Journal: eLife
Article Title: An Anatomical and Physiological Basis for Flexible Coincidence Detection in the Auditory System
doi: 10.7554/elife.100492
Figure Lengend Snippet: Figure 4. Octopus cells receive glycinergic inhibitory post synaptic potentials. (A) Voltage responses to a –200 pA current injection. This representative neuron hyperpolarized 0.7 mV (black) in control conditions. After bath application of 100 µM 4-Aminopyridine (4-AP) and 50 µM ZD 7288 (ZD), hyperpolarizing responses to the same –200 pA current injection increased to 8.8 mV at steady state (green). (B) Postsynaptic responses to ChR2 stimulation of glycinergic terminals (Slc6a5-ChR2) with a 5 Hz train (gray) of 1ms full-field blue light pulses before (black) and after bath application of 100 µM 4-AP, 50 µM ZD, and 15 µM NBQX (green: n=9 cells, 8 mice). Increased input resistance reveals inhibitory potentials that are otherwise difficult to detect. (C) Postsynaptic responses to Slc6a5-ChR2 stimulation after bath application of 100 µM 4-AP, 50 µM ZD, and 15 µM NBQX (green), with further sequential addition of 20 µM picrotoxin (PTX, pink), 100 µM cyclothiazide (CTZ, blue), and 500 nM strychnine (STN, orange: n=6 cells, 5 mice). (D) Change in membrane voltage in response to hyperpolarizing somatic current steps in a morphologically and biophysically realistic model of octopus cells before (black) and after removal of voltage-gated potassium (Kv) and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels (blue). As in in vitro current-clamp recordings (A), removing Kv and HCN channels increased the magnitude of voltage responses (ΔVm) to hyperpolarizing current. (E) IPSP magnitude in experimental data (green) and the model (dark and light blue) as a function of input resistance. In somatic measurements, IPSP size increases with input resistance. Modeled IPSPs are shown for two conductance levels (1nS, dark blue; 100nS light blue). (F) IPSPs measured at the soma of a modeled octopus cell before (black) and after removal of Kv and HCN channels (blue). As in in vitro current-clamp recordings, this allows for somatic IPSP detection. (G) Change in the magnitude of soma-measured IPSPs after removal of Kv and HCN channels. IPSP magnitude increases with Kv and HCN block for all glycine conductance levels. (H) Change in the magnitude of locally measured IPSCs at proximal (orange) and distal (blue) dendritic locations after removal of Kv and HCN channels. IPSC magnitude at the synapse decreases with Kv and HCN block for all glycine conductance levels. Change in IPSC magnitude is largest on distal dendrites.
Article Snippet: (species) or resource Designation Source or reference Identifiers Additional information Biological sample (Mus musculus) Foxg1Cre/+: Foxg1tm1.1(cre)Ddmo Jackson Laboratory RRID:IMSR_JAX:029690 Biological sample (Mus musculus) Foxg1tm1.1Fsh Miyoshi and Fishell, 2012 MGI:5441367 Biological sample (Mus musculus) Tg(EIIa- cre)C5379Lmgd Jackson Laboratory RRID:IMSR_JAX:003314 Biological sample (Mus musculus) Ntng1Cre/+: Ntng1em1(cre)Kfra Bolding et al., 2020 MGI:6740547 Biological sample (Mus musculus) Myo15 iCre/+: Myo15atm1.1(cre)Ugds Caberlotto et al., 2011 MGI:4361284 Biological sample (Mus musculus) Slc6a5Cre/+: Slc6a5tm1.1(cre)Ksak Kakizaki et al., 2017 MGI:6382286 Biological sample (Mus musculus) Ai14: Gt(ROSA)26Sortm14(CAG- tdTomato) Jackson Laboratory RRID:IMSR_JAX:007914 Biological sample (Mus musculus) Ai34: Gt(Rosa)26Sortm34.1(CAG- Syp/tdTomato) Jackson Laboratory RRID:IMSR_JAX:012570 Biological sample (Mus musculus) RCE:FRT: Gt(Rosa)26Sortm1.2(CAG- EGFP)Fsh Sousa et al., 2009 RRID:MMRRC_032038JAX Biological sample (Mus musculus) Ai32: Gt(Rosa)26Sortm32(CAG- COP4*H134R.EYFP) Jackson Laboratory RRID:IMSR_JAX:01256 Biological sample (Mus musculus) Thy1: Tg(Thy1- YFP)HJrs Jackson Laboratory RRID:IMSR_JAX:003782 Antibody Chicken polyclonal anti- GFP Aves Labs Cat# GFP- 1020; RRID:AB_10000240 1:1000 Antibody Rabbit polyclonal anti- RFP Rockland Cat# 600- 401- 379; RRID:AB_2209751 1:1000 Antibody Goat polyclonal anti- Calretinin Swant Cat# CG1; RRID:AB_1000034 1:1000 Antibody Guinea Pig polyclonal anti- VGlut1 Synaptic Systems Cat# 135 304; RRID:AB_887878 1:500 Chemical compound, drug 4- Amynopyridine Tocris CAS: 504- 24- 5 Chemical compound, drug 2,3- dioxo- 6- nitro- 7- sulfamoyl- benzo[f] quinoxaline (NBQX) Tocris CAS: 479347- 86- 9 Chemical compound, drug ZD 7288 Tocris CAS: 133059- 99- 1 Chemical compound, drug Cyclothiazide Tocris CAS: 2259- 96- 3 Kreeger et al. eLife 2024;13:RP100492.
Techniques: Injection, Control, Membrane, In Vitro, Blocking Assay