Research ArticleNitric Oxide-Dependent LTD at Infralimbic Cortex
Section snippets
INTRODUCTION
The infralimbic cortex (IL) is a portion of ventromedial prefrontal cortex (mPFC) that receives projection from the basolateral complex of the amygdala and play an essential role in the extinction of fear-conditioning responses (Little and Carter, 2012, Little and Carter, 2013, Do-Monte et al., 2015). The amygdala projects to layer 2/3 of IL (Little and Carter, 2012, Little and Carter, 2013) and most subcortical projection pathways originated predominantly from layer 5 of the IL (Gabbott et
Ethics statement
All animal procedures were approved by the Ethical Committee of the Universidad Autónoma de Madrid (CEI72–1286-A156) and in accordance with European Community Council Directive 2010/63/UE. All effort was made to minimize animal suffering and to promote the animal welfare.
Slice preparation
Sprague–Dawley rats (12–18 days old) were decapitated, and brains were removed and submerged in cold (4 °C) cutting solution containing (in mM): 189.0 sucrose, 10.0 glucose, 26.0 NaHCO3, 3.0 KCl, 5.0 Mg2SO4, 0.1 CaCl2, and 1.25
The Ca2+-spikes induce LTD of the postsynaptic currents
Recordings were obtained from the soma of L5 PNs of the IL (Fig. 1A). In control ACSF, basal stimulation induced an PSP followed by a single AP when the depolarization reached a threshold level. Indeed, The AP rode on a slow depolarization wave (peak amplitude 24.91 ± 2.28 mV; duration 176.24 ± 14.23 ms; Fig. 1C) that exhibit the all-or-none behavior of a calcium spike (Ca2+-spike) because it was not modified when stimulation intensity was increased. Indeed, the Ca2+-spike was absent in the
DISCUSSION
In this work we show a LTD of excitatory synaptic transmission induced by low frequency stimulation at basal dendrites of L5 PNs in IL. We demonstrate that this stimulation generates an PSP followed by an AP and a Ca2+-spike. The PSP followed by the Ca2+-spikes produce the necessary calcium influx through the NMDARs and L-type VGCCs for the induction of the LTD of the EPSCs. We show that this LTD is mediated by a decrease in the probability of release of glutamate and requires the activation of
Acknowledgements
This work was supported by grants from Ministerio de Ciencia e innovación, Spain (MICINN; BFU2011-23522) and Ministerio de Economía y Competitividad, Spain (MINECO; BFU2013-43668-P and BFU2016-80802-P AEI/FEDER, UE) to Dr. D. Fernández de Sevilla, professor at the Departamento de Anatomía, Histología y Neurociencia, Facultad de Medicina, Universidad Autónoma de Madrid.
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