PMID- 7545230 OWN - NLM STAT- MEDLINE DCOM- 19951010 LR - 20190512 IS - 0022-3751 (Print) IS - 1469-7793 (Electronic) IS - 0022-3751 (Linking) VI - 485 ( Pt 2) IP - Pt 2 DP - 1995 Jun 1 TI - Ca(2+)-permeable AMPA and NMDA receptor channels in basket cells of rat hippocampal dentate gyrus. PG - 383-402 AB - 1. Glutamate receptor (GluR) channels were studied in basket cells in the dentate gyrus of rat hippocampal slices. Basket cells were identified by their location, dendritic morphology and high frequency of action potentials generated during sustained current injection. 2. Dual-component currents were activated by fast application of glutamate to outside-out membrane patches isolated from basket cell somata (10 microM glycine, no external Mg2+). The fast component was selectively blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), the slow component by D-2-amino-5-phosphonopentanoic acid (D-AP5). This suggests that the two components were mediated by alpha-amino-3- hydroxy-5-methyl-4-isoxazolepropionate receptor (AMPAR)/kainate receptor and N-methyl-D-aspartate receptor (NMDAR) channels, respectively. The mean ratio of the peak current of the NMDAR component to that of the AMPAR/kainate receptor component was 0.22 (1 ms pulses of 10 mM glutamate). 3. The AMPAR/kainate receptor component, which was studied in isolation in the presence of D-AP5, was identified as AMPAR mediated on the basis of the preferential activation by AMPA as compared with kainate, the weak desensitization of kainate-activated currents, the cross-desensitization between AMPA and kainate, and the reduction of desensitization by cyclothiazide. 4. Deactivation of basket cell AMPARs following 1 ms pulses of glutamate occurred with a time constant (tau) of 1.2 +/- 0.1 ms (mean +/- S.E.M.). During 100 ms glutamate pulses AMPARs desensitized with a tau of 3.7 +/- 0.2ms. 5. The peak current-voltage (I-V) relation of AMPAR-mediated currents in Na(+)-rich extracellular solution showed a reversal potential of -4.0 +/- 2.6 mV and was characterized by a a doubly rectifying shape. The conductance of single AMPAR channels was estimated as 22.6 +/- 1.6 pS using non-stationary fluctuation analysis. AMPARs expressed in hippocampal basket cells were highly Ca2+ permeable (PCa/PK = 1.79). 6. NMDARs in hippocampal basket cells were studied in isolation in the presence of CNQX. Deactivation of NMDARs activated by glutamate pulses occurred bi-exponentially with mean tau values of 266 +/- 23 ms (76%) and 2620 +/- 383 ms (24%). 7. The peak I-V relation of the NMDAR-mediated component in Na(+)-rich extracellular solution showed a reversal potential of 1.5 +/- 0.6 mV and a region of negative slope at negative membrane potentials in the presence of external Mg2+, due to voltage-dependent block by these ions. The conductance of single NMDAR channels in the main open state was 50.2 +/- 1.8 pS.(ABSTRACT TRUNCATED AT 400 WORDS) FAU - Koh, D S AU - Koh DS AD - Max-Planck-Institut fur medizinische Forschung, Abteilung Zellphysiologie, Heidelberg, Germany. FAU - Geiger, J R AU - Geiger JR FAU - Jonas, P AU - Jonas P FAU - Sakmann, B AU - Sakmann B LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't PL - England TA - J Physiol JT - The Journal of physiology JID - 0266262 RN - 0 (Benzothiadiazines) RN - 0 (Calcium Channels) RN - 0 (Diuretics) RN - 0 (Receptors, AMPA) RN - 0 (Receptors, N-Methyl-D-Aspartate) RN - 0 (Sodium Chloride Symporter Inhibitors) RN - 3KX376GY7L (Glutamic Acid) RN - 77521-29-0 (alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid) RN - 9NEZ333N27 (Sodium) RN - I38ZP9992A (Magnesium) RN - P71U09G5BW (cyclothiazide) RN - SIV03811UC (Kainic Acid) SB - IM MH - Animals MH - Benzothiadiazines/pharmacology MH - Calcium Channels/drug effects/*metabolism MH - Dendrites/drug effects/metabolism MH - Diuretics MH - Glutamic Acid/pharmacology MH - Hippocampus/cytology/drug effects/*metabolism MH - In Vitro Techniques MH - Kainic Acid/pharmacology MH - Kinetics MH - Magnesium/pharmacology MH - Patch-Clamp Techniques MH - Rats MH - Rats, Wistar MH - Receptors, AMPA/antagonists & inhibitors/*metabolism MH - Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors/*metabolism MH - Sodium/metabolism MH - Sodium Chloride Symporter Inhibitors/pharmacology MH - alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/pharmacology PMC - PMC1158000 EDAT- 1995/06/01 00:00 MHDA- 1995/06/01 00:01 PMCR- 1995/06/01 CRDT- 1995/06/01 00:00 PHST- 1995/06/01 00:00 [pubmed] PHST- 1995/06/01 00:01 [medline] PHST- 1995/06/01 00:00 [entrez] PHST- 1995/06/01 00:00 [pmc-release] AID - 10.1113/jphysiol.1995.sp020737 [doi] PST - ppublish SO - J Physiol. 1995 Jun 1;485 ( Pt 2)(Pt 2):383-402. doi: 10.1113/jphysiol.1995.sp020737.