scholarly journals Activity-Dependent Induction of Multitransmitter Signaling Onto Pyramidal Cells and Interneurons of Hippocampal Area CA3

2003 ◽  
Vol 89 (6) ◽  
pp. 3155-3167 ◽  
Author(s):  
Héctor Romo-Parra ◽  
Carmen Vivar ◽  
Jasmín Maqueda ◽  
Miguel A. Morales ◽  
Rafael Gutiérrez
Keyword(s):  
Granule Cells ◽  
Mossy Fibers ◽  
Pyramidal Cells ◽  
Acid Decarboxylase ◽  
Dependent Manner ◽  
Amino Butyric Acid ◽  
Cholinergic Pathway ◽  
Hippocampal Area ◽  
Activity Dependent ◽  
Area Ca3

The granule cells of the dentate gyrus (DG) are considered to be glutamatergic, but they contain glutamic acid decarboxylase, γ-amino butyric acid (GABA), and the vesicular GABA transporter mRNA. Their expression is regulated in an activity-dependent manner and coincides with the appearance of GABAergic transmission from the mossy fibers (MF) to pyramidal cells in area CA3. These data support the hypothesis that MF are able to release glutamate and GABA. Following the principle that a given neuron releases the same neurotransmitter(s) onto all its targets, we here demonstrate the emergence, after a generalized convulsive seizure, of MF GABAergic signaling sensitive to activation mGluR-III onto pyramidal cells and interneurons of CA3. Despite this, excitation overrides inhibition in interneurons, preventing disinhibition. Furthermore, on blockade of GABA and glutamate ionotropic receptors, an M1-cholinergic depolarizing signal is also revealed in both targets, which postsynaptically modulates the glutamatergic and GABAergic fast neurotransmission. The emergence of these nonglutamatergic signals depends on protein synthesis. In contrast to cholinergic responses evoked by associational/commissural fibers activation, cholinergic transmission evoked by DG stimulation is only observed after seizures and is strongly depressed by the activation of mGluR-II, whereas both are depressed by M2-AChR activation. With immunohistological experiments, we show that this cholinergic pathway runs parallel to the MF. Thus seizures compromise a delicate balance of excitation and inhibition, on which a complex interaction of different neurotransmitters emerges to counteract excitation at pre- and postsynaptic sites. Particularly, MF GABAergic inhibition emerges to exert an overall inhibitory action on CA3.

Electrophysiological and Pharmacological Characterization of the Direct Perforant Path Input to Hippocampal Area CA3

1998 ◽  
Vol 79 (4) ◽  
pp. 2111-2118 ◽  
Author(s):  
Julia Berzhanskaya ◽  
Nathaniel N. Urban ◽  
German Barrionuevo
Keyword(s):  
Hippocampal Slices ◽  
Mossy Fibers ◽  
Pyramidal Cells ◽  
Perforant Path ◽  
Pharmacological Characterization ◽  
Paired Pulse ◽  
Postsynaptic Currents ◽  
Hippocampal Area ◽  
Area Ca3

Berzhanskaya, Julia, Nathaniel N. Urban, and German Barrionuevo. Electrophysiological and pharmacological characterization of the direct perforant path input to hippocampal area CA3. J. Neurophysiol. 79: 2111–2118, 1998. Monosynaptic perforant path responses evoked by subicular stimulation were recorded from CA3 pyramidal cells of rat hippocampal slices. These monosynaptic responses were isolated by using low intensities of stimulation and by placing a cut through the mossy fibers. Perforant path–evoked responses consisted of both excitatory and inhibitory components. Excitatory postsynaptic currents (EPSCs) were mediated by both α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acidreceptors (AMPAR) and N-methyl-d-aspartate receptors (NMDAR).Inhibitory postsynaptic currents consisted of γ-aminobutyric acid-A (GABAA-) and -B (GABAB)-receptor–mediated components. At membrane potentials more positive than -60 mV and at physiological [Ca2+]/[Mg2+] ratios, >30% of perforant path evoked EPSC was mediated by NMDARs. This value varied as a function of the membrane voltage and external [Mg2+]. Two types of responses were observed after low-intensity stimulation of the perforant path. The first type of response showed paired-pulse facilitation and was reduced by 2-amino-4-phosphonobutyric acid (AP4). The second type of response showed paired-pulse depression and was reduced by baclofen. Electrophysiological and pharmacological characteristics of these two types of responses are similar to the properties of lateral and medial perforant path–evoked EPSPs in the dentate gyrus.

