Excitation of rat hippocampal neurones by the stereoisomers of cis- and trans-1-amino-1,3-cyclopentane dicarboxylate

1987 ◽  
Vol 65 (11) ◽  
pp. 2196-2201 ◽  
Author(s):  
K. Curry ◽  
D. S. K. Magnuson ◽  
H. McLennan ◽  
M. J. Peet
Keyword(s):  
Membrane Potential ◽  
Action Potentials ◽  
Burst Firing ◽  
Stratum Radiatum ◽  
Side Chain ◽  
Intracellular Recordings ◽  
Dendritic Region ◽  
Cis And Trans ◽  
Rhythmic Burst ◽  
Slow Depolarization

Intracellular recordings were obtained from rat hippocampal neurones during the microiontophoretic ejection of the stereoisomers of cis- and trans-1-amino-1,3-cyclopentane dicarboxylate into the dendritic region (stratum radiatum) of the impaled cells. L-(+)-cis-1-Amino-1,3-cyclopentane dicarboxylate, D-(+)-trans-1-amino-1,3-cyclopentane dicarboxylate, and 1-(−)-trans-1-amino-1,3-cyclopentane dicarboxylate all evoked patterns of excitation resembling that elicited by kainate. All of these responses were unaffected by D-(−)-2-amino-5-phosphonovalerate but were antagonized at comparable currents by kynurenate. The excitation produced by D-(−)-cis-1-amino-1,3-cyclopentane dicarboxylate was similar to that evoked by N-methyl-D-aspartate. At low ejection currents a slow depolarization triggered rhythmic burst firing, each burst consisting of a depolarizing shift in membrane potential upon which were superimposed four to five action potentials. These responses were antagonized both by D-(−)-2-amino-5-phosphonovalerate and by kynurenate. The results are discussed with respect to the conformational requirements considered to be necessary for interaction at the kainate and N-methyl-D-aspartate receptors on CA1 pyramidal neurones. It is important to note that the isopropylene side chain of kainate is absent from the 1-amino-1-3-cyclopentane dicarboxylate molecule.

Electrical properties of neurons recorded from the rat supraoptic nucleus in vitro

1983 ◽  
Vol 217 (1207) ◽  
pp. 141-161 ◽  
Keyword(s):  
Membrane Potential ◽  
Electrical Properties ◽  
Time Constant ◽  
Synaptic Input ◽  
Action Potentials ◽  
Supraoptic Nucleus ◽  
Synaptic Activity ◽  
Intracellular Recordings ◽  
Average Cell ◽  
Spike Threshold

The electrical properties of neurons in the supraoptic nucleus (so.n.) have been studied in the hypothalamic slice preparation by intracellular and extracellular recording techniques, with Lucifer Yellow CH dye injection to mark the recording site as being the so. n. Intracellular recordings from so. n. neurons revealed them to have an average membrane potential of ─ 67±0.8 mV (mean±s. e. m.), membrane resistance of 145±9 MΩ with linear current–voltage relations from 40 mV in the hyperpolarizing direction to the level of spike threshold in the depolarizing direction. Average cell time constant was 14±2.2 ms. So. n. action potentials ranged in amplitude from 55 to 95 mV, with a mean of 76±2 mV, and a spike width of 2.6±0.5 ms at 30% of maximal spike height. Both single spikes and trains of spikes were followed by a strong, long-lasting hyperpolarization with a decay fitted by a single exponential having a time constant of 8.6±1.8 ms. Action potentials could be blocked by 10 -6 m tetrodotoxin. Spontaneously active so. n. neurons were characterized by synaptic input in the form of excitatory and inhibitory postsynaptic potentials, the latter being apparently blocked when 4 m KCI electrodes were used. Both forms of synaptic activity were blocked by application of divalent cations such as Mg 2+ , Mn 2+ or Co 2+ . 74% of so. n. neurons fired spontaneously at rates exceeding 0.1 spikes per second, with a mean for all cells of 2.9±0.2 s -1 . Of these cells, 21% fired slowly and continuously at 0.1─1.0 s -1 , 45 % fired continuously at greater than 1 Hz, and the remaining 34% fired phasically in bursts of activity followed by silence or low frequency firing. Spontaneously firing phasic cells showed a mean burst length of 16.7± 4.5 s and a silent period of 28.2±4.2 s. Intracellular recordings revealed the presence of slow variations in membrane potential which modified the neuron’s proximity to spike threshold, and controlled phasic firing. Variations in synaptic input were not observed to influence firing in phasic cells.

