434. Spruston N, Jonas P and Sakmann B. (1995) Dendritic glutamate receptor channels in rat hippocampal CA3 and CA1 pyramidal neurons. J Physiol 482 ( Pt 2):325-52.

NeuronCompartmentPropertyConnectivityNotes
Hippocampus CA3 pyramidal cellDistal apical dendriteAMPAPerforant pathway entorhinal 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 (Pozzo Miller LD et al, 1996168 ). Recordings from membrane patches of dendrites and soma reveal fast and slow responses to fast application of glutamate, mediated by AMPA amd NMDA receptors, respectively (Spruston N et al, 1995434 ).
Hippocampus CA3 pyramidal cellDistal apical dendriteNMDAPerforant pathway entorhinal pyramidal neuron terminals (T)Quantitative autoradiography has been used to localize sites at which L-[3H]-glutamate is displaced by NMDA. The labelling of these receptors was somewhat lower than in CA1 overall, being highest in s. oriens and s. radiatum and very low in s.pyramidale and s. lucidum (Monaghan DT and Cotman CW, 1985169 ). In contrast, a study using radioactive in situ hybridization histochemistry looked at mRNA coding an NMDA glutamate binding protein and at NMDAR1 (an NMDAR subunit) expression and found heavy labeling for both in the pyramidal and polymorphic layers but little in the molecular layer (Sato K et al, 1995 [rat ]172 ).The physiology of these receptors has been studied in outside-out patches from the proximal apical dendrites. It was found that an APV-sensitive component of the synaptic current evoked by fast aplication of glutamate could be isolated (and was presumed to be the result of NMDA channel opening). It was calculated that NMDA channels had a main conductance state conductance of 45 pS and it was confirmed that the channel was permeable to Ca2+. The NMDAR-mediated conductance was blocked by Mg2+ in a voltage-dependent way and by Zn2+ in a non-voltage-dependent fashion (Spruston N et al, 1995174 ; see also Jahr CE and Stevens CF, 2000 [rat ]159 ). NMDA iontophoretically applied to basal dendrites evoked inward currents near resting potential. Changing levels of bath calcium concentration downwards by 50% caused an increase in the inward current (Gerber U et al, 1993 [rat ]155 ). MK801 (an NMDAR antagonist) blocks the transient intracellular Ca2+ release normally associated with stratum lucidum stimulation (found by simultaneous Ca imaging and intracellular recording in rat brain slices by Pozzo Miller LD et al, 1996168 ). While NMDA receptor activation may be necessary for LTP at the commissural/associational synapses (Gorter JA and Brady RJ, 1995 [rat ]156 ), it has been shown to occur at mossy fiber synapses even in the presence of NMDA receptor antagonists under certain conditions (Gorter JA and Brady RJ, 1995 [rat ]156 ; Harris EW and Cotman CW, 1986157 ) Differential induction of potentiation and depression at commissural and mossy fiber synapses has also been shown by #R#158#E#. Recordings from membrane patches of dendrites and soma reveal fast and slow responses to fast application of glutamate, mediated by AMPA amd NMDA receptors, respectively (Spruston N et al, 1995434 ).
Hippocampus CA3 pyramidal cellSomaAMPA-----Quantitative autoradiography has been used to localize [3H]AMPA binding sites. In CA3, labeling was substantially heavier in s. pyramidale than in s.radiatum and s. lacunosum-moleculare (Monaghan DT et al, 1984 [rat ]170 ). [ed. note: we are not aware of glutamatergic synapses onto the soma] Recordings from membrane patches of dendrites and soma reveal fast and slow responses to fast application of glutamate, mediated by AMPA amd NMDA receptors, respectively (Spruston N et al, 1995434 ).
Hippocampus CA3 pyramidal cellSomaNMDA-----Quantitative autoradiography has been used to localize sites at which L-[3H]-glutamate is displaced by NMDA. The labelling of these receptors was somewhat lower than in CA1 overall, being highest in s. oriens and s. radiatum and very low in s.pyramidale and s. lucidum (Monaghan DT and Cotman CW, 1985169 ). In contrast, a study using radioactive in situ hybridization histochemistry looked at mRNA coding an NMDA glutamate binding protein and at NMDAR1 (an NMDAR subunit) expression and found heavy labeling for both in the pyramidal and polymorphic layers but little in the molecular layer (Sato K et al, 1995 [rat ]172 ). [ed. note: These data disagree on the presence of NMDA receptors in the soma. For a full description of the properties of NMDA receptors in CA3 pyramidal neurons, please see the apical dendritic compartments.] Recordings from membrane patches of dendrites and soma reveal fast and slow responses to fast application of glutamate, mediated by AMPA amd NMDA receptors, respectively (Spruston N et al, 1995434 ).
Hippocampus CA1 pyramidal cellDistal apical dendriteAMPA.EM showed colocalization at axodendritic asymmetric synapses within the CA1 subfield of rat hippocampus. AMPA/NMDA receptor colocalization was found in non-GABAergic dendritic shafts as well as dendritic spines, suggesting that excitatory neuronal transmission in CA1 neurons may generally involve activation of both NMDA and AMPA receptor subunits at a single synapse (He Y et al, 1998250 ). Recordings from membrane patches of dendrites and soma reveal fast and slow responses to fast application of glutamate, mediated by AMPA and NMDA receptors, respectively (Spruston N et al, 1995434 ).
Hippocampus CA1 pyramidal cellDistal apical dendriteNMDA.The way that different parts of a neuron carry out multiple information processing roles is illustrated by the CA1 pyramidal cell in the hippocampus. The authors used 2-photon microscopy to obtain high resolution images of calcium signals in the apical dendrites while activating Schaffer collateral inputs to induce long-term potentiation (LTP) of different durations. Short-duration LTP (LTP 1) was associated with Ca increase in dendritic spines, due to activation of NMDA receptors and local ryanodine receptors (RyRs). Intermediate duration LTP (LTP 2) was associated with Ca increase in dendritic branches, due to activation of NMDA receptors and local IP3 receptors (IP3Rs). For Ca increase in long duration LTP (LTP3), see Ca channels in CA1 pyramidal cell apical dendrite. The authors conclude that "selective induction of different forms of LTP is achieved via spatial segregation of functionally distinct calcium signals"(Raymond CR and Redman SJ, 2006540 ). EM showed colocalization at axodendritic asymmetric synapses within the CA1 subfield of rat hippocampus. AMPA/NMDA receptor colocalization was found in non-GABAergic dendritic shafts as well as dendritic spines, suggesting that excitatory neuronal transmission in CA1 neurons may generally involve activation of both NMDA and AMPA receptor subunits at a single synapse (He Y et al, 1998250 ). Recordings from membrane patches of dendrites and soma reveal fast and slow responses to fast application of glutamate, mediated by AMPA and NMDA receptors, respectively (Spruston N et al, 1995434 ).
Hippocampus CA1 pyramidal cellSomaAMPA.Recordings from membrane patches of dendrites and soma reveal fast and slow responses to fast application of glutamate, mediated by AMPA and NMDA receptors, respectively (Spruston N et al, 1995434 ).
Hippocampus CA1 pyramidal cellSomaNMDA.Recordings from membrane patches of dendrites and soma reveal fast and slow responses to fast application of glutamate, mediated by AMPA and NMDA receptors, respectively (Spruston N et al, 1995434 ).

References
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