Oxytocin and estrogen promote rapid formation of functional GABA synapses in the adult supraoptic nucleus

Dionysia T. Theodosis, Jan-Jurjen Koksma, Andrei Trailin, Sarah L. Langle, Richard Piet, Johannes C. Lodder, Jaap Timmerman, Huibert Mansvelder, Dominique A. Poulain, Stéphane H.R. Oliet, Arjen B. Brussaard
Molecular and Cellular Neuroscience. 2006-04-01; 31(4): 785-794
DOI: 10.1016/j.mcn.2006.01.006

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1. Mol Cell Neurosci. 2006 Apr;31(4):785-94. Epub 2006 Feb 20.

Oxytocin and estrogen promote rapid formation of functional GABA synapses in the
adult supraoptic nucleus.

Theodosis DT(1), Koksma JJ, Trailin A, Langle SL, Piet R, Lodder JC, Timmerman J,
Mansvelder H, Poulain DA, Oliet SH, Brussaard AB.

Author information:
(1)Inserm, U 378, Bordeaux F33077 France; University Victor Segalen, Bordeaux
F33077, France.

We here investigated inhibitory synapse turnover in the adult brain using the
hypothalamic supraoptic nucleus where new synapses form during different
physiological conditions, in particular on oxytocin neurons largely controlled by
GABAergic inputs and locally released oxytocin. Patch clamp recordings and
ultrastructural analysis of the nucleus in acute slices from late gestating rats
showed that oxytocin and estrogen promoted rapid formation of inhibitory
synapses. Thus, after 2-h exposure to a combination of oxytocin and 17-beta
estradiol, the frequency of miniature inhibitory postsynaptic currents was
significantly enhanced. Since their amplitude and presynaptic GABA release
probability were unmodified, this indicated an increased number of synapses.
Electron microscopy confirmed increased densities of symmetric, putative
GABAergic synapses within 2-h exposure to the peptide or steroid, effects which
were reversible and oxytocin receptor mediated. Our observations thus offer
direct evidence that hypothalamic GABAergic microcircuitries can undergo rapid
and functional remodeling under changing neuroendocrine conditions.

DOI: 10.1016/j.mcn.2006.01.006
PMID: 16488155 [Indexed for MEDLINE]

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