173. Sheng M, Tsaur ML, Jan YN and Jan LY. (1994) Contrasting subcellular localization of the Kv1.2 K+ channel subunit in different neurons of rat brain. J Neurosci 14:2408-17.

NeuronCompartmentPropertyConnectivityNotes
Hippocampus CA3 pyramidal cellDistal apical dendriteI K.Bath application of Pb2+ shifted the neurons curent-voltage relation in patch-clamp recording from acutely isolated pyramidal neurons. These results were interpreted to "demonstrate that Pb2+ in micromolar concentration is a voltage-dependent, reversible blocker of delayed-rectifier potassium currents of hippocampal neurons" (Madeja M et al, 1997164 ). In a study of acutely isolated rat cells under whole cell recording across development states (Day 6 - Day 29), it was found that delayed rectifier currents decayed along a double-exponential time course and were 50% blocked by TEA (tetraethylammonium, a I(K) antagonist) at +30 mV at a concentration of about 1mM, as well as being partially blocked by 4-AP (4-aminopyridine). The current also appeared to increase over this development period. This increase was approximately 300% much larger in CA1 cells than in CA3 cells, with only approximately 50% (Klee R et al, 1995 [rat ]162 ). A combined in situ hybridization and immunocytochemical study demonstrated that Kv1.2 (which may correspond to I(K) channels) is concentrated in the dendrites of CA3 neurons (Sheng M et al, 1994 [rat ]173 ).
Hippocampus CA3 pyramidal cellMiddle apical dendriteAMPACA3 Pyramidal neuron terminals (T)Quantitative autoradiography has been used to localize [3H]AMPA binding sites. It was found that AMPARs are found in a high concentration in the hippocampus relative to other areas in the brain. In CA3, labeling was substantially heavier in s. pyramidale than in s.radiatum and s. lacunosum-moleculare (Monaghan DT et al, 1984 [rat ]170 ). The physiology of these receptors has been studied in outside-out patches from the proximal apical dendrites. It was found that a CNQX-sensitive component of the synaptic current evoked by fast aplication of glutamate could be isolated (and was presumed to be the result of AMPA channel opening). It was calculated that AMPA channels had a mean elementary conductance of 10 pS (estimated by non-stationary fluctuation analysis) and was found that the channels had a low permeability to Ca2+. The reversal potential for AMPA receptors was found to be about 0 mV with an almost linear peak current-voltage relationship (Spruston N et al, 1995174 ; see also Jahr CE and Stevens CF, 2000 [rat ]159 ). It has also been found that CNQX does not block the intracellular calcium concentration increase normally associated with stratum lucidum stimulation (Sheng M et al, 1994 [rat ]173 ).
Hippocampus CA3 pyramidal cellMiddle apical dendriteI K.Bath application of Pb2+ shifted the neurons curent-voltage relation in patch-clamp recording from acutely isolated pyramidal neurons. These results were interpreted to "demonstrate that Pb2+ in micromolar concentration is a voltage-dependent, reversible blocker of delayed-rectifier potassium currents of hippocampal neurons" (Madeja M et al, 1997164 ). In a study of acutely isolated rat cells under whole cell recording across development states (Day 6 - Day 29), it was found that delayed rectifier currents decayed along a double-exponential time course and were 50% blocked by TEA (tetraethylammonium, a K(DR) antagonist) at +30 mV at a concentration of about 1mM, as well as being partially blocked by 4-AP (4-aminopyridine). The current also appeared to increase over this development period. This increase was approximately 300% much larger in CA1 cells than in CA3 cells, with only approximately 50% (Klee R et al, 1995 [rat ]162 ). A combined in situ hybridization and immunocytochemical study demonstrated that Kv1.2 (which probably corresponds to I(K) channels) is concentrated in the dendrites of CA3 neurons (Sheng M et al, 1994 [rat ]173 ).
Hippocampus CA3 pyramidal cellSomaI K.Bath application of Pb2+ shifted the neurons'' current-voltage relation in patch-clamp recording from acutely isolated pyramidal neurons. These results were interpreted to "demonstrate that Pb2+ in micromolar concentration is a voltage-dependent, reversible blocker of delayed-rectifier potassium currents of hippocampal neurons" (Madeja M et al, 1997164 ). In a study of acutely isolated rat cells under whole cell recording across development states (Day 6 - Day 29), it was found that delayed rectifier currents decayed along a double-exponential time course and were 50% blocked by TEA (tetraethylammonium, a I(K) antagonist) at +30 mV at a concentration of about 1mM, as well as being partially blocked by 4-AP (4-aminopyridine). The current also appeared to increase over this development period. This increase was approximately 300% much larger in CA1 cells than in CA3 cells, with only approximately 50% (Klee R et al, 1995 [rat ]162 ). A combined in situ hybridization and immunocytochemical study demonstrated that Kv1.2 (which may correspond to I(K) channels) is concentrated in the dendrites of CA3 neurons (Sheng M et al, 1994 [rat ]173 ).
Hippocampus CA3 pyramidal cellProximal apical dendriteI K.Bath application of Pb2+ shifted the neurons curent-voltage relation in patch-clamp recording from acutely isolated pyramidal neurons. These results were interpreted to "demonstrate that Pb2+ in micromolar concentration is a voltage-dependent, reversible blocker of delayed-rectifier potassium currents of hippocampal neurons" (Madeja M et al, 1997164 ). In a study of acutely isolated rat cells under whole cell recording across development states (Day 6 - Day 29), it was found that delayed rectifier currents decayed along a double-exponential time course and were 50% blocked by TEA (tetraethylammonium, a K(DR) antagonist) at +30 mV at a concentration of about 1mM, as well as being partially blocked by 4-AP (4-aminopyridine). The current also appeared to increase over this development period. This increase was approximately 300% much larger in CA1 cells than in CA3 cells, with only approximately 50% (Klee R et al, 1995 [rat ]162 ). A combined in situ hybridization and immunocytochemical study demonstrated that Kv1.2 (which probably corresponds to I(K) channels) is concentrated in the dendrites of CA3 neurons (Sheng M et al, 1994 [rat ]173 ).

References
164. Madeja M, Musshoff U, Binding N, Witting U and Speckmann EJ. (1997) Effects of Pb2+ on delayed-rectifier potassium channels in acutely isolated hippocampal neurons. J Neurophysiol 78:2649-54.
162. Klee R, Ficker E and Heinemann U. (1995) Comparison of voltage-dependent potassium currents in rat pyramidal neurons acutely isolated from hippocampal regions CA1 and CA3. J Neurophysiol 74:1982-95 [Journal] .
173. Sheng M, Tsaur ML, Jan YN and Jan LY. (1994) Contrasting subcellular localization of the Kv1.2 K+ channel subunit in different neurons of rat brain. J Neurosci 14:2408-17.
170. Monaghan DT, Yao D and Cotman CW. (1984) Distribution of [3H]AMPA binding sites in rat brain as determined by quantitative autoradiography. Brain Res 324:160-4.
174. 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.
159. Jahr CE and Stevens CF. (2000) Glutamate activates multiple single channel conductances in hippocampal neurons. Nature 325:522-5.
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