scholarly journals TRPM4 Expression During Postnatal Developmental of Mouse CA1 Pyramidal Neurons

2021 ◽  
Vol 15 ◽  
Author(s):  
Denise Riquelme ◽  
Oscar Cerda ◽  
Elias Leiva-Salcedo
Keyword(s):  
Membrane Potential ◽  
Patch Clamp ◽  
Postnatal Development ◽  
Pyramidal Neurons ◽  
Brain Slices ◽  
Long Term Potentiation ◽  
Neuronal Firing ◽  
Resting Membrane Potential ◽  
Ca1 Pyramidal Neurons ◽  
Apical Dendrites

TRPM4 is a non-selective cation channel activated by intracellular calcium and permeable to monovalent cations. This channel participates in the control of neuronal firing, neuronal plasticity, and neuronal death. TRPM4 depolarizes dendritic spines and is critical for the induction of NMDA receptor-dependent long-term potentiation in CA1 pyramidal neurons. Despite its functional importance, no subcellular localization or expression during postnatal development has been described in this area. To examine the localization and expression of TRPM4, we performed duplex immunofluorescence and patch-clamp in brain slices at different postnatal ages in C57BL/6J mice. At P0 we found TRPM4 is expressed with a somatic pattern. At P7, P14, and P35, TRPM4 expression extended from the soma to the apical dendrites but was excluded from the axon initial segment. Patch-clamp recordings showed a TRPM4-like current active at the resting membrane potential from P0, which increased throughout the postnatal development. This current was dependent on intracellular Ca2+ (ICAN) and sensitive to 9-phenanthrol (9-Ph). Inhibiting TRPM4 with 9-Ph hyperpolarized the membrane potential at P14 and P35, with no effect in earlier stages. Together, these results show that TRPM4 is expressed in CA1 pyramidal neurons in the soma and apical dendrites and associated with a TRPM4-like current, which depolarizes the neurons. The expression, localization, and function of TRPM4 throughout postnatal development in the CA1 hippocampal may underlie an important mechanism of control of membrane potential and action potential firing during critical periods of neuronal development, particularly during the establishment of circuits.

scholarly journals Neurotoxicity of NMDA antagonists: a glutamatergic theory of schizophrenia based on selective impairment of local inhibitory feedback circuits

2000 ◽  
Vol 2 (3) ◽  
pp. 287-298
Keyword(s):  
Pyramidal Neurons ◽  
Brain Slices ◽  
Nmda Antagonist ◽  
Long Term Potentiation ◽  
Normal Function ◽  
Recurrent Inhibition ◽  
Resting Membrane Potential ◽  
Nmda Antagonists ◽  
Inhibitory Feedback

Modulation of recurrent inhibition is critical not only for the normal function of highly excitable regions of the brain, especially the limbic system, but may also be a primary determining factor for the viability of neurons in these regions. Standard extracellular and intracellular recordings from in vitro brain slices of rat hippocampi were employed to show that recurrent inhibition onto CA1 neurons can be modulated by N-methyl-D-aspartate (NMDA) antagonists. Besides reducing the amplitude of inhibitory postsynaptic potentials (IPSPs) at resting membrane potential conditions, different NMDA antagonists, including the endogenous substance N-acetyl-L-aspartyl-L-glutamic acid (NAAG), are able to block long-term potentiation (LIP) of recurrent inhibition completely at concentrations that are not sufficient to block LTP of the excitatory drive onto pyramidal neurons. This LTP of recurrent inhibition may play a significant role in stimulus discrimination and learning, as simulated in a biophysical computer model of a basic neuronal circuit. Both the amplitude of the IPSP and LTP of the recurrent inhibitory circuit also undergo developmental changes showing their highest expression and vulnerability to chronic NMDA antagonist injections in juvenile rats. Finally, blocking NMDA receptor-dependent transmission in the recurrent inhibition loop may lead to an overall increased excitability of the neuronal network. This may resemble the positive schizophrenic symptoms observed in man, presumably caused by elevated levels of the endogenous NMDA antagonist NAAG.

