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.

scholarly journals Properties of the Nucleo-Olivary Pathway: An In Vivo Whole-Cell Patch Clamp Study

PLoS ONE ◽  
2012 ◽  
Vol 7 (9) ◽  
pp. e46360 ◽  
Author(s):  
Paolo Bazzigaluppi ◽  
Tom Ruigrok ◽  
Payam Saisan ◽  
Chris I. De Zeeuw ◽  
Marcel de Jeu
Keyword(s):  
Patch Clamp ◽  
Whole Cell ◽  
Cell Patch Clamp ◽  
Whole Cell Patch Clamp ◽  
Clamp Study

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.

scholarly journals Postnatal development of synaptic properties of the GABAergic projection from the inferior colliculus to the auditory thalamus

2013 ◽  
Vol 109 (12) ◽  
pp. 2866-2882 ◽  
Author(s):  
Yamini Venkataraman ◽  
Edward L Bartlett
Keyword(s):  
Inferior Colliculus ◽  
Temporal Processing ◽  
Brain Slices ◽  
Critical Time ◽  
Membrane Properties ◽  
Auditory Temporal Processing ◽  
Postsynaptic Potentials ◽  
Auditory Thalamus ◽  
Inhibitory Postsynaptic Potentials ◽  
Medial Geniculate

The development of auditory temporal processing is important for processing complex sounds as well as for acquiring reading and language skills. Neuronal properties and sound processing change dramatically in auditory cortex neurons after the onset of hearing. However, the development of the auditory thalamus or medial geniculate body (MGB) has not been well studied over this critical time window. Since synaptic inhibition has been shown to be crucial for auditory temporal processing, this study examined the development of a feedforward, GABAergic connection to the MGB from the inferior colliculus (IC), which is also the source of sensory glutamatergic inputs to the MGB. IC-MGB inhibition was studied using whole cell patch-clamp recordings from rat brain slices in current-clamp and voltage-clamp modes at three age groups: a prehearing group [ postnatal day (P)7–P9], an immediate posthearing group (P15–P17), and a juvenile group (P22–P32) whose neuronal properties are largely mature. Membrane properties matured substantially across the ages studied. GABAA and GABAB inhibitory postsynaptic potentials were present at all ages and were similar in amplitude. Inhibitory postsynaptic potentials became faster to single shocks, showed less depression to train stimuli at 5 and 10 Hz, and were overall more efficacious in controlling excitability with age. Overall, IC-MGB inhibition becomes faster and more precise during a time period of rapid changes across the auditory system due to the codevelopment of membrane properties and synaptic properties.

scholarly journals Noradrenaline modulates mechanically evoked responses in the rat spinal dorsal horn: an in vivo patch-clamp study

2019 ◽  
Vol Volume 12 ◽  
pp. 1269-1278 ◽  
Author(s):  
Motoki Sonohata ◽  
Atsushi Doi ◽  
Toshiharu Yasaka ◽  
Daisuke Uta ◽  
Masaaki Mawatari ◽  
...  
Keyword(s):  
Patch Clamp ◽  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
Evoked Responses ◽  
Spinal Dorsal ◽  
Clamp Study

Freshly Isolated Astrocytes From Rat Hippocampus Show Two Distinct Current Patterns and Different [K+]oUptake Capabilities

2000 ◽  
Vol 84 (6) ◽  
pp. 2746-2757 ◽  
Author(s):  
Min Zhou ◽  
Harold K. Kimelberg
Keyword(s):  
Electrophysiological Study ◽  
Potassium Currents ◽  
Rat Hippocampus ◽  
Membrane Properties ◽  
Resting Membrane Potential ◽  
Current Pattern ◽  
Ca1 Region ◽  
Inward Currents

