Intracellular recording of identified neostriatal patch and matrix spiny cells in a slice preparation preserving cortical inputs

1989 ◽  
Vol 62 (5) ◽  
pp. 1052-1068 ◽  
Author(s):  
Y. Kawaguchi ◽  
C. J. Wilson ◽  
P. C. Emson
Keyword(s):  
Time Constant ◽  
Input Resistance ◽  
Dendritic Morphology ◽  
Slice Preparation ◽  
Epsp Amplitude ◽  
Membrane Polarization ◽  
Current Pulses ◽  
Axon Collaterals ◽  
The Matrix ◽  
Medial Agranular Cortex

1. The morphology, electrical membrane properties, and corticostriatal excitatory postsynaptic potentials (EPSPs) of two groups of neostriatal projection cells, patch cells, and matrix spiny cells were compared in the rat by the use of an in vitro slice preparation that preserves inputs from medial agranular cortex. Spiny cells were stained intracellularly with biocytin and identified as belonging to the patch (striosomal) compartment or to the matrix by immunohistochemistry for the 28 kD calcium-binding protein calbindin on the same sections. 2. Patch and matrix neurons had very similar axonal and dendritic morphology. Both patch and matrix cells extended their dendrites and local axon collaterals almost exclusively in their respective compartments. Patch cells and most matrix cells had local axon collaterals within or near the parent dendritic domain. However there was a class of matrix cells that extended axon collaterals over a much wider portion of the neostriatum but still restricted to the matrix compartment. 3. Input resistance and membrane time constant were estimated from the membrane response to intracellularly applied current pulses. The average values of matrix cells were and 8.41 ms. The values of patch cells were 31.8 M omega and 8.19 ms and were within the range of those of matrix cells. Both types of cells showed the same kinds of membrane nonlinearities when tested with the use of current pulses. Input resistance and time constant were both strongly affected by a fast anomalous rectification and were thus voltage-dependent, decreasing with membrane polarization. Slow ramplike depolarizing responses were observed in response to depolarizing current steps. 4. Repetitive firing was examined with the use of depolarizing current pulses. In both types of spiny cells, trains of action potentials showed little adaptation of spike frequency and linearly increased with current intensities less than 1 nA. The slopes frequency, calculated from the first and second intervals, were 115.0 and 107.2 Hz/nA, respectively, for matrix cells and 86.0 and 82.8 Hz/nA for patch cells. 5. Stimulation of the medial agranular cortex induced EPSPs in some striatal cells in both compartments. EPSP in matrix cells often showed both short-latency and long-latency components, corresponding to two early components of the response observed in vivo. Some matrix cells, and all patch cells, showed only the longer latency EPSP component. The average latency was 6.3 ms in matrix cells and 9.1 ms in patch cells. The relationship between EPSP amplitude and membrane potential was nonlinear, with EPSP amplitude and duration increasing with decreasing membrane polarization.(ABSTRACT TRUNCATED AT 400 WORDS)

Ca2+-Activated Nonselective Cationic Current (I CAN) in Turtle Motoneurons

1999 ◽  
Vol 82 (2) ◽  
pp. 730-735 ◽  
Author(s):  
Jean-François Perrier ◽  
Jørn Hounsgaard
Keyword(s):  
Action Potentials ◽  
Input Resistance ◽  
Plateau Potentials ◽  
Slice Preparation ◽  
Metabotropic Receptors ◽  
Cationic Current ◽  
Current Pulses ◽  
Extracellular Sodium ◽  
Calcium Action Potentials ◽  
Nonselective Cationic Current

The presence of a calcium-activated nonspecific cationic (CAN) current in turtle motoneurons and its involvement in plateau potentials, bistability, and windup was investigated by intracellular recordings in a spinal cord slice preparation. In the presence of tetraethylammonium (TEA) and tetrodotoxin (TTX), calcium action potentials evoked by depolarizing current pulses were always followed by an afterdepolarization associated with a decrease in input resistance. The presence of the afterdepolarization depended on the calcium spike and not on membrane potential. Replacement of extracellular sodium by choline or N-methyl-d-glucamine (NMDG) reduced the afterdepolarization, confirming that it was mediated by a CAN current. Plateau potentials and windup were evoked in response to intracellular current pulses in the presence of agonist for different metabotropic receptors. Replacement of extracellular sodium by choline or NMDG did not abolish the generation of plateau potentials, bistability, or windup, showing that Na+ was not the principal charge carrier. It is concluded that plateau potentials, bistability and windup in turtle motoneurons do not depend on a CAN current even though its presence can be detected.

