Spatial profile of dendritic calcium transients evoked by action potentials in rat neocortical pyramidal neurones

摘要: 1. Simultaneous measurements of intracellular free calcium concentration ([Ca2+]i) and intrasomatic intradendritic membrane potential (Vm) were performed using fura-2 fluorimetry whole-cell recording in neocortical layer V pyramidal neurones rat brain slices. 2. Back-propagating action potentials (APs) evoked [Ca2+]i transients the entire neurone including soma, axon initial segment, apical dendrite up to distal tuft branches, oblique basal dendrites, indicating that following suprathreshold activation dendritic tree is depolarized sufficiently open voltage-dependent channels (VDCCs). 3. The transient peak by APs showed large differences between various compartments neurone. Following a single AP, 6-fold measured, ranging from 43 +/- 14 nM soma 267 109 dendrites. 4. Along main dendrite, or trains had largest amplitude fastest decay proximal region; time constant AP 128 25 420 150 ms, respectively, train five (at 10-12 Hz), 710 214 390 respectively. gradually decreased broadened more portions bifurcation. 5. In profile was dependent on frequency.(ABSTRACT TRUNCATED AT 250 WORDS)