AMPA receptor mediated synaptic excitation drives state-dependent bursting in Purkinje neurons of zebrafish larvae
- National Centre for Biological Sciences, India
Figures
Figure 1
Zebrafish cerebellar circuitry and experimental preparation.
(A) Schematic of the cerebellar circuitry in zebrafish. PN: Purkinje neuron; E: Eurydendroid cell; G: Granule cell; S: Stellate cell. (B) Schematic of the set up for in vivo whole cell recordings in …
Figure 2
Spontaneous activity in Purkinje neurons.
(A) Representative traces of loose patch recording from a Purkinje neuron at 7 dpf showing tonic (top trace) and bursting (bottom trace) activity patterns. Small amplitude events (red arrowheads) …
Figure 3 with 2 supplements
Small events are sodium dependent action potentials.
(A) Tetrodotoxin (TTX) abolishes sodium action potentials in Purkinje neurons (N = 3 cells). Representative trace from one cell in the absence (top trace) and presence (bottom trace) of 1 μM TTX. …
Figure 3—figure supplement 1
Sodium action potentials are recruited during depolarizing current injections (N = 5 cells in each condition).
Representative traces showing cellular response to the current injection protocol (grey, bottom panel) in control (top panel) and in the presence of QX-314 (middle panel). The cell in control rested …
Figure 3—figure supplement 2
Narrow spikes observed in the presence of synaptic receptor blockers are abolished by TTX.
(A) Representative traces from the same cell showing narrow spikes in the presence of synaptic receptor blockers (top trace) that are abolished with bath application of TTX (bottom trace). (B) …
Figure 4
Broad events are calcium spikes.
(A) Calcium spikes have higher rheobase than sodium spikes (N = 8 cells). Representative trace of current clamp recordings of cellular response from one cell to current injections (grey, bottom …
Figure 5 with 2 supplements
Large amplitude events are climbing fiber (CF) EPSPs mediated by AMPARs.
(A) Mean peak amplitude of large amplitude events as a function of the holding potential. Inset: Expanded trace of a single large amplitude event to illustrate the slow kinetics and large amplitude. …
Figure 5—figure supplement 1
Large amplitude events do not require activation of NMDA receptors.
Representative trace of a Purkinje neuron recorded in voltage clamp mode at −65 mV in the absence (top trace) and presence of APV (N = 5 cells).
Figure 5—figure supplement 2
CF and PF glutamatergic synaptic inputs are clearly distinguishable.
(A) Representative trace from one cell held at −65 mV showing large amplitude (blue arrowheads) and small amplitude (green arrowheads) EPSCs. (B) Box plot showing distribution of peak amplitudes of …
Figure 6
Purkinje neurons toggle between bursting and tonic states as a function of membrane potential and AMPAR-mediated synaptic input.
(A) Representative trace of a bursting cell (bursts not shown) which rested at −65 mV spontaneously depolarizing and spiking tonically. (B) Scatter plot of membrane potential of cells in tonic vs …
Figure 7
Bursting is triggered by AMPAR-mediated olivary synaptic inputs.
(A) Representative trace showing CF EPSPs (blue arrowheads) occurring near burst onset as defined by the first sodium spike (red arrowhead). (B) Peri-event time histogram showing CF EPSPs clustered …
Figure 8
Purkinje neuron bursts are timed to occur with motor neuron bursts.
(A) Representative trace showing intracellular recording from a Purkinje neuron (top trace) and suction electrode recording from axial myotomes (bottom trace). Purkinje neuron bursts (blue …
Figure 9
Bistability in Purkinje neurons appears soon after they are specified, but CF EPSC frequency is developmentally regulated.
(A) Representative trace of bursting at 4 dpf (top trace) and at 19 dpf (bottom trace). (B) Representative traces of CF inputs at three developmental stages: 4, 7 and 19 dpf. (C) Cumulative …
Tables
Table 1
Summary of properties of narrow spikes, broad spikes and large amplitude events observed in Purkinje neurons at 7 dpf (N = 13 cells)
| Narrow spikes (bursts, 1152 events) | Narrow spikes (tonic, 997 events) | Large amplitude events (758 events) | Broad spikes (79 events) | |
|---|---|---|---|---|
| Peak amplitude (mV) | 15.9 ± 0.17 | 11 ± 0.09 | 51.2 ± 0.25 | 32.8 ± 0.6 |
| Frequency (Hz) | 34.8 ± 4.5 | 11.7 ± 1.1 | 1.5 ± 0.07 | 5.6 ± 3.8 |
| Full width at half max. amp (ms) | 7.7 ± 0.1 | 11.4 ± 0.1 | 15.8 ± 0.3 | 64.7 ± 5.4 |
| Rise time, 10–90% (ms) | 3.1 ± 0.1 | 3.6 ± 0.1 | 2.2 ± 0.04 | 6.5 ± 1.2 |
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Table 1—source data 1
Amplitudes and kinetics of the three types of spontaneous events.
- https://doi.org/10.7554/eLife.09158.006