Electrotonic parameters of rat dentate granule cells measured using short current pulses and HRP staining

1983 ◽  
Vol 50 (5) ◽  
pp. 1080-1097 ◽  
Author(s):  
D. Durand ◽  
P. L. Carlen ◽  
N. Gurevich ◽  
A. Ho ◽  
H. Kunov
Keyword(s):  
Time Constant ◽  
Granule Cells ◽  
Short Pulse ◽  
Dendritic Tree ◽  
Input Resistance ◽  
Synaptic Activity ◽  
Branch Points ◽  
Pulse Technique ◽  
Current Pulses ◽  
Branching Points

The passive electrotonic parameters of nerve cells in the dentate gyrus of the rat were studied in vitro. Intracellular recordings from 30 granule cells and 3 pyramidal basket cells followed by intracellular injection of horseradish peroxidase (HRP), allowed calculations of input resistance (RN), membrane time constant (tau m), electrotonic length (L), ratio of dendritic to somatic conductance (rho), membrane specific capacitance and resistance (Rm, Cm), and specific axoplasmic resistance (Ri). The analysis of the voltage decays from long saturating (100 ms) and short (0.5 ms) current pulses showed that the short-pulse method gave better resolution for the measurement of the time constants and avoided some of the time-dependent nonlinearities but required larger currents than the long pulse. Morphological analysis of 49 branching points taken from the dendritic trees of granule cells showed that the branching power, n, is equal to 1.56 +/- 0.186 and was fairly constant throughout the tree. Given the fact that all dendrites have approximately the same length and number of branch points, the granule cell dendritic tree can be meaningfully collapsed into an equivalent cable. Moreover, electrophysiological data suggested that the cable had a "sealed" end or at least a high-impedance termination. Based on an equivalent cable model with a sealed end and a lumped soma impedance, a method was implemented to analyze the multiexponential decays from hyperpolarizing current pulses and to solve the equations of the model. This was done successfully in only 40% of the cells and yielded the following mean values for L = 1.13 and rho = 7.58. From the measurements of the soma surface area (S) and the equivalent cable diameter (D), the average specific membrane parameters were calculated: Rm = 2,726 alpha x cm2, Cm = 5.24 microF/cm2, Ri = 101 alpha x cm. The input resistance and time constant of the granule cells as measured from the short-pulse technique averaged to RN 58.57 M alpha and tau m = 16.21 ms. The failure of the model to fit 60% of the cells was interpreted to be due to the presence of a somatic shunt resulting from electrode injury, tonic synaptic activity, a lower somatic membrane specific resistance, or electronic coupling.(ABSTRACT TRUNCATED AT 400 WORDS)

Calcium-dependent potassium conductance in rat supraoptic nucleus neurosecretory neurons

1985 ◽  
Vol 54 (6) ◽  
pp. 1375-1382 ◽  
Author(s):  
C. W. Bourque ◽  
J. C. Randle ◽  
L. P. Renaud
Keyword(s):  
Time Constant ◽  
Action Potentials ◽  
Supraoptic Nucleus ◽  
Potassium Conductance ◽  
Reversal Potential ◽  
Input Resistance ◽  
Mean Amplitude ◽  
Progressive Increase ◽  
Calcium Dependent ◽  
Neurosecretory Neurons

