scholarly journals Neural circuit mechanism underlying the feeding controlled by insula-central amygdala pathway

2019 ◽  
Author(s):  
Calvin Zhang-Molina ◽  
Matthew B Schmit ◽  
Haijiang Cai
Keyword(s):  
Neural Circuit ◽  
Insular Cortex ◽  
Central Nucleus ◽  
Synaptic Organization ◽  
Feeding Behaviors ◽  
Electrophysiological Properties ◽  
Network Computer ◽  
Systems Model ◽  
Circuit Structure ◽  
Circuit Output

SummaryCentral nucleus of amygdala (CeA) contains distinct populations of neurons that play opposing roles in feeding. The circuit mechanism of how CeA neurons process information sent from their upstream inputs to regulate feeding is still unclear. Here we show that activation of the neural pathway projecting from insular cortex neurons to CeA suppresses food intake. Surprisingly, we find that the inputs from insular cortex form excitatory connections with similar strength to all types of CeA neurons. To reconcile this puzzling result, and previous findings, we developed a conductance-based dynamical systems model for the CeA neuronal network. Computer simulations showed that both the intrinsic electrophysiological properties of individual CeA neurons and the overall synaptic organization of the CeA circuit play a functionally significant role in shaping the CeA neural dynamics. We successfully identified a specific CeA circuit structure that reproduces the desired circuit output consistent with existing experimentally observed feeding behaviors.

scholarly journals Differences in chloride gradients allow for three distinct types of synaptic modulation by endocannabinoids

2016 ◽  
Vol 116 (2) ◽  
pp. 619-628 ◽  
Author(s):  
Yanqing Wang ◽  
Brian D. Burrell
Keyword(s):  
Neural Circuit ◽  
Critical Role ◽  
Low Frequency ◽  
Inhibitory Synapses ◽  
Primary Role ◽  
Synaptic Modulation ◽  
Hirudo Verbana ◽  
Frequency Stimulation ◽  
Circuit Output

Endocannabinoids can elicit persistent depression of excitatory and inhibitory synapses, reducing or enhancing (disinhibiting) neural circuit output, respectively. In this study, we examined whether differences in Cl−gradients can regulate which synapses undergo endocannabinoid-mediated synaptic depression vs. disinhibition using the well-characterized central nervous system (CNS) of the medicinal leech, Hirudo verbana. Exogenous application of endocannabinoids or capsaicin elicits potentiation of pressure (P) cell synapses and depression of both polymodal (Npoly) and mechanical (Nmech) nociceptive synapses. In P synapses, blocking Cl−export prevented endocannabinoid-mediated potentiation, consistent with a disinhibition process that has been indicated by previous experiments. In Nmechneurons, which are depolarized by GABA due to an elevated Cl−equilibrium potentials (ECl), endocannabinoid-mediated depression was prevented by blocking Cl−import, indicating that this decrease in synaptic signaling was due to depression of excitatory GABAergic input (disexcitation). Npolyneurons are also depolarized by GABA, but endocannabinoids elicit depression in these synapses directly and were only weakly affected by disruption of Cl−import. Consequently, the primary role of elevated EClmay be to protect Npolysynapses from disinhibition. All forms of endocannabinoid-mediated plasticity required activation of transient potential receptor vanilloid (TRPV) channels. Endocannabinoid/TRPV-dependent synaptic plasticity could also be elicited by distinct patterns of afferent stimulation with low-frequency stimulation (LFS) eliciting endocannabinoid-mediated depression of Npolysynapses and high-frequency stimulus (HFS) eliciting endocannabinoid-mediated potentiation of P synapses and depression of Nmechsynapses. These findings demonstrate a critical role of differences in Cl−gradients between neurons in determining the sign, potentiation vs. depression, of synaptic modulation under normal physiological conditions.

Postsynaptic Cell Type–Dependent Cholinergic Regulation of GABAergic Synaptic Transmission in Rat Insular Cortex

2010 ◽  
Vol 104 (4) ◽  
pp. 1933-1945 ◽  
Author(s):  
Kiyofumi Yamamoto ◽  
Yuko Koyanagi ◽  
Noriaki Koshikawa ◽  
Masayuki Kobayashi
Keyword(s):  
Synaptic Transmission ◽  
Pyramidal Cell ◽  
Insular Cortex ◽  
Pyramidal Cells ◽  
Gaba Release ◽  
Patch Clamp Recording ◽  
Electrophysiological Properties ◽  
Heterogeneous Effects ◽  
Postsynaptic Cell ◽  
Gabaergic Synaptic Transmission