Origin of the Apparent Asynchronous Activity of Hippocampal Mossy Fibers

1997 ◽  
Vol 78 (1) ◽  
pp. 24-30 ◽  
Author(s):  
Darrell A. Henze ◽  
Nathaniel N. Urban ◽  
German Barrionuevo
Keyword(s):  
Mossy Fiber ◽  
Molecular Layer ◽  
Mossy Fibers ◽  
Pyramidal Cells ◽  
Antidromic Activation ◽  
Stratum Lucidum ◽  
Hippocampal Area ◽  
Ca3 Pyramidal Cells ◽  
Area Ca3

Henze, Darrell A., Nathaniel N. Urban, and German Barrionuevo. Origin of the apparent asynchronous activity of hippocampal mossy fibers. J. Neurophysiol. 78: 24–30, 1997. Fiber volleys (FVs) from the stratum lucidum of rat hippocampal area CA3 were recorded extracellularly from in vitro slices in the presence of 10 mM kynurenic acid. In agreement with previous work, bulk stimulation of the dentate gyrus (DG) near the hilar border leads to an asynchronous FV. Transection of the stratum lucidum between the DG stimulation site and the CA3 recording site reduced or eliminated the early components of the asynchronous FV, indicating that they are of mossy fiber (MF) origin. In contrast, moving the stimulating electrode away from the hilus toward the hippocampal fissure reduced or eliminated the late components of the FV. Subsequently, we found that bulk stimulation on the DG/hilar border induces an antidromic population spike in CA3 pyramidal cells. Finally, the MFs and associational collaterals have differentconduction velocities (0.51 and 0.37 m/s, respectively; temperature =33°C). From these data, we conclude that the late components of the asynchronous FV are due to antidromic activation of CA3 collaterals that have been shown to be present in the DG and hilus. A corollary of these findings is that bulk stimulation on the DG/hilar border can lead to at least two different monosynaptic inputs to CA3 pyramidal cells: the MFs and the antidromically activated associational collaterals. We suggest that when MF synaptic responses are being evoked with the use of bulk stimulation, stimulating electrodes should be placed in the outer molecular layer of the DG to prevent the activation of hilar-projecting associational collaterals. This procedure should be added to the previously proposed criteria for preventing polysynaptic contamination of the intracellularly recorded evoked MF synaptic response.

Evidence from simultaneous intracellular recordings in rat hippocampal slices that area CA3 pyramidal cells innervate dentate hilar mossy cells

1994 ◽  
Vol 72 (5) ◽  
pp. 2167-2180 ◽  
Author(s):  
H. E. Scharfman
Keyword(s):  
Pyramidal Cell ◽  
Action Potentials ◽  
Granule Cells ◽  
Hippocampal Slices ◽  
Pyramidal Cells ◽  
Probability Of Failure ◽  
Mossy Cells ◽  
Mossy Cell ◽  
Ca3 Pyramidal Cells ◽  
Area Ca3

