Analysis of repolarization of presynaptic motor terminals in Drosophila larvae using potassium-channel-blocking drugs and mutations

1992 ◽  
Vol 170 (1) ◽  
pp. 93-111
Author(s):  
M. Gho ◽  
B. Ganetzky
Keyword(s):  
Transmitter Release ◽  
Neuronal Cell ◽  
Potassium Currents ◽  
Ionic Currents ◽  
Major Effect ◽  
Synaptic Activity ◽  
Synaptic Currents ◽  
Presynaptic Terminals ◽  
Neuronal Cell Bodies ◽  
Drosophila Larvae

In Drosophila melanogaster muscles and neuronal cell bodies at least four different potassium currents have been identified whose activity shapes the electrical properties of these cells. Potassium currents also control repolarization of presynaptic terminals and, therefore, exert a major effect on transmitter release and synaptic plasticity. However, because of the small size of presynaptic terminals in Drosophila, it has not been possible to analyze the potassium currents they express. As a first approach to characterizing the ionic currents present at presynaptic motor terminals of Drosophila larvae, we recorded synaptic currents at the neuromuscular junction. From the alterations in evoked synaptic currents caused by various drugs and by mutations known to affect potassium currents in other tissues, we suggest that the repolarizing mechanism in presynaptic terminals consists of at least four distinct currents. One is affected by aminopyridines or Sh mutations, a second component is affected by the slo mutation, a third is sensitive to quinidine and one or more additional components are blocked by tetraethylammonium. Depolarization depends on a presynaptic calcium current, which displays only slight voltage-dependent inactivation. Because the mechanism of repolarization exerts a major effect on synaptic activity, this analysis provides a framework for further genetic and molecular dissection of the basic processes involved in the regulation of transmitter release.

The Red Neuronal Pigment in the Nervous System of the Mussel, Mytilus Edulis: Localization and Its Effect on Lateral Ciliary Activity with Spectral and Analytical Changes

1981 ◽  
Vol 39 ◽  
pp. 494-495
Author(s):  
Anthony A. Paparo ◽  
Judith A. Murphy
Keyword(s):  
Nervous System ◽  
Mytilus Edulis ◽  
Neuronal Cell ◽  
Ciliary Activity ◽  
Neuronal Cell Bodies ◽  
The Central Nervous System ◽  
Intracellular Organelles ◽  
The Common ◽  
The Individual ◽  
Cryostat Sections

The purpose of this study was to localize the red neuronal pigment in Mytilus edulis and examine its role in the control of lateral ciliary activity in the gill. The visceral ganglia (Vg) in the central nervous system show an over al red pigmentation. Most red pigments examined in squash preps and cryostat sec tions were localized in the neuronal cell bodies and proximal axon regions. Unstained cryostat sections showed highly localized patches of this pigment scattered throughout the cells in the form of dense granular masses about 5-7 um in diameter, with the individual granules ranging from 0.6-1.3 um in diame ter. Tissue stained with Gomori's method for Fe showed bright blue granular masses of about the same size and structure as previously seen in unstained cryostat sections.Thick section microanalysis (Fig.l) confirmed both the localization and presence of Fe in the nerve cell. These nerve cells of the Vg share with other pigmented photosensitive cells the common cytostructural feature of localization of absorbing molecules in intracellular organelles where they are tightly ordered in fine substructures.

Immunohistochemical Study of Intralaryngeal Ganglia in the Cat

1992 ◽  
Vol 106 (1) ◽  
pp. 42-46 ◽  
Author(s):  
Kuniyoshi Tsuda ◽  
Takemoto Shin ◽  
Sadahiko Masuko
Keyword(s):  
Neuronal Cell ◽  
Superior Laryngeal Nerve ◽  
Exocrine Secretion ◽  
Nerve Fibers ◽  
Neuronal Cell Bodies ◽  
Calcitonin Gene ◽  
Dense Distribution ◽  
Recurrent Laryngeal Nerves ◽  
Immunohistochemical Techniques ◽  
Almost All

