Calcium currents in acutely isolated stellate and pyramidal neurons of rat entorhinal cortex

1999 ◽  
Vol 816 (2) ◽  
pp. 554-562 ◽  
Author(s):  
Claus Bruehl ◽  
Wytse J Wadman
Keyword(s):  
Entorhinal Cortex ◽  
Pyramidal Neurons ◽  
Calcium Currents

Calcium currents in rat entorhinal cortex layer II stellate and layer III pyramidal neurons in acute brain slice

2002 ◽  
Vol 327 (3) ◽  
pp. 153-156 ◽  
Author(s):  
Violeta Visan ◽  
Uwe Heinemann ◽  
Andriy Volynets ◽  
Wolfgang Müller
Keyword(s):  
Entorhinal Cortex ◽  
Brain Slice ◽  
Pyramidal Neurons ◽  
Calcium Currents

scholarly journals Lateral entorhinal cortex inputs modulate hippocampal dendritic excitability by recruiting a local disinhibitory microcircuit

2022 ◽  
Author(s):  
Olesia M Bilash ◽  
Spyridon Chavlis ◽  
Panayiota Poirazi ◽  
Jayeeta Basu
Keyword(s):  
Entorhinal Cortex ◽  
Pyramidal Neurons ◽  
Inhibitory Neuron ◽  
Inhibitory Neurons ◽  
Environmental Cues ◽  
Memory Processing ◽  
Ca1 Pyramidal Neurons ◽  
Dendritic Spikes ◽  
Hippocampal Area ◽  
Insight Into

The lateral entorhinal cortex (LEC) provides information about multi-sensory environmental cues to the hippocampus through direct inputs to the distal dendrites of CA1 pyramidal neurons. A growing body of work suggests that LEC neurons perform important functions for episodic memory processing, coding for contextually-salient elements of an environment or the experience within it. However, we know little about the functional circuit interactions between LEC and the hippocampus. In this study, we combine functional circuit mapping and computational modeling to examine how long-range glutamatergic LEC projections modulate compartment-specific excitation-inhibition dynamics in hippocampal area CA1. We demonstrate that glutamatergic LEC inputs can drive local dendritic spikes in CA1 pyramidal neurons, aided by the recruitment of a disinhibitory vasoactive intestinal peptide (VIP)-expressing inhibitory neuron microcircuit. Our circuit mapping further reveals that, in parallel, LEC also recruits cholecystokinin (CCK)-expressing inhibitory neurons, which our model predicts act as a strong suppressor of dendritic spikes. These results provide new insight into a cortically-driven GABAergic microcircuit mechanism that gates non-linear dendritic computations, which may support compartment-specific coding of multi-sensory contextual features within the hippocampus.

Calcium Currents in Retrogradely Labeled Pyramidal Cells From Rat Sensorimotor Cortex

2000 ◽  
Vol 83 (4) ◽  
pp. 2349-2354 ◽  
Author(s):  
Ansalan Stewart ◽  
Robert C. Foehring
Keyword(s):  
Pyramidal Neurons ◽  
Pyramidal Cells ◽  
Cell Types ◽  
Calcium Currents ◽  
Patch Clamp Technique ◽  
Whole Cell ◽  
Multiple Populations ◽  
Whole Cell Patch Clamp ◽  
The Mean ◽  
P Type

Our previous studies of calcium (Ca2+) currents in cortical pyramidal cells revealed that the percentage contribution of each Ca2+ current type to the whole cell Ca2+ current varies from cell to cell. The extent to which these currents are modulated by neurotransmitters is also variable. This study was directed at testing the hypothesis that a major source of this variability is recording from multiple populations of pyramidal cells. We used the whole cell patch-clamp technique to record from dissociated corticocortical, corticostriatal, and corticotectal projecting pyramidal cells. There were significant differences between the three pyramidal cell types in the mean percentage of L-, P-, and N-type Ca2+ currents. For both N- and P-type currents, the range of percentages expressed was small for corticostriatal and corticotectal cells as compared with cells which project to the corpus callosum or to the general population. The variance was significantly different between cell types for N- and P-type currents. These results suggest that an important source of the variability in the proportions of Ca2+ current types present in neocortical pyramidal neurons is recording from multiple populations of pyramidal cells.

