scholarly journals Intrinsic excitability differs between murine hypoglossal and spinal motoneurons

2016 ◽  
Vol 115 (5) ◽  
pp. 2672-2680 ◽  
Author(s):  
M. A. Tadros ◽  
A. J. Fuglevand ◽  
A. M. Brichta ◽  
R. J. Callister
Keyword(s):  
Action Potentials ◽  
Membrane Properties ◽  
Intrinsic Excitability ◽  
Spinal Motoneurons ◽  
Patch Clamp Recording ◽  
Electrophysiological Properties ◽  
Hypoglossal Motoneurons ◽  
Whole Cell Patch Clamp ◽  
Two Populations ◽  
Passive Membrane Properties

Motoneurons differ in the behaviors they control and their vulnerability to disease and aging. For example, brain stem motoneurons such as hypoglossal motoneurons (HMs) are involved in licking, suckling, swallowing, respiration, and vocalization. In contrast, spinal motoneurons (SMs) innervating the limbs are involved in postural and locomotor tasks requiring higher loads and lower movement velocities. Surprisingly, the properties of these two motoneuron pools have not been directly compared, even though studies on HMs predominate in the literature compared with SMs, especially for adult animals. Here we used whole cell patch-clamp recording to compare the electrophysiological properties of HMs and SMs in age-matched neonatal mice (P7–P10). Passive membrane properties were remarkably similar in HMs and SMs, and afterhyperpolarization properties did not differ markedly between the two populations. HMs had narrower action potentials (APs) and a faster upstroke on their APs compared with SMs. Furthermore, HMs discharged APs at higher frequencies in response to both step and ramp current injection than SMs. Therefore, while HMs and SMs have similar passive properties, they differ in their response to similar levels of depolarizing current. This suggests that each population possesses differing suites of ion channels that allow them to discharge at rates matched to the different mechanical properties of the muscle fibers that drive their distinct motor functions.

Biophysical Properties and Responses to Neurotransmitters of Petrosal and Geniculate Ganglion Neurons Innervating the Tongue

2000 ◽  
Vol 84 (3) ◽  
pp. 1404-1413 ◽  
Author(s):  
Tomoshige Koga ◽  
Robert M. Bradley
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Membrane Properties ◽  
Patch Clamp Recording ◽  
Potential Decay ◽  
Ganglion Neurons ◽  
Fast Rise ◽  
Posterior Tongue ◽  
Passive Membrane Properties

The properties of afferent sensory neurons supplying taste receptors on the tongue were examined in vitro. Neurons in the geniculate (GG) and petrosal ganglia (PG) supplying the tongue were fluorescently labeled, acutely dissociated, and then analyzed using patch-clamp recording. Measurement of the dissociated neurons revealed that PG neurons were significantly larger than GG neurons. The active and passive membrane properties of these ganglion neurons were examined and compared with each other. There were significant differences between the properties of neurons in the PG and GG ganglia. The mean membrane time constant, spike threshold, action potential half-width, and action potential decay time of GG neurons was significantly less than those of PG neurons. Neurons in the PG had action potentials that had a fast rise and fall time (sharp action potentials) as well as action potentials with a deflection or hump on the falling phase (humped action potentials), whereas action potentials of GG neurons were all sharp. There were also significant differences in the response of PG and GG neurons to the application of acetylcholine (ACh), serotonin (5HT), substance P (SP), and GABA. Whereas PG neurons responded to ACh, 5HT, SP, and GABA, GG neurons only responded to SP and GABA. In addition, the properties of GG neurons were more homogeneous than those of the PG because all the GG neurons had sharp spikes and when responses to neurotransmitters occurred, either all or most of the neurons responded. These differences between neurons of the GG and PG may relate to the type of receptor innervated. PG ganglion neurons innervate a number of receptor types on the posterior tongue and have more heterogeneous properties, while GG neurons predominantly innervate taste buds and have more homogeneous properties.