1. Simultaneous intracellular recordings of area CA3 pyramidal cells and dentate hilar “mossy” cells were made in rat hippocampal slices to test the hypothesis that area CA3 pyramidal cells excite mossy cells monosynaptically. Mossy cells and pyramidal cells were differentiated by location and electrophysiological characteristics. When cells were impaled near the border of area CA3 and the hilus, their identity was confirmed morphologically after injection of the marker Neurobiotin. 2. Evidence for monosynaptic excitation of a mossy cell by a pyramidal cell was obtained in 7 of 481 (1.4%) paired recordings. In these cases, a pyramidal cell action potential was followed immediately by a 0.40 to 6.75 (mean, 2.26) mV depolarization in the simultaneously recorded mossy cell (mossy cell membrane potentials, -60 to -70 mV). Given that pyramidal cells used an excitatory amino acid as a neurotransmitter (Cotman and Nadler 1987; Ottersen and Storm-Mathisen 1987) and recordings were made in the presence of the GABAA receptor antagonist bicuculline (25 microM), it is likely that the depolarizations were unitary excitatory postsynaptic potentials (EPSPs). 3. Unitary EPSPs of mossy cells were prone to apparent “failure.” The probability of failure was extremely high (up to 0.72; mean = 0.48) if the effects of all presynaptic action potentials were examined, including action potentials triggered inadvertently during other spontaneous EPSPs of the mossy cell. Probability of failure was relatively low (as low as 0; mean = 0.24) if action potentials that occurred during spontaneous activity of the mossy cell were excluded. These data suggest that unitary EPSPs produced by pyramidal cells are strongly affected by concurrent synaptic inputs to the mossy cell. 4. Unitary EPSPs were not clearly affected by manipulation of the mossy cell's membrane potential. This is consistent with the recent report that area CA3 pyramidal cells innervate distal dendrites of mossy cells (Kunkel et al. 1993). Such a distal location also may contribute to the high incidence of apparent failures. 5. Characteristics of unitary EPSPs generated by pyramidal cells were compared with the properties of the unitary EPSPs produced by granule cells. In two slices, pyramidal cell and granule cell inputs to the same mossy cell were compared. In other slices, inputs to different mossy cells were compared. In all experiments, unitary EPSPs produced by granule cells were larger in amplitude but similar in time course to unitary EPSPs produced by pyramidal cells. Probability of failure was lower and paired-pulse facilitation more common among EPSPs triggered by granule cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Amplification of Perforant-Path EPSPs in CA3 Pyramidal Cells by LVA Calcium and Sodium Channels

1998 ◽  
Vol 80 (3) ◽  
pp. 1558-1561 ◽  
Author(s):  
Nathaniel N. Urban ◽  
Darrell A. Henze ◽  
German Barrionuevo
Keyword(s):  
Sodium Channels ◽  
Entorhinal Cortex ◽  
Low Voltage ◽  
Pyramidal Cells ◽  
Perforant Path ◽  
Monosynaptic Connection ◽  
Voltage Dependent ◽  
Hippocampal Area ◽  
Ca3 Pyramidal Cells ◽  
Area Ca3

Urban, Nathaniel N., Darrell A. Henze, and German Barrionuevo. Amplification of perforant-path EPSPs in CA3 pyramidal cells by LVA calcium and sodium channels. J. Neurophysiol. 80: 1558–1561, 1998. The perforant path forms a monosynaptic connection between the cells of layer II of the entorhinal cortex and the pyramidal cells in hippocampal area CA3. Although this projection is prominent anatomically, very little is known about the physiological properties of this input. The distal location of these synapses suggests that somatically recorded perforant-path excitatory postsynaptic potentials (EPSPs) may be influenced by the activation of voltage-dependent channels in CA3 cells. We observed that perforant-path EPSPs are reduced (by ∼25%) by blockade of postsynaptic low-voltage–activated calcium and sodium channels, indicating that perforant-path EPSPs are amplified by the activation of these channels. These data suggest that the perforant path may represent an important and highly modifiable direct connection between the entorhinal cortex and area CA3.

scholarly journals Information processing in the hemisphere of the cerebellar cortex for control of wrist movement

2016 ◽  
Vol 115 (1) ◽  
pp. 255-270 ◽  
Author(s):  
Saeka Tomatsu ◽  
Takahiro Ishikawa ◽  
Yoshiaki Tsunoda ◽  
Jongho Lee ◽  
Donna S. Hoffman ◽  
...  
Keyword(s):  
Information Processing ◽  
Cerebellar Cortex ◽  
Granule Cells ◽  
Mossy Fibers ◽  
Movement Direction ◽  
Dependent Manner ◽  
Wrist Movement ◽  
Movement Onset ◽  
Filtering Function ◽  
Peripheral Motor

