Neuromodulatory Effect of GnRH on the Synaptic Transmission of the Olfactory Bulbar Neural Circuit in Goldfish, Carassius auratus

2010 ◽  
Vol 104 (6) ◽  
pp. 3540-3550 ◽  
Author(s):  
Takafumi Kawai ◽  
Hideki Abe ◽  
Yasuhisa Akazome ◽  
Yoshitaka Oka
Keyword(s):  
Carassius Auratus ◽  
Neural Circuits ◽  
Neural Circuit ◽  
Granule Cells ◽  
Glutamate Release ◽  
Sensory Information ◽  
Field Potential ◽  
Field Potentials ◽  
Goldfish Carassius Auratus

Gonadotropin-releasing hormone (GnRH) is well known as a hypophysiotropic hormone that is produced in the hypothalamus and facilitates the release of gonadotropins from the pituitary gonadotropes. On the other hand, the functions of extrahypothalamic GnRH systems still remain elusive. Here we examined whether the activity of the olfactory bulbar neural circuits is modulated by GnRH that originates mainly from the terminal nerve (TN) GnRH system in goldfish ( Carassius auratus). As the morphological basis, we first observed that goldfish TNs mainly express salmon GnRH (sGnRH) mRNA and that sGnRH-immunoreactive fibers are distributed in both the mitral and the granule cell layers. We then examined by extracellular recordings the effect of GnRH on the electrically evoked in vitro field potentials that arise from synaptic activities from mitral to granule cells. We found that GnRH enhances the amplitude of the field potentials. Furthermore, these effects were observed in both cases when the field potentials were evoked by stimulating either the lateral or the medial olfactory tract, conveying functionally different sensory information, separately, and suggesting that GnRH may modulate the responsiveness to wide categories of odorants in the olfactory bulb. Because GnRH also changed the paired-pulse ratio, it is suggested that the increased amplitude of the field potential results from changes in the presynaptic glutamate release of mitral cells rather than the increase in the glutamate receptor sensitivity of granule cells. These results suggest that TN regulates the olfactory responsiveness of animals appropriately by releasing sGnRH peptides in the olfactory bulbar neural circuits.

Dopaminergic neuromodulation of synaptic transmission between mitral and granule cells in the teleost olfactory bulb

2012 ◽  
Vol 107 (5) ◽  
pp. 1313-1324 ◽  
Author(s):  
Takafumi Kawai ◽  
Hideki Abe ◽  
Yoshitaka Oka
Keyword(s):  
Olfactory Bulb ◽  
Synaptic Transmission ◽  
Granule Cells ◽  
Glutamate Release ◽  
Field Potential ◽  
Olfactory Nerve ◽  
Oscillatory Activity ◽  
Cellular Mechanisms ◽  
Olfactory Information

A growing body of evidence suggests that teleosts are important models for the study of neural processing of olfactory information, and the functional role of dopamine (DA), which is a potent neuromodulator endogenous to the mammalian olfactory bulb, has been one of the strongest focuses in this field. However, the cellular mechanisms of dopaminergic neuromodulation in olfactory bulbar neural circuits have not been fully understood. We investigated such mechanisms by using the goldfish, which offers several advantages for analyzing olfactory information processing by electrophysiological methods. First, we found in the olfactory bulb that numerous cell bodies of the dopaminergic neurons are mainly distributed in the mitral cell layer and extend fine processes to the glomerular layer. Next, we made in vitro field potential recordings and showed that synaptic transmissions from mitral to granule cells were suppressed by DA application. DA also increased the paired-pulse ratio, suggesting that the suppression of synaptic transmission is caused by a decrease in presynaptic glutamate release from the mitral cells. Furthermore, DA significantly suppressed the oscillatory activity of the olfactory bulb in response to olfactory stimuli. Although DA suppresses the synaptic inputs from the olfactory nerve to the olfactory bulbar neurons in mammals, this phenomenon was not observed in the goldfish. These findings indicate that suppression of the mitral to granule cell synaptic transmission in the reciprocal synapses plays an important role in the negative regulation of olfactory responsiveness in the goldfish olfactory bulb.

