title: Long term depression of MNTB-LSO synapses is expressed postsynaptically in developing circling mice.
abstract: Early onset long term depression (LTD) during the first postnatal week has rarely been demonstrated at the medial nucleus of trapezoid body (MNTB) - lateral superior olive (LSO) synapses in spite of many favorable conditions, such as depolarizing synapses and glutamate co-release from MNTB terminals. Thus, we tested the early expression of LTD at MNTB-LSO synapses during the first postnatal week using circling mice, whose main transmitter is glutamate at MNTB-LSO synapses. Tetanic stimulation on MNTB elicited LTD of postsynaptic currents recorded at LSO neurons in P0-P3 homozygous (cir/cir) mice (45.8 ± 0.3% of the control, n = 7) and heterozygous (+/cir) mice (43.3 ± 0.4% of the control, n = 7). The magnitude of LTD decreased in P8-P12 heterozygous (+/cir) mice (84.5 ± 0.3% of the control, n = 7), but was maintained in P8-P12 homozygous (cir/cir) mice (38.2 ± 0.3% of the control, n = 9). Glutamatergic LTD observed in homozygous (cir/cir) mice and glycinergic LTD observed heterozygous (+/cir) mice showed similar pattern of change. As currents induced by the pressure application of glycine on LSO neurons were reduced by tetanic stimulation in P0-P3 heterozygous (+/cir) mice, LTD was thought to occur at postsynaptic sites. Our results suggest that LTD might occur in vivo and participate in the synaptic silencing and strengthening of MNTB-LSO synapses, which is most active during the first postnatal week.
authors.affiliation: Department of Nanobio Medical Science, Dankook University, San 29, Anseo-dong, Cheonan-si, Chungnam 330-714, South Korea.
authors.forename: Jonu
authors.initials: J
authors.lastname: Pradhan
authors.forename: Dhiraj
authors.initials: D
authors.lastname: Maskey
authors.forename: Seung Cheol
authors.initials: SC
authors.lastname: Ahn
mesh_terms: D000367:Age Factors; D000818:Animals; D004558:Electric Stimulation / Q000379:methods; D018698:Glutamic Acid / Q000502:physiology; D005998:Glycine / Q000494:pharmacology / Q000502:physiology; D036881:Long-Term Synaptic Depression / Q000502:physiology*; D051379:Mice; D008818:Mice, Neurologic Mutants; D009433:Neural Inhibition / Q000502:physiology; D009847:Olivary Nucleus / Q000502:physiology*; D055366:Synaptic Potentials / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*
chemical_list: D018698:Glutamic Acid; D005998:Glycine