scholarly journals Functional subgroups of rat and human sensory neurons: a systematic review of electrophysiological properties

2022 ◽  
Author(s):  
Jannis Körner ◽  
Angelika Lampert
Keyword(s):  
Systematic Review ◽  
Action Potential ◽  
Sensory Neurons ◽  
Input Resistance ◽  
Immune Reactivity ◽  
Electrophysiological Properties ◽  
Electrophysiological Data ◽  
Electrophysiological Studies ◽  
Dorsal Root Ganglia Neurons ◽  
Definition Of

AbstractSensory neurons are responsible for the generation and transmission of nociceptive signals from the periphery to the central nervous system. They encompass a broadly heterogeneous population of highly specialized neurons. The understanding of the molecular choreography of individual subpopulations is essential to understand physiological and pathological pain states. Recently, it became evident that species differences limit transferability of research findings between human and rodents in pain research. Thus, it is necessary to systematically compare and categorize the electrophysiological data gained from human and rodent dorsal root ganglia neurons (DRGs). In this systematic review, we condense the available electrophysiological data defining subidentities in human and rat DRGs. A systematic search on PUBMED yielded 30 studies on rat and 3 studies on human sensory neurons. Defined outcome parameters included current clamp, voltage clamp, cell morphology, pharmacological readouts, and immune reactivity parameters. We compare evidence gathered for outcome markers to define subgroups, offer electrophysiological parameters for the definition of neuronal subtypes, and give a framework for the transferability of electrophysiological findings between species. A semiquantitative analysis revealed that for rat DRGs, there is an overarching consensus between studies that C-fiber linked sensory neurons display a lower action potential threshold, higher input resistance, a larger action potential overshoot, and a longer afterhyperpolarization duration compared to other sensory neurons. They are also more likely to display an infliction point in the falling phase of the action potential. This systematic review points out the need of more electrophysiological studies on human sensory neurons.

Basic electrophysiological properties of spinal cord motoneurons during old age in the cat

1987 ◽  
Vol 58 (1) ◽  
pp. 180-194 ◽  
Author(s):  
F. R. Morales ◽  
P. A. Boxer ◽  
S. J. Fung ◽  
M. H. Chase
Keyword(s):  
Spinal Cord ◽  
Membrane Potential ◽  
Action Potential ◽  
Old Age ◽  
Conduction Velocity ◽  
Input Resistance ◽  
Action Potential Amplitude ◽  
Electrophysiological Properties ◽  
Potential Amplitude ◽  
Versus Input

1. The electrophysiological properties of alpha-motoneurons in old cats (14–15 yr) were compared with those of adult cats (1–3 yr). These properties were measured utilizing intracellular recording and stimulating techniques. 2. Unaltered in the old cat motoneurons were the membrane potential, action potential amplitude, and slopes of the initial segment (IS) and soma dendritic (SD) spikes, as well as the duration and amplitude of the action potential's afterhyperpolarization. 3. In contrast, the following changes in the electrophysiological properties of lumbar motoneurons were found in the old cats: a decrease in axonal conduction velocity, a shortening of the IS-SD delay, an increase in input resistance, and a decrease in rheobase. 4. In spite of these considerable changes in motoneuron properties in the old cat, normal correlations between different electrophysiological properties were maintained. The following key relationships, among others, were the same in adult and old cat motoneurons: membrane potential polarization versus action potential amplitude, duration of the afterhyperpolarization versus motor axon conduction velocity, and rheobase versus input conductance. 5. A review of the existing literature reveals that neither chronic spinal cord section nor deafferentation (13, 21) in adult animals produce the changes observed in old cats. Thus we consider it unlikely that a loss of synaptic contacts was responsible for the modifications in electrophysiological properties observed in old cat motoneurons. 6. We conclude that during old age there are significant changes in the soma-dendritic portion of cat motoneurons, as indicated by the modifications found in input resistance, rheobase, and IS-SD delay, as well as significant changes in their axons, as indicated by a decrease in conduction velocity.