scholarly journals Oscillatory integration windows in neurons

2016 ◽  
Author(s):  
Nitin Gupta ◽  
Swikriti Saran Singh ◽  
Mark Stopfer
Keyword(s):  
Neural Circuits ◽  
Neural Circuit ◽  
Field Potential ◽  
Coincidence Detection ◽  
Uniform Structure ◽  
Detection Mechanism ◽  
Oscillation Frequencies ◽  
Local Field Potential Lfp ◽  
Oscillatory Cycle

AbstractOscillatory synchrony among neurons occurs in many species and brain areas, and has been proposed to help neural circuits process information. One hypothesis states that oscillatory input creates cyclic integration windows: specific times in each oscillatory cycle when postsynaptic neurons become especially responsive to inputs. With paired local field potential (LFP) and intracellular recordings and controlled stimulus manipulations we directly tested this idea in the locust olfactory system. We found that inputs arriving in Kenyon cells (KCs) sum most effectively in a preferred window of the oscillation cycle. With a computational model, we found that the non-uniform structure of noise in the membrane potential helps mediate this process. Further experiments performed in vivo demonstrated that integration windows can form in the absence of inhibition and at a broad range of oscillation frequencies. Our results reveal how a fundamental coincidence-detection mechanism in a neural circuit functions to decode temporally organized spiking.

scholarly journals Deep Learning Based Proarrhythmia Analysis Using Field Potentials Recorded from Human Pluripotent Stem Cells Derived Cardiomyocytes

2018 ◽  
Author(s):  
Zeinab Golgooni ◽  
Sara Mirsadeghi ◽  
Mahdieh Soleymani Baghshah ◽  
Pedram Ataee ◽  
Hossein Baharvand ◽  
...  
Keyword(s):  
Neural Network ◽  
Stem Cells ◽  
Deep Learning ◽  
Pluripotent Stem Cells ◽  
Field Potential ◽  
Input Sequence ◽  
Patient Specific ◽  
Field Potentials ◽  
Drug Induced

AbstractAimAn early characterization of drug-induced cardiotoxicity may be possible by combining comprehensive in vitro pro-arrhythmia assay and deep learning techniques. The goal of this study was to develop a deep learning method to automatically detect irregular beating rhythm as well as abnormal waveforms of field potentials in an in vitro cardiotoxicity assay using human pluripotent stem cell (hPSC) derived cardiomyocytes and multi-electrode array (MEA) system.Methods and ResultsWe included field potential waveforms from 380 experiments which obtained by application of some cardioactive drugs on healthy and/or patient-specific induced pluripotent stem cells derived cardiomyocytes (iPSC-CM). We employed convolutional and recurrent neural networks, in order to develop a new method for automatic classification of field potential recordings without using any hand-engineered features. In the proposed method, a preparation phase was initially applied to split 60-second long recordings into a series of 5-second long windows. Thereafter, the classification phase comprising of two main steps was designed. In the first step, 5-second long windows were classified using a designated convolutional neural network (CNN). In the second step, the results of 5-second long window assessments were used as the input sequence to a recurrent neural network (RNN). The output was then compared to electrophysiologist-level arrhythmia (irregularity or abnormal waveforms) detection, resulting in 0.84 accuracy, 0.84 sensitivity, 0.85 specificity, and 0.88 precision.ConclusionA novel deep learning approach based on a two-step CNN-RNN method can be used for automated analysis of “irregularity or abnormal waveforms” in an in vitro model of cardiotoxicity experiments.

scholarly journals Prominent Inhibitory Projections Guide Sensorimotor Computation: An Invertebrate Perspective

2019 ◽  
Author(s):  
Samantha Hughes ◽  
Tansu Celikel
Keyword(s):  
Motor Neurons ◽  
Neural Circuits ◽  
Neural Circuit ◽  
Sensory Information ◽  
Circuit Complexity ◽  
Inhibitory Circuits ◽  
Invertebrate Species ◽  
Gating Mechanism ◽  
Motor Actions ◽  
Sensorimotor Representations

From single-cell organisms to complex neural networks, all evolved to provide control solutions to generate context and goal-specific actions. Neural circuits performing sensorimotor computation to drive navigation employ inhibitory control as a gating mechanism, as they hierarchically transform (multi)sensory information into motor actions. Here, we focus on this literature to critically discuss the proposition that prominent inhibitory projections form sensorimotor circuits. After reviewing the neural circuits of navigation across various invertebrate species, we argue that with increased neural circuit complexity and the emergence of parallel computations inhibitory circuits acquire new functions. The contribution of inhibitory neurotransmission for navigation goes beyond shaping the communication that drives motor neurons, instead, include encoding of emergent sensorimotor representations. A mechanistic understanding of the neural circuits performing sensorimotor computations in invertebrates will unravel the minimum circuit requirements driving adaptive navigation.