Intracellular recordings of rat supraoptic nucleus neurons were obtained from perfused hypothalamic explants. Individual action potentials were followed by hyperpolarizing afterpotentials (HAPs) having a mean amplitude of -7.4 +/- 0.8 mV (SD). The decay of the HAP was approximated by a single exponential function having a mean time constant of 17.5 +/- 6.1 ms. This considerably exceeded the cell time constant of the same neurons (9.5 +/- 0.8 ms), thus indicating that the ionic conductance underlying the HAP persisted briefly after each spike. The HAP had a reversal potential of -85 mV and was unaffected by intracellular Cl- ionophoresis of during exposure to elevated extracellular concentrations of Mg2+. In contrast, the peak amplitude of the HAP was proportional to the extracellular Ca2+ concentration and could be reversibly eliminated by replacing Ca2+ with Co2+, Mn2+, or EGTA in the perfusion fluid. During depolarizing current pulses, evoked action potential trains demonstrated a progressive increase in interspike intervals associated with a potentiation of successive HAPs. This spike frequency adaptation was reversibly abolished by replacing Ca2+ with Co2+, Mn2+, or EGTA. Bursts of action potentials were followed by a more prolonged afterhyperpolarization (AHP) whose magnitude was proportional to the number of impulses elicited (greater than 20 Hz) during a burst. Current injection revealed that the AHP was associated with a 20-60% decrease in input resistance and showed little voltage dependence in the range of -70 to -120 mV. The reversal potential of the AHP shifted with the extracellular concentration of K+ [( K+]o) with a mean slope of -50 mV/log[K+]o.(ABSTRACT TRUNCATED AT 250 WORDS)

The Electrical Properties of a Crustacean Sensory Dendrite

1979 ◽  
Vol 78 (1) ◽  
pp. 1-27
Author(s):  
MAURIZIO MIROLLI
Keyword(s):  
Time Course ◽  
Short Circuit ◽  
Input Resistance ◽  
Scylla Serrata ◽  
Current Pulses ◽  
Length Constant ◽  
Voltage Transient ◽  
Intracellular Microelectrodes ◽  
Voltage Transients ◽  
Sensory Endings

1. The input properties and the response to stretch of a coxal receptor, the S fibre of the crab Scylla serrata, were studied using two and three intracellular microelectrodes. 2. In the relaxed receptor the transmembrane potential ranged from about −60 to −70 mV, and the input resistance, RT, from 1 to 3 MΩ. The input IV relationship, studied by injecting slow-rising current ramps, was not linear either in the hyperpolarizing or in the depolarizing quadrants. 3. Low values of RT and a linear IV relationship were associated with a large leakage of the microelectrodes. 4. The response to step stretches was complex, consisting of an initial depolarizing transient, Vα, and a steady-state depolarizing plateau, V8. Both Vα and V8 propagated with decrement in the fibre which was about 9 mm long. The spatial decrement of Vα and V8 was equal to that of the response to distally injected current pulses of comparable duration and amplitude. 5. On the basis of the spatial decrement of both Vα and V8 the dendrite can be considered equivalent, for current flowing from its distal to its proximal end, to a semi-infinite cable having a length constant of between 4 and 6 cm. 6. The voltage transients recorded in response to long current pulses reached 84% of their final value in a time (t84%) ranging from 150 to 180 ms in fibres in which RT was 2 Mω or larger. t84% was smaller in fibres having a lower RT. 7. The time course of the transients recorded in response to injected current pulses deviated from the semi-infinite cable model in a manner suggesting the presence of a partial short circuit. For this reason the membrane time constant of the fibre is considered larger (by an undetermined amount) than t84%. 8. The fibre presented less resistance to current flowing from its proximal to its distal end than to current flowing in the opposite direction. For this reason, and also because of the time course of the voltage transient, it is concluded that the distal sensory endings of the fibre have the properties of a leaky end termination, even in the non-stimulated receptors.

Voltage behavior along the irregular dendritic structure of morphologically and physiologically characterized vagal motoneurons in the guinea pig

1990 ◽  
Vol 63 (2) ◽  
pp. 333-346 ◽  
Author(s):  
R. Nitzan ◽  
I. Segev ◽  
Y. Yarom
Keyword(s):  
Steady State ◽  
Guinea Pig ◽  
Time Constant ◽  
Dendritic Structure ◽  
Input Resistance ◽  
Membrane Properties ◽  
Small Cells ◽  
Physiological Data ◽  
Motor Nucleus ◽  
Cable Length

