scholarly journals Neuroligin3 splice isoforms shape inhibitory synaptic function in the mouse hippocampus

2020 ◽  
Vol 295 (25) ◽  
pp. 8589-8595 ◽  
Author(s):  
Motokazu Uchigashima ◽  
Ming Leung ◽  
Takuya Watanabe ◽  
Amy Cheung ◽  
Timmy Le ◽  
...  
Keyword(s):  
Synaptic Transmission ◽  
Single Cell ◽  
Pyramidal Neurons ◽  
Autism Spectrum ◽  
Synaptic Function ◽  
Synaptic Activity ◽  
Dependent Manner ◽  
Splice Isoforms ◽  
Inhibitory Synaptic Transmission ◽  
Ca1 Pyramidal Neurons

Synapse formation is a dynamic process essential for the development and maturation of the neuronal circuitry in the brain. At the synaptic cleft, trans-synaptic protein–protein interactions are major biological determinants of proper synapse efficacy. The balance of excitatory and inhibitory synaptic transmission (E-I balance) stabilizes synaptic activity, and dysregulation of the E-I balance has been implicated in neurodevelopmental disorders, including autism spectrum disorders. However, the molecular mechanisms underlying the E-I balance remain to be elucidated. Here, using single-cell transcriptomics, immunohistochemistry, and electrophysiology approaches to murine CA1 pyramidal neurons obtained from organotypic hippocampal slice cultures, we investigate neuroligin (Nlgn) genes that encode a family of postsynaptic adhesion molecules known to shape excitatory and inhibitory synaptic function. We demonstrate that the NLGN3 protein differentially regulates inhibitory synaptic transmission in a splice isoform–dependent manner at hippocampal CA1 synapses. We also found that distinct subcellular localizations of the NLGN3 isoforms contribute to the functional differences observed among these isoforms. Finally, results from single-cell RNA-Seq analyses revealed that Nlgn1 and Nlgn3 are the major murine Nlgn genes and that the expression levels of the Nlgn splice isoforms are highly diverse in CA1 pyramidal neurons. Our results delineate isoform-specific effects of Nlgn genes on the E-I balance in the murine hippocampus.

scholarly journals Neuroligin3 Splice Isoforms Shape Mouse Hippocampal Inhibitory Synaptic Function

2020 ◽  
Author(s):  
Motokazu Uchigashima ◽  
Ming Leung ◽  
Takuya Watanabe ◽  
Amy Cheung ◽  
Masahiko Watanabe ◽  
...  
Keyword(s):  
Synaptic Transmission ◽  
Molecular Mechanisms ◽  
Splice Variants ◽  
Autism Spectrum ◽  
Synaptic Function ◽  
Synaptic Activity ◽  
Sequencing Analysis ◽  
Dependent Manner ◽  
Splice Isoforms ◽  
Inhibitory Synaptic Transmission

ABSTRACTSynapse formation is a dynamic process essential for neuronal circuit development and maturation. At the synaptic cleft, trans-synaptic protein-protein interactions constitute major biological determinants of proper synapse efficacy. The balance of excitatory and inhibitory synaptic transmission (E-I balance) stabilizes synaptic activity. Dysregulation of the E-I balance has been implicated in neurodevelopmental disorders including autism spectrum disorders. However, the molecular mechanisms underlying E-I balance remain to be elucidated. Here, we investigate Neuroligin (Nlgn) genes that encode a family of postsynaptic adhesion molecules known to shape excitatory and inhibitory synaptic function. We demonstrate that Nlgn3 protein differentially regulates inhibitory synaptic transmission in a splice isoform-dependent manner at hippocampal CA1 synapses. Distinct subcellular localization patterns of Nlgn3 isoforms contribute to the functional differences observed among splice variants. Finally, single-cell sequencing analysis reveals that Nlgn1 and Nlgn3 are the major Nlgn genes and that expression of Nlgn splice isoforms are highly diverse in CA1 pyramidal neurons.

