scholarly journals Cannabinoid Modulation of Backpropagating Action Potential-Induced Calcium Transients in Layer 2/3 Pyramidal Neurons

2012 ◽  
Vol 23 (7) ◽  
pp. 1731-1741 ◽  
Author(s):  
L. S. Hsieh ◽  
E. S. Levine
Keyword(s):  
Action Potential ◽  
Pyramidal Neurons ◽  
Calcium Transients ◽  
Layer 2 ◽  
Backpropagating Action Potential

scholarly journals Roles of specific Kv channel types in repolarization of the action potential in genetically identified subclasses of pyramidal neurons in mouse neocortex

2016 ◽  
Vol 115 (5) ◽  
pp. 2317-2329 ◽  
Author(s):  
Dhruba Pathak ◽  
Dongxu Guan ◽  
Robert C. Foehring
Keyword(s):  
Action Potential ◽  
Pyramidal Cell ◽  
Pyramidal Neurons ◽  
Pyramidal Cells ◽  
Excitable Cells ◽  
Long Distance ◽  
Cell Subtype ◽  
Layer 2 ◽  
Neuronal Types ◽  
Underlying Mechanisms

The action potential (AP) is a fundamental feature of excitable cells that serves as the basis for long-distance signaling in the nervous system. There is considerable diversity in the appearance of APs and the underlying repolarization mechanisms in different neuronal types (reviewed in Bean BP. Nat Rev Neurosci 8: 451–465, 2007), including among pyramidal cell subtypes. In the present work, we used specific pharmacological blockers to test for contributions of Kv1, Kv2, or Kv4 channels to repolarization of single APs in two genetically defined subpopulations of pyramidal cells in layer 5 of mouse somatosensory cortex ( etv1 and glt) as well as pyramidal cells from layer 2/3. These three subtypes differ in AP properties (Groh A, Meyer HS, Schmidt EF, Heintz N, Sakmann B, Krieger P. Cereb Cortex 20: 826–836, 2010; Guan D, Armstrong WE, Foehring RC. J Neurophysiol 113: 2014–2032, 2015) as well as laminar position, morphology, and projection targets. We asked what the roles of Kv1, Kv2, and Kv4 channels are in AP repolarization and whether the underlying mechanisms are pyramidal cell subtype dependent. We found that Kv4 channels are critically involved in repolarizing neocortical pyramidal cells. There are also pyramidal cell subtype-specific differences in the role for Kv1 channels. Only Kv4 channels were involved in repolarizing the narrow APs of glt cells. In contrast, in etv1 cells and layer 2/3 cells, the broader APs are partially repolarized by Kv1 channels in addition to Kv4 channels. Consistent with their activation in the subthreshold range, Kv1 channels also regulate AP voltage threshold in all pyramidal cell subtypes.

scholarly journals Two Populations of Layer V Pyramidal Cells of the Mouse Neocortex: Development and Sensitivity to Anesthetics

2005 ◽  
Vol 94 (5) ◽  
pp. 3357-3367 ◽  
Author(s):  
Elodie Christophe ◽  
Nathalie Doerflinger ◽  
Daniel J. Lavery ◽  
Zoltán Molnár ◽  
Serge Charpak ◽  
...  
Keyword(s):  
Action Potential ◽  
Calcium Binding ◽  
Pyramidal Neurons ◽  
Pyramidal Cells ◽  
Membrane Properties ◽  
Subcortical Structures ◽  
Contralateral Cortex ◽  
Layer V ◽  
Intrinsic Membrane Properties ◽  
Two Populations

Previous studies have shown that layer V pyramidal neurons projecting either to subcortical structures or the contralateral cortex undergo different morphological and electrophysiological patterns of development during the first three postnatal weeks. To isolate the determinants of this differential maturation, we analyzed the gene expression and intrinsic membrane properties of layer V pyramidal neurons projecting either to the superior colliculus (SC cells) or the contralateral cortex (CC cells) by combining whole cell recordings and single-cell RT-PCR in acute slices prepared from postnatal day (P) 5–7 or P21–30 old mice. Among the 24 genes tested, the calcium channel subunits α1B and α1C, the protease Nexin 1, and the calcium-binding protein calbindin were differentially expressed in adult SC and CC cells and the potassium channel subunit Kv4.3 was expressed preferentially in CC cells at both stages of development. Intrinsic membrane properties, including input resistance, amplitude of the hyperpolarization-activated current, and action potential threshold, differed quantitatively between the two populations as early as from the first postnatal week and persisted throughout adulthood. However, the two cell types had similar regular action potential firing behaviors at all developmental stages. Surprisingly, when we increased the duration of anesthesia with ketamine–xylazine or pentobarbital before decapitation, a proportion of mature SC cells, but not CC cells, fired bursts of action potentials. Together these results indicate that the two populations of layer V pyramidal neurons already start to differ during the first postnatal week and exhibit different firing capabilities after anesthesia.