The cerebral cortex consists of multiple neuron subtypes whose electrophysiological properties exhibit diverse modulation patterns in response to neurotransmitters, including noradrenaline and acetylcholine (ACh). We performed multiple whole cell patch-clamp recording from layer V GABAergic interneurons and pyramidal cells of rat insular cortex (IC) to examine whether cholinergic effects on unitary inhibitory postsynaptic currents (uIPSCs) are differentially regulated by ACh receptors, depending on their presynaptic and postsynaptic cell subtypes. In fast-spiking (FS) to pyramidal cell synapses, carbachol (10 μM) invariably decreased uIPSC amplitude by 51.0%, accompanied by increases in paired-pulse ratio (PPR) of the second to first uIPSC amplitude, coefficient of variation (CV) of the first uIPSC amplitude, and failure rate. Carbachol-induced uIPSC suppression was dose dependent and blocked by atropine, a muscarinic ACh receptor antagonist. Similar cholinergic suppression was observed in non-FS to pyramidal cell synapses. In contrast, FS to FS/non-FS cell synapses showed heterogeneous effects on uIPSC amplitude by carbachol. In roughly 40% of pairs, carbachol suppressed uIPSCs by 35.8%, whereas in a similar percentage of pairs uIPSCs were increased by 34.8%. Non-FS to FS/non-FS cell synapses also showed carbachol-induced uIPSC facilitation by 29.2% in about half of the pairs, whereas nearly 40% of pairs showed carbachol-induced suppression of uIPSCs by 40.3%. Carbachol tended to increase uIPSC amplitude in interneuron-to-interneuron synapses with higher PPR, suggesting that carbachol facilitates GABA release in interneuron synapses with lower release probability. These results suggest that carbachol-induced effects on uIPSCs are not homogeneous but preiotropic: i.e., cholinergic modulation of GABAergic synaptic transmission is differentially regulated depending on postsynaptic neuron subtypes.

scholarly journals GLP-1 Suppresses Feeding Behaviors and Modulates Neuronal Electrophysiological Properties in Multiple Brain Regions

2021 ◽  
Vol 14 ◽  
Author(s):  
Xin-Yi Chen ◽  
Lei Chen ◽  
Wu Yang ◽  
An-Mu Xie
Keyword(s):  
Food Intake ◽  
Neuronal Excitability ◽  
Functional Organization ◽  
Brain Regions ◽  
Future Research ◽  
Cellular Mechanisms ◽  
Feeding Behaviors ◽  
Gabaergic Neurotransmission ◽  
Electrophysiological Properties ◽  
Glucagon Like Peptide 1

The glucagon-like peptide-1 (GLP-1) plays important roles in the regulation of food intake and energy metabolism. Peripheral or central GLP-1 suppresses food intake and reduces body weight. The electrophysiological properties of neurons in the mammalian central nervous system reflect the neuronal excitability and the functional organization of the brain. Recent studies focus on elucidating GLP-1-induced suppression of feeding behaviors and modulation of neuronal electrophysiological properties in several brain regions. Here, we summarize that activation of GLP-1 receptor (GLP-1R) suppresses food intake and induces postsynaptic depolarization of membrane potential and/or presynaptic modulation of glutamatergic or GABAergic neurotransmission in brain nuclei located within the medulla oblongata, pons, mesencephalon, diencephalon, and telencephalon. This review may provide a background to guide future research about the cellular mechanisms of GLP-1-induced feeding inhibition.

scholarly journals Conserved neural circuit structure across Drosophila larval development revealed by comparative connectomics

2017 ◽  
Author(s):  
Stephan Gerhard ◽  
Ingrid Andrade ◽  
Richard D. Fetter ◽  
Albert Cardona ◽  
Casey M. Schneider-Mizell
Keyword(s):  
Structural Changes ◽  
Neural Circuit ◽  
Postembryonic Development ◽  
Neuronal Morphology ◽  
The Body ◽  
Structural Adaptation ◽  
Circuit Structure ◽  
Section Electron ◽  
Structural Growth ◽  
Serial Section Electron Microscopy

AbstractThroughout an animal’s postembryonic development, neuronal circuits must maintain appropriate output even as the body grows. The contribution of structural adaptation — neuronal morphology and synaptic connectivity — to circuit development remains unclear. In a previous paper (Schneider-Mizell et al., 2016), we measured the detailed neuronal morphological structures subserving neuronal connectivity in Drosophila. Here, we examine how neuronal morphology and connectivity change across postembyronic development. Using new and existing serial section electron microscopy volumes, we reconstructed an identified nociceptive circuit in two larvae, one 1st instar and one 3rd instar. We found extremely consistent, topographically-arranged circuit structure. Five-fold increases in size of interneurons were associated with compensatory structural changes that maintained cell-type-specific synaptic input as a fraction of total inputs. An increase in number of synaptic contacts was accompanied with a disproportionate increase in the number of small dendritic terminal branches relative to other neuronal compartments. We propose that these precise patterns of structural growth act to conserve the computational function of a circuit, for example determining the location of a nociceptive stimulus.

