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Keywords:

  • cerebral cortical neurons in primary culture;
  • CREB;
  • dopamine D1 receptors;
  • methamphetamine;
  • protein kinase A;
  • ryanodine receptors

J. Neurochem. (2011) 118, 773–783.

Abstract

Regulatory mechanisms of ryanodine receptor (RyR) expression are not well known, although methamphetamine (METH) has been reported to up-regulate RyRs in mouse brain. This study investigate regulatory mechanisms of RyR expression by dopaminergic system using the midbrain and cerebral cortical neurons in primary culture intermittently exposed to METH and dopamine receptor (DR) agonists (1 h/day, for 3 days). Intermittent METH (10 μM) exposure enhanced RyR-1 and -2 proteins and their mRNA, but not RyR-3 expression in the both types of the neurons. These METH-induced increases of RyR proteins and their mRNA were dose-dependently blocked by SCH23390 (a selective D1DR antagonist), but not a D2DR antagonist sulpiride, suggesting a regulatory role of D1DRs in RyR expression by METH in these neurons. In cerebral cortical neurons, intermittent SKF82958 (a selective D1DR agonist) exposure increased RyR-1 and -2 proteins and their mRNA, whereas quinpirole (a selective D2DR agonist) showed no effects. KT5720, a protein kinase A inhibitor, dose-dependently attenuated the METH-stimulated RyR-1 and -2 expressions in cerebral cortical neurons. METH significantly increased phosphorylation of cAMP-response element-binding protein, which was completely suppressed by SCH23390. These results indicate that RyR-1 and -2 expressions are regulated by D1DRs via the signal transduction linked to D1DRs.