To study the mechanism of autonomic regulation in the larynx, intralaryngeal local ganglia of the cat were investigated using immunohistochemical techniques. Small intralaryngeal ganglia were found in the peripheral portions of internal branches of the superior laryngeal nerve. Ninety-one percent of the ganglionic neurons were immunoreactive (IR) to vasoactive intestinal polypeptide (VIP), and 10% of the VIP-IR cells were also immunoreactive to enkephalin (ENK) and/or substance P (SP). The immunoreactivity of neuronal cell bodies remained unchanged even after denervation of the bilateral superior and recurrent laryngeal nerves. A dense distribution of calcitonin gene-related peptide (CGRP)-IR nerve fibers was found around almost all neuronal cells in the intralaryngeal. ganglia. A few VIP-IR, ENK-IR, and SP-IR nerve fibers were also observed. Only the CGRP-IR fibers disappeared after the denervation experiments. in the laryngeal glands and mucosal arterioles, VIP-IR nerve terminals were found that were also immunoreactive to ENK and/or SP. However, these Immunoreactive nerve endings in the glands and arterioles remained after the denervation experiments. The results of our study indicate that laryngeal exocrine secretion and blood flow are regulated by postganglionic autonomic parasympathetic fibers from intralaryngeal ganglia that contain VIP alone or VIP with ENK and/or SP, and that these ganglionic neurons may be innervated by CGRP-IR extrinsic nerve fibers.

Excitatory amino acid receptors in commissural nucleus of the NTS mediate carotid chemoreceptor responses

1993 ◽  
Vol 264 (1) ◽  
pp. R41-R50 ◽  
Author(s):  
A. Vardhan ◽  
A. Kachroo ◽  
H. N. Sapru
Keyword(s):  
Amino Acid ◽  
Carotid Body ◽  
Excitatory Amino Acid ◽  
Minute Ventilation ◽  
Neuronal Cell ◽  
Excitatory Amino Acid Receptors ◽  
Amino Acid Receptors ◽  
Neuronal Cell Bodies ◽  
Carotid Body Chemoreceptors ◽  
Stimulation Of

Stimulation of carotid body chemoreceptors by saline saturated with 100% CO2 elicited an increase in mean arterial pressure, respiratory rate, tidal volume, and minute ventilation (VE). Microinjections of L-glutamate into a midline area 0.5-0.75 mm caudal and 0.3-0.5 mm deep with respect to the calamus scriptorius increased VE. Histological examination showed that the site was located in the commissural nucleus of the nucleus tractus solitarii (NTS). The presence of excitatory amino acid receptors [N-methyl-D-aspartic acid (NMDA); kainate, quisqualate/alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) and trans 1-amino-cyclopentane-trans-1,3-dicarboxylic acid (ACPD)] in this area was demonstrated by microinjections of appropriate agonists. Simultaneous blockade of NMDA and non-NMDA receptors by combined injections of DL-2-aminophosphonoheptanoate (AP-7; 1 nmol) and 6,7-dinitro-quinoxaline-2,3-dione (DNQX; 1 nmol) abolished the responses to stimulation of carotid body on either side. Combined injections of AP-7 and DNQX did not produce a nonspecific depression of neurons because the responses to another agonist, carbachol, remained unaltered. Inhibition of the neurons in the aforementioned area with microinjections of muscimol (which hyperpolarizes neuronal cell bodies but not fibers of passage) also abolished the responses to subsequent carotid body stimulation on either side.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of postsynaptic Ca2+ signals at the Drosophila larval NMJ

2011 ◽  
Vol 106 (2) ◽  
pp. 710-721 ◽  
Author(s):  
Sunil A. Desai ◽  
Gregory A. Lnenicka
Keyword(s):  
Transmitter Release ◽  
Postsynaptic Membrane ◽  
Synaptic Activity ◽  
Synaptic Efficacy ◽  
Single Action ◽  
Synaptic Homeostasis ◽  
Multiple Transcripts ◽  
Quantal Size ◽  
Intracellular Ca ◽  
Larval Neuromuscular Junction

Postsynaptic intracellular Ca2+ concentration ([Ca2+]i) has been proposed to play an important role in both synaptic plasticity and synaptic homeostasis. In particular, postsynaptic Ca2+ signals can alter synaptic efficacy by influencing transmitter release, receptor sensitivity, and protein synthesis. We examined the postsynaptic Ca2+ transients at the Drosophila larval neuromuscular junction (NMJ) by injecting the muscle fibers with Ca2+ indicators rhod-2 and Oregon Green BAPTA-1 (OGB-1) and then monitoring their increased fluorescence during synaptic activity. We observed discrete postsynaptic Ca2+ transients along the NMJ during single action potentials (APs) and quantal Ca2+ transients produced by spontaneous transmitter release. Most of the evoked Ca2+ transients resulted from the release of one or two quanta of transmitter and occurred largely at synaptic boutons. The magnitude of the Ca2+ signals was correlated with synaptic efficacy; the Is terminals, which produce larger excitatory postsynaptic potentials (EPSPs) and have a greater quantal size than Ib terminals, produced a larger Ca2+ signal per terminal length and larger quantal Ca2+ signals than the Ib terminals. During a train of APs, the postsynaptic Ca2+ signal increased but remained localized to the postsynaptic membrane. In addition, we showed that the plasma membrane Ca2+-ATPase (PMCA) played a role in extruding Ca2+ from the postsynaptic region of the muscle. Drosophila melanogaster has a single PMCA gene, predicted to give rise to various isoforms by alternative splicing. Using RT-PCR, we detected the expression of multiple transcripts in muscle and nervous tissues; the physiological significance of the same is yet to be determined.

