Dendrite elongation and dendritic branching are affected separately by different forms of intrinsic motoneuron excitability.
Dendrites are the fundamental determinant of neuronal wiring. Consequently dendritic defects are associated with numerous neurological diseases and mental retardation. Neuronal activity can have profound effects on dendritic structure, but the mechanisms controlling distinct aspects of dendritic architecture are not fully understood. We use the Drosophila genetic model system to test the effects of altered intrinsic excitability on postembryonic dendritic architecture development. Targeted dominant negative knock-downs of potassium channel subunits allow for selectively increasing the intrinsic excitability of a selected subset of motoneurons, whereas targeted expression of a genetically modified noninactivating potassium channel decrease intrinsic excitability in vivo. Both manipulations cause significant dendritic overgrowth, but by different mechanisms. Increased excitability causes increased dendritic branch formation, whereas decreased excitability causes increased dendritic branch elongation. Therefore dendritic branching and branch elongation are controlled by separate mechanisms that can be addressed selectively in vivo by different manipulations of neuronal intrinsic excitability.
Duch
Carsten
C
School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA. Carsten.duch@asu.edu
Vonhoff
Fernando
F
Ryglewski
Stefanie
S
D000704:Analysis of Variance; D000818:Animals; D030801:Animals, Genetically Modified; D000831:Animals, Newborn; D001522:Behavior, Animal; D016827:CD8 Antigens / Q000235:genetics / Q000378:metabolism; D003712:Dendrites / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster; D004558:Electric Stimulation; D005260:Female; D017952:Ganglia, Invertebrate / Q000166:cytology; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D066298:In Vitro Techniques; D008124:Locomotion / Q000235:genetics; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D009043:Motor Activity / Q000235:genetics; D009046:Motor Neurons / Q000145:classification* / Q000166:cytology* / Q000502:physiology; D018408:Patch-Clamp Techniques; D051637:Shaker Superfamily of Potassium Channels / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D016827:CD8 Antigens; D029721:Drosophila Proteins; C496929:Sh protein, Drosophila; D051637:Shaker Superfamily of Potassium Channels; D014157:Transcription Factors; D049452:Green Fluorescent Proteins