scholarly journals Melatonin Reduces Excitability in Dorsal Root Ganglia Neurons with Inflection on the Repolarization Phase of the Action Potential

2019 ◽  
Vol 20 (11) ◽  
pp. 2611 ◽  
Author(s):  
Klausen Oliveira-Abreu ◽  
Nathalia Silva-dos-Santos ◽  
Andrelina Coelho-de-Souza ◽  
Francisco Ferreira-da-Silva ◽  
Kerly Silva-Alves ◽  
...  
Keyword(s):  
Action Potential ◽  
Dorsal Root Ganglia ◽  
Dorsal Root ◽  
Neuronal Excitability ◽  
Input Resistance ◽  
Cell Types ◽  
Neuronal Population ◽  
Resting Membrane Potential ◽  
Electrophysiological Properties ◽  
Repolarization Phase

Melatonin is a neurohormone produced and secreted at night by pineal gland. Many effects of melatonin have already been described, for example: Activation of potassium channels in the suprachiasmatic nucleus and inhibition of excitability of a sub-population of neurons of the dorsal root ganglia (DRG). The DRG is described as a structure with several neuronal populations. One classification, based on the repolarizing phase of the action potential (AP), divides DRG neurons into two types: Without (N0) and with (Ninf) inflection on the repolarization phase of the action potential. We have previously demonstrated that melatonin inhibits excitability in N0 neurons, and in the present work, we aimed to investigate the melatonin effects on the other neurons (Ninf) of the DRG neuronal population. This investigation was done using sharp microelectrode technique in the current clamp mode. Melatonin (0.01–1000.0 nM) showed inhibitory activity on neuronal excitability, which can be observed by the blockade of the AP and by the increase in rheobase. However, we observed that, while some neurons were sensitive to melatonin effect on excitability (excitability melatonin sensitive—EMS), other neurons were not sensitive to melatonin effect on excitability (excitability melatonin not sensitive—EMNS). Concerning the passive electrophysiological properties of the neurons, melatonin caused a hyperpolarization of the resting membrane potential in both cell types. Regarding the input resistance (Rin), melatonin did not change this parameter in the EMS cells, but increased its values in the EMNS cells. Melatonin also altered several AP parameters in EMS cells, the most conspicuously changed was the (dV/dt)max of AP depolarization, which is in coherence with melatonin effects on excitability. Otherwise, in EMNS cells, melatonin (0.1–1000.0 nM) induced no alteration of (dV/dt)max of AP depolarization. Thus, taking these data together, and the data of previous publication on melatonin effect on N0 neurons shows that this substance has a greater pharmacological potency on Ninf neurons. We suggest that melatonin has important physiological function related to Ninf neurons and this is likely to bear a potential relevant therapeutic use, since Ninf neurons are related to nociception.

scholarly journals Effect of Formaldehyde and Glutaraldehyde on Electrical Properties of Cardiac Purkinje Fibers

1969 ◽  
Vol 53 (5) ◽  
pp. 530-540 ◽  
Author(s):  
H. A. Fozzard ◽  
G. Dominguez
Keyword(s):  
Action Potential ◽  
Negative Charge ◽  
Input Resistance ◽  
Membrane Resistance ◽  
Rapid Loss ◽  
Purkinje Fibers ◽  
Electrophysiological Properties ◽  
Cardiac Purkinje Fibers ◽  
Length Constant ◽  
Upstroke Velocity

The effects of formaldehyde, glutaraldehyde, 1-fluoro-2,4-dinitrobenzene, and 1,5-difluoro-2,4-dinitrobenzene on the electrophysiological properties of cardiac Purkinje fibers were studied. At concentrations of 2.5 mM the aldehydes produced a transient hyperpolarization, lengthening of the plateau of the action potential, and an increase in action potential overshoot and upstroke velocity. If exposure to aldehyde was continued, the fiber failed to repolarize after an action potential and the membrane potential stabilized at about -30 mv. If exposure was terminated before this, recovery was usually complete. At the time the fibers were hyperpolarized the input resistance was increased without much change in length constant, leading to an increase in both calculated membrane resistance and calculated core resistance. Although it was anticipated that an effect of the aldehydes on the membrane was to increase fixed negative charge, it was difficult to explain all the electrophysiological changes on this basis. The major effects of the fluorobenzene compounds were not the same; they produced a shortening of the action potential and a rapid loss of excitability.

