Endogenous dopamine maintains synchronous oscillation of intracellular calcium in primary cultured-mouse midbrain neurons.
We demonstrated synchronous oscillation of intracellular Ca2+ in cultured-mouse mid-brain neurons. This synchronous oscillation was thought to result from spontaneous and synchronous neural bursts in a synaptic neural network. We also examined the role of endogenous dopamine in neural networks showing synchronous oscillation. Immunocytochemical study revealed a few tyrosine hydroxylase (TH)-positive dopaminergic neurons, and that cultured neurons expressed synaptophysin and synapsin I. Western blot analyses comfirmed synaptophysin, TH, and 2 types of dopamine receptor (DR), D1R and D2R expression. The synchronous oscillation in midbrain neurons was abolished by the application of R(-)-2-amino-5-phosphonopentanoic acid (AP-5) as an N-methyl-D-aspartate receptor (NMDAR) antagonist. This result suggests that the synchronous oscillation in midbrain neurons requires glutamatergic transmissions, as was the case in previously reported cortical neurons. SCH-12679, a D1R antagonist, inhibited synchronous oscillation in midbrain neurons, while raclopride, a D2R antagonist, induced a transient increase of intracellular Ca2+ and inhibited synchronous oscillation. We consider that endogenous dopamine maintains synchronous oscillation of intracellular Ca2+ through D1R and D2R, and that these DRs regulate intracellular Ca2+in distinctly different ways. Synchronous oscillation of midbrain neurons would be a useful tool for in vitro researches into various neural disorders directly or indirectly caused by dopaminergic neurons.
Yasumoto
Fumie
F
Department of Biomedical Science, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan. aa37169@mail.eccu-tokyo.ac.jp
Negishi
Takayuki
T
Ishii
Yoshiyuki
Y
Kyuwa
Shigeru
S
Kuroda
Yoichiro
Y
Yoshikawa
Yasuhiro
Y
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001683:Biological Clocks / Q000187:drug effects / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D004298:Dopamine / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005333:Fetus; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism; D008636:Mesencephalon / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D017447:Receptors, Dopamine D1 / Q000187:drug effects / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000187:drug effects / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D016708:Synaptophysin / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D018492:Dopamine Antagonists; D018691:Excitatory Amino Acid Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D016708:Synaptophysin; D014446:Tyrosine 3-Monooxygenase; D002118:Calcium; D004298:Dopamine