Glycinergic/GABAergic synapses in the lateral superior olive are excitatory in neonatal C57Bl/6J mice.
The lateral superior olive (LSO), a nucleus involved in sound localization, receives tonotopically organized, inhibitory input from the medial nucleus of the trapezoid body (MNTB). To better understand the development of this glycinergic/GABAergic pathway, we used Gramicidin-perforated patch clamp recordings to characterize MNTB-evoked postsynaptic potentials in LSO neurons of neonatal C57Bl/6J mice. We found that during the first postnatal week, MNTB-evoked responses change from being depolarizing to being hyperpolarizing. Most interestingly, depolarizing glycinergic/GABAergic synaptic potentials were able to trigger action potentials, demonstrating that the MNTB-LSO pathway can act as a true excitatory pathway. This transient excitatory action of immature MNTB-LSO synapses might play an important role in activity-dependent sharpening of the tonotopic organization of inhibitory connections in the LSO.
Kullmann
P H
PH
Department of Neurobiology, University of Pittsburgh School of Medicine, 3500 Terrace Street, Pittsburgh, PA 15261, USA.
Kandler
K
K
D000818:Animals; D000831:Animals, Newborn; D001306:Auditory Pathways / Q000254:growth & development / Q000502:physiology; D002712:Chlorides / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005998:Glycine / Q000502:physiology*; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D009847:Olivary Nucleus / Q000254:growth & development* / Q000502:physiology*; D018408:Patch-Clamp Techniques; D013017:Sound Localization / Q000502:physiology; D013569:Synapses / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D002712:Chlorides; D005680:gamma-Aminobutyric Acid; D005998:Glycine