Journal: PLoS ONE

Article Title: Predominant Functional Expression of Kv1.3 by Activated Microglia of the Hippocampus after S tatus epilepticus

doi: 10.1371/journal.pone.0006770

Figure Lengend Snippet: The leak conductances of the cells in A, B and C were 338, 862 and 332 pS, respectively. The graphs on the right represent the conductance, normalized to its maximum value, as a function of the membrane potential and its inhibition by α-dendrotoxin (A, n = 4, Dtx), agitoxin-2 (B, AgTx, n = 14 for 10 nM, n = 6 for 50 nM) and margatoxin (C, MgTX, n = 8 for 1 nM, n = 11 for 10 nM).

Article Snippet: Alpha-dendrotoxin, recombinant agitoxin-2 and recombinant margatoxin were purchased from Alomone labs (Jerusalem, Israel).

Techniques: Inhibition

Journal: Scientific Reports

Article Title: Kv1 potassium channels control action potential firing of putative GABAergic deep cerebellar nuclear neurons

doi: 10.1038/s41598-020-63583-7

Figure Lengend Snippet: The spontaneous and evoked changes in AP firing activity of GAD + DCNs are sensitive to DTX-alpha. ( A ) From left to right: The traces illustrate typical example of spontaneous action potentials recorded from one GAD + DCN under control conditions (red), DTX-alpha (100 nM, DTX-alpha, blue), and with current injection to match the control ISI-Vm during DTX-alpha application (DTX-alpha& DC, green see text for details). (For comparison, same neuron as in Fig. ). The black circles on top of each spike represent the instantaneous frequency (IF, Hz). Note the scale on the left indicate both the membrane potential (Vm) and the IF. A’ detail of A in expanded time scale. The color code used here applies to all figures. ( B ) Bar plots of the mean spontaneous frequency under control and during DTX-alpha application and changes in individual results indicated by the gray lines (see details in main text). ( C ) Top, left: typical examples from the same GAD + DCNs illustrating changes in spiking activity induced by injection of depolarizing current pulses of 1 second duration and increasing current intensity (bottom to top), used to determine the maximum repetitive frequency (MRF), defined as the maximum frequency at steady state before depolarizing block (middle trace, detail shown in the inset) (see methods for further details). ( D ) Mean MRF for GAD + DCNs before (control) and during DTX-alpha application, individual results depicted as in B (details in the main text). ( E ) Mean maximum rebound frequency, the firing rate over the first half second after the step (as in the examples in the inset, see methods for details, “maximum rebound frequency under control (red) and during DTX application (blue), and individual results depicted as in ( B ) (see main text for details).

Article Snippet: The specific Kv1 channel blockers: αDendrotoxin (DTX-alpha), DTX-I and DTX-K (100 nM) were diluted as recommend by the providers (Alomone, Latoxan) to prepare aliquots that were frozen and diluted to the final concentration in ACSF containing neurotransmitter blockers before use.

Techniques: Activity Assay, Injection, Blocking Assay

Journal: Scientific Reports

Article Title: Kv1 potassium channels control action potential firing of putative GABAergic deep cerebellar nuclear neurons

doi: 10.1038/s41598-020-63583-7

Figure Lengend Snippet: The action potential (AP) waveform of GAD + DCNs is sensitive to DTX-alpha application. ( A ) From left to right: Typical example of averaged spontaneous APs recorded from one GAD + DCN during application of neurotransmitter blockers (control), during DTX-alpha (100 nM) application (DTX-alpha), and after correcting the ISI Vm by current injection during DTX-alpha application (DTX-alpha& DC), and all traces superimposed. The insets depict in expanded scale the control and DTX-alpha traces. The first one illustrates the hyperpolarization during the ISI (marked by the arrow). The second one, the different voltage threshold (noted by arrows). ( B ) Phase plots corresponding to the AP traces in A (the derivative of the Vm as a function of the Vm). B’-Detail of B in expanded scale showing the shift in AP voltage threshold (indicated by the horizontal dashed line, see methods) from control (red vertical dashed line) to more hyperpolarized levels during DTX, even after matching the ISI-Vm (green vertical dashed line). ( C ) Mean AP threshold for all recorded GAD + DCNs under control (red bar) and DTX-alpha application (ISI-Vm matching control levels, green bar) and individual results (depicted by the gray lines). Error lines indicate here and in the next figures SEM. ( D ) Mean AP HW for all recorded GAD + DCNs under control (red dot) and DTX-alpha plus DC (green dot), with individual results depicted as in ( C ). ( E ) Mean AP repolarizing rate (minimum dV/dt) for all recorded GAD + DCNs under control (red) and DTX-alpha plus DC (green), with individual results depicted as in ( C ). ( F ) Mean minimum ISI-membrane potential (ISI-Vm) for all recorded GAD + DCNs under control (red) and DTX-alpha plus DC (green), with individual results as in ( C ).

