Comparison of Responses of Neurons in the Mouse Inferior Colliculus to Current Injections, Tones of Different Durations, and Sinusoidal Amplitude-Modulated Tones

2007 ◽  
Vol 98 (1) ◽  
pp. 454-466 ◽  
Author(s):  
M. L. Tan ◽  
J.G.G. Borst
Keyword(s):  
Inferior Colliculus ◽  
Inhibitory Response ◽  
Current Injection ◽  
Membrane Properties ◽  
Constant Current ◽  
Special Role ◽  
Whole Cell Patch Clamp ◽  
Voltage Dependent ◽  
Intrinsic Membrane Properties

We made in vivo whole cell patch-clamp recordings from the inferior colliculus of young-adult, anesthetized C57/Bl6 mice to compare the responses to constant-current injections with the responses to tones of different duration or to sinusoidal amplitude-modulated (SAM) tones. We observed that voltage-dependent ion channels contributed in several ways to the response to tones. A sustained response to long tones was observed only in cells showing little accommodation during current injection. Cells showing burst-onset firing during current injection showed a small response to SAM tones, whereas burst-sustained cells showed a good response to SAM tones. The hyperpolarization-activated nonselective cation channel Ih had a special role in shaping the responses: Ih was associated with an increased excitability, with chopper and pauser responses, and with an afterhyperpolarization following tones. Synaptic properties were more important in determining the responses to tones of different durations. A short-latency inhibitory response appeared to contribute to the long-pass response in some cells and short-pass and band-pass neurons were characterized by their slow recovery from synaptic adaptation. Cells that recovered slowly from synaptic adaptation showed a relatively small response to SAM tones. Our results show an important role for both intrinsic membrane properties—most notably the presence of Ih and the extent of accommodation—and synaptic adaptation in shaping the response to tones in the inferior colliculus.

Membrane Properties and Firing Patterns of Inferior Colliculus Neurons: An In Vivo Patch-Clamp Study in Rodents

2007 ◽  
Vol 98 (1) ◽  
pp. 443-453 ◽  
Author(s):  
M. L. Tan ◽  
H. P. Theeuwes ◽  
L. Feenstra ◽  
J.G.G. Borst
Keyword(s):  
Patch Clamp ◽  
Inferior Colliculus ◽  
Membrane Properties ◽  
Resting Membrane Potential ◽  
Firing Patterns ◽  
Postsynaptic Potentials ◽  
Whole Cell Patch Clamp ◽  
Auditory Nucleus ◽  
Clamp Study

The inferior colliculus (IC) is a large auditory nucleus in the midbrain, which is a nearly obligatory relay center for ascending auditory projections. We made in vivo whole cell patch-clamp recordings of IC cells in young-adult anesthetized C57/Bl6 mice and Wistar rats to characterize their membrane properties and spontaneous inputs. We observed spikelets in both rat (18%) and mouse (13%) IC neurons, suggesting that IC neurons may be connected by electrical synapses. In many cells, spontaneous postsynaptic potentials were sufficiently large to contribute to spike irregularity. Cells differed considerably in the number of simultaneous spontaneous postsynaptic potentials that would be needed to trigger an action potential. Depolarizing and hyperpolarizing current injections showed six different types of firing patterns: buildup, accelerating, burst-onset, burst-sustained, sustained, and accommodating. Their relative frequencies were similar in both species. In mice, about half of the cells showed a clear depolarizing sag, suggesting that they have the hyperpolarization-activated current Ih. This sag was observed more often in burst and in accommodating cells than in buildup, accelerating, or sustained neurons. Cells with Ih had a significantly more depolarized resting membrane potential. They were more likely to fire rebound spikes and generally showed long-lasting afterhyperpolarizations following long depolarizations. We therefore suggest a separate functional role for Ih.

