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Original Research ARTICLE

Front. Cell. Neurosci., 08 March 2012 | http://dx.doi.org/10.3389/fncel.2012.00007

Midbrain dopaminergic neurons generate calcium and sodium currents and release dopamine in the striatum of pups

Diana C. Ferrari1,2, Baya J. Mdzomba1,2†, Nathalie Dehorter1,2†, Catherine Lopez1,2, François J. Michel1,2, Frédéric Libersat1,2† and Constance Hammond1,2*
  • 1Institut National de la Recherche Médicale et de la Santé Inserm, INMED UMR 901, Marseille, France
  • 2Faculté des Sciences, Aix Marseille Université, Marseille, France

Midbrain dopaminergic neurons (mDA neurons) are essential for the control of diverse motor and cognitive behaviors. However, our understanding of the activity of immature mDA neurons is rudimentary. Rodent mDA neurons migrate and differentiate early in embryonic life and dopaminergic axons enter the striatum and contact striatal neurons a few days before birth, but when these are functional is not known. Here, we recorded Ca2+ transients and Na+ spikes from embryonic (E16–E18) and early postnatal (P0–P7) mDA neurons with dynamic two-photon imaging and patch clamp techniques in slices from tyrosine hydroxylase-GFP mice, and measured evoked dopamine release in the striatum with amperometry. We show that half of identified E16–P0 mDA neurons spontaneously generate non-synaptic, intrinsically driven Ca2+ spikes and Ca2+ plateaus mediated by N- and L-type voltage-gated Ca2+ channels. Starting from E18–P0, half of the mDA neurons also reliably generate overshooting Na+ spikes with an abrupt maturation at birth (P0 = E19). At that stage (E18–P0), dopaminergic terminals release dopamine in a calcium-dependent manner in the striatum in response to local stimulation. This suggests that mouse striatal dopaminergic synapses are functional at birth.

Keywords: development, basal ganglia, substantia nigra, dopamine, immature activity, patch clamp, two-photons imaging

Citation: Ferrari DC, Mdzomba BJ, Dehorter N, Lopez C, Michel FJ, Libersat F and Hammond C (2012) Midbrain dopaminergic neurons generate calcium and sodium currents and release dopamine in the striatum of pups. Front. Cell. Neurosci. 6:7. doi: 10.3389/fncel.2012.00007

Received: 16 December 2011; Accepted: 11 February 2012;
Published online: 08 March 2012.

Edited by:

Enrico Cherubini, International School for Advanced Studies, Italy

Reviewed by:

Nicola B. Mercuri, University of Rome, Italy
Kazuto Kobayashi, Fukushima Medical University, Japan

Copyright: © 2012 Ferrari, Mdzomba, Dehorter, Lopez, Michel, Libersat and Hammond. This is an open-access article distributed under the terms of the Creative Commons Attribution Non Commercial License, which permits non-commercial use, distribution, and reproduction in other forums, provided the original authors and source are credited.

*Correspondence: Constance Hammond, Institut National de la Recherche Médicale et de la Santé Inserm, INMED UMR 901, 163 route de Luminy, BP13, 13273 Marseille Cédex 9, France. e-mail: hammond@inmed.univ-mrs.fr

Present address: Baya J. Mdzomba, Bernstein Focus Neurotechnology and Johann-Friedrich-Blumenbach Institute for Zoology and Anthropology, University of Göttingen, D-37075 Göttingen, Germany.
Nathalie Dehorter, Instituto de Neurociencias de Alicante CSIC, Universidad Miguel Hernández 03550 Alicante, España.
Frédéric Libersat, Department of Life Sciences, Ben Gurion University, POB 653, Beer Sheva, Israel.