scholarly journals Fast Optical Recordings of Membrane Potential Changes From Dendrites of Pyramidal Neurons

1999 ◽  
Vol 82 (3) ◽  
pp. 1615-1621 ◽  
Author(s):  
Srdjan Antic ◽  
Guy Major ◽  
Dejan Zecevic
Keyword(s):  
Membrane Potential ◽  
Pyramidal Neurons ◽  
Spatial Dynamics ◽  
Brain Slices ◽  
Optical Recording ◽  
Neuronal Processes ◽  
Voltage Sensitive Dyes ◽  
Apical Dendrites ◽  
The Brain ◽  
Extracellular Environment

Understanding the biophysical properties of single neurons and how they process information is fundamental to understanding how the brain works. A technique that would allow recording of temporal and spatial dynamics of electrical activity in neuronal processes with adequate resolution would facilitate further research. Here, we report on the application of optical recording of membrane potential transients at many sites on neuronal processes of vertebrate neurons in brain slices using intracellular voltage-sensitive dyes. We obtained evidence that 1) loading the neurons with voltage-sensitive dye using patch electrodes is possible without contamination of the extracellular environment; 2) brain slices do not show any autofluorescence at the excitation/emission wavelengths used; 3) pharmacological effects of the dye were completely reversible; 4) the level of photodynamic damage already allows meaningful measurements and could be reduced further; 5) the sensitivity of the dye was comparable to that reported for invertebrate neurons; 6) the dye spread ∼500 μm into distal processes within 2 h incubation period. This distance should increase with longer incubation; 7) the optically recorded action potential signals from basolateral dendrites (that are difficult or impossible to approach by patch electrodes) and apical dendrites show that both direct soma stimulation and synaptic stimulation triggered action potentials that originated near the soma. The spikes backpropagated into both basolateral dendrites and apical processes; the propagation was somewhat faster in the apical dendrites.

Posttetanic Excitation Mediated by GABAA Receptors in Rat CA1 Pyramidal Neurons

1997 ◽  
Vol 77 (4) ◽  
pp. 2213-2218 ◽  
Author(s):  
Tomi Taira ◽  
Karri Lamsa ◽  
Kai Kaila
Keyword(s):  
Pyramidal Neurons ◽  
Hippocampal Slices ◽  
Pyramidal Cells ◽  
Long Term Potentiation ◽  
Neuronal Firing ◽  
Stratum Radiatum ◽  
Tetanic Stimulation ◽  
Glutamate Antagonists ◽  
Ca1 Pyramidal Neurons ◽  
Spike Firing

Taira, Tomi, Karri Lamsa, and Kai Kaila. Posttetanic excitation mediated by GABAA receptors in rat CA1 pyramidal neurons. J.Neurophysiol. 77: 2213–2218, 1997. The contributions of γ-aminobutyric acid (GABA) receptors to posttetanic excitation of CA1 pyramidal neurons in rat hippocampal slices were studied using extracellular and intracellular recording techniques. Synaptic responses were evoked on tetanic stimulation (100–200 Hz, 40–100 pulses) applied in stratum radiatum close (300–600 μm) to the recording site. Under control conditions, tetanic stimulation resulted in a triphasic depolarization/hyperpolarization/sustained depolarization sequence in area CA1 pyramidal cells. The late depolarization usually gave rise to a prolonged (≤3 s) spike firing. The late depolarization and the associated spike firing were blocked both specifically and completely (within a time window of 3–6 min starting from picrotoxin application) by the GABAA receptor antagonist picrotoxin (PiTX, 100 μM). Paradoxically, at this early stage of PiTX application, overall neuronal firing was attenuated to a higher degree than what was achieved by ionotropic glutamate antagonists. Complete block of ionotropic glutamate receptors by the antagonists d-2-amino-5-phosphonopentoate (AP5, 80 μM), 6-nitro-7-sulphamoylbenzo[f]quinoxaline-2,3-dione (NBQX, 10 μM), and ketamine (50 μM) blocked the initial fast depolarization and suppressed the late one. Exposure to a permeable inhibitor of carbonic anhydrase, ethoxyzolamide (EZA, 50 μM) inhibited the late, apparently GABA-mediated depolarization. It is concluded that GABA can provide the main posttetanic excitatory drive in the adult hippocampus. The present results suggest that intense activation of GABAergic interneurons may accentuate the excitation of principal neurons and, hence, play an important facilitatory role in the induction of long-term potentiation (LTP) and epileptogenesis.

