Mechanism of dopamine D2 receptor-induced Ca(2+) release in PC-12 cells.
Intracellular Ca(2+) levels are tightly regulated in the neuronal system. The loss of Ca(2+) homeostasis is associated with many neurological diseases and neuropsychiatric disorders such as Parkinson's, Alzheimer's, and schizophrenia. We investigated the mechanisms involved in intracellular Ca(2+) signaling in PC-12 cells. The stimulation of NGF-differentiated PC-12 cells with 3μM ATP caused an early Ca(2+) release followed by a delayed Ca(2+) release. The delayed Ca(2+) release was dependent on prior ATP priming and on dopamine secretion by PC-12 cells. Delayed Ca(2+) release was abolished in the presence of spiperone, suggesting that it is due to the activation of D2 dopamine receptors (D2R) by dopamine secreted by PC-12 cells. This was shown to be independent of PKA activation but dependent on PLC activity. An endocytosis step was required for inducing the delayed Ca(2+) release. Given the importance of calcyon in clathrin-mediated endocytosis, we verified the role of this protein in the delayed Ca(2+) release phenomenon. siRNA targeting of calcyon blocked the delayed Ca(2+) release, decreased ATP-evoked IP3R-mediated Ca(2+) release, and impaired subsequent Ca(2+) oscillations. Our results suggested that calcyon is involved in an unknown mechanism that causes a delayed IP3R-mediated Ca(2+) release in PC-12 cells. In schizophrenia, Ca(2+) dysregulation may depend on the upregulation of calcyon, which maintains elevated Ca(2+) levels as well as dopamine signaling.
Faculty of Medicine and Health sciences, Department of Pharmacology, Université de Sherbrooke, Sherbrooke, Québec, J1H 5N4 Canada.
Marc-Olivier
MO
Frégeau
Maxime
M
Carrier
Gaétan
G
Guillemette
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D004298:Dopamine / Q000378:metabolism; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D016716:PC12 Cells / Q000378:metabolism*; D051381:Rats; D017448:Receptors, Dopamine D2 / Q000378:metabolism*
D053496:Inositol 1,4,5-Trisphosphate Receptors; D017448:Receptors, Dopamine D2; D000255:Adenosine Triphosphate; D002118:Calcium; D004298:Dopamine
50% effective concentration; Bont X F; CaMKII; Calcium; Calcyon; DMSO; DR; Dopamine; EC50; G protein coupled receptor; GPCR; IP(3); IP(3) receptor; IP(3)R; PC-12 cells; PKA; PLC; ROCE; SERCA; SOCE; botulinum toxin type F; calmodulin kinase II; dimethylsulfoxid; dopamine receptor; inositol 1,4,5-trisphospate receptor; inositol 1,4,5-trisphosphate; phospholipase C; protein kinase A; receptor-operated Ca(2+) entry; sarco/endoplasmic reticulum calcium ATPase; store-operated Ca(2+) entry