Action of brief pulses of glutamate on AMPA/kainate receptors in patches from different neurones of rat hippocampal slices. Colquhoun, D., Jonas, P., & Sakmann, B. J. Physiol. (Lond.), 458:261--287, Dec, 1992. abstract bibtex 1. Outside-out patches were isolated from granule cells of dentate gyrus and pyramidal cells of CA3 and CA1 regions of rat hippocampal slices. Patches were exposed briefly to L-glutamate using a piezo-driven double-barrelled application pipette. 2. Applications of glutamate (1 mM) of 1 ms duration activated patch currents which rose and decayed rapidly. The 20-80% rise time of these glutamate receptor (GluR)-mediated currents was usually 0.2-0.6 ms. At -50 mV the peak current varied from 10 to 500 pA in different patches. 3. The peak current-voltage relation for brief pulses of 1 mM glutamate was virtually linear in normal extracellular solution for patches from the three cell types (-100 to 60 mV). 4. The permeability of GluR channels activated at the peak to Ca2+, relative to K+, was less than 0.1 for all three cell types (under bi-ionic conditions with Ca2+ on the extracellular side and K+ on the intracellular side of the membrane). 5. The offset decay time constant of the current following 1 ms pulses of 1 mM glutamate was brief, with mean values of 3.0 +/- 0.8, 2.5 +/- 0.7, and 2.3 +/- 0.7 ms for dentate, CA3 and CA1 cell patches, respectively. Offset time constants were independent of membrane potential and independent of glutamate concentration (200 microM and 1 mM) for the three cell types. 6. Applications of 1 mM glutamate of 100 ms duration showed that glutamate responses desensitized rapidly. The time constants for desensitization were 9.4 +/- 2.7, 11.3 +/- 2.8, and 9.3 +/- 2.8 ms for patches from dentate, CA3 and CA1 cells respectively. Desensitization time constants were only weakly dependent on glutamate concentration (200 microM and 1 mM) for the three cell types. Thus offset time constants are about four times faster than desensitization time constants for both glutamate concentrations. 7. Double pulse application of glutamate indicated that even a 1 ms pulse of 1 mM glutamate causes partial (about 60%) desensitization of GluR channels. The time course of recovery from desensitization was slower in dentate gyrus granule cell patches than in CA3 or CA1 pyramidal cell patches. 8. Desensitization was studied at equilibrium by exposing patches to low glutamate concentrations for at least 15 s before a 1 ms test pulse of 1 mM glutamate.(ABSTRACT TRUNCATED AT 400 WORDS)
@article{ Colquhoun_etal92,
author = {Colquhoun, D. and Jonas, P. and Sakmann, B.},
title = {{{A}ction of brief pulses of glutamate on {A}{M}{P}{A}/kainate receptors
in patches from different neurones of rat hippocampal slices}},
journal = {J. Physiol. (Lond.)},
year = {1992},
volume = {458},
pages = {261--287},
month = {Dec},
abstract = {1. Outside-out patches were isolated from granule cells of dentate
gyrus and pyramidal cells of CA3 and CA1 regions of rat hippocampal
slices. Patches were exposed briefly to L-glutamate using a piezo-driven
double-barrelled application pipette. 2. Applications of glutamate
(1 mM) of 1 ms duration activated patch currents which rose and decayed
rapidly. The 20-80% rise time of these glutamate receptor (GluR)-mediated
currents was usually 0.2-0.6 ms. At -50 mV the peak current varied
from 10 to 500 pA in different patches. 3. The peak current-voltage
relation for brief pulses of 1 mM glutamate was virtually linear
in normal extracellular solution for patches from the three cell
types (-100 to 60 mV). 4. The permeability of GluR channels activated
at the peak to Ca2+, relative to K+, was less than 0.1 for all three
cell types (under bi-ionic conditions with Ca2+ on the extracellular
side and K+ on the intracellular side of the membrane). 5. The offset
decay time constant of the current following 1 ms pulses of 1 mM
glutamate was brief, with mean values of 3.0 +/- 0.8, 2.5 +/- 0.7,
and 2.3 +/- 0.7 ms for dentate, CA3 and CA1 cell patches, respectively.
Offset time constants were independent of membrane potential and
independent of glutamate concentration (200 microM and 1 mM) for
the three cell types. 6. Applications of 1 mM glutamate of 100 ms
duration showed that glutamate responses desensitized rapidly. The
time constants for desensitization were 9.4 +/- 2.7, 11.3 +/- 2.8,
and 9.3 +/- 2.8 ms for patches from dentate, CA3 and CA1 cells respectively.
Desensitization time constants were only weakly dependent on glutamate
concentration (200 microM and 1 mM) for the three cell types. Thus
offset time constants are about four times faster than desensitization
time constants for both glutamate concentrations. 7. Double pulse
application of glutamate indicated that even a 1 ms pulse of 1 mM
glutamate causes partial (about 60%) desensitization of GluR channels.
The time course of recovery from desensitization was slower in dentate
gyrus granule cell patches than in CA3 or CA1 pyramidal cell patches.
