Abstract

Afferent input regulates neuronal dendritic patterning locally and globally through distinct mechanisms. To begin to understand these mechanisms, we differentially manipulate afferent input in vivo and assess effects on dendritic patterning of individual neurons in chicken nucleus laminaris (NL). Dendrites of NL neurons segregate into dorsal and ventral domains, receiving excitatory input from the ipsilateral and contralateral ears, respectively, via nucleus magnocellularis (NM). Blocking action potentials from one ear, by either cochlea removal or temporary treatment with tetrodotoxin (TTX), leads to rapid and significant retraction of affected NL dendrites (dorsal ipsilaterally and ventral contralaterally) within 8 h compared with the other dendrites of the same neurons. The degree of retraction is comparable with that induced by direct deafferentation resulting from transection of NM axons. Importantly, when inner ear activity is allowed to recover from TTX treatments, retracted NL dendrites regrow to their normal length within 48 h. The retraction and growth involve elimination of terminal branches and addition of new branches, respectively. Examination of changes in NL dendrites at 96 h after unilateral cochlea removal, a manipulation that induces cell loss in NM and persistent blockage of afferent excitatory action potentials, reveals a significant correlation between cell death in the ipsilateral NM and the degree of dendritic retraction in NL. These results demonstrate that presynaptic action potentials rapidly and reversibly regulate dendritic patterning of postsynaptic neurons in a compartment specific manner, whereas long-term dendritic maintenance may be regulated in a way that is correlated with the presence of silent presynaptic appositions.

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Publisher Full Text

Authors

Wang Y, Rubel EW

Institution

Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington School of Medicine, Seattle, Washington 98195, USA.

Source

The Journal of neuroscience : the official journal of the Society for Neuroscience 32:33 2012 Aug 15 pg 11495-504

MeSH

Acoustic Stimulation
Analysis of Variance
Animals
Animals, Newborn
Auditory Pathways
Brain Stem
Cell Death
Chickens
Dendrites
Dextrans
Evoked Potentials, Auditory, Brain Stem
Female
Imaging, Three-Dimensional
Male
Microtubule-Associated Proteins
Models, Neurological
Psychoacoustics
Sensory Deprivation
Sensory Receptor Cells
Sodium Channel Blockers
Tetrodotoxin
Time Factors

Pub Type(s)

In Vitro
Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22895732