Contribution of the Hyperpolarization-Activated Current (I h) to Membrane Potential and GABA Release in Hippocampal Interneurons

2001 ◽  
Vol 86 (1) ◽  
pp. 261-268 ◽  
Author(s):  
Carl R. Lupica ◽  
James A. Bell ◽  
Alexander F. Hoffman ◽  
Patricia L. Watson
Keyword(s):  
Membrane Potential ◽  
Action Potential ◽  
Pyramidal Neurons ◽  
Membrane Potentials ◽  
Resting Membrane Potential ◽  
Inhibitory Input ◽  
Ca1 Pyramidal Neurons ◽  
Spontaneous Action Potential ◽  
Spontaneous Action ◽  
Zd 7288

Intrinsic GABAergic interneurons provide inhibitory input to the principal neurons of the hippocampus. The majority of interneurons located in stratum oriens (s.o.) of the CA1 region express the hyperpolarization-activated cation current known as I h. In an effort to elucidate the role of this current in regulating the baseline excitability of these neurons and its participation in the regulation of the release of GABA onto CA1 pyramidal neurons, we utilized whole cell electrophysiological recordings from both populations of cells. In voltage-clamp experiments, hyperpolarization of the interneuron membrane initiated a large inward current with an estimated activation threshold of 51.6 ± 7.6 mV and a half-maximal voltage of −73.0 ± 7.0 mV. This current was blocked by bath application of the I h inhibitors ZD 7288 (50 μM) or cesium (2 mM). Current-clamp experiments at the interneuron resting membrane potential (−61.3 ± 1.2 mV) revealed a significant hyperpolarization, a decrease in the rate of spontaneous action potential discharge, an increase in the cellular input resistance, and the elimination of rebound afterdepolarizations during blockade of I h with ZD 7288 (50 μM). The hyperpolarizing effect of ZD 7288 was also substantially larger in interneurons clamped near −80 mV using current injection through the pipette. In addition to neurons exhibiting I h, recordings were obtained from a small population of s.o. interneurons that did not exhibit this current. These cells demonstrated resting membrane potentials that were significantly more negative (−73.6 ± 5.5 mV) than those observed in neurons expressing I h, suggesting that this current contributes to more depolarized membrane potentials in these cells. Recordings from postsynaptic pyramidal neurons demonstrated that blockade of I h with ZD 7288 caused a substantial reduction (∼43%) in the frequency of spontaneous action potential-dependent inhibitory postsynaptic currents (IPSCs), without altering their average amplitude. However, miniature action-potential-independent IPSC frequency, amplitude, and decay kinetics were unaltered by ZD 7288. These data suggest that I h is active at the resting membrane potential in s.o. interneurons and as a result contributes to the spontaneous activity of these cells and to the tonic inhibition of CA1 pyramidal neurons in the hippocampus.