Two populations of sympathetic neurons project selectively to mesenteric artery or vein

1999 ◽  
Vol 276 (4) ◽  
pp. H1263-H1272 ◽  
Author(s):  
Kirsteen N. Browning ◽  
Zhongling Zheng ◽  
David L. Kreulen ◽  
R. Alberto Travagli
Keyword(s):  
Mesenteric Artery ◽  
Sympathetic Neurons ◽  
Mesenteric Arteries ◽  
Patch Clamp Recording ◽  
Mesenteric Veins ◽  
Electrophysiological Properties ◽  
Whole Cell Patch Clamp ◽  
Mesenteric Ganglion ◽  
Two Populations

The objective of this study was to determine whether sympathetic neurons of the inferior mesenteric ganglion (IMG) projecting to mesenteric arteries could be distinguished by their localization, neurochemical phenotype, and electrophysiological properties from neurons projecting to mesenteric veins. In an in vitro intact vasculature-IMG preparation, neurons were labeled following intraluminal injection of Fluoro-Gold or rhodamine beads into the inferior mesenteric artery (IMA) or vein (IMV). The somata of neurons projecting to IMA were localized in the central part of the IMG, whereas those projecting to IMV were localized more peripherally. None of the labeled neurons was doubly labeled. Neuropeptide Y immunoreactivity was found in 18.9% of neurons innervating the IMA, but not in neurons innervating the IMV. Identified neurons were dissociated and characterized using whole cell patch-clamp recording. After direct soma depolarization, all of the labeled arterial and venous neurons were classified as tonic firing, compared with only 40% of unlabeled neurons; the remaining 60% of unlabeled neurons were phasic firing. The results indicate that IMG neurons projecting to mesenteric arteries are distinct from neurons projecting to mesenteric veins.

The influence of a 5-wk whole body vibration on electrophysiological properties of rat hindlimb spinal motoneurons

2013 ◽  
Vol 109 (11) ◽  
pp. 2705-2711 ◽  
Author(s):  
M. Bączyk ◽  
A. Hałuszka ◽  
W. Mrówczyński ◽  
J. Celichowski ◽  
P. Krutki
Keyword(s):  
Whole Body Vibration ◽  
Motor Units ◽  
Membrane Properties ◽  
Whole Body ◽  
Control Group ◽  
Spinal Motoneurons ◽  
Body Vibration ◽  
Electrophysiological Properties ◽  
Male Wistar Rats ◽  
Firing Properties

The study aimed at determining the influence of a whole body vibration (WBV) on electrophysiological properties of spinal motoneurons. The WBV training was performed on adult male Wistar rats, 5 days a week, for 5 wk, and each daily session consisted of four 30-s runs of vibration at 50 Hz. Motoneuron properties were investigated intracellularly during experiments on deeply anesthetized animals. The experimental group subjected to the WBV consisted of seven rats, and the control group of nine rats. The WBV treatment induced no significant changes in the passive membrane properties of motoneurons. However, the WBV-evoked adaptations in excitability and firing properties were observed, and they were limited to fast-type motoneurons. A significant decrease in rheobase current and a decrease in the minimum and the maximum currents required to evoke steady-state firing in motoneurons were revealed. These changes resulted in a leftward shift of the frequency-current relationship, combined with an increase in slope of this curve. The functional relevance of the described adaptive changes is the ability of fast motoneurons of rats subjected to the WBV to produce series of action potentials at higher frequencies in a response to the same intensity of activation. Previous studies proved that WBV induces changes in the contractile parameters predominantly of fast motor units (MUs). The data obtained in our experiment shed a new light to possible explanation of these results, suggesting that neuronal factors also play a substantial role in MU adaptation.

scholarly journals Electrophysiological Properties of Substantia Gelatinosa Neurons in the Preparation of a Slice of Middle-Aged Rat Spinal Cord

2021 ◽  
Vol 13 ◽  
Author(s):  
Yang Li ◽  
Shanchu Su ◽  
Jiaqi Yu ◽  
Minjing Peng ◽  
Shengjun Wan ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Patch Clamp ◽  
Molecular Mechanisms ◽  
Substantia Gelatinosa ◽  
Membrane Properties ◽  
Middle Aged ◽  
Patch Clamp Recording ◽  
Electrophysiological Properties ◽  
Glutamatergic Neurons ◽  
Single Spike

A patch-clamp recording in slices generated from the brain or the spinal cord has facilitated the exploration of neuronal circuits and the molecular mechanisms underlying neurological disorders. However, the rodents that are used to generate the spinal cord slices in previous studies involving a patch-clamp recording have been limited to those in the juvenile or adolescent stage. Here, we applied an N-methyl-D-glucamine HCl (NMDG-HCl) solution that enabled the patch-clamp recordings to be performed on the superficial dorsal horn neurons in the slices derived from middle-aged rats. The success rate of stable recordings from substantia gelatinosa (SG) neurons was 34.6% (90/260). When stimulated with long current pulses, 43.3% (39/90) of the neurons presented a tonic-firing pattern, which was considered to represent γ-aminobutyric acid-ergic (GABAergic) signals. Presumptive glutamatergic neurons presented 38.9% (35/90) delayed and 8.3% (7/90) single-spike patterns. The intrinsic membrane properties of both the neuron types were similar but delayed (glutamatergic) neurons appeared to be more excitable as indicated by the decreased latency and rheobase values of the action potential compared with those of tonic (GABAergic) neurons. Furthermore, the glutamatergic neurons were integrated, which receive more excitatory synaptic transmission. We demonstrated that the NMDG-HCl cutting solution could be used to prepare the spinal cord slices of middle-aged rodents for the patch-clamp recording. In combination with other techniques, this preparation method might permit the further study of the functions of the spinal cord in the pathological processes that occur in aging-associated diseases.