Disinhibition in cat motor cortex by ammonia

1975 ◽  
Vol 38 (2) ◽  
pp. 347-355 ◽  
Author(s):  
W. Raabe ◽  
R. J. Gumnit
Keyword(s):  
Membrane Potential ◽  
Motor Cortex ◽  
Action Potentials ◽  
Pyramidal Tract ◽  
Ammonium Salts ◽  
Resting Membrane Potential ◽  
Intracellular Recordings ◽  
Action Potential Generation ◽  
Potential Generation ◽  
Postsynaptic Inhibition

The effect of intravenously administered ammonium salts on postsynaptic inhibition of pyramidal tract cells was investigated in cat motor cortex. Extracellular recordings revealed that pyramidally or thalamically mediated inhibition of antidromic action potentials is abolished by ammonia. Intracellular recordings demonstrated that hyperpolarizing IPSPs vanished and EPSPs appeared while the inhibitory stimuli still triggered a decrease of neuronal resistance and the resting membrane potential was unchanged. It is concluded that ammonia disinhibited action-potential generation and EPSPs by shifting E(IPSP) to the level of the resting membrane potential. With disinhibition and facilitation replacing inhibitation of action potentials, ammonia clearly disturbs those cortical functions involving postsynaptic inhibition.

Giant cells of the dorsal cochlear nucleus of mice: intracellular recordings in slices

1993 ◽  
Vol 69 (5) ◽  
pp. 1398-1408 ◽  
Author(s):  
S. Zhang ◽  
D. Oertel
Keyword(s):  
Membrane Potential ◽  
Giant Cell ◽  
Cochlear Nucleus ◽  
Action Potentials ◽  
Deep Layer ◽  
Giant Cells ◽  
Dorsal Cochlear Nucleus ◽  
Intracellular Recordings ◽  
Nuclear Complex ◽  
Cochlear Nuclear Complex

1. In slices of the murine cochlear nuclear complex, intracellular recordings were made from five giant cells that were identified by intracellular labeling with biocytin. Giant cells form one of the two output pathways of the dorsal cochlear nucleus (DCN). Understanding how neuronal circuits and intrinsic electrical properties interact to control the firing of giant cells is a step toward understanding what acoustic information is conveyed through these cells. 2. Cell bodies of the labeled giant cells lay in the deep layer of the DCN. Dendrites, widespread both along the isofrequency axis and along the tonotopic axis, occupied mainly the deep layer, but some distal ends strayed into the molecular layer. Axons of giant cells were large, varying between 1 and 2 microns diam, and left through the dorsal acoustic stria. They were not observed to branch in the cochlear nuclei. 3. Giant cells fired large, overshooting action potentials that were followed by two afterhyperpolarizations. The first brought the membrane potential below rest, independent of the strength of injected current. The more variable second one produced either an undershoot or an inflection in the membrane potential between action potentials. 4. In each of the five labeled giant cells, shocks to the nerve root or to the anteroventral cochlear nucleus (AVCN) evoked a monosynaptic excitatory postsynaptic potential and two tandem inhibitory postsynaptic potentials (IPSPs) in the first 10 ms. Later IPSPs followed after latencies of between 10 and 50 ms. Monosynaptic excitation was usually cut short by the inhibition. 5. Strychnine, at 1 microM, blocked all IPSPs in the one giant cell tested, indicating that inhibitory input to this giant cell from circuits intrinsic to the cochlear nuclear complex was glycinergic. 6. The location of afferents was mapped for two giant cells. Both excitatory and inhibitory inputs to giant cells could be driven by the local application of glutamate to many loci in the AVCN and posteroventral cochlear nucleus, indicating that the ventral cochlear nucleus VCN contains interneurons that are monosynaptically or polysynaptically connected to giant cells. 7. An interpretation consistent with the results is that giant cells are excited by auditory nerve fibers and are inhibited by tuberculoventral cells. Giant cells may also be excited by granule or T stellate cells.

New Molecular Scaffolds for Fluorescent Voltage Indicators

2018 ◽  
Author(s):  
Steven Boggess ◽  
Shivaani Gandhi ◽  
Brian Siemons ◽  
Nathaniel Huebsch ◽  
Kevin Healy ◽  
...  
Keyword(s):  
Membrane Potential ◽  
Action Potentials ◽  
Induced Pluripotent Stem Cell ◽  
Molecular Wire ◽  
Voltage Sensing ◽  
Design Synthesis ◽  
Cardiac Action ◽  
Action Potential Waveform ◽  
Induced Pluripotent ◽  
Voltage Sensing Domain

