Oxytocin and estrogen promote rapid formation of functional GABA synapses in the adult supraoptic nucleus.
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.
Inserm, U 378, Bordeaux F33077 France; University Victor Segalen, Bordeaux F33077, France. dionysia.theodosis@bordeaux.inserm.fr
Dionysia T
DT
Theodosis
Jan-Jurjen
JJ
Koksma
Andrei
A
Trailin
Sarah L
SL
Langle
Richard
R
Piet
Johannes C
JC
Lodder
Jaap
J
Timmerman
Huibert
H
Mansvelder
Dominique A
DA
Poulain
Stéphane H R
SH
Oliet
Arjen B
AB
Brussaard
D000818:Animals; D004967:Estrogens / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010121:Oxytocin / Q000378:metabolism / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D013495:Supraoptic Nucleus / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D013569:Synapses / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D004967:Estrogens; D010121:Oxytocin; D005680:gamma-Aminobutyric Acid