity, according to morphometric (cell and nucleus diameters) and ultrastructural criteria (dimensions of the Golgi complex). By comparison, no significant variation of the synthetic activity was noted in freshwater-adapted trout treated with reserpine. A second type of innervation was also identified as cholinergic by histochemical localization of acetylcholinesterase. Electron microscopic analysis also revealed axosomatic and axoaxonic cholinergic synaptic connections with characteristic small 500-Å diameter lucent vesicles. The injection of fenitrothion, an anticholinesterase agent, enhanced discharge of neurosecretory material from axonal endings of caudal cells while the synthetic activity did not appear to be modified. Our findings suggest an important role of aminergic and cholinergic controls over the response of the caudal neurosecretory system of Salvelinus fontinalis during hyperosmotic adaptation.

The effect of feeding on the cerebral neurosecretory system of the adult male tsetse, Glossina austeni Newst

1978 ◽  
Vol 56 (9) ◽  
pp. 1988-1992 ◽  
Author(s):  
M. Grossman ◽  
K. G. Davey
Keyword(s):  
Adult Male ◽  
Neurosecretory Cells ◽  
Neurosecretory System ◽  
Neurosecretory Material ◽  
Corpus Cardiacum ◽  
Pars Intercerebralis ◽  
Corpora Cardiaca ◽  
Glossina Austeni ◽  
Effect Of Feeding

An analysis of the intensity of staining of the corpus cardiacum and of the neurosecretorty cells of the pars intercerebralis in 3-day-old fed or fasting adult male tsetse has revealed two periods of apparent release of neurosecretion. In fed males, stainable neurosecretion disappears from 14 of the 20 recognizable neurosecretory cells within 10 min of the termination of feeding. There is always less neurosecretory material in the corpora cardiaca of fed males. Secondly, there is an indication of a depletion of material from the cardiaca of both fed and fasted males at about 1700 hours EST.

Bursting properties of caudal neurosecretory cells in the flounder Platichthys flesus, in vitro

2001 ◽  
Vol 204 (15) ◽  
pp. 2733-2739 ◽  
Author(s):  
M. J. Brierley ◽  
A. J. Ashworth ◽  
J. R. Banks ◽  
R. J. Balment ◽  
C. R. McCrohan
Keyword(s):  
Cell Activity ◽  
Extracellular Recording ◽  
Neurosecretory Cells ◽  
Neurosecretory System ◽  
Repetitive Firing ◽  
Physiological Status ◽  
Cycle Period ◽  
Caudal Neurosecretory System ◽  
Bursting Activity

SUMMARY Bursting activity in type 1 Dahlgren cells was studied using intra- and extracellular recording from an in vitro preparation of the caudal neurosecretory system of the euryhaline flounder. 45% of cells showed spontaneous bursts of approximately 120s duration and 380s cycle period. Similar bursts were triggered by short duration (<5s) depolarising or hyperpolarising pulses. Cells displayed a characteristic depolarising after potential, following either an action potential with associated afterhyperpolarisation, or a hyperpolarising current pulse. This depolarising after potential was related to a ‘sag’ potential, which developed during the hyperpolarising pulse. Both the depolarising after potential and the sag potential occurred only in cells at more depolarised (<60mV) holding potentials. In addition, the amplitude of the depolarising after potential was dependent on the amplitude and the duration of the hyperpolarising pulse. The depolarising after potential following action potentials may provide a mechanism for facilitating repetitive firing during a burst. Extracellular recording revealed similar bursting in individual units which was not, however, synchronised between units. Spontaneous bursting activity recorded both intra- and extracellularly was inhibited by application of a known neuromodulator of the system, 5-hydroxytryptamine. This study provides a basis for investigating the relationship between physiological status, Dahlgren cell activity and neuropeptide secretion.

A simple technique for selective staining of neurosecretory products in epoxy sections with paraldehyde fuchsin

1977 ◽  
Vol 55 (9) ◽  
pp. 1571-1575 ◽  
Author(s):  
Colin G. H. Steel ◽  
G. P. Morris
Keyword(s):  
Electron Microscopy ◽  
Peracetic Acid ◽  
Simple Technique ◽  
Light And Electron Microscopy ◽  
Sodium Methylate ◽  
Neurosecretory Cells ◽  
Neurosecretory Material ◽  
Neurosecretory Granules ◽  
Thin Sections ◽  
Selective Staining

A technique for correlative light and electron microscopy of neurosecretory cells (NSC) is described. Neurosecretory material is selectively stained in 0.5-μm epoxy sections with paraldehyde fuchsin (PAF) after partial resin removal with sodium methylate in methanol and oxidation in peracetic acid. Adjacent 'thin' sections permit electron microscopy of the same cells. The organelles responsible for the affinity of NSC for PAF are in part neurosecretory granules and in part lysosomes. The technique reveals great ultrastructural differences between NSC which appear similar in the light microscope.

