143. Christie BR, Eliot LS, Ito K, Miyakawa H and Johnston D. (1995) Different Ca2+ channels in soma and dendrites of hippocampal pyramidal neurons mediate spike-induced Ca2+ influx. J Neurophysiol 73:2553-7 [Journal] .

NeuronCompartmentPropertyConnectivityNotes
Hippocampus CA1 pyramidal cellDistal apical dendriteI T low threshold.Patch recordings yield an approximate channel density of 7 pS/micron^2 in juvenile rats < 4 wks of age, rising to 10 pS/micron^2 in older rats. Ca channel density was similar in other dendritic compartments, and in general lower than Na channel density (Magee JC and Johnston D, 1995 [rat ]140 ). However, in a few apical patches the channel density was increased X 3, which could indicate channel clustering. Ca fluorescence imaging shows that application of T-channel antagonists reduces the Ca influx associated with backpropagating action potentials, and has a two-fold greater effect in the soma than in the dendrites (Christie BR et al, 1995143 ).
Hippocampus CA1 pyramidal cellMiddle apical dendriteI T low threshold.Patch recordings yield an approximate channel density of 7 pS/micron^2 in juvenile rats < 4 wks of age, rising to 10 pS/micron^2 in older rats. Ca channel density was similar in other dendritic compartments, and in general lower than Na channel density (Magee JC and Johnston D, 1995 [rat ]140 ). However, in a few apical patches the channel density was increased X 3, which could indicate channel clustering. Ca fluorescence imaging shows that application of T-channel antagonists reduces the Ca influx associated with backpropagating action potentials, and has a two-fold greater effect in the dendrites than in the soma (Christie BR et al, 1995143 ).
Hippocampus CA1 pyramidal cellProximal apical dendriteI L high threshold.Using a monoclonal antibody Westenbroek RE et al, 1990196 showed that the proximal dendrites and somata of hippocampal neurons label for L-type Ca2+ channels and that these channels tend to cluster near the bases of the neural processes. In patch recordings, "HVA-l channels reminiscent of L-type channels were occasionally encountered primarily in the more proximal dendrites" (and in the soma) (Magee JC and Johnston D, 1995 [rat ]140 ). Ca fluorescence imaging shows that application of L-channel antagonists reduces the Ca influx associated with backpropagating action potentials, and has a significantly greater effect in the proximal dendrites than in more distal dendrites (Christie BR et al, 1995143 ).
Hippocampus CA1 pyramidal cellDistal apical dendriteI L high threshold.Ca fluorescence imaging shows that application of L-channel antagonists reduces the Ca influx associated with backpropagating action potentials, and has a significantly greater effect in the proximal dendrites than in more distal dendrites (Christie BR et al, 1995143 ).
Hippocampus CA1 pyramidal cellMiddle apical dendriteI L high threshold.Ca fluorescence imaging shows that application of L-channel antagonists reduces the Ca influx associated with backpropagating action potentials, and has a significantly greater effect in the proximal dendrites than in more distal dendrites (Christie BR et al, 1995143 ).
Hippocampus CA1 pyramidal cellProximal apical dendriteI N.Ca fluorescence imaging shows that application of N-channel antagonists slightly reduces the Ca influx associated with backpropagating action potentials (Christie BR et al, 1995143 ). Using confocal microscopy, these channels were found to be localized on the soma, dendrites, and a subpopulation of dendritic spines (Mills LR et al, 1994402 ).

References
140. Magee JC and Johnston D. (1995) Characterization of single voltage-gated Na+ and Ca2+ channels in apical dendrites of rat CA1 pyramidal neurons. J Physiol 487 ( Pt 1):67-90.
143. Christie BR, Eliot LS, Ito K, Miyakawa H and Johnston D. (1995) Different Ca2+ channels in soma and dendrites of hippocampal pyramidal neurons mediate spike-induced Ca2+ influx. J Neurophysiol 73:2553-7 [Journal] .
196. Westenbroek RE, Ahlijanian MK and Catterall WA. (1990) Clustering of L-type Ca2+ channels at the base of major dendrites in hippocampal pyramidal neurons. Nature 347:281-4.
402. Mills LR, Niesen CE, So AP, Carlen PL, Spigelman I and Jones OT. (1994) N-type Ca2+ channels are located on somata, dendrites, and a subpopulation of dendritic spines on live hippocampal pyramidal neurons. J Neurosci 14:6815-24.
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