Long-Term Depression of Synaptic Inhibition Is Expressed Postsynaptically in the Developing Auditory System

2003 ◽  
Vol 90 (3) ◽  
pp. 1479-1488 ◽  
Author(s):  
Eric H. Chang ◽  
Vibhakar C. Kotak ◽  
Dan H. Sanes
Keyword(s):  
Release Kinetics ◽  
Mean Amplitude ◽  
Ruthenium Red ◽  
Synapse Elimination ◽  
Long Term Depression ◽  
Medial Nucleus ◽  
Auditory Brain Stem ◽  
Pulse Ratio ◽  
Activity Dependent

Inhibitory transmission is critically involved in the functional maturation of neural circuits within the brain. However, the mechanisms involved in its plasticity and development remain poorly understood. At an inhibitory synapse of the developing auditory brain stem, we used whole cell recordings to determine the site of induction and expression of long-term depression (LTD), a robust activity-dependent phenomenon that decreases inhibitory synaptic gain and is postulated to underlie synapse elimination. Recordings were obtained from lateral superior olivary (LSO) neurons, and hyperpolarizing inhibitory potentials were evoked by stimulation of the medial nucleus of the trapezoid body (MNTB). Both postsynaptic glycine and GABAA receptors could independently display LTD when isolated pharmacologically. Focal application of GABA, but not glycine, on the postsynaptic LSO neuron was sufficient to induce depression of the amino acid–evoked response, or MNTB-evoked inhibitory postsynaptic potentials. This GABA-mediated depression, in the absence of MNTB stimulation, was blocked by a GABAB receptor antagonist. To assess whether a change in neurotransmitter release is associated with the LTD, the polyvalent cation, ruthenium red, was used to increase the frequency of miniature inhibitory synaptic events. Consistent with a postsynaptic locus of expression, we found that the mean amplitude of miniature events decreased after LTD with no change in their frequency of occurrence. Furthermore, there was no change in the paired-pulse ratio or release kinetics of evoked inhibitory responses. Together, these results provide direct evidence that activity-dependent LTD of inhibition has a postsynaptic locus of induction and alteration, and that GABA but not glycine plays a pivotal role.

Conditions for the Induction of Long-Term Potentiation and Long-Term Depression by Conjunctive Pairing in the Dentate Gyrus In Vitro

1997 ◽  
Vol 78 (5) ◽  
pp. 2569-2573 ◽  
Author(s):  
Yue Wang ◽  
Jianqun Wu ◽  
Michael J. Rowan ◽  
Roger Anwyl
Keyword(s):  
Membrane Potential ◽  
Dentate Gyrus ◽  
Kinase Inhibitor ◽  
Long Term Potentiation ◽  
Ruthenium Red ◽  
Long Term Depression ◽  
Afferent Stimulation ◽  
Term Potentiation

Wang, Yue, Jianqun Wu, Michael J. Rowan, and Roger Anwyl. Conditions for the induction of long-term potentiation and long-term depression by conjunctive pairing in the dentate gyrus in vitro. J. Neurophysiol. 78: 2569–2573, 1997. The conditions under which long-term potentiation (LTP) and long-term depression (LTD) of excitatory postsynaptic currents were induced by the conjunctive pairing-type protocol of afferent stimulation and postsynaptic depolarization were studied in the medial perforant pathway-granule cell synapse of the dentate gyrus in vitro. The conjunctive pairing of 1-Hz afferent stimulation and steady state postsynaptic depolarization to 0 mV did not induce LTP or LTD. Inhibition of LTD induction with a phosphatase inhibitor or ruthenium red resulted in induction of LTP after the conjunctive pairing. Such LTP induction was N-methyl-d-aspartate dependent. Conversely, inhibition of LTP induction with a kinase inhibitor resulted in LTD induction after the conjunctive pairing. Thus the failure to induce LTP or LTD with the pairing protocol involving depolarization to 0 mV membrane potential was due to simultaneous activation of intracellular processes that generate the induction of LTP and LTD. Increasing the frequency of afferent stimulation to 200 Hz, even for just eight stimuli, resulted in LTP induction. The studies show that two factors govern the induction of LTP/LTD, membrane potential and frequency of afferent stimulation, with either increased depolarization or increased afferent stimulation favoring LTP induction.