scholarly journals Distance- and activity-dependent modulation of spike back-propagation in layer V pyramidal neurons of the medial entorhinal cortex

2011 ◽  
Vol 105 (3) ◽  
pp. 1372-1379 ◽  
Author(s):  
Sonia Gasparini
Keyword(s):  
Entorhinal Cortex ◽  
High Speed ◽  
Pyramidal Neurons ◽  
Back Propagation ◽  
Medial Entorhinal Cortex ◽  
Type K ◽  
Whole Cell Patch Clamp ◽  
Voltage Dependent ◽  
Layer V ◽  
Activity Dependent

Layer V principal neurons of the medial entorhinal cortex receive the main hippocampal output and relay processed information to the neocortex. Despite the fundamental role hypothesized for these neurons in memory replay and consolidation, their dendritic features are largely unknown. High-speed confocal and two-photon Ca2+ imaging coupled with somatic whole cell patch-clamp recordings were used to investigate spike back-propagation in these neurons. The Ca2+ transient associated with a single back-propagating action potential was considerably smaller at distal dendritic locations (>200 μm from the soma) compared with proximal ones. Perfusion of Ba2+ (150 μM) or 4-aminopyridine (2 mM) to block A-type K+ currents significantly increased the amplitude of the distal, but not proximal, Ca2+ transients, which is strong evidence for an increased density of these channels at distal dendritic locations. In addition, the Ca2+ transients decreased with each subsequent spike in a 20-Hz train; this activity-dependent decrease was also more prominent at more distal locations and was attenuated by the perfusion of the protein kinase C activator phorbol-di-acetate. These data are consistent with a phosphorylation-dependent control of back-propagation during trains of action potentials, attributable mainly to an increase in the time constant of recovery from voltage-dependent inactivation of dendritic Na+ channels. In summary, dendritic Na+ and A-type K+ channels control spike back-propagation in layer V entorhinal neurons. Because the activity of these channels is highly modulated, the extent of the dendritic Ca2+ influx is as well, with important functional implications for dendritic integration and associative synaptic plasticity.

scholarly journals Medial and Lateral Entorhinal Cortex Differentially Excite Deep versus Superficial CA1 Pyramidal Neurons

Cell Reports ◽  
2017 ◽  
Vol 18 (1) ◽  
pp. 148-160 ◽  
Author(s):  
Arjun V. Masurkar ◽  
Kalyan V. Srinivas ◽  
David H. Brann ◽  
Richard Warren ◽  
Daniel C. Lowes ◽  
...  
Keyword(s):  
Entorhinal Cortex ◽  
Pyramidal Neurons ◽  
Ca1 Pyramidal Neurons

Direct projections of non-pyramidal neurons of Ammon's horn to the amygdala and the entorhinal cortex

1990 ◽  
Vol 115 (2-3) ◽  
pp. 161-166 ◽  
Author(s):  
Tadashi Ino ◽  
Shigeru Matsuzaki ◽  
Yasuhide Shinonaga ◽  
Hitoshi Ohishi ◽  
Reiko Ogawa-Meguro ◽  
...  
Keyword(s):  
Entorhinal Cortex ◽  
Pyramidal Neurons ◽  
Ammon's Horn ◽  
Ammon’S Horn

Modulation of excitability in CA1 pyramidal neurons via the interplay of entorhinal cortex and CA3 inputs

2007 ◽  
Vol 70 (10-12) ◽  
pp. 1735-1740 ◽  
Author(s):  
Eleftheria Kyriaki Pissadaki ◽  
Panayiota Poirazi
Keyword(s):  
Entorhinal Cortex ◽  
Pyramidal Neurons ◽  
Ca1 Pyramidal Neurons