Sciatic Chronic Constriction Injury Produces Cell-Type-Specific Changes in the Electrophysiological Properties of Rat Substantia Gelatinosa Neurons

2006 ◽  
Vol 96 (2) ◽  
pp. 579-590 ◽  
Author(s):  
Sridhar Balasubramanyan ◽  
Patrick L. Stemkowski ◽  
Martin J. Stebbing ◽  
Peter A. Smith
Keyword(s):  
Action Potential ◽  
Dorsal Horn ◽  
Chronic Constriction Injury ◽  
Input Resistance ◽  
Substantia Gelatinosa ◽  
Resting Membrane Potential ◽  
Cellular Mechanisms ◽  
Electrophysiological Properties ◽  
Putative Role ◽  
Cell Recording

Peripheral nerve injury increases spontaneous action potential discharge in spinal dorsal horn neurons and augments their response to peripheral stimulation. This “central hypersensitivity, ” which relates to the onset and persistence of neuropathic pain, reflects spontaneous activity in primary afferent fibers as well as long-term changes in the intrinsic properties of the dorsal horn (centralization). To isolate and investigate cellular mechanisms underlying “centralization,” sciatic nerves of 20-day-old rats were subjected to 13–25 days of chronic constriction injury (CCI; Mosconi-Kruger polyethylene cuff model). Spinal cord slices were then acutely prepared from sham-operated or CCI animals, and whole cell recording was used to compare the properties of five types of substantia gelatinosa neuron. These were defined as tonic, irregular, phasic, transient, or delay according to their discharge pattern in response to depolarizing current. CCI did not affect resting membrane potential, rheobase, or input resistance in any neuron type but increased the amplitude and frequency of spontaneous and miniature excitatory postsynaptic currents (EPSCs) in delay, transient, and irregular cells. These changes involved alterations in the action potential-independent neurotransmitter release machinery and possible increases in the postsynaptic effectiveness of glutamate. By contrast, in tonic cells, CCI reduced the amplitude and frequency of spontaneous and miniature EPSCs. Such changes may relate to the putative role of tonic cells as inhibitory GABAergic interneurons, whereas increased synaptic drive to delay cells may relate to their putative role as the excitatory output neurons of the substantia gelatinosa. Complementary changes in synaptic excitation of inhibitory and excitatory neurons may thus contribute to pain centralization.

Changes in the electrophysiological properties of cat spinal motoneurons following the intramuscular injection of adriamycin compared with changes in the properties of motoneurons in aged cats

1995 ◽  
Vol 74 (5) ◽  
pp. 1972-1981 ◽  
Author(s):  
R. H. Liu ◽  
J. Yamuy ◽  
M. C. Xi ◽  
F. R. Morales ◽  
M. H. Chase
Keyword(s):  
Electrical Properties ◽  
Action Potential ◽  
Conduction Velocity ◽  
Time Constant ◽  
Correlation Coefficients ◽  
Input Resistance ◽  
Resting Membrane Potential ◽  
Electrophysiological Properties ◽  
Axonal Conduction ◽  
Adult Cat