Protracted Postnatal Development of Inhibitory Synaptic Transmission in Rat Hippocampal Area CA1 Neurons

2000 ◽  
Vol 84 (5) ◽  
pp. 2465-2476 ◽  
Author(s):  
Akiva S. Cohen ◽  
Dean D. Lin ◽  
Douglas A. Coulter
Keyword(s):  
Synaptic Transmission ◽  
Postnatal Development ◽  
Pyramidal Neurons ◽  
Synaptic Function ◽  
Ca1 Neurons ◽  
Inhibitory Synaptic Transmission ◽  
The Third ◽  
Ca1 Pyramidal Neurons ◽  
Decay Times ◽  
And Function

In the CNS, inhibitory synaptic function undergoes profound transformation during early postnatal development. This is due to variations in the subunit composition of subsynaptic GABAA receptors (GABAARs) at differing developmental stages as well as other factors. These include changes in the driving force for chloride-mediated conductances as well as the quantity and/or cleft lifetime of released neurotransmitter. The present study was undertaken to investigate the nature and time course of developmental maturation of GABAergic synaptic function in hippocampal CA1 pyramidal neurons. In neonatal [postnatal day (P) 1–7] and immature (P8–14) CA1 neurons, miniature inhibitory postsynaptic currents (mIPSCs) were significantly larger, were less frequent, and had slower kinetics compared with mIPSCs recorded in more mature neurons. Adult mIPSC kinetics were achieved by the third postnatal week in CA1 neurons. However, despite this apparent maturation of mIPSC kinetics, significant differences in modulation of mIPSCs by allosteric agonists in adolescent (P15–21) neurons were still evident. Diazepam (1–300 nM) and zolpidem (200 nM) increased the amplitude of mIPSCs in adolescent but not adult neurons. Both drugs increased mIPSC decay times equally at both ages. These differential agonist effects on mIPSC amplitude suggest that in adolescent CA1 neurons, inhibitory synapses operate differently than adult synapses and function as if subsynaptic receptors are not fully occupied by quantal release of GABA. Rapid agonist application experiments on perisomatic patches pulled from adolescent neurons provided additional support for this hypothesis. In GABAAR currents recorded in these patches, benzodiazepine amplitude augmentation effects were evident only when nonsaturating GABA concentrations were applied. Furthermore nonstationary noise analysis of mIPSCs in P15–21 neurons revealed that zolpidem-induced mIPSC augmentation was not due to an increase in single-channel conductance of subsynaptic GABAARs but rather to an increase in the number of open channels responding to a single GABA quantum, further supporting the hypothesis that synaptic receptors may not be saturated during synaptic function in adolescent neurons. These data demonstrate that inhibitory synaptic transmission undergoes a markedly protracted postnatal maturation in rat CA1 pyramidal neurons. In the first two postnatal weeks, mIPSCs are large in amplitude, are slow, and occur infrequently. By the third postnatal week, mIPSCs have matured kinetically but retain distinct responses to modulatory drugs, possibly reflecting continued immaturity in synaptic structure and function persisting through adolescence.

scholarly journals Latrophilin-2 and latrophilin-3 are redundantly essential for parallel-fiber synapse function in cerebellum

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Roger Shen Zhang ◽  
Kif Liakath-Ali ◽  
Thomas C Südhof
Keyword(s):  
Synaptic Transmission ◽  
Purkinje Cells ◽  
Cerebellar Cortex ◽  
Pyramidal Neurons ◽  
Bergmann Glia ◽  
Parallel Fiber ◽  
Excitatory Synapses ◽  
Inhibitory Synaptic Transmission ◽  
Ca1 Pyramidal Neurons ◽  
Double Deletion

Latrophilin-2 (Lphn2) and latrophilin-3 (Lphn3) are adhesion GPCRs that serve as postsynaptic recognition molecules in CA1 pyramidal neurons of the hippocampus, where they are localized to distinct dendritic domains and are essential for different sets of excitatory synapses. Here, we studied Lphn2 and Lphn3 in the cerebellum. We show that latrophilins are abundantly and differentially expressed in the cerebellar cortex. Using conditional KO mice, we demonstrate that the Lphn2/3 double-deletion but not the deletion of Lphn2 or Lphn3 alone suppresses parallel-fiber synapses and reduces parallel-fiber synaptic transmission by ~50% without altering release probability. Climbing-fiber synapses, conversely, were unaffected. Even though ~50% of total cerebellar Lphn3 protein is expressed in Bergmann glia, Lphn3 deletion from Bergmann glia did not detectably impair excitatory or inhibitory synaptic transmission. Our studies demonstrate that Lphn2 and Lphn3 are selectively but redundantly required in Purkinje cells for parallel-fiber synapses.