Medium Afterhyperpolarization and Firing Pattern Modulation in Interneurons of Stratum Radiatum in the CA3 Hippocampal Region

2001 ◽  
Vol 85 (5) ◽  
pp. 1986-1997 ◽  
Author(s):  
Natas̆a Savić ◽  
Paola Pedarzani ◽  
Marina Sciancalepore
Keyword(s):  
In Situ Hybridization ◽  
Firing Rate ◽  
Action Potentials ◽  
Membrane Properties ◽  
Stratum Radiatum ◽  
Resting Potential ◽  
Hippocampal Region ◽  
Patch Clamp Recording ◽  
Current Pulses

Stratum (st.) radiatum interneurons represent a heterogeneous class of hippocampal cells with as yet poorly characterized physiological properties. Intracellular staining with biocytin, in situ hybridization, and patch-clamp recording have been combined to investigate the morphological and electrophysiological properties of these cells in the CA3 hippocampal region in young rats [ postnatal days 10 to 21 ( P10–21)]. Labeled cells presented a heterogeneous morphology with various soma shapes, often found multipolar, and dendritic arborizations confined to st. radiatum. The passive membrane properties of these st. radiatum interneurons showed instead no significant differences between P10 and P21. Low resting potential, high-input resistance, and short time constants characterized CA3 st. radiatum interneurons, which were silent at rest. Action potentials, elicited by brief current pulses, were lower and shorter than in pyramidal cells and followed by a Ca2+-dependent medium-duration afterhyperpolarizing potential (mAHP). Prolonged depolarizing current injection generated trains of action potentials that fired at constant frequency after a slight accommodation. The maximum steady-state firing rate was 31 ± 4 (SD) Hz. Hyperpolarizing current pulses revealed a prominent inward rectification characterized by a “sag,” followed by a depolarizing rebound that triggered action potentials. Sag and anodal brake excitation were blocked by Cs+, suggesting that they were mediated by a hyperpolarization-activated cation conductance ( I h). In the presence of tetrodotoxin and tetraethylammonium, biphasic tail currents were elicited in voltage clamp after a depolarizing step inducing Ca2+influx. Tail currents presented a fast Ca2+-activated and apamin-sensitive component ( I AHP) and were further reduced by carbachol. The presence of I AHP was consistent with the high expression level of the apamin-sensitive SK2 subunit transcript in CA3 st. radiatum interneurons as detected by in situ hybridization. Different pharmacological agents were shown to affect the afterhyperpolarizing potential as well as the firing properties of st. radiatum interneurons. Exposure to Ca2+-free solutions mainly affected the late phase of repolarization and strongly reduced the mAHP. The mAHP was also attenuated by carbachol and by apamin, suggesting it to be partly mediated by I AHP. Reduction of the mAHP increased the interneuron firing frequency. In conclusion, st. radiatum interneurons of CA3 hippocampal region represent a class of nonpyramidal cells with action potentials followed by an AHP of relatively short duration, partially generated by apamin and carbachol-sensitive conductances involved in the regulation of the cell firing rate.

scholarly journals Increased Intrinsic Excitability of Lateral Wing Serotonin Neurons of the Dorsal Raphe: A Mechanism for Selective Activation in Stress Circuits

2010 ◽  
Vol 103 (5) ◽  
pp. 2652-2663 ◽  
Author(s):  
LaTasha K. Crawford ◽  
Caryne P. Craige ◽  
Sheryl G. Beck
Keyword(s):  
Dorsal Raphe ◽  
Membrane Properties ◽  
Intrinsic Excitability ◽  
Small Subset ◽  
Adaptive Responses ◽  
Lateral Wing ◽  
Whole Cell Patch Clamp ◽  
Serotonin Neurons ◽  
Dorsal Raphé