1. This study was undertaken to investigate the effects of adriamycin (ADM, Doxorubicin) on the basic electrophysiological properties of spinal cord motoneurons in the adult cat. ADM was injected into the biceps, gastrocnemius, semitendinosus, and semimembranosus muscles of the left hindlimb (1.2 mg per muscle). Intracellular recordings from motoneurons innervating these muscles were carried out 12, 20, or 40 days after ADM administration and from corresponding motoneurons in untreated control cats. 2. Twelve days after ADM injection, motoneurons innervating ADM-treated muscles (ADM MNs) exhibited statistically significant increases in input resistance, membrane time constant, and amplitude of the action potential's afterhyperpolarization (AHP). In addition, there was a statistically significant decrease in rheobase and in the delay between the action potential of the initial segment (IS) and that of the somadendritic (SD) portion of the motoneuron (IS-SD delay). There were no significant changes in the resting membrane potential, threshold depolarization, action potential amplitude, or axonal conduction velocity. 3. The changes in electrical properties of motoneurons at 20 and 40 days after ADM injection were qualitatively similar to those observed at 12 days. However, at 40 days after ADM injection there was a statistically significant decrease in the axonal conduction velocity of the ADM MNs. 4. The normal correlations that are present between the AHP duration and electrical properties of the control motoneurons were observed in the ADM MNs, e.g., AHP duration was positively correlated with the input resistance and time constant and negatively correlated with the axonal conduction velocity. The correlation coefficients, however, were reduced in comparison with the control data. 5. This study demonstrates that ADM exerts significant effects on the electrical properties of motoneurons when injected into their target muscles. The majority of the changes in motoneuron electrical properties caused by ADM resemble those observed in motoneurons of aged cats. Additional research is required to determine whether the specific changes induced in motoneurons by ADM and those that occur in motoneurons in old age are due to similar degradative mechanisms.

Intracellular recordings from morphologically identified neurons of the basolateral amygdala

1993 ◽  
Vol 69 (4) ◽  
pp. 1350-1362 ◽  
Author(s):  
D. G. Rainnie ◽  
E. K. Asprodini ◽  
P. Shinnick-Gallagher
Keyword(s):  
Action Potential ◽  
Time Constant ◽  
Firing Pattern ◽  
Pyramidal Neurons ◽  
Input Resistance ◽  
Class Ii ◽  
Class I ◽  
Sectional Area ◽  
Cross Sectional ◽  
Electrophysiological Properties

1. Intracellular current-clamp recordings were made from neurons of the basolateral nucleus of the amygdala (BLA) of the rat in the in vitro slice preparation. Neurons were identified morphologically after intracellular injection of biocytin, and the electrophysiological properties and morphological characteristics were correlated. 2. Three distinct morphological subtypes were identified: Class I pyramidal neurons, Class I stellate neurons, and Class II neurons. Each morphological subtype could also be distinguished according to its characteristic electrophysiological properties. 3. Class I pyramidal neurons typically had pyramidal perikarya (cross-sectional area = 245 microns2) with spine-laden apical and basal dendrites. The axon originated from the largest basal dendrite and produced several collaterals that ramified throughout the dendritic arborization of the parent cell. These neurons were characterized electrophysiologically by their higher input resistance (65.6 M omega), long time constant of membrane charging tau 0 (27.8 ms), long duration action potential (half-width = 0.85 ms), and regular firing pattern [1st interspike interval ISI) = 91 ms]. 4. Class I stellate neurons differed morphologically from Class I pyramidal neurons only in the size (cross sectional area = 330 microns 2) and stellate appearance of their perikarya. These neurons had characteristic lower input resistance (40.1 M omega), shorter time constant of membrane charging tau 0 (14.5 ms), shorter duration action potential (half-width = 0.7 ms), and a burst firing pattern (1st ISI = 6.0 ms), all of which were statistically different from Class I pyramidal neurons. 5. Class II neurons were multipolar (cross sectional area = 235 microns 2) and were distinguishable from Class I neurons by the almost complete absence of dendritic spines. Class II neurons were characterized electrophysiologically by a midrange input resistance (58 M omega), intermediate time constant of membrane charging tau 0 (19 ms), intermediate action-potential duration (half-width = 0.77 ms), and a burst firing pattern (1st ISI = 6.0 ms). In contrast to Class I neurons, action-potential firing of Class II neurons did not accommodate in response to prolonged depolarizing current injection. 6. In conclusion, BLA neurons may be characterized by their specific electrophysiological properties as well as by their morphological traits. Therefore, permitting assessment of signal transduction in identified populations of neurons within this nucleus.