Humoral Regulation of the Cerebral Neurosecretory System of Rhodnius Prolixus (Stal.) During Growth and Moulting

1973 ◽  
Vol 58 (1) ◽  
pp. 177-187
Author(s):  
C. G. H. STEEL
Keyword(s):  
Critical Period ◽  
Endocrine System ◽  
Feedback Regulation ◽  
Neurosecretory Cells ◽  
Corpus Allatum ◽  
Neurosecretory System ◽  
Neurosecretory Material ◽  
Before And After ◽  
Cytological Changes ◽  
The Brain

1. In normal fifth instar Rhodnius the cytological changes occurring in the medial neurosecretory cells (MNC) of the brain are very different before and after the ‘critical period’ for decapitation. 2. When a decapitated insect which has reached the ‘critical period’ (8 days after feeding) is joined in parabiosis to an insect with an intact cerebral endocrine system and which has not yet reached the ‘critical period’ (1 day after feeding) the MNC of the younger insect are induced to switch over from their normal sequence of cytological changes to those characteristic of the older insect. The induced changes do not occur in normal insects of the same age or in insects joined in parabiosis to others of the same age. 3. The nature of the changes indicates that release of stainable neurosecretory material is inhibited and its synthesis stimulated by the older insect. It is inferred that the haemolymph of insects which have reached the ‘critical period’ contains a factor which induces in the MNC an inhibition of release and a stimulation of synthesis. These are the events which occur in the MNC of normal insects at the critical period. 4. Considerable circumstantial evidence suggests that the factor is ecdysone. It may act either directly on the brain or on the corpus allatum. Its contribution to a feedback regulation of the endocrine system controlling growth and moulting is discussed.

Cytochemical characteristics of the neurosecretory cells ofCeylonocotyle scoliocoelium(Trematoda: Digenea)

1981 ◽  
Vol 55 (3) ◽  
pp. 223-229 ◽  
Author(s):  
P. N. Sharma ◽  
A. N. Sharma
Keyword(s):  
Neurosecretory Cells ◽  
Synthetic Activity ◽  
Neurosecretory Material ◽  
Secretory Material ◽  
Β Cells ◽  
A Cells ◽  
Aldehyde Fuchsin

ABSTRACTTwo types of neurosecretory cells (NSC), large a cells and small β cells were detected on the basis of their size and characteristics as shown by aldehyde fuchsin and chrome haematoxylin-phloxin staining. A histochemical survey of the neurosecretory material indicates that it is a glycoprotein. Phosphatases and esterases present in NSC probably help in the transfer of metabolites and their hydrolysis and in the control of secretory material produced in a NSC, while SDH provides the necessary energy for the synthetic activity of the latter. The role of neurosecretion in governing the reproduction of this parasite is discussed.

Histopathological and electron microscopic studies of gills of brook trout, Salvelinus fontinalis, from acidified lakes

1985 ◽  
Vol 63 (9) ◽  
pp. 2062-2070 ◽  
Author(s):  
Gaston Chevalier ◽  
Laurent Gauthier ◽  
Guy Moreau
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Gill Tissue ◽  
Low Ph ◽  
Chloride Cells ◽  
Electron Microscopic ◽  
Secondary Lamellae ◽  
Microscopic Studies ◽  
Acidified Lakes ◽  
High Level

Histopathological and electron microscopic studies of gill tissue were carried out in brook trout, Salvelinus fontinalis, from wild populations inhabiting three acidified lakes and in others from three nonacidified lakes located in the Canadian Shield (Québec). The acidified lakes were characterized by low pH (5.5), poor buffering capacity, and low conductivity. By comparison with trout from nonacidified lakes, gills of trout from acidified lakes showed extensive epithelial damage, mainly separation of the epithelial layer from underlying tissue, deformation of secondary lamellae, and degeneration of chloride cells, which was accompanied by pronounced hyperplasia of undifferentiated epithelial cells in the primary lamellae. Histopathological changes were quantified by morphometry. Most damaged gills were also shown to contain a higher concentration of aluminum. The observed changes in gill cells and tissues are interpreted as reactions to sublethal environmental conditions adverse to the osmoregulatory balance of the fish, specifically chronic exposure to low pH and low calcium concentrations, possibly combined with a high level of aluminum.

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