Different Ca2+ channels in soma and dendrites of hippocampal pyramidal neurons mediate spike-induced Ca2+ influx.
1. Intracellular recordings, in conjunction with fura-2 fluorescence imaging, were used to evaluate the contribution of the different Ca2+ channel subtypes to the Ca2+ influx induced by back-propagating trains of action potentials. High-threshold channels contributed mainly to Ca2+ influx in pyramidal cell somata and proximal dendrites, whereas low-threshold and other Ni(2+)-sensitive channels played a greater role in more distal dendritic signaling. These data suggest that the different Ca2+ channel types participate in distinct physiological functions; low-threshold channels likely play a greater role in dendritic integration, whereas high-threshold channels are more important for somatic Ca(2+)-dependent processes.
Christie
B R
BR
Division of Neuroscience, Baylor College of Medicine, Houston, Texas 77030, USA.
Eliot
L S
LS
Ito
K
K
Miyakawa
H
H
Johnston
D
D
D000200:Action Potentials; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D003712:Dendrites / Q000502:physiology; D016257:Fura-2; D006624:Hippocampus / Q000502:physiology*; D009532:Nickel / Q000494:pharmacology; D009553:Nimodipine / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology; D017966:Pyramidal Cells / Q000502:physiology*; D020866:omega-Conotoxin GVIA
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D010455:Peptides; D009553:Nimodipine; D009532:Nickel; D020866:omega-Conotoxin GVIA; D002118:Calcium; D016257:Fura-2