Oxoanions stimulate in vitro ovulation and signal transduction pathways in goldfish (Carassius auratus) follicles

1992 ◽  
Vol 263 (5) ◽  
pp. E943-E949 ◽  
Author(s):  
S. Y. Hsu ◽  
F. W. Goetz
Keyword(s):  
Signal Transduction ◽  
Carassius Auratus ◽  
Sodium Tungstate ◽  
Sodium Molybdate ◽  
Vanadyl Sulfate ◽  
Signal Transduction Pathways ◽  
Sodium Selenate ◽  
Sodium Chromate ◽  
Goldfish Carassius Auratus

The present study investigated the effects of a number of oxoanion compounds on in vitro ovulation of goldfish follicles and ovarian second messenger activities. Significant levels of ovulation were induced by 0.1 mM sodium chromate, 0.1 mM sodium metavanadate, 10 mM sodium molybdate, 0.1 mM sodium orthovanadate, 5 mM sodium selenate, 0.5 mM sodium tungstate, and 0.1 mM vanadyl sulfate. At levels that significantly stimulated ovulation, metavanadate, molybdate, orthovanadate, tungstate, and vanadyl sulfate also stimulated follicular phosphatidylinositol cycling and inhibited ovarian alkaline phosphatase activity. Moreover, the ovulation induced by these oxoanions was not inhibited by indomethacin (10 micrograms/ml), while ovulation induced by selenate and chromate was. In contrast, only vanadium-containing compounds significantly stimulated prostaglandin (PG) synthesis, and, in fact, selenate significantly inhibited PG production. Finally, only sodium molybdate- and vanadium-containing compounds appeared to increase follicular adenosine 3',5'-cyclic monophosphate content. While all oxoanions stimulated in vitro ovulation, they had differential effects on certain signal transduction pathways when tested at concentrations that stimulated in vitro ovulation. From the results, two basic groups could be delineated, one containing tungstate-, molybdate-, and vanadium-containing compounds and the other selenate and chromate. Thus the mechanism by which ovulation is induced by chromate and selenate may be different from that of vanadium-containing compounds, molybdate, and tungstate.(ABSTRACT TRUNCATED AT 250 WORDS)

Presynaptic Muscarinic Receptors Enhance Glutamate Release at the Mitral/Tufted to Granule Cell Dendrodendritic Synapse in the Rat Main Olfactory Bulb

2009 ◽  
Vol 101 (4) ◽  
pp. 2052-2061 ◽  
Author(s):  
Ambarish S. Ghatpande ◽  
Alan Gelperin
Keyword(s):  
Olfactory Bulb ◽  
Granule Cell ◽  
Basal Forebrain ◽  
Granule Cells ◽  
Calcium Influx ◽  
Glutamate Release ◽  
Gaba Release ◽  
Cellular Mechanisms ◽  
Tufted Cells

The mammalian olfactory bulb receives multiple modulatory inputs, including a cholinergic input from the basal forebrain. Understanding the functional roles played by the cholinergic input requires an understanding of the cellular mechanisms it modulates. In an in vitro olfactory bulb slice preparation we demonstrate cholinergic muscarinic modulation of glutamate release onto granule cells that results in γ-aminobutyric acid (GABA) release onto mitral/tufted cells. We demonstrate that the broad-spectrum cholinergic agonist carbachol triggers glutamate release from mitral/tufted cells that activates both AMPA and NMDA receptors on granule cells. Activation of the granule cell glutamate receptors leads to calcium influx through voltage-gated calcium channels, resulting in spike-independent, asynchronous GABA release at reciprocal dendrodendritic synapses that granule cells form with mitral/tufted cells. This cholinergic modulation of glutamate release persists through much of postnatal bulbar development, suggesting a functional role for cholinergic inputs from the basal forebrain in bulbar processing of olfactory inputs and possibly in postnatal development of the olfactory bulb.

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