Calcium currents in acutely isolated human neocortical neurons

1993 ◽  
Vol 69 (5) ◽  
pp. 1596-1606 ◽  
Author(s):  
R. J. Sayer ◽  
A. M. Brown ◽  
P. C. Schwindt ◽  
W. E. Crill
Keyword(s):  
Pyramidal Neurons ◽  
Intractable Epilepsy ◽  
Pyramidal Cells ◽  
Cell Voltage ◽  
Threshold Current ◽  
Calcium Currents ◽  
High Threshold ◽  
Peak Current ◽  
Neocortical Neurons ◽  
Low Threshold

1. Ca2+ currents were investigated in neurons acutely isolated from adult human temporal neocortex. The aim was to compare the basic characteristics of the currents with those previously described in animals and to examine the effects of dihydropyridine Ca2+ antagonists and antiepileptic drugs. The tissue, obtained from patients undergoing temporal lobe surgery for medically intractable epilepsy, was sliced, incubated in papain, and triturated. 2. Most of the isolated neurons (34 of 36) were judged to be pyramidal cells by their morphology. Whole-cell voltage-clamp recordings revealed two components of Ca2+ current: 1) a low-threshold (T-type) current that was transient, small in amplitude, and required hyperpolarization more negative than -70 mV for removal of inactivation and 2) a high-threshold current that was slowly inactivating and was available for activation from more positive potentials. The characteristics of the Ca2+ currents were very similar to those in the neocortical neurons of young rats, although the low-threshold current was less prominent in the human cells. 3. Subcomponents of the high-threshold current were identified by pharmacology. About 20% of the peak current was blocked by omega-conotoxin GVIA (presumed N current) and 40-50% of the peak current was blocked by micromolar concentrations of the dihydropyridine Ca2+ antagonists nifedipine and nimodipine (presumed L current). In two neurons tested with a range of nimodipine concentrations, the threshold for suppression of the high-threshold current was approximately 10 nM. 4. The antiepileptic agents ethosuximide, carbamazepine, and valproate did not affect the Ca2+ currents at therapeutically relevant concentrations. Phenytoin marginally reduced the low- and high-threshold Ca2+ currents at 8 microM (a concentration corresponding to the upper therapeutic range). The results do not support the hypothesis that inhibition of Ca2+ currents in neocortical pyramidal neurons is a major action of these drugs.

Unique Properties of R-Type Calcium Currents in Neocortical and Neostriatal Neurons

2000 ◽  
Vol 84 (5) ◽  
pp. 2225-2236 ◽  
Author(s):  
Robert C. Foehring ◽  
Paul G. Mermelstein ◽  
Wen-Jie Song ◽  
Sasha Ulrich ◽  
D. James Surmeier
Keyword(s):  
Pyramidal Neurons ◽  
Cell Types ◽  
Calcium Currents ◽  
Medium Spiny Neurons ◽  
Cell Type ◽  
Channel Current ◽  
Spiny Neurons ◽  
Deactivation Kinetics ◽  
Whole Cell Recordings ◽  
Neocortical Pyramidal Neurons

Whole cell recordings from acutely dissociated neocortical pyramidal neurons and striatal medium spiny neurons exhibited a calcium-channel current resistant to known blockers of L-, N-, and P/Q-type Ca2+ channels. These R-type currents were characterized as high-voltage–activated (HVA) by their rapid deactivation kinetics, half-activation and half-inactivation voltages, and sensitivity to depolarized holding potentials. In both cell types, the R-type current activated at potentials relatively negative to other HVA currents in the same cell type and inactivated rapidly compared with the other HVA currents. The main difference between cell types was that R-type currents in neocortical pyramidal neurons inactivated at more negative potentials than R-type currents in medium spiny neurons. Ni2+ sensitivity was not diagnostic for R-type currents in either cell type. Single-cell RT-PCR revealed that both cell types expressed the α1E mRNA, consistent with this subunit being associated with the R-type current.

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