Dendritic Calcium Activity Precedes Inspiratory Bursts in preBotzinger Complex Neurons
Del Negro, Christopher A. Hayes, John A. Rekling, Jens C.
Del Negro, Christopher A.
Hayes, John A.
Rekling, Jens C.
Abstract
Medullary interneurons of the preBotzinger complex assemble excitatory networks that produce inspiratory-related neural rhythms, but the importance of somatodendritic conductances in rhythm generation is still incompletely understood. Synaptic input may cause Ca(2+) accumulation postsynaptically to evoke a Ca(2+)-activated inward current that contributes to inspiratory burst generation. We measured Ca(2+) transients by two-photon imaging dendrites while recording neuronal somata electrophysiologically. Dendritic Ca(2+) accumulation frequently precedes inspiratory bursts, particularly at recording sites 50-300 mu m distal from the soma. Preinspiratory Ca(2+) transients occur in hotspots, not ubiquitously, in dendrites. Ca(2+) activity propagates orthodromically toward the soma (and antidromically to more distal regions of the dendrite) at rapid rates (300-700 mu m/s). These high propagation rates suggest that dendritic Ca(2+) activates an inward current to electrotonically depolarize the soma, rather than propagate as a regenerative Ca(2+) wave. These data provide new evidence that respiratory rhythmogenesis may depend on dendritic burst-generating conductances activated in the context of network activity.
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2011-01-01
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Applied Science
DOI
https://doi.org/10.1523/JNEUROSCI.4731-10.2011