Premium
Dendritic excitability and calcium signalling in the mitral cell distal glomerular tuft
Author(s) -
Zhou Zhishang,
Xiong Wenhui,
Zeng Shaoqun,
Xia Andong,
Shepherd Gordon M.,
Greer Charles A.,
Chen Wei R.
Publication year - 2006
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2006.05076.x
Subject(s) - tuft , soma , glomerulus , neuroscience , olfactory bulb , dendritic spike , calcium imaging , chemistry , excitatory postsynaptic potential , dendrite (mathematics) , calcium , anatomy , biology , biophysics , central nervous system , inhibitory postsynaptic potential , physics , endocrinology , geometry , mathematics , organic chemistry , kidney , thermodynamics
The processing of odour information starts at the level of the olfactory glomerulus, where the mitral cell distal dendritic tuft not only receives olfactory nerve sensory input but also generates dendrodendritic output to form complicated glomerular synaptic circuits. Analysing the membrane properties and calcium signalling mechanisms in these tiny dendritic branches is crucial for understanding how the glomerular tuft transmits and processes olfactory signals. With the use of two‐photon Ca 2+ imaging in rat olfactory bulb slices, we found that these distal dendritic branches displayed a significantly larger Ca 2+ signal than the soma and primary dendrite trunk. A back‐propagating action potential was able to trigger a Ca 2+ increase throughout the entire glomerular tuft, indicative of the presence of voltage‐gated Ca 2+ conductances in all branches at different levels of ramification. In response to a train of action potentials evoked at 60 Hz from the soma, the tuft Ca 2+ signal increased linearly with the number of action potentials, suggesting that these glomerular branches were able to support repetitive penetration of Na + action potentials. When a strong olfactory nerve excitatory input was paired with an inhibition from mitral cell basal dendrites, a small spike‐like fast prepotential was revealed at both the soma and distal primary dendrite trunk. Corresponding to this fast prepotential was a Ca 2+ increase confined locally within the glomerular tuft. In summary, the mitral cell distal dendritic tuft possesses both Na + and Ca 2+ voltage‐dependent conductances which can mediate glomerular Ca 2+ responsiveness critical for dendrodendritic output and synaptic plasticity.