Dendritic arbor of locus coeruleus neurons contributes to opioid inhibition

1996 ◽  
Vol 75 (5) ◽  
pp. 2029-2035 ◽  
Author(s):  
R. A. Travagli ◽  
M. Wessendorf ◽  
J. T. Williams
Keyword(s):  
Locus Coeruleus ◽  
Horizontal Plane ◽  
Reversal Potential ◽  
Outward Current ◽  
Membrane Properties ◽  
Equilibrium Potential ◽  
Intrinsic Membrane Properties ◽  
In Cells

1. The nucleus locus coeruleus (LC) is made up of noradrenergic cells all of which are hyperpolarized by opioids. Recent work has shown that the reversal potential of the opioid-induced current is more negative than the potassium equilibrium potential. The aim of the present study was to determine whether the extent of the dendritic field could contribute to the very negative opioid reversal potential. 2. Individual LC cells were labeled in the brain slice preparation. The number of dendrites found on cells in slices sectioned in the horizontal plane was greater than cells in coronal slices. However, the dimensions of the cell body slices from each plane were not significantly different. 3. The resting conductance of neurons from slices cut in the horizontal plane was significantly larger than in cells from coronal plane. 4. The amplitude of the outward current induced by [Met5]-enkephalin (ME) was larger in cells from horizontal slices and the reversal potential was more negative than that of cells in coronal slices. 5. The results show that the plane of section influences the membrane properties and opioid actions of LC neurons in vitro and suggest that these differences correlate with the numbers of dendrites. The results suggest that in vivo, in addition to intrinsic membrane properties and synaptic inputs, the structural makeup of the nucleus is an important factor in determining the activity.

Effects of relaxin on rat atrial myocytes. I. Inhibition of I(to) via PKA-dependent phosphorylation

1997 ◽  
Vol 272 (4) ◽  
pp. H1791-H1797 ◽  
Author(s):  
E. S. Piedras-Renteria ◽  
O. D. Sherwood ◽  
P. M. Best
Keyword(s):  
Potassium Current ◽  
Peptide Hormone ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Electrophysiological Properties ◽  
Whole Cell Patch Clamp ◽  
Rat Hearts ◽  
Voltage Dependent

The peptide hormone relaxin has direct, positive inotropic and chronotropic effects on rat hearts in vivo and in vitro. Relaxin's effects on the electrophysiological properties of single quiescent atrial cells from normal rats were investigated with a whole cell patch clamp. Relaxin had a significant inhibitory effect on outward potassium currents. The outward potassium current consisted of a transient component (I(to)) and a sustained component (I(S)). The addition of 100 ng/ml of relaxin inhibited the peak I(to) in a voltage-dependent manner (74% inhibition at a membrane potential of -10 mV to 30% inhibition at +70 mV). The time to reach peak I(to) and the apparent time constant of inactivation of I(to) were increased by relaxin. Dialysis with the protein kinase A inhibitor 5-24 amide (2 microM) prevented relaxin's effects, suggesting an obligatory role for this kinase in the relaxin-dependent regulation of the potassium current.

scholarly journals Intrinsic membrane properties determine hippocampal differential firing pattern in vivo in anesthetized rats

Hippocampus ◽  
2015 ◽  
Vol 26 (5) ◽  
pp. 668-682 ◽  
Author(s):  
Janina Kowalski ◽  
Jian Gan ◽  
Peter Jonas ◽  
Alejandro J. Pernía‐Andrade
Keyword(s):  
Firing Pattern ◽  
Membrane Properties ◽  
Anesthetized Rats ◽  
Intrinsic Membrane Properties

Response Sensitivity of Barrel Neuron Subpopulations to Simulated Thalamic Input

2010 ◽  
Vol 103 (6) ◽  
pp. 3001-3016 ◽  
Author(s):  
Michael J. Pesavento ◽  
Cynthia D. Rittenhouse ◽  
David J. Pinto
Keyword(s):  
Barrel Cortex ◽  
Brain Slices ◽  
Input Resistance ◽  
Inhibitory Neurons ◽  
Membrane Properties ◽  
Cortical Function ◽  
Thalamic Input ◽  
Intrinsic Membrane Properties