The primary center of serotonin (5-HT) projections to the forebrain is the dorsal raphe nucleus (DR), a region known for its role in the limbic stress response. The ventromedial subregion of the DR (vmDR) has the highest density of 5-HT neurons and is the major target in experiments that involve the DR. However, studies have demonstrated that a variety of stressors induce activation of neurons that is highest in the lateral wing subregion (lwDR) and includes activation of lwDR 5-HT neurons. Despite the functional role that the lwDR is known to play in stress circuits, little is known about lwDR 5-HT neuron physiology. Whole cell patch clamp electrophysiology in mice revealed that lwDR 5-HT cells have active and passive intrinsic membrane properties that make them more excitable than vmDR 5-HT neurons. In addition, lwDR 5-HT neurons demonstrated faster in vitro firing rates. Finally, within the vmDR there was a positive correlation between rostral position and increased excitability, among several other membrane parameters. These results are consistent with stressor induced patterns of activation of 5-HT neurons that includes, in addition to lwDR neurons, a small subset of rostral vmDR neurons. Thus increased intrinsic excitability likely forms a major part of the mechanism underlying the propensity to be activated by a stressor. The membrane properties identified in lwDR recordings may thereby contribute to a unique role of lwDR 5-HT neurons in adaptive responses to stress and in the pathobiology of stress-related mood disorders.

scholarly journals Q&A: using Patch-seq to profile single cells

BMC Biology ◽  
2017 ◽  
Vol 15 (1) ◽  
Author(s):  
Cathryn R. Cadwell ◽  
Rickard Sandberg ◽  
Xiaolong Jiang ◽  
Andreas S. Tolias
Keyword(s):  
Gene Expression ◽  
Nervous System ◽  
Patch Clamp ◽  
Single Cell ◽  
Single Cells ◽  
Cell Types ◽  
Patch Clamp Recording ◽  
Electrophysiological Properties ◽  
Whole Cell Patch Clamp ◽  
Single Cell Rna Sequencing

Abstract Individual neurons vary widely in terms of their gene expression, morphology, and electrophysiological properties. While many techniques exist to study single-cell variability along one or two of these dimensions, very few techniques can assess all three features for a single cell. We recently developed Patch-seq, which combines whole-cell patch clamp recording with single-cell RNA-sequencing and immunohistochemistry to comprehensively profile the transcriptomic, morphologic, and physiologic features of individual neurons. Patch-seq can be broadly applied to characterize cell types in complex tissues such as the nervous system, and to study the transcriptional signatures underlying the multidimensional phenotypes of single cells.

Internal cesium ions block various K conductances in spinal motoneurons

1981 ◽  
Vol 59 (12) ◽  
pp. 1280-1284 ◽  
Author(s):  
E. Puil ◽  
R. Werman
Keyword(s):  
Action Potentials ◽  
Considerable Increase ◽  
Membrane Conductance ◽  
Membrane Properties ◽  
Resting Potential ◽  
Large Reduction ◽  
Spinal Motoneurons ◽  
Spike Generation ◽  
Cesium Ions ◽  
Voltage Dependent

Conventional intracellular recording with low resistance electrodes was used to examine the effects of iontophoretic injections of Cs+ ions (30–200 nA for 30–500 s) into spinal motoneurons of cats anesthetized with pentobarbital and paralyzed with gallamine. The most striking effects of internal Cs+ were a great prolongation of the falling phase of action potentials, a large reduction in the amplitude of their afterhyperpolarizations, and a considerable increase in the size of delayed depolarizations. A reduction of resting membrane conductance (up to half of control values) and a small increase in membrane potential usually were evident. Although the rate of rise and amplitude of spikes sometimes were increased, the above effects on membrane properties usually were accompanied by block of antidromic invasion or synaptic spike generation, and inactivation of directly evoked spikes. Recovery of spike genesis was very rapid but the prolongation of spikes and other effects of Cs+ lasted 4–35 min, depending on the amount of Cs+ application. Larger injections of Cs+ resulted in greater depolarizations of up to 13 mV. It is concluded that internal Cs+ ions block voltage-dependent K+ conductance of spike repolarization, the Ca2+-activated K+ conductance responsible for the afterhyperpolarization, and some of the K+ conductance responsible for the resting potential. It is suggested that the enhanced delayed depolarization may result from a Cs+-blockade of an early outward K+ current which would unmask an inward current of Ca2+ ions.

scholarly journals Distinct Subtypes of Cholecystokinin (CCK)-Containing Interneurons of the Basolateral Amygdala Identified Using a CCK Promoter-Specific Lentivirus

