Abstract
The ionic mechanism of the membrane permeability changes caused by l-glutamate in hippocampal neurons prepared from 17- to 19-day-old fetal rat in dispersed cell cultures was studied with the whole-cell variation of the patch electrode voltage-clamp technique. The cultured hippocampal neurons became sensitive to glutamate 7 days after plating, and thereafter the sensitivity gradually increased. The conductance increase caused by glutamate was voltage-sensitive, decreasing with membrane hyperpolarization at potentials more negative than -40 mV. The relative permeability of glutamate-activated channels to alkali metal and alkaline earth cations was estimated by reversal potential measurements. The alkali metal cations, Li+, Na+, K+, Rb+ and Cs+ were permeant to the glutamate channels, and the selectively among them was weak. The alkaline earth cations, Ca2+, Sr2+ and Ba2+ were more permeant than the alkali metals. The permeability ratios of these divalent cations relative to Na+ were 2.4 (Ca2+), 2.4 (Sr2+) and 2.8 (Ba2+), respectively. Mg2+ was much less permeant and the permeability ratio (PMg/PNa) was only 0.1. Anion conductance made no contribution to the glutamate-induced current. Functional implications of the glutamate-induced increase in Ca2+-influx were discussed.
| Original language | English |
|---|---|
| Pages (from-to) | 85-94 |
| Number of pages | 10 |
| Journal | Brain Research |
| Volume | 443 |
| Issue number | 1-2 |
| DOIs | |
| Publication status | Published - 1988 Mar 8 |
| Externally published | Yes |
Fingerprint
Keywords
- Alkali metal cation
- Calcium
- Cultured hippocampal neuron
- l-Glutamate
- Magnesium
- Membrane permeability
- Whole-cell voltage-clamp
ASJC Scopus subject areas
- Developmental Biology
- Molecular Biology
- Clinical Neurology
- Neuroscience(all)
Cite this
Cation permeability change caused by l-glutamate in cultured rat hippocampal neurons. / Ozawa, Seiji; Nakamura, Tomoko; Yuzaki, Michisuke.
In: Brain Research, Vol. 443, No. 1-2, 08.03.1988, p. 85-94.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Cation permeability change caused by l-glutamate in cultured rat hippocampal neurons
AU - Ozawa, Seiji
AU - Nakamura, Tomoko
AU - Yuzaki, Michisuke
PY - 1988/3/8
Y1 - 1988/3/8
N2 - The ionic mechanism of the membrane permeability changes caused by l-glutamate in hippocampal neurons prepared from 17- to 19-day-old fetal rat in dispersed cell cultures was studied with the whole-cell variation of the patch electrode voltage-clamp technique. The cultured hippocampal neurons became sensitive to glutamate 7 days after plating, and thereafter the sensitivity gradually increased. The conductance increase caused by glutamate was voltage-sensitive, decreasing with membrane hyperpolarization at potentials more negative than -40 mV. The relative permeability of glutamate-activated channels to alkali metal and alkaline earth cations was estimated by reversal potential measurements. The alkali metal cations, Li+, Na+, K+, Rb+ and Cs+ were permeant to the glutamate channels, and the selectively among them was weak. The alkaline earth cations, Ca2+, Sr2+ and Ba2+ were more permeant than the alkali metals. The permeability ratios of these divalent cations relative to Na+ were 2.4 (Ca2+), 2.4 (Sr2+) and 2.8 (Ba2+), respectively. Mg2+ was much less permeant and the permeability ratio (PMg/PNa) was only 0.1. Anion conductance made no contribution to the glutamate-induced current. Functional implications of the glutamate-induced increase in Ca2+-influx were discussed.
AB - The ionic mechanism of the membrane permeability changes caused by l-glutamate in hippocampal neurons prepared from 17- to 19-day-old fetal rat in dispersed cell cultures was studied with the whole-cell variation of the patch electrode voltage-clamp technique. The cultured hippocampal neurons became sensitive to glutamate 7 days after plating, and thereafter the sensitivity gradually increased. The conductance increase caused by glutamate was voltage-sensitive, decreasing with membrane hyperpolarization at potentials more negative than -40 mV. The relative permeability of glutamate-activated channels to alkali metal and alkaline earth cations was estimated by reversal potential measurements. The alkali metal cations, Li+, Na+, K+, Rb+ and Cs+ were permeant to the glutamate channels, and the selectively among them was weak. The alkaline earth cations, Ca2+, Sr2+ and Ba2+ were more permeant than the alkali metals. The permeability ratios of these divalent cations relative to Na+ were 2.4 (Ca2+), 2.4 (Sr2+) and 2.8 (Ba2+), respectively. Mg2+ was much less permeant and the permeability ratio (PMg/PNa) was only 0.1. Anion conductance made no contribution to the glutamate-induced current. Functional implications of the glutamate-induced increase in Ca2+-influx were discussed.
KW - Alkali metal cation
KW - Calcium
KW - Cultured hippocampal neuron
KW - l-Glutamate
KW - Magnesium
KW - Membrane permeability
KW - Whole-cell voltage-clamp
UR - http://www.scopus.com/inward/record.url?scp=0023845133&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0023845133&partnerID=8YFLogxK
U2 - 10.1016/0006-8993(88)91601-0
DO - 10.1016/0006-8993(88)91601-0
M3 - Article
C2 - 2896060
AN - SCOPUS:0023845133
VL - 443
SP - 85
EP - 94
JO - Brain Research
JF - Brain Research
SN - 0006-8993
IS - 1-2
ER -