scholarly journals Changes in Membrane Properties of Chick Embryonic Hearts during Development

1972 ◽  
Vol 60 (4) ◽  
pp. 430-453 ◽  
Author(s):  
Nick Sperelakis ◽  
K. Shigenobu
Keyword(s):  
Action Potential ◽  
Input Resistance ◽  
Membrane Properties ◽  
Resting Potential ◽  
Lower Sensitivity ◽  
Na Channels ◽  
Electrophysiological Properties ◽  
Ventricular Cells ◽  
High K ◽  
Pacemaker Potentials

The electrophysiological properties of embryonic chick hearts (ventricles) change during development; the largest changes occur between days 2 and 8. Resting potential (Em) and peak overshoot potential (+Emax) increase, respectively, from -35 mv and +11 mv at day 2 to -70 mv and +28 mv at days 12–21. Action potential duration does not change significantly. Maximum rate of rise of the action potential (+Vmax) increases from about 20 v/sec at days 2–3 to 150 v/sec at days 18–21; + Vmax of young cells is not greatly increased by applied hyperpolarizing current pulses. In resting Em vs. log [K+]o curves, the slope at high K+ is lower in young hearts (e.g. 30 mv/decade) than the 50–60 mv/decade obtained in old hearts, but the extrapolated [K+]i values (125–140 mM) are almost as high. Input resistance is much higher in young hearts (13 MΩ at day 2 vs. 4.5 MΩ at days 8–21), suggesting that the membrane resistivity (Rm) is higher. The ratio of permeabilities, PNa/PK, is high (about 0.2) in young hearts, due to a low PK, and decreases during ontogeny (to about 0.05). The low K+ conductance (gK) in young hearts accounts for the greater incidence of hyperpolarizing afterpotentials and pacemaker potentials, the lower sensitivity (with respect to loss of excitability) to elevation of [K+]o, and the higher chronaxie. Acetylcholine does not increase gK of young or old ventricular cells. The increase in (Na+, K+)-adenosine triphosphatase (ATPase) activity during development tends to compensate for the increase in gK. +Emax and + Vmax are dependent on [Na+]o in both young and old hearts. However, the Na+ channels in young hearts (2–4 days) are slow, tetrodotoxin (TTX)-insensitive, and activated-inactivated at lower Em. In contrast, the Na+ channels of cells in older hearts (> 8 days) are fast and TTX-sensitive, but they revert back to slow channels when placed in culture.

TNBS ileitis evokes hyperexcitability and changes in ionic membrane properties of nociceptive DRG neurons

2002 ◽  
Vol 282 (6) ◽  
pp. G1045-G1051 ◽  
Author(s):  
Beverley A. Moore ◽  
Timothy M. R. Stewart ◽  
Ceredwyn Hill ◽  
Stephen J. Vanner
Keyword(s):  
Action Potential ◽  
Intestinal Inflammation ◽  
Input Resistance ◽  
Membrane Properties ◽  
Resting Membrane Potential ◽  
Cell Diameter ◽  
Trinitrobenzene Sulfonic Acid ◽  
Drg Neurons ◽  
Nociceptive Neurons ◽  
Electrophysiological Properties

