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.

NeuronCompartmentPropertyConnectivityNotes
Hippocampus CA1 pyramidal cellSomaI T low threshold.T-type channels are less dense in the soma than in the dendrites (Magee JC and Johnston D, 1995 [rat ]140 ).
Hippocampus CA1 pyramidal cellSomaI Na,t.Patch recordings yield an approximate channel density of 45 pS/micron^2 (compared with 28 pS/micron^2 in dendrites) in juvenile rats < 4 wks of age, rising modestly to 56 pS/micron^2 (compared with 61 pS/micron^2 in dendrites) in older rats (Magee JC and Johnston D, 1995 [rat ]140 ). Tsubokawa H et al, 2000180 . Recordings using the intracellular perfusion method showed no differences between the I-V characteristics of CA1 and CA3 neurones for this current. In contrast to this, the steady-state inactivation of both types of neurones was significantly different (Steinhäuser C et al, 1990 [rats ]292 ). Inactivation of dendritic Na channel contributes to the attenuation of activity-dependent backpropagation of APs (Jung HY et al, 1997435 ). Slow inactivation of sodium channels in dendrites and soma will modulate neuronal excitability in a way that depends in a complicated manner on the resting potential and previous history of action potential firing (Mickus T et al, 1999436 ).
Hippocampus CA1 pyramidal cellSomaI L high threshold.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 ).
Hippocampus CA1 pyramidal cellSomaI N.Patch recordings (Magee JC and Johnston D, 1995 [rat ]140 ). 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 ).
Hippocampus CA1 pyramidal cellSomaI p,q.Patch recordings indicate channels similar in basic characteristics to one or more of the HVAm channel types (most likely Q- or R-type channels)(Magee JC and Johnston D, 1995 [rat ]140 ).
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 cellDistal apical dendriteI Na,t.Na impulses may underly "fast prepotentials" that boost distal EPSPs (Spencer WA and Kandel ER, 196175 ). Na action potentials support backpropagating impulses (Spruston N et al, 1995 [mammal ]57 ), and can activate Ca action potentials (Spruston N et al, 1995 [mammal ]57 ). Patch recordings yield an approximate channel density of 28 pS/micron^2 in juvenile rats < 4 wks of age, rising to 61 pS/micron^2 in older rats. Channel density was similar in other dendritic compartments (Magee JC and Johnston D, 1995 [rat ]140 ). Tsubokawa H et al, 2000180 . Inactivation of dendritic Na channel contributes to the attenuation of activity-dependent backpropagation of APs (Jung HY et al, 1997435 ). Slow inactivation of sodium channels in dendrites and soma will modulate neuronal excitability in a way that depends in a complicated manner on the resting potential and previous history of action potential firing (Mickus T et al, 1999436 ). Single action potential backpropagations show dichotomy of either strong attenuation (26-42%) or weak attenuation (71-87%). The dichotomy seems to be conferred primarily by differences in distribution, density, etc. of voltage dependent sodium and potassium channel (A-type, especially ) along the somatodendritic axis (Golding NL et al, 2001439 )
Hippocampus CA1 pyramidal cellMiddle apical dendriteI Na,t.Na impulses may underly "fast prepotentials" that boost distal EPSPs (Spencer WA and Kandel ER, 196175 ). Na action potentials support backpropagating impulses (Spruston N et al, 1995 [mammal ]57 ), and can activate Ca action potentials (Spruston N et al, 1995 [mammal ]57 ). Patch recordings yield an approximate channel density of 28 pS/micron^2 in juvenile rats < 4 wks of age, rising to 61 pS/micron^2 in older rats. Channel density was similar in other dendritic compartments (Magee JC and Johnston D, 1995 [rat ]140 ). Tsubokawa H et al, 2000180 . Inactivation of dendritic Na channel contributes to the attenuation of activity-dependent backpropagation of APs (Jung HY et al, 1997435 ). Slow inactivation of sodium channels in dendrites and soma will modulate neuronal excitability in a way that depends in a complicated manner on the resting potential and previous history of action potential firing (Mickus T et