Whether astrocytes predominantly express ohmic K+ channels in vivo, and how expression of different K+ channels affects [K+]ohomeostasis in the CNS have been long-standing questions for how astrocytes function. In the present study, we have addressed some of these questions in glial fibrillary acidic protein [GFAP(+)], freshly isolated astrocytes (FIAs) from CA1 and CA3 regions of P7–15 rat hippocampus. As isolated, these astrocytes were uncoupled allowing a higher resolution of electrophysiological study. FIAs showed two distinct ion current profiles, with neither showing a purely linear I-V relationship. One population of astrocytes had a combined expression of outward potassium currents ( I Ka, I Kd) and inward sodium currents ( I Na). We term these outwardly rectifying astrocytes (ORA). Another population of astrocytes is characterized by a relatively symmetric potassium current pattern, comprising outward I Kdr, I Ka, and abundant inward potassium currents ( I Kin), and a larger membrane capacitance ( C m ) and more negative resting membrane potential (RMP) than ORAs. We term these variably rectifying astrocytes (VRA). The I Kin in 70% of the VRAs was essentially insensitive to Cs+, while I Kin in the remaining 30% of VRAs was sensitive. The I Ka of VRAs was most sensitive to 4-aminopyridine (4-AP), while I Kdr of ORAs was more sensitive to tetraethylammonium (TEA). ORAs and VRAs occurred approximately equally in FIAs isolated from the CA1 region (52% ORAs versus 48% VRAs), but ORAs were enriched in FIAs isolated from the CA3 region (71% ORAs versus 29% VRAs), suggesting an anatomical segregation of these two types of astrocytes within the hippocampus. VRAs, but not ORAs, showed robust inward currents in response to an increase in extracellular K+ from 5 to 10 mM. As VRAs showed a similar current pattern and other passive membrane properties (e.g., RMP, R in) to “passive astrocytes”in situ (i.e., these showing linear I-V curves), such passive astrocytes possibly represent VRAs influenced by extensive gap-junction coupling in situ. Thus, our data suggest that, at least in CA1 and CA3 regions from P7–15 rats, there are two classes of GFAP(+) astrocytes which possess different K+ currents. Only VRAs seem suited to uptake of extracellular K+ via I Kin channels at physiological membrane potentials and increases of [K+]o. ORAs show abundant outward potassium currents with more depolarized RMP. Thus VRAs and ORAs may cooperate in vivo for uptake and release of K+, respectively.

Membrane properties of mesopontine cholinergic neurons studied with the whole-cell patch-clamp technique: implications for behavioral state control

1992 ◽  
Vol 68 (4) ◽  
pp. 1359-1372 ◽  
Author(s):  
A. Kamondi ◽  
J. A. Williams ◽  
B. Hutcheon ◽  
P. B. Reiner
Keyword(s):  
Patch Clamp ◽  
Cholinergic Neurons ◽  
Membrane Properties ◽  
Type I ◽  
Type Ii ◽  
Patch Clamp Technique ◽  
Whole Cell ◽  
Type Iii ◽  
Clamp Technique ◽  
Whole Cell Patch Clamp

1. The whole-cell patch-clamp technique was used to study the membrane properties of identified cholinergic and noncholinergic laterodorsal tegmental neurons in slices of rat brain maintained in vitro. 2. On the basis of their expression of the transient outward potassium current IA and the transient inward calcium current IT, three classes of neurons were observed: type I neurons exhibited a large IT; type II neurons exhibited a prominent IA; and type III neurons exhibited both IA and IT. 3. Combining intracellular deposition of biocytin with NADPH diaphorase histochemistry revealed that the vast majority of type III neurons were cholinergic, whereas only a minority of type I and type II neurons were cholinergic. Thus mesopontine cholinergic neurons possess intrinsic ionic currents capable of inducing burst firing. 4. Delineation of the intrinsic membrane properties of identified mesopontine cholinergic neurons, in concert with recent results regarding the responses of these neurons to neurotransmitter agents, has led us to present a unifying and mechanistic hypothesis of brain stem cholinergic function in the control of behavioral states.

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