Apelin and the proopiomelanocortin system: a new regulatory pathway of hypothalamic α-MSH release

2011 ◽  
Vol 301 (5) ◽  
pp. E955-E966 ◽  
Author(s):  
Annabelle Reaux-Le Goazigo ◽  
Laurence Bodineau ◽  
Nadia De Mota ◽  
Lydie Jeandel ◽  
Nicolas Chartrel ◽  
...  
Keyword(s):  
Food Intake ◽  
Neuronal Cell ◽  
Nerve Fibers ◽  
Zucker Rats ◽  
Direct Stimulation ◽  
Melanocyte Stimulating Hormone ◽  
System A ◽  
Neuronal Cell Bodies ◽  
Hypothalamic Arcuate Nucleus ◽  
Apelin Receptor

Neuronal networks originating in the hypothalamic arcuate nucleus (Arc) play a fundamental role in controlling energy balance. In the Arc, neuropeptide Y (NPY)-producing neurons stimulate food intake, whereas neurons releasing the proopiomelanocortin (POMC)-derived peptide α-melanocyte-stimulating hormone (α-MSH) strongly decrease food intake. There is growing evidence to suggest that apelin and its receptor may play a role in the central control of food intake, and both are concentrated in the Arc. We investigated the presence of apelin and its receptor in Arc NPY- and POMC-containing neurons and the effects of apelin on α-MSH release in the hypothalamus. We showed, by immunofluorescence and confocal microscopy, that apelin-immunoreactive (IR) neuronal cell bodies were distributed throughout the rostrocaudal extent of the Arc and that apelin was strongly colocalized with POMC, but weakly colocalized with NPY. However, there were numerous NPY-IR nerve fibers close to the apelin-IR neuronal cell bodies. By combining in situ hybridization with immunohistochemistry, we demonstrated the presence of apelin receptor mRNA in Arc POMC neurons. Moreover, using a perifusion technique for hypothalamic explants, we demonstrated that apelin-17 (K17F) increased α-MSH release, suggesting that apelin released somato-dendritically or axonally from POMC neurons may stimulate α-MSH release in an autocrine manner. Consistent with these data, hypothalamic apelin levels were found to be higher in obese db/db mice and fa/fa Zucker rats than in wild-type animals. These findings support the hypothesis that central apelin is involved in regulating body weight and feeding behavior through the direct stimulation of α-MSH release.

scholarly journals Stimulation by acetylcholine of phosphatidylinositol labelling. Subcellular distribution in rat cerebral-cortex slices

1972 ◽  
Vol 126 (5) ◽  
pp. 1141-1147 ◽  
Author(s):  
Eduardo G. Lapetina ◽  
Robert H. Michell
Keyword(s):  
Cerebral Cortex ◽  
Specific Radioactivity ◽  
Neuronal Cell ◽  
Subcellular Fractionation ◽  
Rat Cerebral Cortex ◽  
Marker Enzymes ◽  
Fresh Tissue ◽  
Cell Structures ◽  
Neuronal Cell Bodies ◽  
Cortex Slices

1. Rat cerebral-cortex slices were incubated with 32Pi, acetylcholine and eserine for periods of 10min and 2h. The specific radioactivity of phosphatidylinositol was elevated during these treatments by 36 and 106% respectively. 2. The specific radioactivities of the phosphatidylinositol in different cell structures were determined after subcellular fractionation. They were highest in the nuclear, microsomal and synaptic-vesicle fractions and lowest in myelin, both in the controls and in the acetylcholine-treated slices. 3. The stimulated labelling of phosphatidylinositol was relatively evenly distributed: no subcellular fraction showed a stimulation markedly higher than that in the homogenate. 4. Studies of the distributions and activities of marker enzymes indicated that the subcellular fractionation achieved was similar to that with fresh tissue. 5. The results are discussed in relation to the previous report that the stimulation is observed throughout the neuronal cell-bodies and in relation to the hypothesis that the labelled phosphatidylinositol produced by stimulation is a component of an acetylcholine-receptor proteolipid localized in the synaptic junction.