scholarly journals Autism spectrum disorder-like behavior caused by reduced excitatory synaptic transmission in pyramidal neurons of mouse prefrontal cortex

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hiroaki Sacai ◽  
Kazuto Sakoori ◽  
Kohtarou Konno ◽  
Kenichiro Nagahama ◽  
Honoka Suzuki ◽  
...  
Keyword(s):  
Autism Spectrum Disorder ◽  
Prefrontal Cortex ◽  
Social Interaction ◽  
Synaptic Transmission ◽  
Pyramidal Neurons ◽  
Autism Spectrum ◽  
Synaptic Function ◽  
Spectrum Disorder ◽  
Excitatory Synaptic Transmission ◽  
Layer 2

Abstract Autism spectrum disorder (ASD) is thought to result from deviation from normal development of neural circuits and synaptic function. Many genes with mutation in ASD patients have been identified. Here we report that two molecules associated with ASD susceptibility, contactin associated protein-like 2 (CNTNAP2) and Abelson helper integration site-1 (AHI1), are required for synaptic function and ASD-related behavior in mice. Knockdown of CNTNAP2 or AHI1 in layer 2/3 pyramidal neurons of the developing mouse prefrontal cortex (PFC) reduced excitatory synaptic transmission, impaired social interaction and induced mild vocalization abnormality. Although the causes of reduced excitatory transmission were different, pharmacological enhancement of AMPA receptor function effectively restored impaired social behavior in both CNTNAP2- and AHI1-knockdown mice. We conclude that reduced excitatory synaptic transmission in layer 2/3 pyramidal neurons of the PFC leads to impaired social interaction and mild vocalization abnormality in mice.

scholarly journals Hypoxia Results in GABAergic Channelopathy

2005 ◽  
Vol 5 (6) ◽  
pp. 234-235 ◽  
Author(s):  
Nicholas P. Poolos
Keyword(s):  
Synaptic Transmission ◽  
Ampa Receptors ◽  
Pyramidal Neurons ◽  
Immature Brain ◽  
Fk 506 ◽  
Inhibitory Synaptic Transmission ◽  
Ca1 Pyramidal Neurons ◽  
Developing Rat ◽  
In Vivo Administration

AMPA/Kainate Receptor–mediated Downregulation of GABAergic Synaptic Transmission by Calcineurin after Seizures in the Developing Rat Brain Sanchez RM, Dai W, Levada RE, Lippman JJ, Jensen FE J Neurosci 2005;25:3442–3451 Hypoxia is the most common cause of perinatal seizures and can be refractory to conventional anticonvulsant drugs, suggesting an age-specific form of epileptogenesis. A model of hypoxia-induced seizures in immature rats reveals that seizures result in immediate activation of the phosphatase calcineurin (CaN) in area CA1 of hippocampus. After seizures, CA1 pyramidal neurons exhibit a downregulation of GABAA receptor (GABAAR)-mediated inhibition that was reversed by CaN inhibitors. CaN activation appears to be dependent on seizure-induced activation of Ca2+-permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors (AMPARs), because the upregulation of CaN activation and GABAAR inhibition were attenuated by GYKI 52466 [1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3-benzodiazepine hydrochloride] or Joro spider toxin. GABAAR β2/3 subunit protein was dephosphorylated at 1 h after seizures, suggesting this subunit as a possible substrate of CaN in this model. Finally, in vivo administration of the CaN inhibitor FK-506 significantly suppressed hypoxic seizures, and posttreatment with NBQX (2,3-dihydroxy-6-nitro-7-sulfonylbenzo[ f]quinoxaline) or FK-506 blocked the hypoxic seizure-induced increase in CaN expression. These data suggest that Ca2+-permeable AMPARs and CaN regulate inhibitory synaptic transmission in a novel plasticity pathway that may play a role in epileptogenesis in the immature brain.