<div> <p>The ability to non-invasively monitor membrane potential dynamics in excitable cells like neurons and cardiomyocytes promises to revolutionize our understanding of the physiology and pathology of the brain and heart. Here, we report the design, synthesis, and application of a new class of fluorescent voltage indicator that makes use of a fluorene-based molecular wire as a voltage sensing domain to provide fast and sensitive measurements of membrane potential in both mammalian neurons and human-derived cardiomyocytes. We show that the best of the new probes, fluorene VoltageFluor 2 (fVF 2) readily reports on action potentials in mammalian neurons, detects perturbations to cardiac action potential waveform in human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes, shows a substantial decrease in phototoxicity compared to existing molecular wire-based indicators, and can monitor cardiac action potentials for extended periods of time. Together, our results demonstrate the generalizability of a molecular wire approach to voltage sensing and highlights the utility of fVF 2 for interrogating membrane potential dynamics.</p> </div>

scholarly journals Intracellular recordings from gecko photoreceptors during light and dark adaptation.

1975 ◽  
Vol 66 (5) ◽  
pp. 617-648 ◽  
Author(s):  
J Kleinschmidt ◽  
J E Dowling
Keyword(s):  
Membrane Potential ◽  
Dark Adaptation ◽  
Horizontal Cell ◽  
Intracellular Recordings ◽  
Receptor Sensitivity ◽  
Intensity Curve ◽  
Voltage Range ◽  
Voltage Change ◽  
Sensitivity Change ◽  
Compression Treatment

Intracellular recordings were obtained from rods in the Gekko gekko retina and the adaptation characteristics of their responses studied during light and dark adaptation. Steady background illumination induced graded and sustained hyperpolarizing potentials and compressed the incremental voltage range of the receptor. Steady backgrounds also shifted the receptor's voltage-intensity curve along the intensity axis, and bright backgrounds lowered the saturation potential of the receptor. Increment thresholds of single receptors followed Weber's law over a range of about 3.5 log units and then saturated. Most of the receptor sensitivity change in light derived from the shift of the voltage-intensity curve, only little from the voltage compression. Treatment of the eyecup with sodium aspartate at concentrations sufficient to eliminate the beta-wave of the electroretinogram (ERG) abolished initial transients in the receptor response, possibly indicating the removal of horizontal cell feedback. Aspartate treatment, however, did not significantly alter the adaptation characteristics of receptor responses, indicating that they derive from processes intrinsic to the receptors. Dark adaptation after a strongly adapting stimulus was similarly associated with temporary elevation of membrane potential, initial lowering of the saturation potential, and shift of the voltage-intensity curve. Under all conditions of adaptation studied, small amplitude responses were linear with light intensity. Further, there was no unique relation between sensitivity and membrane potential suggesting that receptor sensitivity is controlled at least in part by a step of visual transduction preceding the generation of membrane voltage change.

Electrical interactions between the giant axons of a polychaete worm (Sabella penicillus L.)

1980 ◽  
Vol 84 (1) ◽  
pp. 119-136
Author(s):  
D. Mellon ◽  
J. E. Treherne ◽  
N. J. Lane ◽  
J. B. Harrison ◽  
C. K. Langley
Keyword(s):  
Safety Factor ◽  
Nerve Cord ◽  
Action Potentials ◽  
Divalent Cations ◽  
Muscular Contraction ◽  
The Body ◽  
The Other ◽  
Intracellular Recordings ◽  
Giant Axons ◽  
Other Hand

Intracellular recordings demonstrated a transfer of impulses between the paired giant axons of Sabella, apparently along narrow axonal processes contained within the paired commissures which link the nerve cords in each segment of the body. This transfer appears not to be achieved by chemical transmission, as has been previously supposed. This is indicated by the spread of depolarizing and hyperpolarizing voltage changes between the giant axons, the lack of effects of changes in the concentrations of external divalent cations on impulse transmission and by the effects of hyperpolarization in reducing the amplitude of the depolarizing potential which precedes the action potentials in the follower axon. The ten-to-one attenuation of electronic potentials between the giant axons argues against the possibility of an exclusively passive spread of potential along the axonal processes which link the axons. Observation of impulse traffic within the nerve cord commissures indicates, on the other hand, that transmission is achieved by conduction of action potentials along the axonal processes which link the giant axons. At least four pairs of intact commissures are necessary for inter-axonal transmission, the overall density of current injected at multiple sites on the follower axon being, it is presumed, sufficient to overcome the reduction in safety factor imposed by the geometry of the system in the region where axonal processes join the giant axons. The segmental transmission between the giant axons ensures effective synchronization of impulse traffic initiated in any region of the body and, thus, co-ordination of muscular contraction, during rapid withdrawal responses of the worm.

