Periglomerular (PG) cells of the olfactory bulb are a heterogeneous population of neurons, of which three distinct subtypes are currently recognized: those containing GABA (comprising also the TH-positive PG cells), and those expressing either calbindin or calretinin (the non-GABAergic PG cells). In this study, we have re-evaluated the neurochemical signature of PG cells using a knock-in mouse line expressing green fluorescent protein (GFP) under the control of GAD67 (Tamamaki et al., J. Comp. Neurol. 467:60-79, 2003). Using antibodies against TH, calbindin and calretinin, we found that all these markers were extensively colocalized with GFP-expressing cells (colocalization rate was 97.8%, 98.8% and 94.5%, respectively). Calretinin-positive cells were the largest group, accounting for 33.4% of all GFP-positive cells, followed by TH-cells (18.8%) and calbindin-cells (15.1%). Because there was no overlap between these neuronal populations, we estimated that they accounted for approximately 70% of all GABA-positive PG cells. To determine whether PG cells expressing calbindin and calretinin establish GABAergic synapses, we labelled sections of rat olfactory bulb with antibodies against the 1 and 3 subunits of GABAA receptors, which are expressed by mitral and tufted cells. Using laser scanning confocal microscopy, we found that profiles labelled for calbindin and calretinin were frequently apposed to GABAA receptor-immunofluorescent clusters, suggesting that they establish synapses with postsynaptic dendrites expressing GABAA receptors. Furthermore, double pre-embedding electron microscopy revealed colocalization of calretinin with glutamic acid decarboxylase in dendritic profiles. Taken together, these findings suggest that GABAergic PG cells are a complex neuronal population which includes distinct subtypes of neurons expressing either TH, calretinin or calbindin.

Neurochemical identity of periglomerular cells in the olfactory bulb of GAD67-GFP knock-in mice

PANZANELLI, Patrizia;SASSOE' POGNETTO, Marco
2005-01-01

Abstract

Periglomerular (PG) cells of the olfactory bulb are a heterogeneous population of neurons, of which three distinct subtypes are currently recognized: those containing GABA (comprising also the TH-positive PG cells), and those expressing either calbindin or calretinin (the non-GABAergic PG cells). In this study, we have re-evaluated the neurochemical signature of PG cells using a knock-in mouse line expressing green fluorescent protein (GFP) under the control of GAD67 (Tamamaki et al., J. Comp. Neurol. 467:60-79, 2003). Using antibodies against TH, calbindin and calretinin, we found that all these markers were extensively colocalized with GFP-expressing cells (colocalization rate was 97.8%, 98.8% and 94.5%, respectively). Calretinin-positive cells were the largest group, accounting for 33.4% of all GFP-positive cells, followed by TH-cells (18.8%) and calbindin-cells (15.1%). Because there was no overlap between these neuronal populations, we estimated that they accounted for approximately 70% of all GABA-positive PG cells. To determine whether PG cells expressing calbindin and calretinin establish GABAergic synapses, we labelled sections of rat olfactory bulb with antibodies against the 1 and 3 subunits of GABAA receptors, which are expressed by mitral and tufted cells. Using laser scanning confocal microscopy, we found that profiles labelled for calbindin and calretinin were frequently apposed to GABAA receptor-immunofluorescent clusters, suggesting that they establish synapses with postsynaptic dendrites expressing GABAA receptors. Furthermore, double pre-embedding electron microscopy revealed colocalization of calretinin with glutamic acid decarboxylase in dendritic profiles. Taken together, these findings suggest that GABAergic PG cells are a complex neuronal population which includes distinct subtypes of neurons expressing either TH, calretinin or calbindin.
2005
35th Annual Meeting Society for Neuroscience
Washington
12 novembre 2005
Soc. Neurosci. Abstr
Society for Neuroscience
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Panzanelli P; Fritschy JM; Yanagawa Y; Sassoe-Pognetto M
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/70469
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