Calcium-Independent Afterdepolarization Regulated by Serotonin in Anterior Thalamus
Department of Psychiatry and Behavioral Neurosciences and Cellular and Clinical Neurobiology Training Program, Wayne State University School of Medicine, Detroit, Michigan 48201 Chapin, Esther M. and Rodrigo Andrade. Calcium-Independent Afterdepolarization Regulated by Serotonin in Anterior Thalamus...
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Published in | Journal of neurophysiology Vol. 83; no. 5; pp. 3173 - 3176 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
United States
Am Phys Soc
01.05.2000
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Subjects | |
Online Access | Get full text |
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Summary: | Department of Psychiatry and Behavioral Neurosciences and Cellular
and Clinical Neurobiology Training Program, Wayne State University
School of Medicine, Detroit, Michigan 48201
Chapin, Esther M. and
Rodrigo Andrade.
Calcium-Independent Afterdepolarization Regulated by Serotonin in
Anterior Thalamus. J. Neurophysiol. 83: 3173-3176, 2000. Previous studies have identified an
afterdepolarization (ADP) in thalamocortical neurons that is mediated
by an upregulation of the hyperpolarization-activated current
I h . This ADP has been suggested to play a
key role in the generation of spindle oscillations. In the lateral
geniculate nucleus, upregulation of I h has
been shown to be signaled by a rise in intracellular calcium leading to
the activation of adenylate cyclase and formation of cAMP. However, it
is unclear how generalizable this mechanism is to other thalamic
nuclei. We have used whole cell recording to examine the
electrophysiological properties of neurons of the anterodorsal thalamic
nucleus, a nucleus thought not to undergo spindle oscillations. We now
report that cells in this nucleus also display an ADP mediated by
I h . Surprisingly, the ADP and the underlying
upregulation of I h persisted even after
buffering intracellular calcium and blocking calcium influx. These
results indicate that, in neurons of the anterodorsal thalamic nucleus,
an I h -mediated ADP can occur through a
mechanism that does not involve a rise in intracellular calcium. We
next examined the possibility that this calcium-independent ADP might
be modulated by serotonin. Serotonin produced a robust enhancement in
the amplitude of the ADP even after strong buffering of intracellular
calcium and blockade of calcium channels. These results indicate that
neurons of the anterodorsal thalamic nucleus display a
calcium-independent, I h -mediated ADP and
that this ADP is a target for regulation by serotonin. These findings
identify a novel mechanism by which serotonin can regulate neuronal excitability. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2 |
ISSN: | 0022-3077 1522-1598 |
DOI: | 10.1152/jn.2000.83.5.3173 |