This study examines whether intestinal inflammation leads to changes in the properties of ion channels in dorsal root ganglia (DRG) neurons. Ileitis was induced by injection of trinitrobenzene sulfonic acid (TNBS), and DRG neurons innervating the ileum were labeled using fast blue. Intracellular recording techniques were used to measure electrophysiological properties of acutely dissociated neurons 12–24 h after dissection. Nociceptive neurons were identified by sensitivity to capsaicin, tetrodotoxin resistance, and size (<30 μm). The action potential threshold in neurons from TNBS-treated animals was reduced by >70% compared with controls ( P < 0.001), but the resting membrane potential was unchanged. Cell diameter, input resistance (67%), and action potential upstroke velocity (22%) increased in the TNBS group ( P < 0.05). The number of action potentials discharged increased in the TNBS group ( P < 0.001), whereas application of 4-aminopyridine to control cells mimicked this effect. This study demonstrates that ileitis induces hyperexcitability in nociceptive DRG neurons and changes in the properties of Na+ and K+channels at the soma, which persist after removal from the inflamed environment.

scholarly journals Canine Myocytes Represent a Good Model for Human Ventricular Cells Regarding Their Electrophysiological Properties

2021 ◽  
Vol 14 (8) ◽  
pp. 748
Author(s):  
Péter P. Nánási ◽  
Balázs Horváth ◽  
Fábián Tar ◽  
János Almássy ◽  
Norbert Szentandrássy ◽  
...  
Keyword(s):  
Action Potential ◽  
Time Course ◽  
Laboratory Animals ◽  
Delayed Rectifier ◽  
Ion Currents ◽  
Human Cardiomyocytes ◽  
Ventricular Cells ◽  
Repolarization Reserve ◽  
Electrophysiological Studies ◽  
K Current

Due to the limited availability of healthy human ventricular tissues, the most suitable animal model has to be applied for electrophysiological and pharmacological studies. This can be best identified by studying the properties of ion currents shaping the action potential in the frequently used laboratory animals, such as dogs, rabbits, guinea pigs, or rats, and comparing them to those of human cardiomyocytes. The authors of this article with the experience of three decades of electrophysiological studies, performed in mammalian and human ventricular tissues and isolated cardiomyocytes, summarize their results obtained regarding the major canine and human cardiac ion currents. Accordingly, L-type Ca2+ current (ICa), late Na+ current (INa-late), rapid and slow components of the delayed rectifier K+ current (IKr and IKs, respectively), inward rectifier K+ current (IK1), transient outward K+ current (Ito1), and Na+/Ca2+ exchange current (INCX) were characterized and compared. Importantly, many of these measurements were performed using the action potential voltage clamp technique allowing for visualization of the actual current profiles flowing during the ventricular action potential. Densities and shapes of these ion currents, as well as the action potential configuration, were similar in human and canine ventricular cells, except for the density of IK1 and the recovery kinetics of Ito. IK1 displayed a largely four-fold larger density in canine than human myocytes, and Ito recovery from inactivation displayed a somewhat different time course in the two species. On the basis of these results, it is concluded that canine ventricular cells represent a reasonably good model for human myocytes for electrophysiological studies, however, it must be borne in mind that due to their stronger IK1, the repolarization reserve is more pronounced in canine cells, and moderate differences in the frequency-dependent repolarization patterns can also be anticipated.

scholarly journals Promotion of Resilience in Migrants: A Systematic Review of Study and Psychosocial Intervention

2021 ◽  
Author(s):  
Maria Ciaramella ◽  
Nadia Monacelli ◽  
Livia Concetta Eugenia Cocimano
Keyword(s):  
Systematic Review ◽  
Psychosocial Intervention ◽  
Life Experiences ◽  
Psychosocial Interventions ◽  
Migrant Population ◽  
Methodological Choices ◽  
Research Questions ◽  
Definition Of ◽  
Selection Of

AbstractThis systematic review aimed to contribute to a better and more focused understanding of the link between the concept of resilience and psychosocial interventions in the migrant population. The research questions concerned the type of population involved, definition of resilience, methodological choices and which intervention programmes were targeted at migrants. In the 90 articles included, an heterogeneity in defining resilience or not well specified definition resulted. Different migratory experiences were not adequately considered in the selection of participants. Few resilience interventions on migrants were resulted. A lack of procedure’s descriptions that keep in account specific migrants’ life-experiences and efficacy’s measures were highlighted.

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