scholarly journals Synergistic inhibition of histone modifiers produces therapeutic effects in adult Shank3-deficient mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Freddy Zhang ◽  
Benjamin Rein ◽  
Ping Zhong ◽  
Treefa Shwani ◽  
Megan Conrow-Graham ◽  
...  
Keyword(s):  
Pyramidal Neurons ◽  
Social Preference ◽  
Intervention Strategy ◽  
Autism Spectrum ◽  
Synaptic Function ◽  
Pharmacological Intervention ◽  
Therapeutic Effects ◽  
Male Mice ◽  
Behavioral Abnormalities ◽  
Deficient Mice

AbstractAutism spectrum disorder (ASD) is a lifelong developmental disorder characterized by social deficits and other behavioral abnormalities. Dysregulation of epigenetic processes, such as histone modifications and chromatin remodeling, have been implicated in ASD pathology, and provides a promising therapeutic target for ASD. Haploinsufficiency of the SHANK3 gene is causally linked to ASD, so adult (3–5 months old) Shank3-deficient male mice were used in this drug discovery study. We found that combined administration of the class I histone deacetylase inhibitor Romidepsin and the histone demethylase LSD1 inhibitor GSK-LSD1 persistently ameliorated the autism-like social preference deficits, while each individual drug alone was largely ineffective. Another behavioral abnormality in adult Shank3-deficient male mice, heightened aggression, was also alleviated by administration of the dual drugs. Furthermore, Romidepsin/GSK-LSD1 treatment significantly increased transcriptional levels of NMDA receptor subunits in prefrontal cortex (PFC) of adult Shank3-deficient mice, resulting in elevated synaptic expression of NMDA receptors and the restoration of NMDAR synaptic function in PFC pyramidal neurons. These results have offered a novel pharmacological intervention strategy for ASD beyond early developmental periods.

Dichotomy of Action-Potential Backpropagation in CA1 Pyramidal Neuron Dendrites

2001 ◽  
Vol 86 (6) ◽  
pp. 2998-3010 ◽  
Author(s):  
Nace L. Golding ◽  
William L. Kath ◽  
Nelson Spruston
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Pyramidal Neurons ◽  
Synaptic Activity ◽  
Resting Potential ◽  
Model Parameters ◽  
Voltage Sensitivity ◽  
Whole Cell ◽  
Ca1 Pyramidal Neurons ◽  
Whole Cell Recordings

In hippocampal CA1 pyramidal neurons, action potentials are typically initiated in the axon and backpropagate into the dendrites, shaping the integration of synaptic activity and influencing the induction of synaptic plasticity. Despite previous reports describing action-potential propagation in the proximal apical dendrites, the extent to which action potentials invade the distal dendrites of CA1 pyramidal neurons remains controversial. Using paired somatic and dendritic whole cell recordings, we find that in the dendrites proximal to 280 μm from the soma, single backpropagating action potentials exhibit <50% attenuation from their amplitude in the soma. However, in dendritic recordings distal to 300 μm from the soma, action potentials in most cells backpropagated either strongly (26–42% attenuation; n = 9/20) or weakly (71–87% attenuation; n = 10/20) with only one cell exhibiting an intermediate value (45% attenuation). In experiments combining dual somatic and dendritic whole cell recordings with calcium imaging, the amount of calcium influx triggered by backpropagating action potentials was correlated with the extent of action-potential invasion of the distal dendrites. Quantitative morphometric analyses revealed that the dichotomy in action-potential backpropagation occurred in the presence of only subtle differences in either the diameter of the primary apical dendrite or branching pattern. In addition, action-potential backpropagation was not dependent on a number of electrophysiological parameters (input resistance, resting potential, voltage sensitivity of dendritic spike amplitude). There was, however, a striking correlation of the shape of the action potential at the soma with its amplitude in the dendrite; larger, faster-rising, and narrower somatic action potentials exhibited more attenuation in the distal dendrites (300–410 μm from the soma). Simple compartmental models of CA1 pyramidal neurons revealed that a dichotomy in action-potential backpropagation could be generated in response to subtle manipulations of the distribution of either sodium or potassium channels in the dendrites. Backpropagation efficacy could also be influenced by local alterations in dendritic side branches, but these effects were highly sensitive to model parameters. Based on these findings, we hypothesize that the observed dichotomy in dendritic action-potential amplitude is conferred primarily by differences in the distribution, density, or modulatory state of voltage-gated channels along the somatodendritic axis.

Sign in / Sign up

Export Citation Format

Share Document