| Role of low-voltage-activated calcium current on the firing pattern alterations induced by hypothyroidism in the rat hippocampus. | |
| | |
MedLine Citation:
|
PMID: 20933578 Owner: NLM Status: In-Process |
Abstract/OtherAbstract:
|
Thyroid hormone deficiency during a critical period of development severely affects cognitive functions, resulting in profound mental retardation. Despite the importance of the disorder, the cellular mechanisms underlying these deficits remain largely unexplored. The aim of this study was to examine the effects of the absence of thyroid hormone on the development of the intrinsic properties of CA1 hippocampal pyramidal cells. These cells are known to exhibit different firing patterns during development, being classified as either regular-spiking or burst-spiking cells. Patch-clamp experiments showed that hypothyroid rats presented a larger number of regular-spiking cells at early postnatal age (P9-11). This difference in firing-pattern distribution disappeared at the pre-weanling age (P17-19), when almost every cell displayed bursting behavior in both control and hypothyroid rats. However, when studied in detail, weanling hypothyroid rats presented a smaller number of spikes per burst than did control animals. One of the major factors behind bursting behavior is sustained depolarization following an action potential. In this study, we show that action potential afterdepolarizations of hypothyroid animals registered shorter half-durations than did controls, a fact which could explain the smaller number of action potentials per burst. Additionally, the afterdepolarizations observed on both hypothyroid and control neurons were highly sensitive to low concentrations of nickel, suggesting that a low-threshold Ca(2+) current is key in the generation of spike afterdepolarizations and in the control of the bursting pattern of firing of these neurons. In agreement with this, experiments performed on dissociated hippocampal neurons have shown that this current is significantly depressed in hypothyroid animals. Therefore, we conclude that an alteration of the low-threshold calcium current is the basic factor explaining the differences observed in the firing behavior of hypothyroid animals. |
| | |
Authors:
|
J L Sánchez-Alonso; J Muñoz-Cuevas; M A Vicente-Torres; A Colino |
Related Documents
:
|
7308358 - The variability of discharge of simple cells in the cat striate cortex. 7738288 - Cardiac rhythmic patterns in neuronal activity are related to the firing rate of the ne... 22606038 - Localization of axonal motor molecules machinery in neurodegenerative disorders. 9756378 - Analgesic and sedative concentrations of lignocaine shunt tonic and burst firing in tha... 9704888 - Parallel nature of hippocampal synaptic plasticity. 12893418 - Brain activation to phobia-related pictures in spider phobic humans: an event-related f... |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-10-08 |
Journal Detail:
|
Title: Neuroscience Volume: 171 ISSN: 1873-7544 ISO Abbreviation: Neuroscience Publication Date: 2010 Dec |
Date Detail:
|
Created Date: 2010-11-24 Completed Date: - Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 7605074 Medline TA: Neuroscience Country: United States |
Other Details:
|
Languages: eng Pagination: 993-1005 Citation Subset: IM |
Copyright Information:
|
Published by Elsevier Ltd. |
Affiliation:
|
Departamento de Fisiología, Facultad de Medicina, Universidad Complutense, Ciudad Universitaria, 28040 Madrid, Spain. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
|
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Enriched environment promotes similar neuronal and behavioral recovery in a young and aged mouse mod...
Next Document: Blockade of central nicotine acetylcholine receptor signaling attenuate ghrelin-induced food intake ...