Activity-Dependent Long-Term Depression of Electrical Synapses

Science ◽  
2011 ◽  
Vol 334 (6054) ◽  
pp. 389-393 ◽  
Author(s):  
J. S. Haas ◽  
B. Zavala ◽  
C. E. Landisman
Keyword(s):  
Long Term Depression ◽  
Electrical Synapses ◽  
Activity Dependent

scholarly journals Activity-dependent formation and location of voltage-gated sodium channel clusters at a CNS nerve terminal during postnatal development

2017 ◽  
Vol 117 (2) ◽  
pp. 582-593 ◽  
Author(s):  
Jie Xu ◽  
Emmanuelle Berret ◽  
Jun Hee Kim
Keyword(s):  
Brain Stem ◽  
Nerve Terminal ◽  
Low Frequency ◽  
Presynaptic Terminal ◽  
Scaffolding Protein ◽  
Unmyelinated Axon ◽  
Voltage Gated ◽  
Medial Nucleus ◽  
Auditory Brain Stem ◽  
Activity Dependent

In auditory pathways, the precision of action potential (AP) propagation depends on axon myelination and high densities of voltage-gated Na (Nav) channels clustered at nodes of Ranvier. Changes in Nav channel expression at the heminode, the final node before the nerve terminal, can alter AP invasion into the presynaptic terminal. We studied the activity-dependent formation of Nav channel clusters before and after hearing onset at postnatal day 12 in the rat and mouse auditory brain stem. In rats, the Nav channel cluster at the heminode formed progressively during the second postnatal week, around hearing onset, whereas the Nav channel cluster at the nodes was present before hearing onset. Initiation of heminodal Nav channel clustering was correlated with the expression of scaffolding protein ankyrinG and paranodal protein Caspr. However, in whirler mice with congenital deafness, heminodal Nav channels did not form clusters and maintained broad expression, but Nav channel clustering was normal at the nodes. In addition, a clear difference in the distance from the heminodal Nav channel to the calyx across the mediolateral axis of the medial nucleus of the trapezoid body (MNTB) developed after hearing onset. In the medial MNTB, where neurons respond best to high-frequency sounds, the heminodal Nav channel cluster was located closer to the terminal than in the lateral MNTB, where neurons respond best to low-frequency sounds. Thus sound-mediated neuronal activities are potentially associated with the refinement of the heminode adjacent to the presynaptic terminal in the auditory brain stem. NEW & NOTEWORTHY Clustering of voltage-gated sodium (Nav) channels and their distribution along the axon, specifically at the unmyelinated axon segment next to the nerve terminal, are essential for tuning propagated action potentials. Nav channel clusters near the nerve terminal and their location as a function of neuronal position along the mediolateral axis are controlled by auditory inputs after hearing onset. Thus sound-mediated neuronal activity influences the tonotopic organization of Nav channels at the nerve terminal in the auditory brain stem.

Mutant γPKC found in spinocerebellar ataxia type 14 disrupts synapse elimination and long-term depression in Purkinje cells in vivo

2011 ◽  
Vol 71 ◽  
pp. e291-e292
Author(s):  
Anton Nikolaevich Shuvaev ◽  
Hajime Horiuchi ◽  
Takahiro Seki ◽  
Gennawan Hanna ◽  
Tomohiko Irie ◽  
...  
Keyword(s):  
Purkinje Cells ◽  
Spinocerebellar Ataxia ◽  
Spinocerebellar Ataxia Type ◽  
Synapse Elimination ◽  
Long Term Depression ◽  
Spinocerebellar Ataxia Type 14

Evidence for common expression mechanisms underlying heterosynaptic and associative long-term depression in the dentate gyrus

1995 ◽  
Vol 74 (3) ◽  
pp. 1244-1247 ◽  
Author(s):  
B. R. Christie ◽  
D. Stellwagen ◽  
W. C. Abraham
Keyword(s):  
Dentate Gyrus ◽  
High Frequency ◽  
Granule Cells ◽  
Perforant Path ◽  
Long Term Depression ◽  
Anesthetized Rats ◽  
Data Support ◽  
Activity Dependent ◽  
Stimulation Of

1. The extent to which heterosynaptic and prime-associative stimulation protocols generate different forms of long-term depression (LTD) was assessed in the lateral perforant path synapses terminating on dentate gyrus granule cells in pentobarbital-anesthetized rats. 2. Heterosynaptic LTD was induced in the lateral path by repeated tetanization of the medial path. Prime-associative LTD of the lateral path was induced by alternating high-frequency conditioning trains to the medial path and single shocks to the lateral path at 100-ms intervals, all occurring 10 min after priming stimulation of the lateral path (5 Hz, 80 pulses). 3. Induction of LTD by one administration of the prime-associative protocol was normally greater in magnitude than the LTD induced by the heterosynaptic protocol. Saturation of LTD by repeated delivery of the prime-associative protocol completely occluded the subsequent induction of LTD by the heterosynaptic protocol. Saturation of LTD by repeated delivery of the heterosynaptic protocol produced an 80% occlusion of the LTD generated by the prime-associative protocol. 4. These data support the hypothesis that activity-dependent (associative) and activity-independent (heterosynaptic) LTD involve overlapping expression mechanisms, despite having demonstrably different induction mechanisms.

Sign in / Sign up

Export Citation Format

Share Document