Developmental increase in postsynaptic alpha-amino-3-hydroxy-5-methyl-4 isoxazolepropionic acid receptor compartmentalization at the calyx of Held synapse.
The pattern of expression of ionotropic glutamate receptor (GluR) subunits 1-4 in the medial nucleus of the trapezoid body (MNTB) has been reported to change during development. The aim of this study was to compare the distribution of the GluR1-4 subunits in the MNTB at postnatal day (P) 9, before high-frequency signal transmission in the auditory system has developed, with that observed in mature adult rats. GluR1-4 subunits were studied by preembedding and postembedding immunocytochemical methods. Increased levels of GluR1, 2/3, and 4 associated with development were evident only at postsynaptic sites of MNTB principal cell bodies receiving calyces of Held synapses, whereas receptor density at nonsynaptic sites was found to remain unaltered. Taken together, the expression pattern of GluR subunits and the density of immunoparticles in postsynaptic specializations are indicative of a compartmentalization of alpha-amino-3-hydroxy-5-methyl-4 isoxazolepropionic acid (AMPA) subunits upon development. These developmental changes provide a morphological basis for establishment of the postsynaptic properties needed for high-frequency synaptic transmission of auditory signals to MNTB principal neurons.
Hermida
Diana
D
Department of Neurosciences, Faculty of Medicine and Dentistry, Basque Country University, E-48080 Bilbao, Vizcaya, Spain.
Elezgarai
Izaskun
I
Puente
Nagore
N
Alonso
Virginia
V
Anabitarte
Naroa
N
Bilbao
Aurora
A
Doñate-Oliver
Francisco
F
Grandes
Pedro
P
D000367:Age Factors; D000818:Animals; D017626:Cochlear Nucleus / Q000166:cytology* / Q000254:growth & development; D018690:Excitatory Amino Acid Agonists / Q000378:metabolism*; D007150:Immunohistochemistry; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D021122:Protein Subunits / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000378:metabolism*; D013569:Synapses / Q000502:physiology*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000378:metabolism*
D018690:Excitatory Amino Acid Agonists; D021122:Protein Subunits; D017470:Receptors, Glutamate; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid