Methamphetamine induces a rapid increase of intracellular Ca(++) levels in neurons overexpressing GCaMP5.
In this study, methamphetamine (Meth)- and glutamate (Glu)-mediated intracellular Ca(++) (Ca(++) i) signals were examined in real time in primary cortical neurons overexpressing an intracellular Ca(++) probe, GCaMP5, by adeno-associated viral (AAV) serotype 1. Binding of Ca(++) to GCaMP increased green fluorescence intensity in cells. Both Meth and Glu induced a rapid increase in Ca(++) i, which was blocked by MK801, suggesting that Meth enhanced Ca(++) i through Glu receptor in neurons. The Meth-mediated Ca(++) signal was also blocked by Mg(++) , low Ca(++) or the L-type Ca(++) channel inhibitor nifedipine. The ryanodine receptor inhibitor dantrolene did not alter the initial Ca(++) influx but partially reduced the peak of Ca(++) i. These data suggest that Meth enhanced Ca(++) influx through membrane Ca(++) channels, which then triggered the release of Ca(++) from the endoplasmic reticulum in the cytosol. AAV-GCaMP5 was also injected to the parietal cortex of adult rats. Administration of Meth enhanced fluorescence in the ipsilateral cortex. Using immunohistochemistry, Meth-induced green fluorescence was found in the NeuN-containing cells in the cortex, suggesting that Meth increased Ca(++) in neurons in vivo. In conclusion, we have used in vitro and in vivo techniques to demonstrate a rapid increase of Ca(++) i by Meth in cortical neurons through overexpression of GCaMP5. As Meth induces behavioral responses and neurotoxicity through Ca(++) i, modulation of Ca(++) i may be useful to reduce Meth-related reactions.
Center for Neuropsychiatric Research, National Health Research Institutes, Taiwan.
Seong-Jin
SJ
Yu
Center for Neuropsychiatric Research, National Health Research Institutes, Taiwan.
Kou-Jen
KJ
Wu
Center for Neuropsychiatric Research, National Health Research Institutes, Taiwan.
Eun K
EK
Bae
Center for Neuropsychiatric Research, National Health Research Institutes, Taiwan.
Man-Jung
MJ
Hsu
National Institute on Drug Abuse, NIH, Baltimore, MD, USA.
Christopher T
CT
Richie
National Institute on Drug Abuse, NIH, Baltimore, MD, USA.
Brandon K
BK
Harvey
Center for Neuropsychiatric Research, National Health Research Institutes, Taiwan.
Yun
Y
Wang
D000704:Analysis of Variance; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects; D002135:Calcium-Binding Proteins / Q000378:metabolism; D002147:Calmodulin / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects; D003620:Dantrolene / Q000494:pharmacology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D015259:Dopamine Agents / Q000494:pharmacology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005260:Female; D018698:Glutamic Acid / Q000494:pharmacology*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007202:Indicators and Reagents / Q000494:pharmacology; D008297:Male; D008694:Methamphetamine / Q000493:pharmacokinetics*; D009125:Muscle Relaxants, Central / Q000494:pharmacology; D009474:Neurons / Q000378:metabolism*; D009543:Nifedipine / Q000494:pharmacology; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D002135:Calcium-Binding Proteins; D002147:Calmodulin; D015259:Dopamine Agents; D018691:Excitatory Amino Acid Antagonists; D007202:Indicators and Reagents; D009125:Muscle Relaxants, Central; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D018698:Glutamic Acid; D008694:Methamphetamine; D016291:Dizocilpine Maleate; D003620:Dantrolene; D009543:Nifedipine; D002118:Calcium
Calcium; glutamate; magnesium; methamphetamine