title: Plasticity of hypothalamic dopamine neurons during lactation results in dissociation of electrical activity and release.
abstract: Tuberoinfundibular dopamine (TIDA) neurons are the central regulators of prolactin (PRL) secretion. Their extensive functional plasticity allows a change from low PRL secretion in the non-pregnant state to the condition of hyperprolactinemia that characterizes lactation. To allow this rise in PRL, TIDA neurons are thought to become unresponsive to PRL at lactation and functionally silenced. Here we show that, contrary to expectations, the electrical properties of the system were not modified during lactation and that the neurons remained electrically responsive to a PRL stimulus, with PRL inducing an acute increase in their firing rate during lactation that was identical to that seen in non-pregnant mice. Furthermore, we show a long-term organization of TIDA neuron electrical activity with an harmonization of their firing rates, which remains intact during lactation. However, PRL-induced secretion of dopamine (DA) at the median eminence was strongly blunted during lactation, at least in part attributable to lack of phosphorylation of tyrosine hydroxylase, the key enzyme involved in DA synthesis. We therefore conclude that lactation, rather than involving electrical silencing of TIDA neurons, represents a condition of decoupling between electrical activity at the cell body and DA secretion at the median eminence.
authors: CNRS, UMR-5203, Institut de Génomique Fonctionnelle, F-34000 Montpellier, France.
authors: Nicola
authors: N
authors: Romanò
authors: Siew H
authors: SH
authors: Yip
authors: David J
authors: DJ
authors: Hodson
authors: Anne
authors: A
authors: Guillou
authors: Sébastien
authors: S
authors: Parnaudeau
authors: Siobhan
authors: S
authors: Kirk
authors: François
authors: F
authors: Tronche
authors: Xavier
authors: X
authors: Bonnefont
authors: Paul
authors: P
authors: Le Tissier
authors: Stephen J
authors: SJ
authors: Bunn
authors: Dave R
authors: DR
authors: Grattan
authors: Patrice
authors: P
authors: Mollard
authors: Agnès O
authors: AO
authors: Martin
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001551:Benz(a)Anthracenes / Q000494:pharmacology; D001703:Biophysics; D004298:Dopamine / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics; D059290:Dopaminergic Neurons / Q000502:physiology*; D004558:Electric Stimulation; D005260:Female; D007026:Hypothalamic Area, Lateral / Q000166:cytology*; D066298:In Vitro Techniques; D007774:Lactation / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009473:Neuronal Plasticity / Q000235:genetics / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011388:Prolactin / Q000378:metabolism / Q000494:pharmacology; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D022661:RNA, Untranslated; D011863:Radioimmunoassay; D050493:Vesicular Monoamine Transport Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C541442:8-(2-amino-ethyl)-2,3,5,6-tetrahydro-1H,4H-11-oxa-3a-aza-benzo(de)anthracen-10-one; D001426:Bacterial Proteins; D001551:Benz(a)Anthracenes; D050483:Dopamine Plasma Membrane Transport Proteins; C110853:Gt(ROSA)26Sor non-coding RNA, mouse; D008164:Luminescent Proteins; D011506:Proteins; D022661:RNA, Untranslated; C493453:Slc18a2 protein, mouse; D050493:Vesicular Monoamine Transport Proteins; C054562:yellow fluorescent protein, Bacteria; D011388:Prolactin; D004298:Dopamine