1. Intracellular recordings from neurons in the dorsal motor nucleus of the vagus (vagal motoneurons, VMs) obtained in the guinea pig brain stem slice preparation were used for both horseradish peroxidase (HRP) labeling of the neurons and for measurements of their input resistance (RN) and time constant (tau 0). Based on the physiological data and on the morphological reconstruction of the labeled cells, detailed steady-state and compartmental models of VM were built and utilized to estimate the range of membrane resistivity, membrane capacitance, and cytoplasm resistivity values (Rm, Cm, and Ri, respectively) and to explore the integrative properties of these cells. 2. VMs are relatively small cells with a simple dendritic structure. Each cell has an average of 5.3 smooth (nonspiny), short (251 microns) dendrites with a low order (2) of branching. The average soma-dendritic surface area of VMs is 9,876 microns 2. 3. Electrically, VMs show remarkably linear membrane properties in the hyperpolarizing direction; they have an average RN of 67 +/- 23 (SD) M omega and a tau 0 of 9.4 +/- 4.1 ms. Several unfavorable experimental conditions precluded the possibility of faithfully recovering ("peeling") the first equalizing time constant (tau 1) and, thereby, of estimating the electrotonic length (Lpeel) of VMs. 4. Reconciling VM morphology with the measured RN and tau 0 through the models, assuming an Ri of 70 omega.cm and a spatially uniform Rm, yielded an Rm estimate of 5,250 omega.cm2 and a Cm of 1.8 microF/cm2. Peeling theoretical transients produced by these models result in an Lpeel of 1.35. Because of marked differences in the length of dendrites within a single cell, this value is larger than the maximal cable length of the dendrites and is twice as long as their average cable length. 5. The morphological and physiological data could be matched indistinguishably well if a possible soma shunt (i.e., Rm, soma less than Rm, dend) was included in the model. Although there is no unique solution for the exact model Rm, a general conclusion regarding the integrative capabilities of VM could be drawn. As long as the model is consistent with the experimental data, the average input resistance at the dendritic terminals (RT) and the steady-state central (AFT----S) and peripheral (AFS----T) attenuation factors are essentially the same in the different models. With Ri = 70 omega.cm, we calculated RT, AFS----T, and AFT----S to be, on the average, 580 M omega, 1.1, and 13, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Input Resistance, Time Constants, and Spike Initiation

1998 ◽  
Author(s):  
Christof Koch
Keyword(s):  
Membrane Potential ◽  
Time Constant ◽  
Action Potentials ◽  
Input Resistance ◽  
Current Injection ◽  
Membrane Conductances ◽  
Voltage Dependent ◽  
Dc Component ◽  
Definition Of ◽  
A Current

This chapter represents somewhat of a tephnical interlude. Having introduced the reader to both simplified and more complex compartmental single neuron models, we need to revisit terrain with which we are already somewhat familiar. In the following pages we reevaluate two important concepts we defined in the first few chapters: the somatic input resistance and the neuronal time constant. For passive systems, both are simple enough variables: Rin is the change in somatic membrane potential in response to a small sustained current injection divided by the amplitude of the current injection, while τm is the slowest time constant associated with the exponential charging or discharging of the neuronal membrane in response to a current pulse or step. However, because neurons express nonstationary and nonlinear membrane conductances, the measurement and interpretation of these two variables in active structures is not as straightforward as before. Having obtained a more sophisticated understanding of these issues, we will turn toward the question of the existence of a current, voltage, or charge threshold at which a biophysical faithful model of a cell triggers action potentials. We conclude with recent work that suggests how concepts from the subthreshold domain, like the input resistance or the average membrane potential, could be extended to the case in which the cell is discharging a stream of action potentials. This chapter is mainly for the cognoscendi or for those of us that need to make sense of experimental data by comparing therp to theoretical models that usually fail to reflect reality adequately. In Sec. 3.4, we defined Kii (f) for passive cable structures as the voltage change at location i in response to a sinusoidal current injection of frequency f at the same location. Its dc component is also referred to as input resistance or Rin. Three difficulties render this definition of input resistance problematic in real cells: (1) most membranes, in particular at the soma, show voltage-dependent nonlinearities, (2) the associated ionic membrane conductances are time dependent and (3) instrumental aspects, such as the effect of the impedance of the recording electrode on Rin, add uncertainty to the measuring process.

