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] .

NeuronCompartmentPropertyConnectivityNotes
Hippocampus CA1 pyramidal cellDistal apical dendriteI A.A-current is reduced in the presence of amyloid-beta (Chen C, 2005517 ). Patch-clamp recordings reveal a high density of A-type K channels in the dendritic tree, which increases with distance from the soma (Hoffman DA et al, 1997 [rat ]144 ). A shift toward more depolarized potentials of the activation curve has also been observed in mid and distal dendrites (more than 100um) (Hoffman DA et al, 1997 [rat ]144 ). These channels "prevent initiation of an action potential in the dendrites, limit the backpropagation of action potentials into the dendrites, and reduce excitatory synaptic events" (Hoffman DA et al, 1997 [rat ]144 ). 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 ) CA1 neurons and subiculum neurons in hippoampus differ in firing pattern (the former being regular and the later being either regular, weakly bursting or strongly bursting) and resting membrane properties (such as input restistance and membran time constant); however, low concentration of 4-AP (50 ?M) can convert neurons in both regions into firing bursting action potentials (Staff NP et al, 2000440 ).
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 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 cellMiddle apical dendriteI A.A-current is reduced in the presence of amyloid-beta (Chen C, 2005517 ). Patch-clamp recordings reveal a high density of A-type K channels in the dendritic tree, which increases with distance from the soma (Hoffman DA et al, 1997 [rat ]144 ). A shift toward more depolarized potentials of the activation curve has also been observed in mid and distal dendrites (more than 100um) (Hoffman DA et al, 1997 [rat ]144 ). These channels "prevent initiation of an action potential in the dendrites, limit the backpropagation of action potentials into the dendrites, and reduce excitatory synaptic events" (Hoffman DA et al, 1997 [rat ]144 ). 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 ) CA1 neurons and subiculum neurons in hippoampus differ in firing pattern (the former being regular and the later being either regular, weakly bursting or strongly bursting) and resting membrane properties (such as input restistance and membran time constant); however, low concentration of 4-AP (50 µM) can convert neurons in both regions into firing bursting action potentials (Staff NP et al, 2000440 ).
Hippocampus CA1 pyramidal cellProximal apical dendriteI A.A-current is reduced in the presence of amyloid-beta (Chen C, 2005517 ). Patch-clamp recordings reveal a high density of A-type K channels in the dendritic tree, which increases with distance from the soma (Hoffman DA et al, 1997 [rat ]144 ). These channels "prevent initiation of an action potential in the dendrites, limit the backpropagation of action potentials into the dendrites, and reduce excitatory synaptic events" (Hoffman DA et al, 1997 [rat ]144 ). 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 ) CA1 neurons and subiculum neurons in hippoampus differ in firing pattern (the former being regular and the later being either regular, weakly bursting or strongly bursting) and resting membrane properties (such as input restistance and membran time constant); however, low concentration of 4-AP (50 µM) can convert neurons in both regions into firing bursting action potentials (Staff NP et al, 2000440 ).

References
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144. Hoffman DA, Magee JC, Colbert CM and Johnston D. (1997) K+ channel regulation of signal propagation in dendrites of hippocampal pyramidal neurons. Nature 387:869-75.
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