Dendritic calcium activity precedes inspiratory bursts in preBotzinger complex neurons

TY - JOUR

T1 - Dendritic calcium activity precedes inspiratory bursts in preBotzinger complex neurons

AU - Del Negro, Christopher A

AU - Hayes, John A

AU - Rekling, Jens C

PY - 2011/1/19

Y1 - 2011/1/19

N2 - Medullary interneurons of the preBötzinger 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 Ca2+ accumulation postsynaptically to evoke a Ca2+-activated inward current that contributes to inspiratory burst generation. We measured Ca2+ transients by two-photon imaging dendrites while recording neuronal somata electrophysiologically. Dendritic Ca2+ accumulation frequently precedes inspiratory bursts, particularly at recording sites 50 -300 μm distal from the soma. Preinspiratory Ca2+ transients occur in hotspots, not ubiquitously, in dendrites. Ca2+ activity propagates orthodromically toward the soma (and antidromically to more distal regions of the dendrite) at rapid rates (300 -700 μm/s). These high propagation rates suggest that dendritic Ca2+ activates an inward current to electrotonically depolarize the soma, rather than propagate as a regenerative Ca2+ wave. These data provide new evidence that respiratory rhythmogenesis may depend on dendritic burst-generating conductances activated in the context of network activity. Copyright

AB - Medullary interneurons of the preBötzinger 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 Ca2+ accumulation postsynaptically to evoke a Ca2+-activated inward current that contributes to inspiratory burst generation. We measured Ca2+ transients by two-photon imaging dendrites while recording neuronal somata electrophysiologically. Dendritic Ca2+ accumulation frequently precedes inspiratory bursts, particularly at recording sites 50 -300 μm distal from the soma. Preinspiratory Ca2+ transients occur in hotspots, not ubiquitously, in dendrites. Ca2+ activity propagates orthodromically toward the soma (and antidromically to more distal regions of the dendrite) at rapid rates (300 -700 μm/s). These high propagation rates suggest that dendritic Ca2+ activates an inward current to electrotonically depolarize the soma, rather than propagate as a regenerative Ca2+ wave. These data provide new evidence that respiratory rhythmogenesis may depend on dendritic burst-generating conductances activated in the context of network activity. Copyright

KW - Action Potentials

KW - Animals

KW - Calcium

KW - Dendrites

KW - Electrophysiology

KW - Mice

KW - Neurons

KW - Respiratory Center

U2 - 10.1523/JNEUROSCI.4731-10.2011

DO - 10.1523/JNEUROSCI.4731-10.2011

M3 - Journal article

C2 - 21248126

SN - 0270-6474

VL - 31

SP - 1017

EP - 1022

JO - Journal of Neuroscience

JF - Journal of Neuroscience

IS - 3

ER -