8. Desensitization was studied at equilibrium by exposing patches
to low glutamate concentrations for at least 15 s before a 1 ms test
pulse of 1 mM glutamate.(ABSTRACT TRUNCATED AT 400 WORDS)}
}
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{"_id":"9b3nt8v7wEcnW8FFj","bibbaseid":"colquhoun-jonas-sakmann-actionofbriefpulsesofglutamateonampakainatereceptorsinpatchesfromdifferentneuronesofrathippocampalslices-1992","downloads":0,"creationDate":"2015-02-08T05:14:40.892Z","title":"Action of brief pulses of glutamate on AMPA/kainate receptors in patches from different neurones of rat hippocampal slices","author_short":["Colquhoun, D.","Jonas, P.","Sakmann, B."],"year":1992,"bibtype":"article","biburl":"http://cnslab.mb.jhu.edu/niebase.bib","bibdata":{"abstract":"1. Outside-out patches were isolated from granule cells of dentate gyrus and pyramidal cells of CA3 and CA1 regions of rat hippocampal slices. Patches were exposed briefly to L-glutamate using a piezo-driven double-barrelled application pipette. 2. Applications of glutamate (1 mM) of 1 ms duration activated patch currents which rose and decayed rapidly. The 20-80% rise time of these glutamate receptor (GluR)-mediated currents was usually 0.2-0.6 ms. At -50 mV the peak current varied from 10 to 500 pA in different patches. 3. The peak current-voltage relation for brief pulses of 1 mM glutamate was virtually linear in normal extracellular solution for patches from the three cell types (-100 to 60 mV). 4. The permeability of GluR channels activated at the peak to Ca2+, relative to K+, was less than 0.1 for all three cell types (under bi-ionic conditions with Ca2+ on the extracellular side and K+ on the intracellular side of the membrane). 5. The offset decay time constant of the current following 1 ms pulses of 1 mM glutamate was brief, with mean values of 3.0 +/- 0.8, 2.5 +/- 0.7, and 2.3 +/- 0.7 ms for dentate, CA3 and CA1 cell patches, respectively. Offset time constants were independent of membrane potential and independent of glutamate concentration (200 microM and 1 mM) for the three cell types. 6. Applications of 1 mM glutamate of 100 ms duration showed that glutamate responses desensitized rapidly. The time constants for desensitization were 9.4 +/- 2.7, 11.3 +/- 2.8, and 9.3 +/- 2.8 ms for patches from dentate, CA3 and CA1 cells respectively. Desensitization time constants were only weakly dependent on glutamate concentration (200 microM and 1 mM) for the three cell types. Thus offset time constants are about four times faster than desensitization time constants for both glutamate concentrations. 7. Double pulse application of glutamate indicated that even a 1 ms pulse of 1 mM glutamate causes partial (about 60%) desensitization of GluR channels. The time course of recovery from desensitization was slower in dentate gyrus granule cell patches than in CA3 or CA1 pyramidal cell patches. 8. Desensitization was studied at equilibrium by exposing patches to low glutamate concentrations for at least 15 s before a 1 ms test pulse of 1 mM glutamate.(ABSTRACT TRUNCATED AT 400 WORDS)","author":["Colquhoun, D.","Jonas, P.","Sakmann, B."],"author_short":["Colquhoun, D.","Jonas, P.","Sakmann, B."],"bibtex":"@article{ Colquhoun_etal92,\n author = {Colquhoun, D. and Jonas, P. and Sakmann, B.},\n title = {{{A}ction of brief pulses of glutamate on {A}{M}{P}{A}/kainate receptors\n\tin patches from different neurones of rat hippocampal slices}},\n journal = {J. Physiol. (Lond.)},\n year = {1992},\n volume = {458},\n pages = {261--287},\n month = {Dec},\n abstract = {1. Outside-out patches were isolated from granule cells of dentate\n\tgyrus and pyramidal cells of CA3 and CA1 regions of rat hippocampal\n\tslices. Patches were exposed briefly to L-glutamate using a piezo-driven\n\tdouble-barrelled application pipette. 2. Applications of glutamate\n\t(1 mM) of 1 ms duration activated patch currents which rose and decayed\n\trapidly. The 20-80% rise time of these glutamate receptor (GluR)-mediated\n\tcurrents was usually 0.2-0.6 ms. At -50 mV the peak current varied\n\tfrom 10 to 500 pA in different patches. 3. The peak current-voltage\n\trelation for brief pulses of 1 mM glutamate was virtually linear\n\tin normal extracellular solution for patches from the three cell\n\ttypes (-100 to 60 mV). 4. The permeability of GluR channels activated\n\tat the peak to Ca2+, relative to K+, was less than 0.1 for all three\n\tcell types (under bi-ionic conditions with Ca2+ on the extracellular\n\tside and K+ on the intracellular side of the membrane). 5. The offset\n\tdecay time constant of the current following 1 ms pulses of 1 mM\n\tglutamate was brief, with mean values of 3.0 +/- 0.8, 2.5 +/- 0.7,\n\tand 2.3 +/- 0.7 ms for dentate, CA3 and CA1 cell patches, respectively.\n\tOffset time constants were independent of membrane potential and\n\tindependent of glutamate concentration (200 microM and 1 mM) for\n\tthe three cell types. 6. Applications of 1 mM glutamate of 100 ms\n\tduration showed that glutamate responses desensitized rapidly. The\n\ttime constants for desensitization were 9.4 +/- 2.7, 11.3 +/- 2.8,\n\tand 9.3 +/- 2.8 ms for patches from dentate, CA3 and CA1 cells respectively.\n\tDesensitization time constants were only weakly dependent on glutamate\n\tconcentration (200 microM and 1 mM) for the three cell types. Thus\n\toffset time constants are about four times faster than desensitization\n\ttime constants for both glutamate concentrations. 7. Double pulse\n\tapplication of glutamate indicated that even a 1 ms pulse of 1 mM\n\tglutamate causes partial (about 60%) desensitization of GluR channels.\n\tThe time course of recovery from desensitization was slower in dentate\n\tgyrus granule cell patches than in CA3 or CA1 pyramidal cell patches.\n\t8. Desensitization was studied at equilibrium by exposing patches\n\tto low glutamate concentrations for at least 15 s before a 1 ms test\n\tpulse of 1 mM glutamate.(ABSTRACT TRUNCATED AT 400 WORDS)}\n}","bibtype":"article","id":"Colquhoun_etal92","journal":"J. Physiol. 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