Amplification of EPSPs by Low Ni2+- and Amiloride-Sensitive Ca2+ Channels in Apical Dendrites of Rat CA1 Pyramidal Neurons

1997 ◽  
Vol 77 (3) ◽  
pp. 1639-1643 ◽  
Author(s):  
Thomas Gillessen ◽  
Christian Alzheimer
Keyword(s):  
Membrane Potential ◽  
Synaptic Input ◽  
Pyramidal Neurons ◽  
Low Voltage ◽  
Stratum Radiatum ◽  
Excitatory Postsynaptic Potential ◽  
Appreciable Effect ◽  
Epsp Amplitude ◽  
Ca1 Pyramidal Neurons ◽  
Apical Dendrites

Gillessen, Thomas and Christian Alzheimer. Amplification of EPSPs by low Ni2+- and amiloride-sensitive Ca2+ channels in apical dendrites of rat CA1 pyramidal neurons. J. Neurophysiol. 77: 1639–1643, 1997. Distal synaptic input to hippocampal CA1 pyramidal neurons was evoked by electrical stimulation of afferent fibers in outer stratum radiatum. Whole cell recordings from CA1 cell somata served to monitor excitatory postsynaptic potential (EPSP) envelopes after dendritic processing. To probe a functional role of low-voltage-activated Ca2+ current [or T current ( I T)] in the apical dendrite, EPSP recordings were combined with local application of antagonists of I T. Dendritic application of low concentrations of Ni2+ (5 μM) and amiloride (50 μM) reduced EPSP amplitude measured at the soma (resting membrane potential −70 mV) by 33.0 ± 2.9% (mean ± SE, n = 27) and 27.0 ± 2.1%( n = 26), respectively. No appreciable effect on EPSP time course was observed. As expected from the voltage dependence of I T activation, the inhibitory effect of both antagonists was strongly attenuated when EPSPs were recorded at hyperpolarized membrane potential (−90 mV). In contrast to dendritic application, somatic application of Ni2+ or amiloride produced only weak reduction of EPSP amplitude. Our data indicate that dendritic low Ni2+- and amiloride-sensitive Ca2+ channels giving rise predominantly to I T can produce substantial amplification of synaptic input. We thus propose that these channels represent an important component of subthreshold signal integration in apical dendrites of CA1 pyramidal cells.

Measurement of spontaneous neuronal membrane activity by time lapse confocal microscopy

1995 ◽  
Vol 53 ◽  
pp. 972-973
Author(s):  
R H. Selinfreund ◽  
A. H. Cornell-Bell
Keyword(s):  
Membrane Potential ◽  
Confocal Microscopy ◽  
Patch Clamp ◽  
Electrical Activity ◽  
Time Lapse ◽  
Neuronal Firing ◽  
Neuronal Membrane ◽  
Pituitary Cells ◽  
Patch Clamp Recording ◽  
Spontaneous Electrical Activity

Cellular electrophysiological properties are normally monitored by standard patch clamp techniques . The combination of membrane potential dyes with time-lapse laser confocal microscopy provides a more direct, least destructive rapid method for monitoring changes in neuronal electrical activity. Using membrane potential dyes we found that spontaneous action potential firing can be detected using time-lapse confocal microscopy. Initially, patch clamp recording techniques were used to verify spontaneous electrical activity in GH4\C1 pituitary cells. It was found that serum depleted cells had reduced spontaneous electrical activity. Brief exposure to the serum derived growth factor, IGF-1, reconstituted electrical activity. We have examined the possibility of developing a rapid fluorescent assay to measure neuronal activity using membrane potential dyes. This neuronal regeneration assay has been adapted to run on a confocal microscope. Quantitative fluorescence is then used to measure a compounds ability to regenerate neuronal firing.The membrane potential dye di-8-ANEPPS was selected for these experiments. Di-8- ANEPPS is internalized slowly, has a high signal to noise ratio (40:1), has a linear fluorescent response to change in voltage.

scholarly journals Membrane Dysfunction Induced by In Vitro Ischemia in Rat Hippocampal CA1 Pyramidal Neurons

