Functional maturation of the first synapse in olfaction: development and adult neurogenesis.
The first synapse in olfaction undergoes considerable anatomical plasticity in both early postnatal development and adult neurogenesis, yet we know very little concerning its functional maturation at these times. Here, we used whole-cell recordings in olfactory bulb slices to describe olfactory nerve inputs to developing postnatal neurons and to maturing adult-born cells labeled with a GFP-encoding lentivirus. In both postnatal development and adult neurogenesis, the maturation of olfactory nerve synapses involved an increase in the relative contribution of AMPA over NMDA receptors, and a decrease in the contribution of NMDA receptors containing the NR2B subunit. These postsynaptic transformations, however, were not mirrored by presynaptic changes: in all cell groups, paired-pulse depression remained constant as olfactory nerve synapses matured. Although maturing cells may therefore offer, transiently, a functionally distinct connection for inputs from the nose, presynaptic function at the first olfactory connection remains remarkably constant in the face of considerable anatomical plasticity.
Grubb
Matthew S
MS
Perception and Memory Laboratory, Unité de Recherche Associée 2182, Centre National de la Recherche Scientifique, Institut Pasteur, F-75724 Paris Cedex 15, France.
Nissant
Antoine
A
Murray
Kerren
K
Lledo
Pierre-Marie
PM
D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation / Q000502:physiology; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009473:Neuronal Plasticity / Q000502:physiology*; D009474:Neurons / Q000166:cytology* / Q000502:physiology*; D012903:Smell / Q000502:physiology*; D013569:Synapses / Q000502:physiology*