Article Snippet: The specific Kv1 channel blockers: αDendrotoxin (DTX-alpha), DTX-I and DTX-K (100 nM) were diluted as recommend by the providers (Alomone, Latoxan) to prepare aliquots that were frozen and diluted to the final concentration in ACSF containing neurotransmitter blockers before use.

Techniques: Injection

Journal: Scientific Reports

Article Title: Kv1 potassium channels control action potential firing of putative GABAergic deep cerebellar nuclear neurons

doi: 10.1038/s41598-020-63583-7

Figure Lengend Snippet: Kv1 channels control the spiking activity and membrane potential of silent and spontaneously active GAD + DCNs. ( A ) Mean spontaneous frequency under control and DTX conditions (data from DTX-alpha, DTX-I and DTX-K together, no DC applied, see details in main text). ( B ) CV of spontaneous ISIs under control and DTX conditions (box illustrates 10 and 90% percentiles and whiskers the error, see details in main text). ( C ) DTX effect on a previously silent DCN (DTX-alpha, 100 nM, time of application indicated by the bar on top), illustrates the depolarization and beginning of tonic firing evoked by DTX. The inset illustrates in expanded time base the beginning of the tonic discharge. (For clarity the responses to short pulses (10 ms) applied every two seconds before spiking started were digitally removed and substituted by a straight line). ( D ) Two examples of GAD + DCN recorded using 25 KHz sampling rate, illustrate typical DTX effects on averaged spontaneous APs. Top, in this example DTX induced a depolarization of the ISI-Vm. After DC injection to match control ISI-Vm (green trace), the spike width was narrower than control (HW: 0.59 and 0.56 for control and DTX&DC respectively). Bottom, in this example, the ISI-Vm hyperpolarized and the AP duration increased during DTX (HW: 0.49 and 0.54 ms for control and DTX respectively). ( E ) Scatter plot of DTX induced changes in HW (ms) as a function of the changes induced in ISI-VM (mV, note that most neurons that hyperpolarized displayed elongations in HW).

Article Snippet: The specific Kv1 channel blockers: αDendrotoxin (DTX-alpha), DTX-I and DTX-K (100 nM) were diluted as recommend by the providers (Alomone, Latoxan) to prepare aliquots that were frozen and diluted to the final concentration in ACSF containing neurotransmitter blockers before use.

Techniques: Activity Assay, Sampling, Injection

Journal: Scientific Reports

Article Title: Kv1 potassium channels control action potential firing of putative GABAergic deep cerebellar nuclear neurons

doi: 10.1038/s41598-020-63583-7

Figure Lengend Snippet: The action potential waveform of non-GAD + DCNs, putative glutamatergic principal DCNs is sensitive to DTX. ( A ) From left to right: Typical example of averaged spontaneous action potentials recorded from a large non-GAD + DCN during application of neurotransmitter blockers (control, red), during DTX-alpha (100 nM) application (DTX-alpha, blue), and after matching the ISI Vm to control levels by current injection during DTX-alpha application (DTX-alpha& DC, green), and all traces superimposed. ( B ) The corresponding phase plots of the traces illustrated in A. ( C ) Mean AP threshold before and during DTX application for putative glutamatergic principal DCNs and individual results depicted by the gray lines (see details in main text). ( D ) Mean AP HW before and during DTX application for putative glutamatergic principal DCNs and individual results depicted as gray lines (see main text for details). ( E ) Mean AP repolarizing rate (minimum dV/dt) before and during DTX application for putative glutamatergic principal DCNs and individual results as gray lines (see details in main text).

Article Snippet: The specific Kv1 channel blockers: αDendrotoxin (DTX-alpha), DTX-I and DTX-K (100 nM) were diluted as recommend by the providers (Alomone, Latoxan) to prepare aliquots that were frozen and diluted to the final concentration in ACSF containing neurotransmitter blockers before use.

Techniques: Injection

Journal: bioRxiv

Article Title: Kv1 potassium channels control action potential firing of putative GABAergic deep cerebellar nuclear neurons

doi: 10.1101/779082

Figure Lengend Snippet: A- From left to right: The traces illustrate typical example of spontaneous action potentials and the dots on top of each spike their corresponding instantaneous frequency using the same scale on the left recorded from one GAD+DCN during application of NT blockers (control), during DTX-alpha (100nM) application (DTX-alpha), application of NT blockers (control), during DTX-alpha (100nM) application (DTX-alpha), and after correcting the ISI Vm by current injection during DTX-alpha application (DTX-alpha& DC) (For comparison, same neuron as in ). B- Mean spontaneous frequency of GAD+DCNs before (control) and during DTX-alpha application (see main text for details). B’- Mean change in spontaneous frequency induced by DTX-alpha application and individual results superimposed (see main text for details). C- Top: left traces illustrate from the typical changes in spiking activity induced by injection of depolarizing current pulses of 1 second duration and increasing current intensity in one GAD+DCN recorded under control conditions used to determine the maximum repetitive frequency (MRF, see methods for details). MRF is determined by measuring the frequency at steady state (rectangle) just before the step inducing depolarizing block (top trace). Bottom left: Mean MRF for GAD+DCNs before (control) and during DTX-alpha application (see main text for details). Top right: The trace illustrates the response induced by injection of hyperpolarizing current pulses of 1 second duration in one GAD+DCN recorded under control conditions. The hyperpolarization typically causes increases in firing rate respect to basal conditions after the hyperpolarization (rebound response). The maximum firing rate over the first second after the step (see methods for details, rectangle, “Maximum Rebound frequency”), was used to characterize changes in the rebound response. Bottom right: Mean Maximum Rebound frequency for GAD+DCNs before (control) and during DTX-alpha application (see main text for details).

Article Snippet: Dendrotoxins DTX-alpha, DTX-I and DTX-K (100nM) were diluted as recommend by the providers (Alomone, Latoxan) to prepare aliquots that were frozen and diluted to the final concentration in ACSF containing neurotransmitter blockers before use.

Techniques: Injection, Activity Assay, Blocking Assay

Journal: bioRxiv

Article Title: Kv1 potassium channels control action potential firing of putative GABAergic deep cerebellar nuclear neurons

doi: 10.1101/779082

Figure Lengend Snippet: A- From left to right: Typical example of averaged spontaneous action potentials recorded from one GAD+DCN during application of NT blockers (control), during DTX-alpha (100nM) application (DTX-alpha), and after correcting the ISI Vm by current injection during DTX-alpha application (DTX-alpha& DC), and all traces superimposed. The inset depicts in expanded scale the control and DTX-alpha traces. B- Phase plots corresponding to the traces in A (the derivative of the Vm as a function of the Vm). B’-Detail of B in expanded time scale to show the hyperpolarizing shift in the rapid raise in dV/dt signaling the AP threshold. C- Mean change in AP threshold for all recorded GAD+DCNs under DTX-alpha and individual results superimposed (some data points overlap). D- Mean change in AP HW for all recorded GAD+DCNs under DTX-alpha and individual results superimposed. E- Mean change in the AP repolarizing rate (minimum dV/dt) for all recorded GAD+DCNs under DTX-alpha and individual results superimposed. F- Mean change in minimum ISI-membrane potential (ISI_Vm) for all recorded GAD+DCNs under DTX-alpha and individual results superimposed.

Article Snippet: Dendrotoxins DTX-alpha, DTX-I and DTX-K (100nM) were diluted as recommend by the providers (Alomone, Latoxan) to prepare aliquots that were frozen and diluted to the final concentration in ACSF containing neurotransmitter blockers before use.

Techniques: Injection

Journal: bioRxiv

Article Title: Kv1 potassium channels control action potential firing of putative GABAergic deep cerebellar nuclear neurons

doi: 10.1101/779082

Figure Lengend Snippet: A- Traces illustrate recordings from one silent DCN before (control) and during application of 4-AP 15μM. Note the depolarization and spiking activity. B- Averaged APs recorded before and during 4-AP application from the same neuron. C- Phase plot corresponding to the traces shown in B. Note the shift in threshold and remarked decrease in minimum dV/dt. D- Traces illustrate recordings from one silent GAD+DCN before (control) and during application of DTX-alpha (100 nM). E- Averaged APs recorded before and during DTX-alpha application from the same neuron as in D. F- Phase plots corresponding to the traces in E.

Article Snippet: Dendrotoxins DTX-alpha, DTX-I and DTX-K (100nM) were diluted as recommend by the providers (Alomone, Latoxan) to prepare aliquots that were frozen and diluted to the final concentration in ACSF containing neurotransmitter blockers before use.

Techniques: Activity Assay

Journal: bioRxiv

Article Title: Kv1 potassium channels control action potential firing of putative GABAergic deep cerebellar nuclear neurons

doi: 10.1101/779082

Figure Lengend Snippet: A- From left to right: Typical example of averaged spontaneous action potentials recorded from a large Non-GAD+DCN during application of NT blockers (control), during DTX-alpha (100 nM) application (DTX-alpha), and after matching the ISI Vm to control levels by current injection during DTX-alpha application (DTX-alpha& DC), and all traces superimposed. B- The corresponding phase plots of the traces illustrated in A. C- Mean AP threshold before and during DTX application for putative glutamatergic principal DCNs (see text for details). D- Mean AP HW before and during DTX application for putative glutamatergic principal DCNs (see text for details). E- Mean AP repolarizing rate (minimum dV/dt) before and during DTX application for putative glutamatergic principal DCNs (see text for details).

Article Snippet: Dendrotoxins DTX-alpha, DTX-I and DTX-K (100nM) were diluted as recommend by the providers (Alomone, Latoxan) to prepare aliquots that were frozen and diluted to the final concentration in ACSF containing neurotransmitter blockers before use.

Techniques: Injection