1999 ◽  
Vol 81 (4) ◽  
pp. 1872-1880 ◽  
Author(s):  
E. Tanaka ◽  
S. Yamamoto ◽  
H. Inokuchi ◽  
T. Isagai ◽  
H. Higashi
Keyword(s):  
Membrane Potential ◽  
Voltage Clamp ◽  
Pyramidal Neurons ◽  
Membrane Surface ◽  
Bathing Medium ◽  
Ca1 Pyramidal Neurons ◽  
In Vitro Ischemia ◽  
Hippocampal Ca1 ◽  
Electrode Voltage

Membrane dysfunction induced by in vitro ischemia in rat hippocampal CA1 pyramidal neurons. Intracellular and single-electrode voltage-clamp recordings were made to investigate the process of membrane dysfunction induced by superfusion with oxygen and glucose-deprived (ischemia-simulating) medium in hippocampal CA1 pyramidal neurons of rat tissue slices. To assess correlation between potential change and membrane dysfunction, the recorded neurons were stained intracellularly with biocytin. A rapid depolarization was produced ∼6 min after starting superfusion with ischemia-simulating medium. When oxygen and glucose were reintroduced to the bathing medium immediately after generating the rapid depolarization, the membrane did not repolarize but depolarized further, the potential reaching 0 mV ∼5 min after the reintroduction. In single-electrode voltage-clamp recording, a corresponding rapid inward current was observed when the membrane potential was held at −70 mV. After the reintroduction of oxygen and glucose, the current induced by ischemia-simulating medium partially returned to preexposure levels. These results suggest that the membrane depolarization is involved with the membrane dysfunction. The morphological aspects of biocytin-stained neurons during ischemic exposure were not significantly different from control neurons before the rapid depolarization. On the other hand, small blebs were observed on the surface of the neuron within 0.5 min of generating the rapid depolarization, and blebs increased in size after 1 min. After 3 min, neurons became larger and swollen. The long and transverse axes and area of the cross-sectional cell body were increased significantly 1 and 3 min after the rapid depolarization. When Ca2+-free (0 mM) with Co2+ (2.5 mM)-containing medium including oxygen and glucose was applied within 1 min after the rapid depolarization, the membrane potential was restored completely to the preexposure level in the majority of neurons. In these neurons, the long axis was lengthened without any blebs being apparent on the membrane surface. These results suggest that the membrane dysfunction induced by in vitro ischemia may be due to a Ca2+-dependent process that commences ∼1.5 min after and is completed 3 min after the onset of the rapid depolarization. Because small blebs occurred immediately after the rapid depolarization and large blebs appeared 1.5–3 min after, it is likely that the transformation from small to large blebs may result in the observed irreversible membrane dysfunction.

Membrane Properties Underlying Patterns of GABA-Dependent Action Potentials in Developing Mouse Hypothalamic Neurons

2001 ◽  
Vol 86 (3) ◽  
pp. 1252-1265 ◽  
Author(s):  
Yu-Feng Wang ◽  
Xiao-Bing Gao ◽  
Anthony N. van den Pol
Keyword(s):  
Membrane Potential ◽  
Action Potentials ◽  
Brain Slices ◽  
Reversal Potential ◽  
Membrane Properties ◽  
Resting Membrane Potential ◽  
Hypothalamic Neurons ◽  
Spike Threshold ◽  
Spike Patterns

