Intrinsic Properties and Mechanisms of Spontaneous Firing in Mouse Cerebellar Unipolar Brush Cells.
From: Department of Physiology, Northwestern University Feinberg School of Medicine, 303 E. Chicago Avenue, Chicago, IL 60611, USA.
The Journal of physiology
- Publish Date: Jun 2007
- ISSN: 0022-3751
- Volume: 581
- Issue: Pt 2
- Pages: 709-24
- Medium: Print
- Language: English
- Citation (JAMA): Russo Marco J, Mugnaini Enrico, Martina Marco, et al. Intrinsic Properties and Mechanisms of Spontaneous Firing in Mouse Cerebellar Unipolar Brush Cells.. J. Physiol. (Lond.) Jun 2007;581:709-24
Abstract
Neuronal firing patterns are determined by the cell’s intrinsic electrical and morphological properties and are regulated by synaptic interactions. While the properties of cerebellar neurons have generally been studied in much detail, little is known about the unipolar brush cells (UBCs), a type of glutamatergic interneuron that is enriched in the granular layer of the mammalian vestibulocerebellum and participates in the representation of head orientation in space. Here we show that UBCs can be distinguished from adjacent granule cells on the basis of differences in membrane capacitance, input resistance and response to hyperpolarizing current injection. We also show that UBCs are intrinsically firing neurons. Using action potential clamp experiments and whole-cell recordings we demonstrate that two currents contribute to this property: a persistent TTX-sensitive sodium current and a ruthenium red-sensitive, TRP-like cationic current, both of which are active during interspike intervals and have reversal potentials positive to threshold. Interestingly, although UBCs are also endowed with a large I(h) current, this current is not involved in their intrinsic firing, perhaps because it activates at voltages that are more hyperpolarized than those associated with autonomous activity.
Mesh Headings (Keywords): Action Potentials, Animals, Cerebellum, Electric Capacitance, Electric Impedance, Electric Stimulation, Glutamic Acid, Interneurons, Membrane Potentials, Mice, Neural Conduction, Patch-Clamp Techniques, Ruthenium Red, Sodium, Sodium Channel Blockers, Sodium Channels, Tetrodotoxin, Transient Receptor Potential Channels
Check for Full Text / PubMed Unique Identifier (PMID): 17379636
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