Membrane potential and intracellular Ca2+ oscillations activated by mGluRs in hippocampal stratum oriens/alveus interneurons
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Membrane potential and intracellular Ca2+ oscillations activated by mGluRs in hippocampal stratum oriens/alveus interneurons. / Woodhall, G; Gee, C E; Robitaille, R; Lacaille, J C.
In: J NEUROPHYSIOL, Vol. 81, No. 1, 01.01.1999, p. 371-82.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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T1 - Membrane potential and intracellular Ca2+ oscillations activated by mGluRs in hippocampal stratum oriens/alveus interneurons
AU - Woodhall, G
AU - Gee, C E
AU - Robitaille, R
AU - Lacaille, J C
PY - 1999/1/1
Y1 - 1999/1/1
N2 - Metabotropic glutamate receptors (mGluRs) are expressed heterogeneously in hippocampal interneurons, and their signal transduction cascades remain largely unclear. We characterized an oscillatory response activated by the mGluR agonist 1S,3R-1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD) in hippocampal interneurons of stratum oriens-alveus (OA) with simultaneous whole cell current-clamp recordings and intracellular Ca2+ imaging with confocal microscopy. 1S,3R-ACPD induced oscillatory membrane depolarizations and rises in intracellular Ca2+ that persisted in tetrodotoxin and were blocked by the antagonist of group I and II mGluRs (S)-alpha-methyl-4-carboxyphenylglycine. Membrane depolarizations and intracellular Ca2+ rises were blocked by extracellular Cd2+ and in Ca2+-free medium. mGluR responses therefore required Ca2+ influx via voltage-gated Ca2+ channels. 1S, 3R-ACPD responses were also antagonized by depleting intracellular stores with thapsigargin and ryanodine, indicating that Ca2+ release from intracellular stores was also necessary. These data suggest that oscillatory responses generated by group I/II mGluRs involve a coupling of Ca2+ entry through voltage-gated Ca2+ channels and Ca2+ release from internal stores. In contrast, 1S,3R-ACPD evoked only smaller depolarizations and intracellular Ca2+ rises, with no oscillations, in other hippocampal interneurons located in or near stratum lacunosum-moleculare. Thus mGluR-mediated oscillatory responses are specifically expressed in certain interneuron subtypes. This heterogeneous expression of glutamate and Ca2+ signaling pathways in specific interneurons may be relevant to their selective vulnerability to excitotoxicity.
AB - Metabotropic glutamate receptors (mGluRs) are expressed heterogeneously in hippocampal interneurons, and their signal transduction cascades remain largely unclear. We characterized an oscillatory response activated by the mGluR agonist 1S,3R-1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD) in hippocampal interneurons of stratum oriens-alveus (OA) with simultaneous whole cell current-clamp recordings and intracellular Ca2+ imaging with confocal microscopy. 1S,3R-ACPD induced oscillatory membrane depolarizations and rises in intracellular Ca2+ that persisted in tetrodotoxin and were blocked by the antagonist of group I and II mGluRs (S)-alpha-methyl-4-carboxyphenylglycine. Membrane depolarizations and intracellular Ca2+ rises were blocked by extracellular Cd2+ and in Ca2+-free medium. mGluR responses therefore required Ca2+ influx via voltage-gated Ca2+ channels. 1S, 3R-ACPD responses were also antagonized by depleting intracellular stores with thapsigargin and ryanodine, indicating that Ca2+ release from intracellular stores was also necessary. These data suggest that oscillatory responses generated by group I/II mGluRs involve a coupling of Ca2+ entry through voltage-gated Ca2+ channels and Ca2+ release from internal stores. In contrast, 1S,3R-ACPD evoked only smaller depolarizations and intracellular Ca2+ rises, with no oscillations, in other hippocampal interneurons located in or near stratum lacunosum-moleculare. Thus mGluR-mediated oscillatory responses are specifically expressed in certain interneuron subtypes. This heterogeneous expression of glutamate and Ca2+ signaling pathways in specific interneurons may be relevant to their selective vulnerability to excitotoxicity.
KW - Animals
KW - Benzoates
KW - Calcium
KW - Calcium Signaling
KW - Cycloleucine
KW - Electric Stimulation
KW - Electrophysiology
KW - Excitatory Amino Acid Antagonists
KW - Glycine
KW - Hippocampus
KW - Image Processing, Computer-Assisted
KW - In Vitro Techniques
KW - Interneurons
KW - Male
KW - Membrane Potentials
KW - Rats
KW - Rats, Sprague-Dawley
KW - Receptors, Metabotropic Glutamate
KW - Tetrodotoxin
M3 - SCORING: Journal article
C2 - 9914296
VL - 81
SP - 371
EP - 382
JO - J NEUROPHYSIOL
JF - J NEUROPHYSIOL
SN - 0022-3077
IS - 1
ER -