title: Plasticity in fast synaptic inhibition of adult oxytocin neurons caused by switch in GABA(A) receptor subunit expression.
abstract: We found that magnocellular oxytocin neurons in adult female rats exhibit an endogenous GABA(A) receptor subunit switch around parturition: a decrease in alpha1:alpha2 subunit mRNA ratio correlated with a decrease in allopregnanolone potentiation and increase in decay time constant of the GABA(A) receptor-mediated IPSCs in these cells. The causal relationship between changes in alpha1:alpha2 mRNA ratio and the ion channel kinetics was confirmed using in vitro antisense deletion. Further, GABA(A) receptors exhibited a tonic inhibitory influence upon oxytocin release in vivo, and allopregnanolone helped to restrain oxytocin neuron in vitro firing only before parturition, when the alpha1:alpha2 subunit mRNA ratio was still high. Such observations provide evidence for the physiological significance of GABA(A) receptor subunit heterogeneity and plasticity in the adult brain.
authors.affiliation: Membrane Physiology Section, Research Institute Neurosciences, Vrije Universiteit Amsterdam, The Netherlands.
authors.forename: A B
authors.initials: AB
authors.lastname: Brussaard
authors.forename: K S
authors.initials: KS
authors.lastname: Kits
authors.forename: R E
authors.initials: RE
authors.lastname: Baker
authors.forename: W P
authors.initials: WP
authors.lastname: Willems
authors.forename: J W
authors.initials: JW
authors.lastname: Leyting-Vermeulen
authors.forename: P
authors.initials: P
authors.lastname: Voorn
authors.forename: A B
authors.initials: AB
authors.lastname: Smit
authors.forename: R J
authors.initials: RJ
authors.lastname: Bicknell
authors.forename: A E
authors.initials: AE
authors.lastname: Herbison
mesh_terms: D000818:Animals; D004553:Electric Conductivity; D004594:Electrophysiology; D005260:Female; D018757:GABA Modulators / Q000494:pharmacology; D007743:Labor, Obstetric / Q000378:metabolism; D009433:Neural Inhibition / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D010121:Oxytocin / Q000378:metabolism*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D011280:Pregnanolone / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011963:Receptors, GABA-A / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013495:Supraoptic Nucleus / Q000166:cytology / Q000378:metabolism; D013569:Synapses / Q000378:metabolism / Q000502:physiology*; D013997:Time Factors
chemical_list: D018757:GABA Modulators; D012333:RNA, Messenger; D011963:Receptors, GABA-A; D010121:Oxytocin; D011280:Pregnanolone