Inward rectifier potassium (Kir) current in dopaminergic periglomerular neurons of the mouse olfactory bulb

Dopaminergic (DA) periglomerular (PG) neurons are critically placed at the entry of the bulbar circuitry, directly in contact with both the terminals of olfactory sensory neurons and the apical dendrites of projection neurons; they are autorhythmic and are the target of numerous terminals releasing...

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Main Authors:	Borin, Mirta, Fogli Iseppe, Alex, Pignatelli, Angela, Belluzzi, Ottorino
Format:	Online
Language:	English
Published:	Frontiers Media S.A. 2014
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4126183/

id	pubmed-4126183
recordtype	oai_dc
spelling	pubmed-41261832014-08-22 Inward rectifier potassium (Kir) current in dopaminergic periglomerular neurons of the mouse olfactory bulb Borin, Mirta Fogli Iseppe, Alex Pignatelli, Angela Belluzzi, Ottorino Neuroscience Dopaminergic (DA) periglomerular (PG) neurons are critically placed at the entry of the bulbar circuitry, directly in contact with both the terminals of olfactory sensory neurons and the apical dendrites of projection neurons; they are autorhythmic and are the target of numerous terminals releasing a variety of neurotransmitters. Despite the centrality of their position, suggesting a critical role in the sensory processing, their properties -and consequently their function- remain elusive. The current mediated by inward rectifier potassium (Kir) channels in DA-PG cells was recorded by adopting the perforated-patch configuration in thin slices; IKir could be distinguished from the hyperpolarization-activated current (Ih) by showing full activation in <10 ms, no inactivation, suppression by Ba2+ in a typical voltage-dependent manner (IC50 208 μM) and reversal potential nearly coincident with EK. Ba2+ (2 mM) induces a large depolarization of DA-PG cells, paralleled by an increase of the input resistance, leading to a block of the spontaneous activity, but the Kir current is not an essential component of the pacemaker machinery. The Kir current is negatively modulated by intracellular cAMP, as shown by a decrease of its amplitude induced by forskolin or 8Br-cAMP. We have also tested the neuromodulatory effects of the activation of several metabotropic receptors known to be present on these cells, showing that the current can be modulated by a multiplicity of pathways, whose activation in some case increases the amplitude of the current, as can be observed with agonists of D2, muscarinic, and GABAA receptors, whereas in other cases has the opposite effect, as it can be observed with agonists of α1 noradrenergic, 5-HT and histamine receptors. These characteristics of the Kir currents provide the basis for an unexpected plasticity of DA-PG cell function, making them potentially capable to reconfigure the bulbar network to allow a better flexibility. Frontiers Media S.A. 2014-08-08 /pmc/articles/PMC4126183/ /pubmed/25152712 http://dx.doi.org/10.3389/fncel.2014.00223 Text en Copyright © 2014 Borin, Fogli Iseppe, Pignatelli and Belluzzi. http://creativecommons.org/licenses/by/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Borin, Mirta Fogli Iseppe, Alex Pignatelli, Angela Belluzzi, Ottorino
spellingShingle	Borin, Mirta Fogli Iseppe, Alex Pignatelli, Angela Belluzzi, Ottorino Inward rectifier potassium (Kir) current in dopaminergic periglomerular neurons of the mouse olfactory bulb
author_facet	Borin, Mirta Fogli Iseppe, Alex Pignatelli, Angela Belluzzi, Ottorino
author_sort	Borin, Mirta
title	Inward rectifier potassium (Kir) current in dopaminergic periglomerular neurons of the mouse olfactory bulb
title_short	Inward rectifier potassium (Kir) current in dopaminergic periglomerular neurons of the mouse olfactory bulb
title_full	Inward rectifier potassium (Kir) current in dopaminergic periglomerular neurons of the mouse olfactory bulb
title_fullStr	Inward rectifier potassium (Kir) current in dopaminergic periglomerular neurons of the mouse olfactory bulb
title_full_unstemmed	Inward rectifier potassium (Kir) current in dopaminergic periglomerular neurons of the mouse olfactory bulb
title_sort	inward rectifier potassium (kir) current in dopaminergic periglomerular neurons of the mouse olfactory bulb
description	Dopaminergic (DA) periglomerular (PG) neurons are critically placed at the entry of the bulbar circuitry, directly in contact with both the terminals of olfactory sensory neurons and the apical dendrites of projection neurons; they are autorhythmic and are the target of numerous terminals releasing a variety of neurotransmitters. Despite the centrality of their position, suggesting a critical role in the sensory processing, their properties -and consequently their function- remain elusive. The current mediated by inward rectifier potassium (Kir) channels in DA-PG cells was recorded by adopting the perforated-patch configuration in thin slices; IKir could be distinguished from the hyperpolarization-activated current (Ih) by showing full activation in <10 ms, no inactivation, suppression by Ba2+ in a typical voltage-dependent manner (IC50 208 μM) and reversal potential nearly coincident with EK. Ba2+ (2 mM) induces a large depolarization of DA-PG cells, paralleled by an increase of the input resistance, leading to a block of the spontaneous activity, but the Kir current is not an essential component of the pacemaker machinery. The Kir current is negatively modulated by intracellular cAMP, as shown by a decrease of its amplitude induced by forskolin or 8Br-cAMP. We have also tested the neuromodulatory effects of the activation of several metabotropic receptors known to be present on these cells, showing that the current can be modulated by a multiplicity of pathways, whose activation in some case increases the amplitude of the current, as can be observed with agonists of D2, muscarinic, and GABAA receptors, whereas in other cases has the opposite effect, as it can be observed with agonists of α1 noradrenergic, 5-HT and histamine receptors. These characteristics of the Kir currents provide the basis for an unexpected plasticity of DA-PG cell function, making them potentially capable to reconfigure the bulbar network to allow a better flexibility.
publisher	Frontiers Media S.A.
publishDate	2014
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4126183/
_version_	1613122388452442112

Inward rectifier potassium (Kir) current in dopaminergic periglomerular neurons of the mouse olfactory bulb

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