Both neurons and astrocytes exhibited tetrodotoxin-resistant metabotropic glutamate receptor-dependent spontaneous slow Ca2+ oscillations in striatum.
The striatum plays an important role in linking cortical activity to basal ganglia outputs. Group I metabotropic glutamate receptors (mGluRs) are densely expressed in the medium spiny projection neurons and may be a therapeutic target for Parkinson's disease. The group I mGluRs are known to modulate the intracellular Ca(2+) signaling. To characterize Ca(2+) signaling in striatal cells, spontaneous cytoplasmic Ca(2+) transients were examined in acute slice preparations from transgenic mice expressing green fluorescent protein (GFP) in the astrocytes. In both the GFP-negative cells (putative-neurons) and astrocytes of the striatum, spontaneous slow and long-lasting intracellular Ca(2+) transients (referred to as slow Ca(2+) oscillations), which lasted up to approximately 200 s, were found. Neither the inhibition of action potentials nor ionotropic glutamate receptors blocked the slow Ca(2+) oscillation. Depletion of the intracellular Ca(2+) store and the blockade of inositol 1,4,5-trisphosphate receptors greatly reduced the transient rate of the slow Ca(2+) oscillation, and the application of an antagonist against mGluR5 also blocked the slow Ca(2+) oscillation in both putative-neurons and astrocytes. Thus, the mGluR5-inositol 1,4,5-trisphosphate signal cascade is the primary contributor to the slow Ca(2+) oscillation in both putative-neurons and astrocytes. The slow Ca(2+) oscillation features multicellular synchrony, and both putative-neurons and astrocytes participate in the synchronous activity. Therefore, the mGluR5-dependent slow Ca(2+) oscillation may involve in the neuron-glia interaction in the striatum.
Department of Radiological Imaging and Informatics, Tohoku University Graduate School of Medicine, Sendai, Japan ; Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Kawaguchi, Japan.
Atsushi
A
Tamura
Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, Suita, Japan.
Naohiro
N
Yamada
Division of Electrical, Electronic and Information Engineering, Graduate School of Engineering, Osaka University, Suita, Japan.
Yuichi
Y
Yaguchi
Department of Medical Imaging and Applied Radiology, Tohoku University Graduate School of Medicine, Sendai, Japan.
Yoshio
Y
Machida
Department of Radiological Imaging and Informatics, Tohoku University Graduate School of Medicine, Sendai, Japan.
Issei
I
Mori
Department of Radiological Imaging and Informatics, Tohoku University Graduate School of Medicine, Sendai, Japan ; Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Kawaguchi, Japan.
Makoto
M
Osanai
D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D018094:Receptors, Metabotropic Glutamate / Q000187:drug effects* / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology*
D018094:Receptors, Metabotropic Glutamate; D049452:Green Fluorescent Proteins; D013779:Tetrodotoxin; D002118:Calcium