---
_id: '3479'
abstract:
- lang: eng
text: 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 μM 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 α-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 (τ) of 1.2 ± 0.1 ms (mean ± S.E.M.).
During 100 ms glutamate pulses, AMPARs desensitized with a τ of 3.7 ± 0.2 ms.
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 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 mere highly Ca2+ permeable (P(Ca)/P(K) = 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 τ 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. NMDARs in hippocampal basket cells were highly permeable
to Ca2+ (P(Ca)/P(K) = 6.68). 8. AMPARs in hippocampal basket cells are characterized
by about threefold faster kinetics and twentyfold higher Ca2+ permeability than
AMPARs in hippocampal granule or pyramidal cells. Simulations show that the Ca2+
influx through basket cell AMPARs is comparable to that through NMDARs at negative
membrane potentials with physiological concentrations of Ca2+ and Mg2+. This suggests
a dual pathway of synaptically mediated Ca2+ entry into interneurones.
acknowledgement: We thank Drs M.Häusser and H.Markram for critically reading the manuscript
and M.Kaiser for technical assistance. Supported by the Deutsche Forschungsgemeinschaft
(SFB-317/B14 grant to P.J. and a Graduiertenkollegstipendium to J.R.P.G.)
article_processing_charge: No
article_type: original
author:
- first_name: Duk
full_name: Koh, Duk
last_name: Koh
- first_name: Jörg
full_name: Geiger, Jörg
last_name: Geiger
- first_name: Peter M
full_name: Jonas, Peter M
id: 353C1B58-F248-11E8-B48F-1D18A9856A87
last_name: Jonas
orcid: 0000-0001-5001-4804
- first_name: Bert
full_name: Sakmann, Bert
last_name: Sakmann
citation:
ama: Koh D, Geiger J, Jonas PM, Sakmann B. Ca(2+)-permeable AMPA and NMDA receptor
channels in basket cells of rat hippocampal dentate gyrus. Journal of Physiology.
1995;485(Pt 2):383-402. doi:10.1113/jphysiol.1995.sp020737
apa: Koh, D., Geiger, J., Jonas, P. M., & Sakmann, B. (1995). Ca(2+)-permeable
AMPA and NMDA receptor channels in basket cells of rat hippocampal dentate gyrus.
Journal of Physiology. Wiley-Blackwell. https://doi.org/10.1113/jphysiol.1995.sp020737
chicago: Koh, Duk, Jörg Geiger, Peter M Jonas, and Bert Sakmann. “Ca(2+)-Permeable
AMPA and NMDA Receptor Channels in Basket Cells of Rat Hippocampal Dentate Gyrus.”
Journal of Physiology. Wiley-Blackwell, 1995. https://doi.org/10.1113/jphysiol.1995.sp020737.
ieee: D. Koh, J. Geiger, P. M. Jonas, and B. Sakmann, “Ca(2+)-permeable AMPA and
NMDA receptor channels in basket cells of rat hippocampal dentate gyrus,” Journal
of Physiology, vol. 485, no. Pt 2. Wiley-Blackwell, pp. 383–402, 1995.
ista: Koh D, Geiger J, Jonas PM, Sakmann B. 1995. Ca(2+)-permeable AMPA and NMDA
receptor channels in basket cells of rat hippocampal dentate gyrus. Journal of
Physiology. 485(Pt 2), 383–402.
mla: Koh, Duk, et al. “Ca(2+)-Permeable AMPA and NMDA Receptor Channels in Basket
Cells of Rat Hippocampal Dentate Gyrus.” Journal of Physiology, vol. 485,
no. Pt 2, Wiley-Blackwell, 1995, pp. 383–402, doi:10.1113/jphysiol.1995.sp020737.
short: D. Koh, J. Geiger, P.M. Jonas, B. Sakmann, Journal of Physiology 485 (1995)
383–402.
date_created: 2018-12-11T12:03:33Z
date_published: 1995-06-01T00:00:00Z
date_updated: 2022-06-28T07:54:44Z
day: '01'
doi: 10.1113/jphysiol.1995.sp020737
extern: '1'
external_id:
pmid:
- '7545230'
intvolume: ' 485'
issue: Pt 2
language:
- iso: eng
main_file_link:
- open_access: '1'
url: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1158000/pdf/jphysiol00319-0104.pdf
month: '06'
oa: 1
oa_version: Published Version
page: 383 - 402
pmid: 1
publication: Journal of Physiology
publication_identifier:
issn:
- 0022-3751
publication_status: published
publisher: Wiley-Blackwell
publist_id: '2908'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Ca(2+)-permeable AMPA and NMDA receptor channels in basket cells of rat hippocampal
dentate gyrus
type: journal_article
user_id: ea97e931-d5af-11eb-85d4-e6957dddbf17
volume: 485
year: '1995'
...