Spikes may play an important role in modulating a number of aspects of brain development. In early hypothalamic development, GABA can either evoke action potentials, or it can shunt other excitatory activity. In both slices and cultures of the mouse hypothalamus, we observed a heterogeneity of spike patterns and frequency in response to GABA. To examine the mechanisms underlying patterns and frequency of GABA-evoked spikes, we used conventional whole cell and gramicidin perforation recordings of neurons ( n = 282) in slices and cultures of developing mouse hypothalamus. Recorded with gramicidin pipettes, GABA application evoked action potentials in hypothalamic neurons in brain slices of postnatal day 2–9( P2- 9) mice. With conventional patch pipettes (containing 29 mM Cl−), action potentials were also elicited by GABA from neurons of 2–13 days in vitro (2–13 DIV) embryonic hypothalamic cultures. Depolarizing responses to GABA could be generally classified into three types: depolarization with no spike, a single spike, or complex patterns of multiple spikes. In parallel experiments in slices, electrical stimulation of GABAergic mediobasal hypothalamic neurons in the presence of glutamate receptor antagonists [10 μM 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), 100 μM 2-amino-5-phosphonopentanoic acid (AP5)] resulted in the occurrence of spikes that were blocked by bicuculline (20 μM). Blocking ionotropic glutamate receptors with AP5 and CNQX did not block GABA-mediated multiple spikes. Similarly, when synaptic transmission was blocked with Cd2+ (200 μM) and Ni2+(300 μM), GABA still induced multiple spikes, suggesting that the multiple spikes can be an intrinsic membrane property of GABA excitation and were not based on local interneurons. When the pipette [Cl−] was 29 or 45 mM, GABA evoked multiple spikes. In contrast, spikes were not detected with 2 or 10 mM intracellular [Cl−]. With gramicidin pipettes, we found that the mean reversal potential of GABA-evoked current ( E GABA) was positive to the resting membrane potential, suggesting a high intracellular [Cl−] in developing mouse neurons. Varying the holding potential from −80 to 0 mV revealed an inverted U-shaped effect on spike probability. Blocking voltage-dependent Na+ channels with tetrodotoxin eliminated GABA-evoked spikes, but not the GABA-evoked depolarization. Removing Ca2+ from the extracellular solution did not block spikes, indicating GABA-evoked Na+-based spikes. Although E GABA was more positive within 2–5 days in culture, the probability of GABA-evoked spikes was greater in 6- to 9-day cells. Mechanistically, this appears to be due to a greater Na+ current found in the older cells during a period when the E GABA is still positive to the resting membrane potential. GABA evoked similar spike patterns in HEPES and bicarbonate buffers, suggesting that Cl−, not bicarbonate, was primarily responsible for generatingmultiple spikes. GABA evoked either single or multiple spikes; neurons with multiple spikes had a greater Na+ current, a lower conductance, a more negative spike threshold, and a greater difference between the peak of depolarization and the spike threshold. Taken together, the present results indicate that the patterns of multiple action potentials evoked by GABA are an inherent property of the developing hypothalamic neuron.

Methods for intracellular recording from hippocampal brain slices under high helium pressure

1991 ◽  
Vol 71 (1) ◽  
pp. 365-371 ◽  
Author(s):  
A. P. Southan ◽  
K. T. Wann
Keyword(s):  
Intracellular Recording ◽  
Pyramidal Neurons ◽  
Brain Slices ◽  
Pressure Chamber ◽  
Resting Membrane Potential ◽  
Helium Pressure ◽  
Remote Manipulation ◽  
Current Voltage ◽  
Chamber Temperature ◽  
Current Voltage Relationship

A method for intracellular recording from rat hippocampal brain slices under helium pressure is described. The preparation is mounted on a horizontal mobile platform that is rolled into the pressure chamber and can be viewed at pressure. Remote manipulation of the glass microelectrodes is achieved by a high-resolution electrically driven commercially available system. The slice is superfused continuously from a closed system within the chamber. Temperature is maintained at 37 degrees C and PO2 at 0.5 atm within the pressure chamber. A pressure of 200 ATA can be obtained, although thus far recordings have been made up to only 130 ATA. The experiments demand that a number of sample recordings be made from the same slice at both ambient and high pressure, and tests have proved that, although difficult, this can be achieved. The resting membrane potential, the current-voltage relationship, and the action potential responses to short (8 ms), medium (80 ms), and long (800 ms) depolarizing current pulses have all been measured in CA1 pyramidal neurons.

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