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.

NeuronCompartmentPropertyConnectivityNotes
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 CA3 pyramidal cellSomaI Na,t.Subthreshold membrane potential oscillations are blocked by bath application of tetrodotoxin (TTX), a potent Na(t)-current antagonist, in rats 3-17 days old (Psarropoulou C and Avoli M, 1995171 ). 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 ).

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.
171. Psarropoulou C and Avoli M. (1995) Subthreshold membrane-potential oscillations in immature rat CA3 hippocampal neurones. Neuroreport 6:2561-4.
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