Electronic structure of motoneurons in spinal cord slice cultures: a comparison of compartmental and equivalent cylinder models

1994 ◽  
Vol 72 (2) ◽  
pp. 861-871 ◽  
Author(s):  
D. Ulrich ◽  
R. Quadroni ◽  
H. R. Luscher
Keyword(s):  
Spinal Cord ◽  
Surface Area ◽  
Voltage Clamp ◽  
Time Constant ◽  
Membrane Surface ◽  
Input Resistance ◽  
Dendritic Trees ◽  
Membrane Surface Area ◽  
The Mean ◽  
Total Membrane

1. Voltage-clamp, current-clamp, and morphological data were obtained from visually identified motoneurons in organotypic cocultures of rat embryonic spinal cord, dorsal root ganglia, and skeletal muscle. The cells were injected with Biocytin during whole-cell patch-clamp recordings and stained with horseradish peroxidase. 2. The somata and dendritic trees of the cells were reconstructed with a semiautomatic reconstruction system. The motoneurons had a common multipolar shape. An elliptic soma gave rise to 3-9 stem dendrites with a mean diameter of 2.5 +/- 0.9 (SD) micron terminating in 24 +/- 7 dendritic endings. The mean total dendritic path length was 3,306 +/- 1,075 microns. The mean total membrane surface area was 15,594 +/- 10,404 microns 2 with a dendritic to somatic membrane surface area ratio of 3.4 +/- 1.4 (n = 7 cells). 3. The ratio between the sum of the diameters of the two daughter branches and the diameter of the parental branch each raised to the 3/2 power at all branch points was 1.3 +/- 0.28 (n = 8 cells). The dendritic trees of the cells tapered continuously from the soma to the distal ends. The mean normalized dendritic trunk parameter of all cells was 0.62 +/- 0.22. 4. The motoneurons had a mean input resistance RN of 498 +/- 374 M delta, a mean membrane time constant (tau m) of 22 +/- 4.6 ms, and a mean dendritic dominance (rho) of 2.7 +/- 0.86 (n = 5 cells). The mean electronic length (L) calculated from tau m and the slowest voltage-clamp time constant (tau VC1) was 0.7 +/- 0.04 (n = 7 cells). 5. The specific membrane capacitance (Cm) estimated from the charge of the capacitive current during a voltage step and the total membrane surface area was 1.08 +/- 0.3 microF/cm2 (n = 6 cells). 6. Compartmental computer models were constructed of individual cells. Experimental and simulated voltage transients were matched with Cm = 1 microF/cm2, a uniform membrane resistivity (Rm) = tau m/Cm and a cytosolic resistivity (Ri) of 308 +/- 39 omega.cm (n = 3 cells). 7. The mean electrotonic length of the dendritic paths was 0.83 +/- 0.2 (n = 5 cells). The mean input resistance at the dendritic terminals (RT) was 1,413 +/- 260 M omega. Synaptic conductances were applied at all distal dendritic compartments of the model cells. The resulting synaptic currents were calculated at the input site and at the soma. The mean transient current attenuation ratio was 4.7 +/- 1.7 under idealized voltage-clamp conditions.(ABSTRACT TRUNCATED AT 400 WORDS)

Enhancement of Whole Cell Synaptic Currents by Low Osmolarity and by Low [NaCl] in Rat Hippocampal Slices

1997 ◽  
Vol 77 (5) ◽  
pp. 2349-2359 ◽  
Author(s):  
Rong Huang ◽  
Daniel F. Bossut ◽  
George G. Somjen
Keyword(s):  
Synaptic Transmission ◽  
Time Constant ◽  
Hippocampal Slices ◽  
Input Resistance ◽  
Tissue Slices ◽  
Synaptic Currents ◽  
Whole Cell ◽  
Input Capacitance ◽  
Postsynaptic Currents ◽  
Inward Currents