al, 1999436 ). Dendritic can fire sodium spikes that can precede somatic action potentials (APs), the probability and amplitude of which depend on previous synaptic and firing history. Some dendritic spikes could occur in the absense of somatic APs, indicating that their propagation to soma is unreliable (Golding NL and Spruston N, 1998437 ). Single action potential backpropagations show dichotomy of either strong attenuation (26-42%) or weak attenuation (71-87%). The dichotomy seems to be conferred primarily by differences in distribution, density, etc. of voltage dependent sodium and potassium channel (A-type, especially ) along the somatodendritic axis (Golding NL et al, 2001439 )
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 Na,t.Na impulses may underly "fast prepotentials" that boost distal EPSPs (Spencer WA and Kandel ER, 196175 ). Na action potentials support backpropagating impulses (Spruston N et al, 1995 [mammal ]57 ), and can activate Ca action potentials (Spruston N et al, 1995 [mammal ]57 ). Patch recordings yield an approximate channel density of 28 pS/micron^2 in juvenile rats < 4 wks of age, rising to 61 pS/micron^2 in older rats. Channel density was similar in other dendritic compartments (Magee JC and Johnston D, 1995 [rat ]140 ). However, channel density varied widely in the proximal compartment, possibly indicating the presence of hot spots. Tsubokawa H et al, 2000180 . Inactivation of dendritic Na channel contributes to the attenuation of activity-dependent backpropagation of APs (Jung HY et al, 1997435 ). Slow inactivation of sodium channels in dendrites and soma will modulate neuronal excitability in a way that depends in a complicated manner on the resting potential and previous history of action potential firing (Mickus T et al, 1999436 ). Single action potential backpropagations show dichotomy of either strong attenuation (26-42%) or weak attenuation (71-87%). The dichotomy seems to be conferred primarily by differences in distribution, density, etc. of voltage dependent sodium and potassium channel (A-type, especially ) along the somatodendritic axis (Golding NL et al, 2001439 )
Hippocampus CA1 pyramidal cellProximal 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 (Storm-Mathisen J, 1977141 ).
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 ).

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.
180. Tsubokawa H, Offermanns S, Simon M and Kano M. (2000) Calcium-dependent persistent facilitation of spike backpropagation in the CA1 pyramidal neurons. J Neurosci 20:4878-84.
292. Steinhäuser C, Tennigkeit M, Matthies H and Gündel J. (1990) Properties of the fast sodium channels in pyramidal neurones isolated from the CA1 and CA3 areas of the hippocampus of postnatal rats. Pflugers Arch 415:756-61.
435. Jung HY, Mickus T and Spruston N. (1997) Prolonged sodium channel inactivation contributes to dendritic action potential attenuation in hippocampal pyramidal neurons. J Neurosci 17:6639-46.
436. Mickus T, Jung H and Spruston N. (1999) Properties of slow, cumulative sodium channel inactivation in rat hippocampal CA1 pyramidal neurons. Biophys J 76:846-60.
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.
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] .
75. Spencer WA and Kandel ER. (1961) ELECTROPHYSIOLOGY OF HIPPOCAMPAL NEURONS: IV. FAST PREPOTENTIALS. J Neurophysiol 24:272-85.
57. Spruston N, Schiller Y, Stuart G and Sakmann B. (1995) Activity-dependent action potential invasion and calcium influx into hippocampal CA1 dendrites. Science 268:297-300.
439. Golding NL, Kath WL and Spruston N. (2001) Dichotomy of action-potential backpropagation in CA1 pyramidal neuron dendrites. J Neurophysiol 86:2998-3010 [Journal] .
437. Golding NL and Spruston N. (1998) Dendritic sodium spikes are variable triggers of axonal action potentials in hippocampal CA1 pyramidal neurons. Neuron 21:1189-200.
141. Storm-Mathisen J. (1977) Localization of transmitter candidates in the brain: the hippocampal formation as a model. Prog Neurobiol 8:119-81.
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.
_2/20/2018 4:25:26 PM