Intrinsic Theta-Frequency Membrane Potential Oscillations in Hippocampal CA1 Interneurons of Stratum Lacunosum-Moleculare

1999 ◽  
Vol 81 (3) ◽  
pp. 1296-1307 ◽  
Author(s):  
C. Andrew Chapman ◽  
Jean-Claude Lacaille
Keyword(s):  
Membrane Potential ◽  
Hippocampal Slices ◽  
Stratum Radiatum ◽  
Potential Oscillations ◽  
Spike Threshold ◽  
Hippocampal Ca1 ◽  
Theta Frequency ◽  
Stratum Lacunosum Moleculare ◽  
Membrane Potential Oscillations

Intrinsic theta-frequency membrane potential oscillations in hippocampal CA1 interneurons of stratum lacunosum-moleculare. The ionic conductances underlying membrane potential oscillations of hippocampal CA1 interneurons located near the border between stratum lacunosum-moleculare and stratum radiatum (LM) were investigated using whole cell current-clamp recordings in rat hippocampal slices. At 22°C, when LM cells were depolarized near spike threshold by current injection, 91% of cells displayed 2–5 Hz oscillations in membrane potential, which caused rhythmic firing. At 32°C, mean oscillation frequency increased to 7.1 Hz. Oscillations were voltage dependent and were eliminated by hyperpolarizing cells 6–10 mV below spike threshold. Blockade of ionotropic glutamate and GABA synaptic transmission did not affect oscillations, indicating that they were not synaptically driven. Oscillations were eliminated by tetrodotoxin, suggesting that Na+ currents generate the depolarizing phase of oscillations. Oscillations were not affected by blocking Ca2+ currents with Cd2+ or Ca2+-free ACSF or by blocking the hyperpolarization-activated current ( I h) with Cs+. Both Ba2+ and a low concentration of 4-aminopyridine (4-AP) reduced oscillations but TEA did not. Theta-frequency oscillations were much less common in interneurons located in stratum oriens. Intrinsic membrane potential oscillations in LM cells of the CA1 region thus involve an interplay between inward Na+ currents and outward K+ currents sensitive to Ba2+ and 4-AP. These oscillations may participate in rhythmic inhibition and synchronization of pyramidal neurons during theta activity in vivo.

scholarly journals Sub-optimal Discontinuous Current-Clamp switching rates lead to deceptive mouse neuronal firing

2020 ◽  
Author(s):  
Marin Manuel
Keyword(s):  
Membrane Potential ◽  
Neuronal Firing ◽  
Intracellular Recordings ◽  
Optimal Switching ◽  
Switching Rate ◽  
Current Clamp ◽  
Care Needs ◽  
Cell Potential ◽  
Cell Excitability

AbstractIntracellular recordings using sharp microelectrodes often rely on a technique called Discontinuous Current-Clamp to accurately record the membrane potential while injecting current through the same microelectrode. It is well known that a poor choice of DCC switching rate can lead to under-or over-estimation of the cell potential, however, its effect on the cell firing is rarely discussed. Here, we show that sub-optimal switching rates lead to an overestimation of cell excitability. We performed intracellular recordings of mouse spinal motoneurons and recorded their firing in response to pulses and ramps of current in Bridge and DCC mode at various switching rates. We demonstrate that using an incorrect (too low) DCC frequency leads not only to an underestimation of the input resistance, but also, paradoxically, to an artificial overestimation of the firing of these cells: neurons fire at lower current, and at higher frequencies than at higher DCC rates, or than the same neuron recorded in Bridge mode. These effects are dependent on the membrane time constant of the recorded cell, and special care needs to be taken in large cells with very short time constants. Our work highlights the importance of choosing an appropriate DCC switching rate to obtain not only accurate membrane potential readings but also an accurate representation of the firing of the cell.Significance StatementDiscontinuous Current-Clamp is a technique often used during intracellular recordings in vivo. However, incorrect usage of this technique can lead to incorrect interpretations. Poor choice of the DCC switching rate can lead to under- or over-estimation of the cell potential. In addition, we show here that sub-optimal switching rates lead to an overestimation of the cell excitability.

Cyclic side-chain-linked opioid analogs utilizing cis - and trans -4-aminocyclohexyl- d -alanine

2014 ◽  
Vol 22 (23) ◽  
pp. 6545-6551 ◽  
Author(s):  
Justyna Piekielna ◽  
Luca Gentilucci ◽  
Rossella De Marco ◽  
Renata Perlikowska ◽  
Anna Adamska ◽  
...  
Keyword(s):  
Side Chain ◽  
Cis And Trans
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