Our goal is to examine the relationship between neuron- and network-level processing in the context of a well-studied cortical function, the processing of thalamic input by whisker-barrel circuits in rodent neocortex. Here we focus on neuron-level processing and investigate the responses of excitatory and inhibitory barrel neurons to simulated thalamic inputs applied using the dynamic clamp method in brain slices. Simulated inputs are modeled after real thalamic inputs recorded in vivo in response to brief whisker deflections. Our results suggest that inhibitory neurons require more input to reach firing threshold, but then fire earlier, with less variability, and respond to a broader range of inputs than do excitatory neurons. Differences in the responses of barrel neuron subtypes depend on their intrinsic membrane properties. Neurons with a low input resistance require more input to reach threshold but then fire earlier than neurons with a higher input resistance, regardless of the neuron's classification. Our results also suggest that the response properties of excitatory versus inhibitory barrel neurons are consistent with the response sensitivities of the ensemble barrel network. The short response latency of inhibitory neurons may serve to suppress ensemble barrel responses to asynchronous thalamic input. Correspondingly, whereas neurons acting as part of the barrel circuit in vivo are highly selective for temporally correlated thalamic input, excitatory barrel neurons acting alone in vitro are less so. These data suggest that network-level processing of thalamic input in barrel cortex depends on neuron-level processing of the same input by excitatory and inhibitory barrel neurons.

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.

Muscarinic Depression of Synaptic Transmission in the Epileptogenic GABA Withdrawal Syndrome Focus

2001 ◽  
Vol 85 (5) ◽  
pp. 2159-2165 ◽  
Author(s):  
C. Silva-Barrat ◽  
M. Szente ◽  
Ch. Menini ◽  
J. C. Velluti ◽  
J. Champagnat
Keyword(s):  
Synaptic Transmission ◽  
Muscarinic Receptors ◽  
Withdrawal Syndrome ◽  
Epileptiform Activity ◽  
Protective Role ◽  
Current Injection ◽  
Membrane Properties ◽  
Epileptic Focus ◽  
Excitatory Postsynaptic Potential

The GABA withdrawal syndrome (GWS) is a model of local status epilepticus consecutive to the interruption of a prolonged GABA infusion into the rat somatomotor cortex. Bursting patterns in slices from GWS rats include intrinsic bursts of action potentials (APs) induced by intracellular depolarizing current injection and/or paroxysmal depolarization shifts (PDSs) induced by white matter stimulation. Possible changes in the effects of cholinergic drugs after in vivo induction of GWS were investigated on bursting cells ( n = 30) intracellularly recorded in neocortical slices. In GWS slices, acetylcholine (Ach, 200-1000 μM) or carbachol (Cch, 50 μM) applications increased the number of bursts induced by depolarizing current injection while synaptically induced PDSs were significantly diminished (by 50–60%) or even blocked independently of the cholinergic-induced depolarization. The intrinsic burst facilitation and PDS depression provoked by Ach or Cch were mimicked by methyl-acetylcholine (mAch, 100–400 μM, n = 11), were reversed by atropine application (1–50 μM, n = 3), and were not mimicked by nicotine (50–100 μM, n = 4), indicating the involvement of muscarinic receptors. In contrast, in nonbursting cells from the same epileptic area ( n = 42) or from equivalent area in control rats ( n = 24), a nonsignificant muscarinic depression of EPSPs was induced by Cch and Ach. The mAch depression of excitatory postsynaptic potential (EPSPs) was significantly lower than that seen for PDSs in GWS rats. None of the cholinergic agonists caused bursting appearance in these cells. Therefore the present study demonstrates a unique implication of muscarinic receptors in exerting opposite effects on intrinsic membrane properties and on synaptic transmission in epileptiform GWS. Muscarinic receptor mechanisms may therefore have a protective role against the development and spread of epileptiform activity from the otherwise-activated epileptic focus.

Opposing Inward and Outward Conductances Regulate Rebound Discharges in Olfactory Mitral Cells

2007 ◽  
Vol 97 (3) ◽  
pp. 1959-1968 ◽  
Author(s):  
Ramani Balu ◽  
Ben W. Strowbridge
Keyword(s):  
Olfactory Bulb ◽  
Outward Current ◽  
Membrane Properties ◽  
Transient Outward Current ◽  
Na Channel ◽  
Mitral Cells ◽  
Na Channels ◽  
Spike Generation ◽  
Intrinsic Membrane Properties