2009 ◽  
Vol 101 (3) ◽  
pp. 1494-1506 ◽  
Author(s):  
Aaron M. Jasnow ◽  
Kerry J. Ressler ◽  
Sayamwong E. Hammack ◽  
Jasmeer P. Chhatwal ◽  
Donald G. Rainnie
Keyword(s):  
Basolateral Amygdala ◽  
Function Analysis ◽  
Hierarchical Cluster ◽  
Heterogeneous Population ◽  
Membrane Properties ◽  
Patch Clamp Recording ◽  
Whole Cell Patch Clamp ◽  
Physiological Properties ◽  
Current Clamp Mode

The basolateral amygdala (BLA) is critical for the formation of emotional memories. Little is known about the physiological properties of BLA interneurons, which can be divided into four subtypes based on their immunocytochemical profiles. Cholecystokinin (CCK) interneurons play critical roles in feedforward inhibition and behavioral fear responses. Evidence suggests that interneurons within a subgroup can display heterogeneous physiological properties. However, little is known about the physiological properties of CCK interneurons in the BLA and/or whether they represent a homogeneous or heterogeneous population. To address this question, we generated a lentivirus-expressing GFP under the control of the CCK promoter to identify CCK neurons in vivo. We combined this with whole cell patch-clamp recording techniques to examine the physiological properties of CCK-containing interneurons of the rat BLA. Here, we describe the physiological properties of 57 cells recorded in current-clamp mode; we used hierarchical cluster and discriminant function analysis to demonstrate that CCK interneurons can be segregated into three distinct subtypes (I, II, III) based on their passive and active membrane properties. Additionally, Type II neurons could be further separated into adapting and nonadapting types based on their rates of spike frequency adaptation. These data suggest that CCK interneurons of the BLA are a heterogeneous population and may be functionally distinct subpopulations that differentially contribute to the processing of emotionally salient stimuli.

Unitary excitatory synaptic currents in preganglionic neurons mediated by two distinct groups of interneurons in neonatal rat sacral parasympathetic nucleus

1996 ◽  
Vol 76 (1) ◽  
pp. 215-226 ◽  
Author(s):  
I. Araki ◽  
W. C. De Groat
Keyword(s):  
Nmda Receptor Antagonist ◽  
Neonatal Rat ◽  
Patch Clamp Recording ◽  
Lumbosacral Spinal Cord ◽  
Postsynaptic Currents ◽  
Preganglionic Neurons ◽  
Sacral Parasympathetic Nucleus ◽  
Whole Cell Patch Clamp ◽  
Two Populations ◽  
Stimulation Of

1. Excitatory postsynaptic currents (EPSCs) in parasympathetic preganglionic neurons (PGNs) were examined by the use of the whole cell patch-clamp recording technique in slice preparations of the neonatal rat lumbosacral spinal cord. Synaptic responses were evoked in PGNs by extracellular stimulation of a neighboring interneuron. 2. Stimulation of interneurons medial to the sacral parasympathetic nucleus (SPN) elicited EPSCs or inhibitory postsynaptic currents in 58 and 11%, respectively, of PGNs. Stimulation of interneurons dorsal to the SPN evoked EPSCs in 70% of PGNs. 3. EPSCs occurred at short latency (2.1 ms) and were usually elicited in an all-or-none manner, indicating that they were monosynaptic and mediated by a single interneuron (i.e., unitary). 4. EPSCs were mediated by both non-N-methyl-D-aspartate (non-NMDA) and NMDA receptors. 5. Unitary excitatory postsynaptic potentials evoked by single stimuli did not induce action potentials in PGNs, but repetitive stimulation (> 20 Hz) of the single interneurons could evoke firing of PGNs. 2-Amino-5-phosphonovalerate, an NMDA receptor antagonist, reduced the synaptic depolarization induced in PGNs by high-frequency interneuronal impulses. 6. EPSCs mediated by dorsal interneurons were smaller in amplitude (36.3 +/- 15.7 pA, mean +/- SD) than EPSCs mediated by medial interneurons (88.4 +/- 45.7 pA). 7. Paired-pulse facilitation of EPSCs was observed in PGNs (147.2 +/- 26.2%). The degree of facilitation was higher in dorsal (174.6 +/- 10.3%) than in medial interneuronal pathways (120.9 +/- 3.6%). Within each of interneuronal pathways the degree of facilitation was independent of the magnitude of the unitary EPSC. 8. The results show that PGNs receive monosynaptic glutamatergic excitatory inputs from two distinct populations of interneurons in the dorsal and medial regions of the SPN. These two populations of interneurons are likely to have different functions in the regulation of the preganglionic outflow to the pelvic organs.

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