Neurons controlling cardiovascular responses to emotion are located in lateral hypothalamus-perifornical region

1990 ◽  
Vol 259 (5) ◽  
pp. R943-R954 ◽  
Author(s):  
O. A. Smith ◽  
J. L. DeVito ◽  
C. A. Astley
Keyword(s):  
Electrical Stimulation ◽  
Lateral Hypothalamus ◽  
Axonal Degeneration ◽  
Neuronal Cell ◽  
Cardiovascular Responses ◽  
Ibotenic Acid ◽  
Defense Reaction ◽  
Autonomic Responses ◽  
Neuronal Cell Bodies ◽  
Thoracic Cord

We did four experiments to determine whether the lateral hypothalamus-perifornical (LH/PF) region is the source of neuronal cell bodies responsible for producing the cardiovascular (CV) responses associated with emotion or the defense reaction. Of particular concern was whether the paraventricular nucleus (PVN) plays a role in the generation of these CV responses. Mapping the hypothalamus with electrical stimulation showed that the CV pattern of responses was never produced by stimulating the PVN and was invariably produced by stimulating the LH/PF region. Complete electrolytic destruction of the PVN and subsequent axonal degeneration did not change the CV pattern of responses elicited by LH/PF stimulation, whereas any encroachment of the lesion on the LH/PF region decreased the magnitude of the CV responses. Injection of the neuroexcitotoxin ibotenic acid (Ibo) into the PVN did not affect responses to LH/PF stimulation, whereas Ibo injection into the LH/PF region eliminated or severely attenuated the CV responses. Retrograde labeling of cells from the thoracic cord and the ventrolateral reticular formation revealed a scattered group of cells in the LH/PF region that may be the cells controlling the CV responses. These results point directly to the LH/PF region as the source of the cell bodies responsible for the autonomic responses associated with emotion or defense reactions.

scholarly journals Modeling Neuronal Systems as an Open Quantum System

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1603
Author(s):  
Yu-Juan Sun ◽  
Wei-Min Zhang
Keyword(s):  
Action Potential ◽  
Open Quantum Systems ◽  
Continuous Distribution ◽  
Neuronal Cell ◽  
Neuronal Model ◽  
Collective State ◽  
Neuronal System ◽  
Open Quantum ◽  
Neuronal Cell Bodies ◽  
Master Equation Approach

We propose a physical model for neurons to describe how neurons interact with one another through the surrounding materials of neuronal cell bodies. We model the neuronal cell surroundings, include the dendrites, the axons and the synapses, as well as the surrounding glial cells, as a continuous distribution of oscillating modes inspired from the electric circuital picture of neuronal action potential. By analyzing the dynamics of this neuronal model by using the master equation approach of open quantum systems, we investigated the collective behavior of neurons. After applying stimulations to the neuronal system, the neuron collective state is activated and shows the action potential behavior. We find that this model can generate random neuron–neuron interactions and is appropriate for describing the process of information transmission in the neuronal system, which may pave a potential route toward understanding the dynamics of nervous system.

scholarly journals Immunoreactivity of the calbindin D28k in the parahippocampal gyrus of chinchilla

2013 ◽  
Vol 57 (3) ◽  
pp. 387-391
Author(s):  
Radosław Szalak ◽  
Jadwiga Jaworska-Adamu ◽  
Karol Rycerz ◽  
Paweł Kulik ◽  
Marcin Bartłomiej Arciszewski
Keyword(s):  
Brain Area ◽  
Neuronal Cell ◽  
Immunofluorescence Staining ◽  
Parahippocampal Gyrus ◽  
Neuronal Cell Bodies ◽  
Entorhinal Area ◽  
Calbindin D28k ◽  
Retzius Cells ◽  
Species Specific ◽  
The Brain

Abstract Ten adult male chinchillas were used. The localisation of calbindin D28k (CB) was examined with the use of two types of reactions: immunocytochemical peroxidase-antiperoxidase and immunofluorescence staining with a specific monoclonal antibody against CB. Immunocytochemical examination demonstrated the presence of CB-positive neurons in the following layers of all parts the parahippocampal gyrus (PG): marginal, external cellular, middle cellular, and internal cellular, i.e. in entorhinal area, parasubiculum, and presubiculum. Immunofluorescence staining revealed the presence of CB in both Hu C/Dimmunoreactive (IR) neurons and nervous fibers of the PG. CB-IR neuronal cell bodies were moderately numerous (ca. 10% of Hu C/D-IR neurons) and clearly distinguished from the background. Each layer of the brain area consisted of two types of neurons: pyramidal and multiform. Among the second type of neurons, four kinds of morphologically different neuronal subclasses were observed: multipolar, bipolar, round, and Cajal-Retzius cells. It is concluded that the expression of CB in the PG of the chinchilla is species specific and limited to several subclasses of neurons

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