The olfactory bulb, a second-order sensory brain region, relays afferent input from olfactory receptor neurons to piriform cortex and other higher brain centers. Although large inhibitory postsynaptic potentials (IPSPs) are evident in in vivo intracellular recordings from mitral cells, the functional significance of these synaptic responses has not been defined. In many brain regions, IPSPs can function to either inhibit spiking by transiently suppressing activity or can evoke spiking directly by triggering rebound discharges. We used whole cell patch-clamp recordings from mitral cells in olfactory bulb slices to investigate the mechanisms by which IPSPs regulate mitral cell spike discharges. Mitral cells have unusual intrinsic membrane properties that support rebound spike generation in response to small-amplitude (3–5 mV) but not large-amplitude hyperpolarizing current injections or IPSPs. Rebound spiking occurring in mitral cells was dependent on recovery of subthreshold Na currents, and could be blocked by tetrodotoxin (TTX, 1 μM) or the subthreshold Na channel blocker riluzole (10 μM). Surprisingly, larger-amplitude hyperpolarizing stimuli impeded spike generation by recruiting a transient outward IA-like current that was sensitive to high concentrations of 4-aminopyridine and Ba. The interplay of voltage-gated subthreshold Na channels and transient outward current produces a narrow range of IPSP amplitudes that generates rebound spikes. We also found that subthreshold Na channels boost subthreshold excitatory stimuli to produce membrane voltages where granule-cell-mediated IPSPs can produce rebound spikes. These results demonstrate how the intrinsic membrane properties of mitral cells enable inhibitory inputs to bidirectionally control spike output from the olfactory bulb.

scholarly journals 108 Neuropathic Pain and Ectopic Spontaneous Action Potential Activity of Human Primary Sensory Neurons

Neurosurgery ◽  
2017 ◽  
Vol 64 (CN_suppl_1) ◽  
pp. 222-222
Author(s):  
Robert Y North ◽  
Laurence D Rhines ◽  
Claudio E Tatsui ◽  
Ganesh Rao ◽  
Patrick M Dougherty
Keyword(s):  
Neuropathic Pain ◽  
Patch Clamp ◽  
Spontaneous Activity ◽  
Sensory Neurons ◽  
Dorsal Root Ganglia ◽  
Dorsal Root ◽  
Membrane Properties ◽  
Primary Sensory Neurons ◽  
Whole Cell Patch Clamp ◽  
Intrinsic Membrane Properties

Abstract INTRODUCTION Hyperexcitability of primary sensory neurons and its most extreme form, spontaneous activity, are key cellular-level drivers of neuropathic pain. Though extensively studied in animal models of neuropathic pain and established as a phenomenon occurring in human primary sensory neurons, this altered electrophysiology has not been rigorously studied for human primary sensory neurons nor has its relationship to clinical symptoms of neuropathic pain been established. METHODS The study was approved by the M.D. Anderson IRB. Written informed consent for participation was obtained from each tissue donor. Human dorsal root ganglia and medical histories were obtained from patients undergoing oncological spine surgery that necessitated sacrifice of spinal nerve roots as part of standard of care. Clinical data regarding presence of radicular/neuropathic pain was obtained through retrospective review of medical records or collected at time of study enrollment. Neurons were dissociated from surrounding tissue, briefly maintained in cell-culture (24-72 hours), and examined with whole-cell patch clamp techniques. RESULTS >Electrophysiological recordings were obtained from a total of 110 neurons, dissociated from 23 dorsal root ganglia, donated by 13 patients. Spontaneous activity was noted in 15% (12/79) of neurons from ganglia with pain in a corresponding dermatome vs 0% (0/31) of neurons from pain free ganglia (P < 0.05) Compared to neurons without spontaneous activity, human sensory neurons with spontaneous activity had significantly altered intrinsic membrane properties; depolarized resting membrane potential, hyperexcitability, and altered action potential kinetics (all P < 0.05). CONCLUSION Utilizing whole-cell patch clamp of dissociated human primary sensory neurons from patients both with and without neuropathic pain this study presents two important new findings: 1) first demonstration of a statistically significant association between in vitro spontaneous activity of dissociated human primary sensory neurons and neuropathic pain 2) the first characterization of the altered intrinsic membrane properties associated with spontaneous activity in human primary sensory neurons.

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