On the Origin of the Extracellular Action Potential Waveform: A Modeling Study

2006 ◽  
Vol 95 (5) ◽  
pp. 3113-3128 ◽  
Author(s):  
Carl Gold ◽  
Darrell A. Henze ◽  
Christof Koch ◽  
György Buzsáki
Keyword(s):  
Action Potential ◽  
Pyramidal Neurons ◽  
Ionic Currents ◽  
Dendritic Morphology ◽  
Electrode Position ◽  
Unit Recording ◽  
Extracellular Recordings ◽  
Ca1 Pyramidal Neurons ◽  
Varied Composition

Although extracellular unit recording is typically used for the detection of spike occurrences, it also has the theoretical ability to report about what are typically considered intracellular features of the action potential. We address this theoretical ability by developing a model system that captures features of experimentally recorded simultaneous intracellular and extracellular recordings of CA1 pyramidal neurons. We use the line source approximation method of Holt and Koch to model the extracellular action potential (EAP) voltage resulting from the spiking activity of individual neurons. We compare the simultaneous intracellular and extracellular recordings of CA1 pyramidal neurons recorded in vivo with model predictions for the same cells reconstructed and simulated with compartmental models. The model accurately reproduces both the waveform and the amplitude of the EAPs, although it was difficult to achieve simultaneous good matches on both the intracellular and extracellular waveforms. This suggests that accounting for the EAP waveform provides a considerable constraint on the overall model. The developed model explains how and why the waveform varies with electrode position relative to the recorded cell. Interestingly, each cell's dendritic morphology had very little impact on the EAP waveform. The model also demonstrates that the varied composition of ionic currents in different cells is reflected in the features of the EAP.

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.

scholarly journals Scavenging reactive oxygen species mimics the anoxic response in goldfish pyramidal neurons

2021 ◽  
Author(s):  
Varshinie Pillai ◽  
Leslie Buck ◽  
Ebrahim Lari
Keyword(s):  
Reactive Oxygen Species ◽  
Action Potential ◽  
Pyramidal Neurons ◽  
Reactive Oxygen ◽  
Severe Hypoxia ◽  
Oxygen Species ◽  
Low Oxygen ◽  
Ros Scavenging ◽  
Patch Clamp Recording ◽  
Whole Cell

Goldfish are one of a few species able to avoid cellular damage during month-long periods in severely hypoxic environments. By suppressing action potentials in excitatory glutamatergic neurons, the goldfish brain decreases its overall energy expenditure. Co-incident with reductions in O2 availability is a natural decrease in cellular reactive oxygen species (ROS) generation, which has been proposed to function as part of a low oxygen signal transduction pathway. Therefore, using live-tissue fluorescence microscopy, we found that ROS production decreased by 10% with the onset of anoxia in goldfish telencephalic brain slices. Employing whole-cell patch-clamp recording, we found that like severe hypoxia the ROS scavengers N-acetyl cysteine (NAC) and MitoTEMPO, added during normoxic periods, depolarized membrane potential (severe hypoxia -73.6 to – 61.4 mV; NAC -76.6 to -66.2 mV; and MitoTEMPO -71.5 mV to -62.5 mV) and increased whole-cell conductance (severe hypoxia 5.7 to 8.0 nS; NAC 6 nS to 7.5 nS; and MitoTEMPO 6.0 nS to 7.6 nS). Also, in a subset of active pyramidal neurons these treatments reduced action potential firing frequency (severe hypoxia 0.18 Hz to 0.03 Hz; NAC 0.27 Hz to 0.06 Hz and MitoTEMPO 0.35 Hz to 0.08 Hz ). Neither severe hypoxia nor ROS scavenging impacted action potential threshold. The addition of exogenous hydrogen peroxide could reverse the effects of the antioxidants. Taken together, this supports a role for a reduction in [ROS] as a low oxygen signal in goldfish brain.

scholarly journals Heterogeneity in Kv2 Channel Expression Shapes Action Potential Characteristics and Firing Patterns in CA1 versus CA2 Hippocampal Pyramidal Neurons

eNeuro ◽  
2017 ◽  
Vol 4 (4) ◽  
pp. ENEURO.0267-17.2017 ◽  
Author(s):  
Stephanie Palacio ◽  
Vivien Chevaleyre ◽  
David H. Brann ◽  
Karl D. Murray ◽  
Rebecca A. Piskorowski ◽  
...  
Keyword(s):  
Action Potential ◽  
Pyramidal Neurons ◽  
Firing Patterns ◽  
Hippocampal Pyramidal Neurons ◽  
Channel Expression
Sign in / Sign up

Export Citation Format

Share Document