scholarly journals Author response: Conserved neural circuit structure across Drosophila larval development revealed by comparative connectomics

2017 ◽  
Author(s):  
Stephan Gerhard ◽  
Ingrid Andrade ◽  
Richard D Fetter ◽  
Albert Cardona ◽  
Casey M Schneider-Mizell
Keyword(s):  
Larval Development ◽  
Neural Circuit ◽  
Author Response ◽  
Circuit Structure

scholarly journals Modulation of Neuronal Activity on Intercalated Neurons of Amygdala Might Underlie Anxiolytic Activity of a Standardized Extract of Centella asiatica ECa233

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Aree Wanasuntronwong ◽  
Oraphan Wanakhachornkrai ◽  
Penphimon Phongphanphanee ◽  
Tadashi Isa ◽  
Boonyong Tantisira ◽  
...  
Keyword(s):  
Ampa Receptors ◽  
Brain Slices ◽  
Centella Asiatica ◽  
Gabaergic Neurons ◽  
Anxiolytic Activity ◽  
Central Nucleus ◽  
Electrophysiological Properties ◽  
Whole Cell Patch Clamp ◽  
External Capsule ◽  
Excitatory Synaptic Input

GABAergic intercalated neurons of amygdala (ITCs) have recently been shown to be important in the suppression of fear-like behavior. Effects of ECa233 (a standardized extract of Centella asiatica), previously demonstrated anxiolytic activity, were then investigated on ITCs. Cluster of GABAergic neurons expressing fluorescence of GFP was identified in GAD67-GFP knock-in mice. We found that neurons of medial paracapsular ITC were GABAergic neurons exhibiting certain intrinsic electrophysiological properties similar to those demonstrated by ITC neurons at the same location in C57BL/6J mice. Therefore, we conducted experiments in both C57BL/6J mice and GAD67-GFP knock-in mice. Excitatory postsynaptic currents (EPSCs) were evoked by stimulation of the external capsule during the whole cell patch-clamp recordings from ITC neurons in brain slices. ECa233 was found to increase the EPSC peak amplitude in the ITC neurons by about 120%. The EPSCs in ITC neurons were completely abolished by the application of an AMPA receptor antagonist. Morphological assessment of the ITC neurons with biocytin demonstrated that most axons of the recorded neurons innervated the central nucleus of the amygdala (CeA). Therefore, it is highly likely that anxiolytic activity of ECa233 was mediated by increasing activation, via AMPA receptors, of excitatory synaptic input to the GABAergic ITC leading to depression of CeA neurons.

Physiological and Morphological Characterization of Local Interneurons in the Drosophila Antennal Lobe

2010 ◽  
Vol 104 (2) ◽  
pp. 1007-1019 ◽  
Author(s):  
Yoichi Seki ◽  
Jürgen Rybak ◽  
Dieter Wicher ◽  
Silke Sachse ◽  
Bill S. Hansson
Keyword(s):  
Antennal Lobe ◽  
Neural Circuit ◽  
Three Dimensional ◽  
Morphological Characterization ◽  
Morphological Properties ◽  
Electrophysiological Properties ◽  
Local Interneurons ◽  
Enhancer Trap Line ◽  
Almost All

The Drosophila antennal lobe (AL) has become an excellent model for studying early olfactory processing mechanisms. Local interneurons (LNs) connect a large number of glomeruli and are ideally positioned to increase computational capabilities of odor information processing in the AL. Although the neural circuit of the Drosophila AL has been intensively studied at both the input and the output level, the internal circuit is not yet well understood. An unambiguous characterization of LNs is essential to remedy this lack of knowledge. We used whole cell patch-clamp recordings and characterized four classes of LNs in detail using electrophysiological and morphological properties at the single neuron level. Each class of LN displayed unique characteristics in intrinsic electrophysiological properties, showing differences in firing patterns, degree of spike adaptation, and amplitude of spike afterhyperpolarization. Notably, one class of LNs had characteristic burst firing properties, whereas the others were tonically active. Morphologically, neurons from three classes innervated almost all glomeruli, while LNs from one class innervated a specific subpopulation of glomeruli. Three-dimensional reconstruction analyses revealed general characteristics of LN morphology and further differences in dendritic density and distribution within specific glomeruli between the different classes of LNs. Additionally, we found that LNs labeled by a specific enhancer trap line (GAL4-Krasavietz), which had previously been reported as cholinergic LNs, were mostly GABAergic. The current study provides a systematic characterization of olfactory LNs in Drosophila and demonstrates that a variety of inhibitory LNs, characterized by class-specific electrophysiological and morphological properties, construct the neural circuit of the AL.

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