Electrophysiological Properties of Neurons: Current-Clamp Recordings in Mouse Brain Slices and Firing-Pattern Analysis

The ventral pallidum is a major source of output for ventral corticobasal ganglia circuits that function in translating motivationally relevant stimuli into adaptive behavioral responses. In this study, whole cell patch-clamp recordings were made from ventral pallidal neurons in brain slices from 6- to 18-day-old rats. Intracellular filling with biocytin was used to correlate the electrophysiological and morphological properties of cholinergic and noncholinergic neurons identified by choline acetyltransferase immunohistochemistry. Most cholinergic neurons had a large whole cell conductance and exhibited marked fast (i.e., anomalous) inward rectification. These cells typically did not fire spontaneously, had a hyperpolarized resting membrane potential, and also exhibited a prominent spike afterhyperpolarization (AHP) and strong spike accommodation. Noncholinergic neurons had a smaller whole cell conductance, and the majority of these cells exhibited marked time-dependent inward rectification that was due to an h-current. This current activated slowly over several hundred milliseconds at potentials more negative than −80 mV. Noncholinergic neurons fired tonically in regular or intermittent patterns, and two-thirds of the cells fired spontaneously. Depolarizing current injection in current clamp did not cause spike accommodation but markedly increased the firing frequency and in some cells also altered the pattern of firing. Spontaneous tetrodotoxin-sensitive GABAA-mediated inhibitory postsynaptic currents (IPSCs) were frequently recorded in noncholinergic neurons. These results show that cholinergic pallidal neurons have similar properties to magnocellular cholinergic neurons in other parts of the forebrain, except that they exhibit strong spike accommodation. Noncholinergic ventral pallidal neurons have large h-currents that could have a physiological role in determining the rate or pattern of firing of these cells.

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The dependence of water content and ?extracellular? marker spaces of incubated mouse brain slices on thickness

Experimental Brain Research ◽

10.1007/bf00238012 ◽

1974 ◽

Vol 20 (5) ◽

Cited By ~ 3

Author(s):

StephenR. Cohen

Keyword(s):

Water Content ◽

Mouse Brain ◽

Brain Slices

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Local protein synthesis is a ubiquitous feature of neuronal pre- and postsynaptic compartments

10.1101/363184 ◽

2018 ◽

Cited By ~ 1

Author(s):

Anne-Sophie Hafner ◽

Paul G. Donlin-Asp ◽

Beulah Leitch ◽

Etienne Herzog ◽

Erin M. Schuman

Keyword(s):

Protein Synthesis ◽

Mouse Brain ◽

Brain Slices ◽

Metabolic Labeling ◽

Presynaptic Terminals ◽

Ample Evidence ◽

Local Protein Synthesis ◽

Axon Terminals ◽

Neuronal Dendrites ◽

Local Protein

AbstractThere is ample evidence for localized mRNAs and protein synthesis in neuronal dendrites, however, demonstrations of these processes in presynaptic terminals are limited. We used expansion microscopy to resolve pre- and postsynaptic compartments in brain slices. Most presynaptic terminals in the hippocampus and forebrain contained mRNA and ribosomes. We sorted fluorescently labeled synaptosomes from mouse brain and then sequenced hundreds of mRNA species present within excitatory boutons. After brief metabolic labeling, more them 30% of all presynaptic terminals exhibited a signal, providing evidence for ongoing protein synthesis. We tested different classic plasticity paradigms and observed unique patterns of rapid pre- and/or postsynaptic translation. Thus presynaptic terminals are translationally competent and local protein synthesis is differentially recruited to drive compartment-specific phenotypes that underlie different forms of plasticity.One sentence summaryProtein synthesis occurs in all synaptic compartments, including excitatory and inhibitory axon terminals.

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Harmaline Attenuates Voltage - Sensitive Ca2+ Currents in Neurons of the Inferior Olive

Journal of Pharmacy & Pharmaceutical Sciences ◽

10.18433/j3w595 ◽

2012 ◽

Vol 15 (5) ◽

pp. 657 ◽

Cited By ~ 5

Author(s):

Xiping Zhan ◽

Werner M Graf

Keyword(s):

Inferior Olive ◽

Low Voltage ◽

Brain Slices ◽

Cell Voltage ◽

Current Clamp ◽

Neuroprotective Effects ◽

Neuron Activation ◽

Harmala Alkaloids ◽

Large Spike ◽

Inferior Olivary

Purpose. Harmaline is one member of a class of tremorgenic harmala alkaloids that have been implicated in neuroprotective effects and neurodegenerative disorders. It has been reported to interact with several neurotransmitter receptors as well as ion exchangers and voltage-sensitive channels. One site of harmaline action in the brain is the inferior olive (IO). Either local or systemic harmaline injection has been reported to increase spiking rate and coherence in the inferior olive and this activation is thought to produce tremor and ataxia through inferior olivary neuron activation of target neurons in the cerebellum, but the cellular mechanism is not yet known. Methods. Here, we have performed whole cell voltage-clamp and current clamp recordings from olivary neurons in brain slices derived from newborn rats. Results. We found that both transient low-voltage activated (LVA) and sustained high voltage-activated (HVA) Ca2+ currents are significantly attenuated by 0.125 – 0.25 mM harmaline applied to the bath and that this attenuation is partially reversible. In current clamp recordings, spike-afterhyperpolarization complexes were evoked by brief positive current injections. Harmaline produced a small attenuation of spike amplitude, but large spike broadening associated with attenuation of the fast and medium afterhyperpolarization. Conclusion. Our data suggest that one mode of olivary neuron activation by harmaline involves attenuation of both HVA and LVA Ca2+ conductances and consequent attenuation of Ca2+-sensitive K+ conductances resulting in spike broadening and attenuation of the afterhyperpolarization. Both of HVA and LVA attenuation also suggests a role to regulate intracelluar Ca2+, thereby to protect neurons from apoptosis. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

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