A region of cerebellar lobules V and VI makes strong loop connections with the primary motor (M1) and premotor (PM) cortical areas and is assumed to play essential roles in limb motor control. To examine its functional role, we compared the activities of its input, intermediate, and output elements, i.e., mossy fibers (MFs), Golgi cells (GoCs), and Purkinje cells (PCs), in three monkeys performing wrist movements in two different forearm postures. The results revealed distinct steps of information processing. First, MF activities displayed temporal and directional properties that were remarkably similar to those of M1/PM neurons, suggesting that MFs relay near copies of outputs from these motor areas. Second, all GoCs had a stereotyped pattern of activity independent of movement direction or forearm posture. Instead, GoC activity resembled an average of all MF activities. Therefore, inhibitory GoCs appear to provide a filtering function that passes only prominently modulated MF inputs to granule cells. Third, PCs displayed highly complex spatiotemporal patterns of activity, with coordinate frames distinct from those of MF inputs and directional tuning that changed abruptly before movement onset. The complexity of PC activities may reflect rapidly changing properties of the peripheral motor apparatus during movement. Overall, the cerebellar cortex appears to transform a representation of outputs from M1/PM into different movement representations in a posture-dependent manner and could work as part of a forward model that predicts the state of the peripheral motor apparatus.

scholarly journals Sex differences in hippocampal area CA3 pyramidal cells

2016 ◽  
Vol 95 (1-2) ◽  
pp. 563-575 ◽  
Author(s):  
Helen E. Scharfman ◽  
Neil J. MacLusky
Keyword(s):  
Sex Differences ◽  
Pyramidal Cells ◽  
Hippocampal Area ◽  
Ca3 Pyramidal Cells ◽  
Area Ca3

Activity-dependent disinhibition. III. Desensitization and GABAB receptor-mediated presynaptic inhibition in the hippocampus in vitro

1989 ◽  
Vol 61 (3) ◽  
pp. 524-533 ◽  
Author(s):  
S. M. Thompson ◽  
B. H. Gahwiler
Keyword(s):  
Receptor Agonist ◽  
Gabab Receptor ◽  
Mossy Fiber ◽  
Reversal Potential ◽  
Pyramidal Cells ◽  
Gabab Receptors ◽  
Initial Time ◽  
Dependent Manner ◽  
Iontophoretic Application ◽  
Activity Dependent

1. Single-electrode voltage-clamp recordings were made from CA3 pyramidal cells in organotypic hippocampal slice cultures for measurement of membrane currents underlying both the gamma-aminobutyric acid (GABA)-mediated, Cl- -dependent inhibitory postsynaptic potential (IPSC), evoked in response to stimulation of the mossy fiber pathway, and responses to iontophoretically applied GABA. Pre- and postsynaptic mechanisms mediating activity-dependent reductions in the conductance underlying the IPSC (gIPSC) were investigated. 2. During 99-s applications of GABA, the mean evoked conductance (gGABA) decreased 43% with an initial time constant of 51 s. Desensitization was never complete. 3. Ca2+-influx, activated with depolarizing voltage commands of 100-ms to 15-s duration in the presence of intracellular Cs+, had no effect on GABA responses. 4. Iontophoretic application of the GABAA-receptor agonist muscimol caused a rapid decrease of 80-100% in the amplitude of IPSCs evoked at depolarized membrane potentials (Vm). Recovery was 80% complete in 30 s. The second of two paired applications of muscimol, delivered at the same iontophoretic intensity, was reduced in amplitude 35%. This was shown to result from a decrease in driving force rather than from desensitization. We conclude that muscimol decreases IPSCs by causing an increase in the intracellular Cl- concentration. 5. Iontophoretic application of the GABAB-receptor agonist (+/-)-baclofen caused a decrease of only 30% in the amplitude of IPSCs evoked at depolarized Vms. This effect outlasted the post-synaptic effects of baclofen; recovery was 80% complete between 60 and 90 s. 6. Bath application of (-)-baclofen was found to decrease gIPSC without affecting the IPSC reversal potential. This effect was rapid in onset, could be observed at concentrations as low as 1 X 10(-7) M, and recovered quickly. The EC50 was roughly 5 X 10(-7) M and appeared similar to that for the baclofen-activated increase in postsynaptic conductance. No effect on responses to iontophoretically applied GABA was observed, demonstrating that baclofen decreases gIPSC by reducing presynaptic release via GABAB receptors. 7. Iontophoretic application of GABA reduced IPSCs in a dose-dependent manner. At low iontophoretic intensities, IPSCs were reduced only 30% and recovered slowly, as with baclofen iontophoresis. At higher iontophoretic intensities, IPSCs were more completely blocked. Recovery was initially fast, but took 60-90 s to be complete.(ABSTRACT TRUNCATED AT 400 WORDS)

Sign in / Sign up

Export Citation Format

Share Document