Huang, Rong, Daniel F. Bossut, and George G. Somjen. Enhancement of whole cell synaptic currents by low osmolarity and by low [NaCl] in rat hippocampal slices. J. Neurophysiol. 77: 2349–2359, 1997. We recorded whole cell currents of patch-clamped neurons in stratum pyramidale of CA1 region of rat hippocampal tissue slices. Synaptic currents were evoked by orthodromic stimulation while holding potential of the neuron was varied from hyperpolarized to depolarized levels. Extracellular osmolarity (πo) was lowered by superfusion with artificial cerebrospinal fluid in which NaCl concentration ([NaCl]) was reduced. The effect of low extracellular NaCl was tested in additional trials in which NaCl was substituted by isosmolar fructose. Both lowering of πo and isosmotic lowering of extracellular [NaCl] ([NaCl]o) caused reversible increase of excitatory postsynaptic currents. The effect of lowering πo was concentration dependent, and it was significantly stronger than the effect of equivalent isosmotic lowering of [NaCl]o. Inhibitory postsynaptic currents also increased in many but not in all cases. Lowering of πo caused a prolongation of the time constant of relaxation of the capacitive charging current induced by small hyperpolarizing voltage steps. A virtual input capacitance, calculated by dividing this time constant by the input resistance, increased during hypotonic exposure. Isosmotic lowering of [NaCl]o had no effect on time constant or input capacitance. Depolarizing voltage commands evoked spikelike inward currents presumably representing Na+-dependent action potentials generated outside the voltage-clamped region of the cell. These current spikes became smaller in low πo and in low [NaCl]o. Broader, voltage-dependent, presumably Ca2+-mediated inward currents became more prominent during hypotonic exposure. We conclude that lowering of [NaCl]o causes enhancement of excitatory synaptic transmission. Transmission may be facilitated by the uptake of Ca2+ into presynaptic terminals as well as into postsynaptic target neurons, induced by the low [NaCl]o. Lowering of πo enhances synaptic transmission more than does a corresponding isosmotic lowering of [NaCl]. The excess increase recorded from the cell soma in low πo may in part be due to changing electrotonic length caused by the swelling of dendrites.

Monosynaptic EPSPs in primate lumbar motoneurons

1993 ◽  
Vol 70 (4) ◽  
pp. 1585-1592 ◽  
Author(s):  
J. S. Carp
Keyword(s):  
Input Resistance ◽  
Triceps Surae ◽  
Medial Gastrocnemius ◽  
Macaca Nemestrina ◽  
Synaptic Connectivity ◽  
Lateral Gastrocnemius ◽  
Mean Values ◽  
Epsp Amplitude ◽  
The Mean ◽  
Stimulation Of

1. Homonymous and heteronymous monosynaptic composite excitatory postsynaptic potentials (EPSPs) were evaluated by intracellular recordings from 89 motoneurons innervating triceps surae (n = 59) and more distal (n = 30) muscles in 14 pentobarbital-anesthetized monkeys (Macaca nemestrina). 2. Homonymous EPSPs were found in all motoneurons tested. The mean values +/- SD for maximum EPSP amplitude of triceps surae motoneurons were 2.5 +/- 1.3, 1.8 +/- 1.3 and 4.5 +/- 2.0 mV for medial gastrocnemius, lateral gastrocnemius, and soleus motoneurons, respectively. Heteronymous EPSPs were almost always smaller than their corresponding homonymous EPSPs. 3. Triceps surae EPSP amplitude was larger in motoneurons with higher input resistance. However, this relationship was weak, suggesting that factors related to input resistance play a limited role in determining the magnitude of the EPSP. 4. The mean ratio +/- SD of the amplitude of the EPSP elicited by combined stimulation of all triceps surae nerves to the amplitude of the algebraic sum of the three individual EPSPs was 0.95 +/- 0.05. This ratio was greater in motoneurons with lower rheobase. 5. Some patterns of synaptic connectivity in the macaque are consistent with previously reported differences between primates and cat (e.g., heteronymous EPSPs elicited by medial gastrocnemius nerve stimulation in soleus motoneurons are small in macaque and other primates but large in cat). However, no overall pattern emerges from a comparison of the similarities and differences in EPSPs among species in which they have been studied (i.e., macaque, baboon, and cat). That is, there are no two species in which EPSP properties are consistently similar to each other, but different from those of the third species.(ABSTRACT TRUNCATED AT 250 WORDS)

Sign in / Sign up

Export Citation Format

Share Document