Abnormal intracellular calcium homeostasis associated with vulnerability in the nerve cells from heroin-dependent rat.
The cellular mechanisms by which opiate addiction develops with repetitive use remain largely unresolved. Intercellular calcium homeostasis is one of the most critical elements to determine neuroadaptive changes and neuronal fate. Heroin, one of the most addictive opiates, may induce neurotoxicity potentially inducing brain impairment, especially for those chronic users who get an overdose. Here we examined changes in intracellular calcium concentration ([Ca2+]i) after repeated exposure to heroin using cultured cerebral cortical neurons. Dynamic changes in [Ca2+]i indicated by fluo-3-AM were monitored using confocal laser scan microscopy, followed by cytotoxicity assessments. It showed that the cells dissociated from heroin-dependent rats had a smaller depolarization-induced [Ca2+]i responses, and a higher elevation in [Ca2+]i when challenged with a high concentration of heroin (500 μM). The restoration ability to remove calcium after washout of these stimulants was impaired. Calcium channel blocker verapamil inhibited the heroin-induced [Ca2+]i elevations as well as the heroin-induced cell damage. The relative [Ca2+]i of the nerve cells closely correlated with the number of damaged cells induced by heroin. These results demonstrate that nerve cells from heroin-dependent rats manifest abnormal [Ca2+]i homeostasis, as well as vulnerability to heroin overdose, suggesting involvement of [Ca2+]i regulation mechanisms in heroin addiction and neurotoxicity.
Department of Forensic Science, Zhongshan School of Medicine, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou 510080, China. Electronic address: xsliusyu@gmail.com.
Xiaoshan
X
Liu
Department of Forensic Science, Zhongshan School of Medicine, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou 510080, China.
Guangyong
G
Wang
The First Affiliated Hospital, Xinjiang Medical University, Urumuqi 830054, China.
Hongwei
H
Pu
Department of Forensic Science, Zhongshan School of Medicine, Sun Yat-Sen University, 74 Zhongshan Road II, Guangzhou 510080, China.
Hualan
H
Jing
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003932:Heroin / Q000633:toxicity*; D006556:Heroin Dependence / Q000378:metabolism; D006706:Homeostasis / Q000187:drug effects; D008297:Male; D009294:Narcotics / Q000633:toxicity*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D009294:Narcotics; D003932:Heroin; D002118:Calcium
Cytotoxicity; Heroin; Intracellular calcium concentration; Opiate; Overdose